January 2013 Permafrost Alert
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13016104 Etana, A. (Swedish University of Agricultural Sciences, Department of Soil and Environment, Uppsala, Sweden); Larsbo, M.; Keller, T.; Arvidsson, J.; Schjonning, P.; Forkman, J. and Jarvis, N. Persistent subsoil compaction and its effects on preferential flow patterns in a loamy till soil: Geoderma, 192, p. 430-436, illus. incl. 3 tables, 47 ref., January 2013.
Persistence of subsoil compaction was investigated in a field experiment in southern Sweden. The investigation compared two treatments (control and compaction by four passes track-by-track), 14 years after the experimental traffic. The compaction experiment was carried out in 1995 with a 6-row sugar beet harvester with a wheel load of c. 10.4 Mg. Investigations included penetration resistance, bulk density, water retention, saturated hydraulic conductivity, in situ near-saturated hydraulic conductivity, and dye tracing experiments. The measurements of penetration resistance and bulk density clearly showed the persistence of subsoil compaction. In addition, both macroporosity and saturated and near-saturated hydraulic conductivity were smaller in the compacted plots, although these differences were not statistically significant. Dye tracing allowed us to visualize flow patterns in the soil and to quantitatively distinguish compacted and non-compacted subsoil profiles. Despite significant soil textural heterogeneity across the experimental field, the dye tracing data showed that persistent compaction may enhance preferential flow. Abstract Copyright (2013) Elsevier, B.V.
13016059 Narhi, Paavo (Geological Survey of Finland, Rovaniemi, Finland); Gustavsson, Nils; Sutinen, Marja-Liisa; Mikkola, Kari and Sutinen, Raimo. Long-term effect of site preparation on soil quality in Tuntsa, Finnish Lapland: Geoderma, 192, p. 1-6, illus. incl. 3 tables, sketch map, 62 ref., January 2013.
Long-term effects of mechanical site preparation on soil chemical properties of Norway spruce (Picea abies) clearcut areas have remained unclear. In 1960 a forest fire burned a Norway spruce forest in Finnish Lapland and the remaining trees were harvested. Subsequent mechanical preparation with disk trenching created continuous cross-contour disturbance tracks. We measured soil dielectric permittivity as dependent on water content, electrical conductivity, temperature, pH, as well as ammonium acetate extractable concentrations of mineral soil elements in a clearcut area. After forty-six years the loss of soil nutrients was considerably high, particularly with exchangeable Ca (-40%) and Mg (-51%), Ca:Al ratio (-57%), and soil electrical conductivity (-53%). The disk trenching had no considerable long-term effect on soil water content. The results indicate that intensive mechanical site preparation is a risk for long-term soil fertility and forest productivity in boreal conifer stands. Abstract Copyright (2013) Elsevier, B.V.
13018226 Retallack, Gregory J. (University of Oregon, Department of Geological Sciences, Eugene, OR). Ediacaran Gaskiers glaciation of Newfoundland reconsidered: Journal of the Geological Society of London, 170(1), p. 19-36, illus. incl. strat. cols., geol. sketch maps, 98 ref., January 2013.
Newly discovered palaeosols in the Gaskiers Formation of Newfoundland provide a new perspective on its palaeoenvironment, and are evidence that it was not a deep submarine tillite, nor an anoxic deep-sea floor, nor a "cap carbonate" from extreme geochemical perturbation of the global ocean. Discovery of oxidized palaeosols and re-evaluation of sedimentary facies and stratigraphic relationships now suggest reinterpretation as a coastal plain with glacial moraines in the forearc basin of a continental volcanic arc, like modern Japan. Ediacaran palaeosols of the Gaskiers Formation lack large root traces, but show soil profile differentiation (clay enrichment and depletion of alkali and alkaline earth elements at the expense of feldspar and rock fragments) and diagnostic soil structures (blocky peds, argillans, sepic plasmic fabric). These palaeosols are evidence of a humid temperate climate and marked marine regression accompanying the Gaskiers Glaciation of the early Ediacaran (580 Ma). Geochemical weathering trends in the palaeosols, especially phosphorus depletion, are characteristic of biologically active soils. Ediacaran microbial earth ecoystems may have been responsible for filamentous disruption of bedding in the palaeosols.
13015996 Amundson, Ronald (University of California at Berkeley, Division of Ecosystem Sciences, Berkeley, CA); Barnes, Jaime D.; Ewing, Stephanie; Heimsath, Arjun and Chong, Guillermo. The stable isotope composition of halite and sulfate of hyperarid soils and its relation to aqueous transport: Geochimica et Cosmochimica Acta, 99, p. 271-286, illus. incl. table, 50 ref., December 15, 2012.
Halite (NaCl) and gypsum or anhydrite (CaSO4) are water-soluble minerals found in soils of the driest regions of Earth, and only modest attention has been given to the hydrological processes that distribute these salts vertically in soil profiles. The two most notable chloride and sulfate-rich deserts on earth are the Dry Valleys of Antarctica and the Atacama Desert of Chile. While each is hyperarid, they possess very different hydrological regimes. We first show, using previously published S and O isotope data for sulfate minerals, that downward migration of water and sulfate is the primary mechanism responsible for depth profiles of sulfate concentration, and S and O isotopes, in both deserts. In contrast, we found quite different soluble Cl concentration and Cl isotope profiles between the two deserts. For Antarctic soils with an ice layer near the soil surface, the Cl concentrations increase with decreasing soil depth, whereas the ratio of 37Cl/35Cl increases. Based on previous field observations by others, we found that thermally driven upward movement of brine during the winter, described by an advection/diffusion model, qualitatively mimics the observed profiles. In contrast, in the Atacama Desert where rare but relatively large rains drive Cl downward through the profiles, Cl concentrations and 37Cl/35Cl ratios increased with depth. The depth trends in Cl isotopes are more closely explained by a rayleigh-like model of downward fluid flow. The isotope profiles, and our modeling, reveal the similarities and differences between these two very arid regions on Earth, and are relevant for constraining models of fluid flow in arid zone soil and vadose zone hydrology. Abstract Copyright (2012) Elsevier, B.V.
13013866 Hinderer, Matthias (Technische Universität Darmstadt, Institut für Angewandte Geowissenschaften, Darmstadt, Germany). From gullies to mountain belts; a review of sediment budgets at various scales: in Actualistic models of sediment generation (von Eynatten, Hilmar, editor; et al.), Sedimentary Geology, 280, p. 21-59, illus. incl. 4 tables, sketch map, 516 ref., December 1, 2012.
This paper reviews the state of the art in the concept as well as in the application of sediment budgets in sedimentary research. Sediments are a product of mass dispersal at the Earth surface and take part in global cycles. Sediment budgets aim at quantifying this mass transfer based on the principle of mass conservation and are the key to determine ancient fluxes of solid matter at the earth surface. This involves fundamental questions about the interplay of uplift, climate and denudation in mountain belts and transfer of sediments from the continents to the oceans as well as applied issues such as soil and gully erosion, reservoir siltation, and coastal protection. First, after introducing basic concepts, relevant scales and methodologies, the different components of Quaternary routing systems from erosion in headwaters, river systems, glacial and paraglacial systems, lakes, deltas, estuaries, coasts, shelves, epicontinental seas, and deep-sea fans are discussed in terms of their sediment budget. Most suitable are sedimentologically closed or semi-closed depositional environments e.g. alluvial fans, lakes, deltas and deep-sea fans. In a second step, the dynamics of passive, active, and collisional tectonic settings and sediment budgets in related sedimentary basins are explored and new concepts of sediment portioning at large geodynamic scales are introduced. Ancient routing systems are more or less incomplete and may be intensively fragmented or destroyed in active tectonic settings. In terms of sedimentary basin types, rifts, intracontinental and epicontinental settings are preferred objects of sediment budgets, because of their persistence and relatively simple overall sedimentary architecture. However, closing basins, such as foreland, forearc, retroarc, piggy-back and wedge-top basins may provide excellent snapshots of orogenic sediment fluxes. In a third step, the large long-lived routing systems of the Amazon, the Ganges-Brahmaputra, and the Rhine are reviewed. For each system estimates of either sediment volumes (mass) or sediment fluxes of continental and marine subsystems have been compiled in order to receive a complete routing in terms of mass conservation for specific time periods since the Late Glacial Maximum as well as the Cenozoic. Following lessons can be taken from these case studies: (i) depositional centers and fluxes show strong shifts in space and time and call for caution when simply looking at subsystems, (ii) the response times of these large systems are within the Milankovich time interval, thus lower than predicted from diffusion models, (iii) cyclic routing of sediments in continental basins is much more dominated by climate (human) control than by eustacy, and (iv) at long time scales, ultimate sinks win over intermittent storage. It is concluded from this review that the quantitative understanding of global sediment cycling over historic and geologic time and its response to allogenic forcing is still in its infancy and further research is needed towards a holistic view of sediment routing systems at various temporal and spatial scales and their coupling with global biogeochemical cycles. This includes (i) to better determine response times of large routing systems by linking Quaternary with Cenozoic sediment budgets and continental with marine sub-systems, (ii) to combine advanced provenance techniques with sediment budgets in order to reconstruct ancient systems, (iii) to study sediment partitioning at the basin scale, (iv) to reconcile continental, supply-dominated sequence stratigraphy with the eustatic-dominated marine concept, and (iv) to account for non-actualism of ancient systems with respect to their erosion and transport mode, in particular, during glaciations and pronounced arid intervals. Glacial and eolian sediment routing may cross over hydrologic boundaries of drainage basins, thus challenging the principle of mass conservation. Abstract Copyright (2012) Elsevier, B.V.
13013957 Jackson, W. Andrew (Texas Tech University, Department of Civil and Environmental Engineering, Lubbock, TX); Dávila, Alfonso F.; Estrada, Nubia; Lyons, W. Berry; Coates, John D. and Priscu, John C. Perchlorate and chlorate biogeochemistry in ice-covered lakes of the McMurdo dry valleys, Antarctica: Geochimica et Cosmochimica Acta, 98, p. 19-30, illus. incl. 1 table, sketch map, 70 ref., December 1, 2012.
We measured chlorate (ClO3-) and perchlorate (ClO4-) concentrations in ice covered lakes of the McMurdo Dry Valleys (MDVs) of Antarctica, to evaluate their role in the ecology and geochemical evolution of the lakes. ClO3- and ClO4- are present throughout the MDV Lakes, streams, and other surface water bodies. ClO3- and ClO4- originate in the atmosphere and are transported to the lakes by surface inflow of glacier melt that has been differentially impacted by interaction with soils and aeolian matter. Concentrations of ClO3- and ClO4- in the lakes and between lakes vary based on both total evaporative concentration, as well as biological activity within each lake. All of the lakes except the East lobe of Lake Bonney support biological reduction of ClO3- and ClO4- either in the anoxic bottom waters or sediment. The younger less saline lakes (Miers and Hoare), have surface ClO3- and ClO4- concentrations, and ratios of ClO3-/Cl- and ClO4-/Cl-, similar to source streams, while Lake Fryxell has concentrations similar to input streams but much lower ClO3-/Cl- and ClO4-/Cl- ratios, reflecting the influence of a large Cl- source in bottom sediments. ClO3- and ClO4- in Lake Bonney are the highest of all the lakes reflecting the lake's greater age and higher concentration of Cl-. ClO4- appears to be stable in the East Lobe and its concentration is highly correlated with Cl- concentration suggesting that some ClO4- at depth is a remnant of the initial seawater that formed Lake Bonney. ClO3- and ClO4- concentrations provide a simple and sensitive means to evaluate microbial activity in these lakes due to their relatively low concentrations and lack of biological sources, unlike NO3-, NO2-, and SO4-2. Abstract Copyright (2012) Elsevier, B.V.
13018114 Naveed, Muhammad (Aarhus University, Department of Agroecology, Tjele, Denmark); Moldrup, Per; Tuller, Markus; Ferre, T. P. A.; Kawamoto, Ken; Komatsu, Toshiko and Wollesen de Jonge, Lis. Prediction of the soil water characteristic from soil particle volume fractions: Soil Science Society of America Journal, 76(6), p. 1946-1956, illus. incl. 2 tables, 29 ref., December 2012.
Modeling water distribution and flow in partially saturated soils requires knowledge of the soil water characteristic (SWC). However, measurement of the SWC is challenging and time-consuming and, in some cases, not feasible. This study introduces two predictive models (FW-model and AW-model) for the SWC, derived from readily available soil properties such as texture and bulk density. A total of 46 undisturbed soils from different horizons at 15 locations across Denmark were used for model evaluation. The FW-model predicts the volumetric water content as a function of volumetric fines content (organic matter and clay). It performed reasonably well for the dry-end of SWC (above a pF value of 2.0; pF = log(|Y|), where Y is the matric potential in cm), but did not do as well closer to saturated conditions. The AW-model predicts the volumetric water content as a function of volumetric content of different particle size fractions (organic matter, clay, silt, and fine and coarse sands). The volumetric content of a particular soil particle size fraction was considered if it contributed to the pore size fraction still occupied with water at the given pF value. Hereby, the AW-model implicitly assumes that a given particle size fraction creates an analogue pore size fraction and further this pore size fraction filled with water is corresponding to a certain pF value according to the well-known capillary rise equation. The AW-model was found to be quite robust, and it performed exceptionally well for pF values ranging from 0.4 to 4.2 for different soil types. For prediction of the continuous SWC, it is recommended to parameterize the van Genuchten model based on the SWC data points predicted by the AW-model.
13016017 Panagiotakopulu, Eva (University of Edinburgh, School of Geosciences, Edinburgh, United Kingdom); Greenwood, Malcolm T. and Buckland, Paul C. Insect fossils and irrigation in Medieval Greenland: Geografiska Annaler. Series A: Physical Geography, 94(4), p. 531-548, illus. incl. 2 tables, sketch map, 102 ref., December 2012.
Initial European, Norse, settlement in south-west Greenland lasted from the late tenth to the fifteenth century, with an economy largely based on secondary products from sheep, goats and cattle, supplemented by caribou and marine mammal hunting. Sustainable subsistence farming required acquisition of sufficient fodder, principally hay, to feed stalled animals through extended subarctic winters. At the cathedral site of Garethar, the modern sheep farm of Igaliku, artefact scatters and geoarchaeological evidence show that infields were improved by manuring, and systems of ditches have been interpreted as evidence for controlled irrigation in an area liable to a potential water deficit. Further palaeoecological evidence, largely from insect remains, is presented which indicates the build up of thick plaggen soils as a result of large-scale manuring with animal, domestic and structural waste, perhaps supplemented by pared turf. It is suggested that the technique of irrigated hayfields was utilized principally to provide fodder for the large numbers of cattle maintained on the bishop's farm. The system appears to have been abandoned abruptly in the late medieval period, when wetland takes over from irrigated hayfield. Abstract Copyright (2012), Swedish Society for Anthropology and Geography.
13016014 Schwamborn, Georg (Alfred Wegener Institute for Polar and Marine Research-Potsdam, Potsdam, Germany); Schirrmeister, Lutz; Frütsch, Franziska and Diekmann, Bernhard. Quartz weathering in freeze-thaw cycles; experiment and application to the El'gygytgyn crater lake record for tracing Siberian permafrost history: Geografiska Annaler. Series A: Physical Geography, 94(4), p. 481-499, illus. incl. 2 tables, geol. sketch map, 88 ref., December 2012.
The object of this study is to test the assumption that cryogenic weathering (here understood as in-situ disintegration of rock under cold-climate conditions including ice as a weathering agent) preferentially breaks up quartz grains. We apply the results of laboratory tests to a Quaternary sediment record. The combination of silt production, relative quartz enrichment in the silt fraction, and quartz grain micromorphology is traced in a multi-100-kyr lake sediment archive as indicator data for cryogenic weathering. Constant cryogenic weathering conditions are inferred for at least the last 220 000 years from a lake sediment core of El'gygytgyn Crater, northeast Russia. This is the longest continuous terrestrial archive currently known for the continental Arctic. Quartz enrichment in the fines evolves from seasonal freeze-thaw weathering as demonstrated in laboratory testing where over 100 freeze and thaw cycles crack quartz grains preferentially over feldspar. Microscopic grain features demonstrate that freeze-thaw cycling probably disrupts quartz grains along mineral impurities such as bubble trails, gas-liquid inclusions, or mineralogical sub-grain boundaries. Single-grain micromorphology (e.g. angular outlines, sharp edges, microcracks, brittle surfaces) illustrates how quartz becomes fragmented due to cryogenic cracking of the grains. The single-grain features stemming from the weathering dynamics are preserved even after a grain is transported off site (i.e. in mobile slope material, in seasonal river run-off, into a lake basin) and may serve as first-order proxy data for permafrost conditions in Quaternary records. Abstract Copyright (2012), Swedish Society for Anthropology and Geography.
13018113 Watanabe, Kunio (Mie University, Graduate School of Bioresources, Tsu, Japan); Takeuchi, Megumi; Osada, Yurie and Ibata, Kazumasa. Micro-chilled-mirror hygrometer for measuring water potential in relatively dry and partially frozen soils: Soil Science Society of America Journal, 76(6), p. 1938-1945, illus., 29 ref., December 2012.
Estimating water potential in a relatively dry soil is fundamentally important, not only for predicting soil water flows in arid areas or during the evaporation process, but also for understanding soil freezing processes. A micro-chilled-mirror hygrometer (FINEDEW) that does not require a sampling chamber and has a rapid response time has recently been developed. The sensor head can be inserted into a soil sample. We confirmed that FINEDEW directly and quickly measures soil water potential in the range of less than -500 kPa in soil under near-equilibrium conditions and in the range of less than -1000 kPa in soil under evaporation at room temperature. The FINEDEW hygrometer was also applied to frozen soil at temperatures between -20 and -0.5°C. At equilibrium, regardless of soil type and freezing-thawing processes, the measured potential corresponded to the calculated potential determined using the Clausius-Clapeyron equation. Soil water potential was found to require time to reach equilibrium after a temperature change. This is thought to be because ice in the soil pores required time to acquire a new equilibrium geometry.
13016012 Watanabe, Tatsuya (University of Tsukuba, Graduate School of Life and Environmental Sciences, Tsukua, Japan); Matsuoka, Norikazu and Christiansen, Hanne H. Mudboil and ice-wedge dynamics investigated by electrical resistivity tomography, ground temperatures and surface movements in Svalbard: Geografiska Annaler. Series A: Physical Geography, 94(4), p. 445-457, illus. incl. sketch map, 40 ref., December 2012.
Arctic tundra surfaces are dominated by a variety of patterned ground forms. Whereas a large number of studies have described morphology, structure and processes of patterned ground, few have monitored detailed patterned ground dynamics and subsurface environments continuously. We applied electrical resistivity tomography (ERT) to understand near-surface conditions of two types of patterned ground, ice-wedge polygons and mudboils in Svalbard, where periglacial processes associated with permafrost are intensively monitored. Automated monitoring shows surface movement characterized by annual cycles of frost heave and thaw settlement, the amounts and rates of which are influenced by the intensity of ice segregation. A time series of ERT shows (1) a distinct resistivity boundary delimiting the active-layer depth, (2) seasonal variation in resistivity controlled by thermo-hydrological dynamics and (3) spatial variation in resistivity reflecting desiccation in summer and intensive ice segregation in winter. These results demonstrate ERT as a useful complementary technique for monitoring active-layer depths and near-surface hydrological conditions at periglacial patterned ground sites, where automated soil thermal and moisture measurements are limited. Abstract Copyright (2012), Swedish Society for Anthropology and Geography.
13015886 Wu Tonghua (Chinese Academy of Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, Cryosphere Research Station on the Qinghai-Tibet Plateau, Laboratory of Cryospheric Sciences, Lanzhou, China); Wang, Qinxue; Zhao Lin; Du Erji; Wang Wu; Batkhishig, Ochirbat; Battogtokh, Dorjgotov and Watanabe, Masataka. Investigating internal structure of permafrost using conventional methods and ground-penetrating radar at Honhor Basin, Mongolia: Environmental Earth Sciences, 67(7), p. 1869-1876, illus. incl. geol. sketch map, 22 ref., December 2012.
A ground-penetrating radar (GPR) survey was conducted at the end of August 2009 in the suburb region of Ulaanbaatar, Honhor basin, Mongolia, in combination with conventional methods such as borehole drilling and measurement of ground temperatures. The interface of frozen and unfrozen sediment was distinctly resolved in the interpreted GPR images, verified by the borehole drilling records and 6-month measurement of ground temperatures. The location of the permafrost table was assessed to be at the depth of 2-4 m in the study region. A conspicuous ice-saturated soil layer (massive ground ice) was detected in the interpreted GPR images with a thickness of 2-5 m. The GPR investigation results were consistent with the borehole drilling records and ground temperatures observation. The borehole logs and ground temperatures profile in the borehole indicates that permafrost at Honhor basin is characterized by high ground temperature and high ice content, which implies that ongoing climatic warming would have great influence on permafrost dynamics. The research results are of great importance to further assess permafrost dynamics to climatic change in the boundary of discontinuous and sporadic permafrost regions in Mongolia in the future. Copyright 2012 Springer-Verlag Berlin Heidelberg and Springer-Verlag
13013708 Baldini, James U. L. (University of Durham, Department of Earth Sciences, Durham, United Kingdom); McDermott, Frank; Baldini, Lisa M.; Ottley, Chris J.; Linge, Kathryn L.; Clipson, Nicholas and Jarvis, Kym E. Identifying short term and seasonal trends in cave drip water trace element concentrations based on a daily scale automatically collected drip water data set: Chemical Geology, 330-331, p. 1-16, illus. incl. 1 table, sketch map, 64 ref., November 10, 2012.
A 13-month long, daily-scale drip water dataset collected by an automatic water sampling device placed in a small cave in Ireland provides evidence for seasonal shifts in hydrochemistry, including a pulse of colloidally-associated elements in the late summer. Ca, Sr, Mg, Na, Ba, P, Cu, Zn, Rb, Y, Cs, U, Th, and Pb concentrations of the collected water samples were determined, and flow rates were also calculated. Alkali and alkali earth metals decreased in concentration during a summer water deficit, whereas colloidally-associated element concentrations increased during the same interval and spiked dramatically in the late summer/early autumn. The observed increase in colloidally-associated element concentrations may have coincided with increased breakdown of soil organic material by microorganisms in the late summer/early autumn, which led to an increased flux of organic colloids in the drip water, or it may relate to increased rates of dry deposition from cave air. The decrease in alkali and alkali earth metal concentrations in the summer most likely resulted from the addition of dilute water linked to condensation of water vapor above the drip site. Drip water Sr and P concentrations are anticorrelated, and their variation over the study period resembles seasonal trends observed in stalagmite calcite at other sites. Because the Sr minima and P maxima are interpreted as reflecting different phenomena (increased proportion of condensation water relative to karst water, and an increased flux of organic colloids, respectively), the relative timing of these two mechanisms in the past may explain the shifting polarity of their correlation observed in some stalagmite trace element records. Abstract Copyright (2012) Elsevier, B.V.
13019735 Evans, David J. A. (Durham University, Department of Geography, Durham, United Kingdom); Harrison, Stephan; Vieli, Andreas and Anderson, Ed. Dartmoor's overlooked glacial legacy: Geology Today, 28(6), p. 224-229, illus. incl. sects., geol. sketch maps, November 2012.
Traditionally regarded as a relict permafrost and periglacial landscape that lay beyond the limits of Pleistocene glaciation, the granite uplands of northern Dartmoor in southwest England in fact contain geomorphological evidence for the former existence of a plateau ice cap, making the area the location of the southernmost independent glacier mass in the British Isles. In addition to weakly U-shaped valleys, the most prominent evidence comprises arcuate and linear bouldery ridges and hummocky valley floor drift, which are interpreted as latero-frontal moraines deposited by the outlet glacier lobes of a plateau ice cap. Inset sequences of these depositional landforms, in association with meltwater channels, demarcate the receding margins of the glacier lobes. A numerical model of ice cap development shows that a predominantly thin plateau icefield type glaciation is required in order to produce significant ice flow into surrounding valleys. The highest and most extensive plateau areas were occupied by ice for the longest cumulative period of time throughout the Pleistocene, thereby explaining: (1) the lack of tors in such areas as the product of "average" glacial conditions preferentially removing tors or dampening their production rates, (2) the survival of high relief tors during glaciation if they occupied summits too narrow to develop thick and erosive glacier ice, and (3) the survival of subdued tors in areas glaciated less regularly during the Pleistocene. Abstract Copyright The Geological Society of London.
13013713 Kaasalainen, Hanna (University of Iceland, Institute of Earth Sciences, Reykjavik, Iceland) and Stefansson, Andri. The chemistry of trace elements in surface geothermal waters and steam, Iceland: Chemical Geology, 330-331, p. 60-85, illus. incl. 5 tables, sketch map, 155 ref., November 10, 2012. Includes appendices.
The geochemistry of trace elements in surface geothermal fluids in Iceland was studied. The sampled fluids included hot springs, mud pots, steam vents and soil solutions with temperatures ranging from 4 to 100°C, pH between 2.01 and 9.10 and total dissolved solids between 86 and 4375 ppm. The surface geothermal waters may be categorized into three groups based on their chemical composition, namely NaCl waters, steam-heated acid-sulfate waters and mixed waters. NaCl waters with pH >8 are considered to represent aquifer geothermal fluids that have undergone boiling in the upflow. They contained only low concentrations of most metals, <0.1 ppb of Cd and Co, <1 ppb of Ni, Pb, Cr and Cu and <10 ppb of Zr, V and Zn, whereas somewhat higher concentrations of Ba (0.06-15 ppb), Sr (1.2-107 ppb), Cs (0.08-19 ppb), Rb (7.1-163 ppb), Li (18-380 ppb), As (<0.2-252 ppb), Sb (0.05-40 ppb), Mo (0.16-50 ppb), W (2.4-88 ppb), Mn (0.1-163 ppb), Fe (1.8-157 ppb) and Al (21-1510 ppb) were found. Steam-heated acid-sulfate waters typically had a pH <4. They form by condensation and mixing of steam in shallow non-thermal water. Compared to NaCl waters, steam-heated acid-sulfate waters typically had high concentrations of Al (0.02-267 ppm), Fe (0.66-360 ppm), Mn (44-4231 ppb), V (1.1-1120 ppb), Cr (0.15-660 ppb), Zn (3.1-633 ppb), Ni (0.20-192 ppb), Cu (0.09-121 ppb), Co (0.02-90 ppb), Ba (1.0-60 ppb) and Sr (2.8-316 ppb), whereas concentrations of Li (<0.03-57 ppb), Cs (<0.01-0.77 ppb), Rb (0.12-24 ppb), As (<0.1-61 ppb), Mo (<0.01-14 ppb), Sb (<0.01-25 ppb) and W (<0.01-6.9 ppb) were lower. Mixed waters are mixtures between NaCl waters, steam-heated acid-sulfate waters and non-thermal water, and showed chemical characteristics of these end-member waters. The steam discharged by the steam vents was found to carry trace elements including B, As, Cu and Cd in the ppt to ppb concentration range. The geochemistry of Li, Cs, Rb, As, Mo, Sb and W in surface geothermal waters was dominated by rock leaching, together with mixing of condensed steam and non-thermal surface waters at a low pH and with incorporation into secondary minerals including aluminum silicates and sulfides under alkaline conditions. In contrast, aqueous Ba and Sr concentrations were largely influenced by the formation of secondary minerals including sulfates, carbonates and Ca-minerals in all water types. At a low pH, the behavior of Al, Fe, Mn, Co, Ni, Zn, Cd, Cu, Pb, Cr and V was generally dominated by rock leaching, though occasionally by mineral precipitation in the case of Fe, Al, Cu, Co and Zr. With increasing pH, these metals became immobile due to their incorporation into secondary sulfide (Fe, Co, Ni, Zn, Cd, Cu, Pb), (hydr)oxide (Al, Fe, Cr, V, Zr) and aluminum- silicate (Al) minerals limiting their aqueous concentrations. Abstract Copyright (2012) Elsevier, B.V.
13019857 Chapuis, Robert P. Check the elevations of monitoring wells; they can change with time: Geotechnical News, 30(3), p. 28-29, illus., 1 ref., September 2012.
13013385 Amitrano, D. (Université Joseph Fourier, Institut des Sciences de la Terre, Grenoble, France); Gruber, S. and Girard, L. Evidence of frost-cracking inferred from acoustic emissions in a high-alpine rock-wall: Earth and Planetary Science Letters, 341-344, p. 86-93, illus., 37 ref., August 2012.
Ice formation within rock is known to be an important driver of near-surface frost weathering as well as of rock damage at the depth of several meters, which may play a crucial role for the slow preconditioning of rock fall in steep permafrost areas. This letter reports results from an experiment where acoustic emission monitoring was used to investigate rock damage in a high-alpine rock-wall induced by natural thermal cycling and freezing/thawing. The analysis of the large catalog of events obtained shows (i) robust power-law distributions in the time and energy domains, a footprint of rock micro-fracturing activity induced by stresses arising from thermal variations and associated freezing/thawing of rock; (ii) an increase in AE activity under sub-zero rock-temperatures, suggesting the importance of freezing-induced stresses. AE activity further increases in locations of the rock-wall that are prone to receiving melt water. These results suggest that the framework of further modeling studies (theoretical and numerical) should include damage, elastic interaction and poro-mechanics in order to describe freezing-related stresses. Abstract Copyright (2012) Elsevier, B.V.
13013387 Behseresht, Javad (University of Texas at Austin, Austin, TX) and Bryant, Steven L. Sedimentological control on saturation distribution in Arctic gas-hydrate-bearing sands: Earth and Planetary Science Letters, 341-344, p. 114-127, illus., 42 ref., August 2012.
A mechanistic model is proposed to predict/explain hydrate saturation distribution in "converted free gas" hydrate reservoirs in sub-permafrost formations in the Arctic. This 1-D model assumes that a gas column accumulates and subsequently is converted to hydrate. The processes considered are the volume change during hydrate formation and consequent fluid phase transport within the column, the descent of the base of gas hydrate stability zone through the column, and sedimentological variations with depth. Crucially, the latter enable disconnection of the gas column during hydrate formation, which leads to substantial variation in hydrate saturation distribution. One form of variation observed in Arctic hydrate reservoirs is that zones of very low hydrate saturations are interspersed abruptly between zones of large hydrate saturations. The model was applied to data from Mount Elbert well, a gas hydrate stratigraphic test well drilled in the Milne Point area of the Alaska North Slope. The model is consistent with observations from the well log and interpretations of seismic anomalies in the area. The model also predicts that a considerable amount of fluid (of order one pore volume of gaseous and/or aqueous phases) must migrate within or into the gas column during hydrate formation. This paper offers the first explanatory model of its kind that addresses "converted free gas reservoirs" from a new angle: the effect of volume change during hydrate formation combined with capillary entry pressure variation versus depth. Abstract Copyright (2012) Elsevier, B.V.
13017776 Luo Ji (Chinese Academy of Sciences, Institute of Mountain Hazards and Environment, Chengdu, China); Chen Youchao; Wu Yanhong; Shi Peili; She Jia and Zhou Peng. Temporal-spatial variation and controls of soil respiration in different primary succession stages on glacier forehead in Gongga Mountain, China: PloS One, 2012(E42354), illus. incl. 3 tables, sketch map, 51 ref., August 6, 2012.
Soil respiration (SR) is an important process in the global carbon cycle. It is difficult to estimate SR emission accurately because of its temporal and spatial variability. Primary forest succession on Glacier forehead provides the ideal environment for examining the temporal-spatial variation and controlling factors of SR. However, relevant studies on SR are relatively scarce, and variations, as well as controlling factors, remain uncertain in this kind of region. In this study, we used a static chamber system to measure SR in six sites which represent different stages of forest succession on forehead of a temperate glacier in Gongga Mountain, China. Our results showed that there was substantial temporal (coefficient of variation (CV) ranged from 39.3% to 73.9%) and spatial (CV ranged from 12.3% to 88.6%) variation in SR. Soil temperature (ST) at 5 cm depth was the major controlling factor of temporal variation in all six sites. Spatial variation in SR was mainly caused by differences in plant biomass and Total N among the six sites. Moreover, soil moisture (SM), microbial biomass carbon (MBC), soil organic carbon (SOC), pH and bulk density could influence SR by directly or indirectly affecting plant biomass and Total N. Q10 values (ranged from 2.1 to 4.7) increased along the forest succession, and the mean value (3.3) was larger than that of temperate ecosystems, which indicated a general tendency towards higher-Q10 in colder ecosystems than in warmer ecosystems. Our findings provided valuable information for understanding temporal-spatial variation and controlling factors of SR.
13015718 Okuno, Mitsuru (Fukuoka University, Department of Earth System Science, Fukuoka, Japan). Various methods in tephrochronology; case studies in the Philippines, China, Korea, Japan, and the Aleutian Islands: Daiyonki-Kenkyu = Quaternary Research, 51(4), p. 275-284, (Japanese) (English sum.), illus. incl. sects., sketch map, 72 ref., August 1, 2012.
Tephra layers provide time markers to sedimentary sequences in marine and terrestrial environments. Therefore, this feature is useful as platform for crosschecking among various dating and environmental studies. On a land surface, continuous accumulation of loam and humic soil layers allows the preservation of tephra layers. Throughout just the Holocene,for example, Adak Island in the Aleutian Islands has been covered by a sequence of soil-tephra complexes. In the Philippines, the discovery of co-ignimbrite ashfalls of Irosin ignimbrite is a first step for establishing a chronological framework. It is necessary to conduct core-drilling and stratigraphic studies in an artificial trench to obtain good samples for various analyses. In Tanegashima Island, the radiocarbon dates for Tn2 and Tn4 imply that accumulation rate is not constant between K-Tz (95 ka) and AT (30 ka). Precise age determination for B-Tm has been done by varve chronology and 14C wiggle-matching methods. This crosschecking process is very important for developing a dating method. Tephra layers in lacustrine play a role as time control. The data sets from varve counting and 14C dates provide accurate ages of tephra layers. Crypto-/microtephras contribute as time-markers. However,this method has the potential to be wrong. In fact, U-Oki has been correlated with U-2 in Ulleung Island, based on recognition of a K-Ah horizon. Radiocarbon dating in the island allows us to correlate U-4 with U-Oki.
13017749 Spohn, Marie (Carl von Ossietzky University of Oldenburg, Department of Biology and Environmental Sciences, Oldenburg, Germany) and Giani, Luise. Carbohydrates, carbon and nitrogen in soils of a marine and a brackish marsh as influenced by inundation frequency: Estuarine, Coastal and Shelf Science, 107, p. 89-96, illus. incl. 4 tables, sketch map, 45 ref., July 10, 2012.
Marshes on the southern North Sea coast store large amounts of organic matter (OM). The objective of this study was to investigate the effect of inundation frequency on carbohydrates, organic carbon (OC), inorganic carbon (IC) and nitrogen (N) in a marine and a brackish marsh. To gain insights into the origin of OC in the marshes we used monosaccharides as biomarkers. We studied soils in a marine and a brackish marsh along a gradient of inundation frequency. It was found that TOC and N stocks in soils of a marine and a brackish marsh increased with decreasing inundation frequency. Concentrations of carbohydrates were significantly higher in the topsoils of the marine marsh than of the brackish marsh. In the upper mid-zone of the marine marsh, which is inundated by the sea approximately 20-times a year, carbohydrate stocks were up to 2.4-times higher than in the upper mid-zone of the brackish marsh with the same inundation frequency. Differences in carbohydrate concentrations can be attributed to differences in the abundance of fine and medium roots in these soils. In the daily-inundated soils of both marshes we observed high hexose-to-pentose ratios, indicating a microbial origin of the carbohydrates, while the hexose-to-pentose ratios were significantly lower in the middle and upper zone of the two marshes, indicating a high proportion of plant-derived carbohydrates. This study shows that monosaccharides are useful biomarkers to explore the origin of OM in coastal soils. Abstract Copyright (2012) Elsevier, B.V.
13015464 Chipman, Melissa L. (University of Illinois, Program in Ecology, Evolution, and Conservation Biology, Urbana, IL); Clegg, Benjamin F. and Hu, Feng Sheng. Variation in the moisture regime of northeastern interior Alaska and possible linkages to the Aleutian Low; inferences from a late-Holocene d18O record: in Holocene paleoenvironmental records from Arctic lake sediment (Kaufman, Darrell S., editor), Journal of Paleolimnology, 48(1), p. 69-81, illus. incl. 3 tables, geol. sketch maps, 37 ref., June 2012.
Analyses of oxygen and carbon isotopes in bulk carbonate and Chara-stem encrustations, X-ray diffraction, and sediment composition from Keche Lake offer new information on climatic change over the past ~3,400 years in northeastern interior Alaska. The d18O and dD values of water samples from the lake and its inlet streams suggest that evaporation plays an important role in determining the isotopic composition of Keche Lake water at present. However, evaporative enrichment does not appear to be a major driver of the pronounced fluctuations in the bulk-carbonate d18O record on the basis of comparison with Chara-d18O values. The d18O values of bulk carbonate in the Keche Lake sediments vary by up to 10 ppm over the past 3,400 years, with maximum values of -12 ppm around 3,400 cal BP and between 2,100 and 1,500 cal BP. High d18O peaks are associated with sediments dominated by quartz, feldspar, and clay minerals suggesting the influence of detrital carbonate. Multi-millennial patterns of d18O variation at Keche Lake appear to be linked with changes in watershed and sediment-depositional processes, which may be driven by varying moisture abundance associated with the position of the Aleutian Low (AL). The increasing trend of carbonate d18O from 3,400 to ~2,100 cal BP probably reflects the increasing importance of a westerly AL, and the high frequency of d18O spikes ~2,100-1,500 cal BP may have resulted from the prevalence of a westerly AL position. Predominance of a westerly AL likely increased snowfall and winter temperature in the region. Such conditions would have promoted soil erosion and thermokarst activity during spring snowmelt, resulting in episodic large influxes of detrital carbonate to Keche Lake and elevating bulk-carbonate d18O. Over the past 1,500 years, bulk-carbonate d18O remained relatively high at Keche Lake but variation was much less pronounced than before. A broad d18O peak centered ~400 cal BP may be related to enhanced winter moisture during the Little Ice Age, although our chronology is inadequate for a rigorous assessment of this interpretation. This study contributes a new d18O record and offers additional information on past moisture-regime shifts associated with changing atmospheric-circulation patterns. Copyright 2012 Springer Science+Business Media B.V.
13015462 Finney, Bruce P. (Idaho State University, Departments of Biological Sciences and Geosciences, Pocatello, ID); Bigelow, Nancy H.; Barber, Valerie A. and Edwards, Mary E. Holocene climate change and carbon cycling in a groundwater-fed, boreal forest lake; Dune Lake, Alaska: in Holocene paleoenvironmental records from Arctic lake sediment (Kaufman, Darrell S., editor), Journal of Paleolimnology, 48(1), p. 43-54, illus. incl. geol. sketch map, 35 ref., June 2012.
Opal, organic C and N contents, and organic d13C and d15N stable isotopes were analyzed on a sedimentary sequence spanning the past ~12,000 years from Dune Lake, a shallow groundwater-fed lake in the boreal forest region of central interior Alaska. The chronology, based on 210Pb and 15 AMS radiocarbon dates on terrestrial materials, indicates that 5 m of biogenic sediment accumulated following dune stabilization at ~10,000 cal yr BP. Previous studies on lake level and pollen were synthesized with these data to assess Holocene changes in hydrogeology and climate. Variability in groundwater level and flux has a strong control on lake level and are negatively correlated with the d13C of organic matter produced within the lake. This relationship results from the input of groundwater with high pCO2 and with dissolved inorganic carbon depleted in 13C, which subsequently affects lake phytoplankton d13C signatures. A rapid rise in lake level between ca. 11,000 and 9,500 cal yr BP coincided with stabilization of the dune field adjacent to the lake and expansion of vegetation around the lake, including white spruce. Organic d13C values are relatively low and constant between about 10,000 and 6,000 cal yr BP, and then steadily increase until about 2,000 cal yr BP, suggesting a pattern of high followed by dropping lake levels generally consistent with results from core-transect studies. Higher-frequency fluctuations of 2-3 ppm in d13C are common, and suggest variability in aspects of the lake-carbon cycle over multi-decadal timescales. Recent trends in groundwater and lake level, river discharge, and precipitation suggest an important role for wintertime precipitation in the regional groundwater system. The unusual hydrology of this system relative to most other lakes studied for paleoclimate in this region provides a novel insight into different seasonal aspects of Alaskan paleoclimatology. The record is consistent with a general long-term decrease in wintertime precipitation, possibly accompanied by an increase in permafrost extent, over the Holocene. Copyright 2012 Springer Science+Business Media B.V.
13015460 Kaufman, Darrell S. (Northern Arizona University, School of Earth Sciences and Environmental Sustainability, Flagstaff, AZ); Axford, Yarrow; Anderson, R. Scott; Lamoureux, Scott F.; Schindler, Daniel E.; Walker, Ian R. and Werner, Al. A multi-proxy record of the last glacial maximum and last 14,500 years of paleoenvironmental change at Lone Spruce Pond, southwestern Alaska: in Holocene paleoenvironmental records from Arctic lake sediment (Kaufman, Darrell S., editor), Journal of Paleolimnology, 48(1), p. 9-26, illus. incl. 1 table, strat. cols., 55 ref., June 2012.
Sediment cores from Lone Spruce Pond (60.007°N, 159.143°W), southwestern Alaska, record paleoenvironmental changes during the global Last Glacial Maximum (LGM), and during the last 14,500 calendar years BP (14.5 cal ka). We analyzed the abundance of organic matter, biogenic silica, carbon, and nitrogen, and the isotope ratios of C and N, magnetic susceptibility, and grain-size distribution of bulk sediment, abundance of alder shrub (Alnus) pollen, and midge (Chironomidae and Chaoboridae) assemblages in a 4.7-m-long sediment sequence from the depocenter at 22 m water depth. The basal unit contains macrofossils dating to 25-21 cal ka (the global LGM), and is interpreted as glacial-lacustrine sediment. The open water requires that the outlet of the Ahklun Mountain ice cap had retreated to within 6 km of the range crest. In addition to cladocerans and diatoms, the glacial-lacustrine mud contains chironomids consistent with deep, oligotrophic conditions; several taxa associated with relatively warm conditions are present, suggestive of relative warmth during the global LGM. The glacial-lacustrine unit is separated from the overlying non-glacial lake sediment by a possible disconformity, which might record a readvance of glacier ice. Non-glacial sediment began accumulating around 14.5 cal ka, with high flux of mineral matter and fluctuating physical and biological properties through the global deglacial period, including a reversal in biogenic-silica (BSi) content during the Younger Dryas (YD). During the global deglacial interval, the d13C values of lake sediment were higher relative to other periods, consistent with low C:N ratios (8), and suggesting a dominant atmospheric CO2 source of C for phytoplankton. Concentrations of aquatic faunal remains (chironomids and Cladocera) were low throughout the deglacial interval, diversity was low and warm-indicator taxa were absent. Higher production and air temperatures are inferred following the YD, when bulk organic-matter (OM) content (LOI 550 °C) increased substantially and permanently, from 10 to 30 %, a trend paralleled by an increase in C and N abundance, an increase in C:N ratio (to about 12), and a decrease in d13C of sediment. Post-YD warming is marked by a rapid shift in the midge assemblage. Between 8.9 and 8.5 cal ka, Alnus pollen tripled (25-75 %), followed by the near-tripling of BSi (7-19 %) by 8.2 cal ka, and d15N began a steady rise, reflecting the buildup of N and an increase in denitrification in soils. Several chironomid taxa indicative of relatively warm conditions were present throughout the Holocene. Quantitative chironomid-based temperature inferences are complicated by the expansion of Alnus and resulting changes in lake nutrient status and production; these changes were associated with an abrupt increase in cladoceran abundance and persistent shift in the chironomid assemblage. During the last 2,000 years, chironomid-assemblage changes suggest cooler temperatures, and BSi and OM values were generally lower than their maximum Holocene values, with minima during the seventh and eighth centuries, and again during the eighteenth century. Copyright 2012 Springer Science+Business Media B.V.
13019453 Lantuit, Hugues (Alfred Wegener Institute for Polar and Marine Research, Research Section Potsdam, Potsdam, Germany); Overduin, Pier Paul; Couture, Nicole; Wetterich, Sebastian; Aré, Felix; Atkinson, David; Brown, Jerry; Cherkashov, Georgy; Drozdov, Dmitry; Forbes, Donald Lawrence; Graves-Gaylord, Allison; Grigoriev, Mikhail; Hubberten, Hans-Wolfgang; Jordan, James; Jorgenson, Torre; Odegard, Rune Strand; Ogorodov, Stanislav; Pollard, Wayne H.; Rachold, Volker; Sedenko, Sergey; Solomon, Steve; Steenhuisen, Frits; Streletskaya, Irina and Vasiliev, Alexander. The Arctic Coastal Dynamics Database; a new classification scheme and statistics on Arctic permafrost coastlines: in The Arctic Ocean estuary (McClelland, James W., editor; et al.), Estuaries and Coasts, 35(2), p. 383-400, illus. incl. 2 tables, sketch map, 72 ref., March 2012. Includes appendices.
Arctic permafrost coasts are sensitive to changing climate. The lengthening open water season and the increasing open water area are likely to induce greater erosion and threaten community and industry infrastructure as well as dramatically change nutrient pathways in the near-shore zone. The shallow, mediterranean Arctic Ocean is likely to be strongly affected by changes in currently poorly observed arctic coastal dynamics. We present a geomorphological classification scheme for the arctic coast, with 101,447 km of coastline in 1,315 segments. The average rate of erosion for the arctic coast is 0.5 m year-1 with high local and regional variability. Highest rates are observed in the Laptev, East Siberian, and Beaufort Seas. Strong spatial variability in associated database bluff height, ground carbon and ice content, and coastline movement highlights the need to estimate the relative importance of shifting coastal fluxes to the Arctic Ocean at multiple spatial scales. Copyright 2011 Coastal and Estuarine Research Federation
13019746 Kejonen, Aimo (Geologian Tutkimuskeskus, Kuopio, Finland). Routajaristyksista ja niiden aiheuttamista routahalkeamista [Frostquakes and associated frost fissures]: Geologi, 64(2), p. 47-50 (English sum.), 13 ref., 2012. Accessed on Feb. 6, 2013.
On Friday 27th Jan 2012, a local frost quake caused rumbling, some seconds long trembling as stark as those caused by a passing lorry, resulting in an over 20 m long, 0,5-1 cm broad and 10 to 50 cm deep frost fissure through Samoilijantie Street in Kuopio, Finland. It was one of the large frost quakes series that took place during the first very cold period (27.1-2.2.) of the winter 2012, when the temperature fell from ranges of -5°C to -10°C to ranges of -25°C to -35°C in eastern Finland and the Oulu area. Frost quakes and frost fissuring are yearly but less well-known occurrences in Finland. Their cause is frost contraction of the frozen earth. When the power of frost shrinkage during quick drops in temperature is stronger than the solidity of the frozen earth material, the frost quake can occur, causing the birth of a frost fissure. Frost fissures cause a lot of road deterioration, and in Lapland they are the cause of the formation of ice wedge formations. Late-glacial and interglacial ice-wedge casts caused by frost fissuring and the freezing of water in these fissures occur in many places in Finland.
13019410 Kuzmin, R. O. (Russian Academy of Sciences, Vernadskiy Institute of Geochemistry and Analytical Chemistry, Moscow, Russian Federation); Zabalueva, E. V.; Evdokimova, N. A. and Christensen, P. R. Mapping of the water ice content within the Martian surficial soil on the periphery of the retreating seasonal northern polar cap based on the TES and the OMEGA data: Journal of Geophysical Research, 117(E), Citation E00J19, illus., 42 ref., 2012. Includes appendices.
Analysis of seasonal data from the Mars Global Surveyor Thermal Emission Spectrometer (TES) shows a significant increase in thermal inertia during autumn, winter and spring in the middle and high latitudes of Mars. At each stage of the northern seasonal polar cap's recession in spring a distinct high thermal inertia (HTI) annulus arises around the cap's edge. Within this annulus, we estimated and mapped the springtime water ice content in the daily thermal skin depth layer using spring and summer values of the thermal inertia in TES surface footprints. The results show that the average water content in the surface soil within the HTI annulus varies from ~5 vol % at the early stages of the seasonal polar cap retreating (Ls = 340°-360°) to ~1 vol % at later stages (Ls = 60°-70°). Maximum values of water ice content within the HTI annulus occur at Ls = 0°-20° (2-6 vol %) and Ls = 20°-40° (4-10 vol %). We analyzed the temporal and spatial relationship between the HTI annuli and the water ice (WI) annuli at the edge of the northern seasonal polar cap. The water ice within the WI annuli was mapped using a water ice spectral index (the absorption band depth at the 1.5 mm wavelength) derived from the OMEGA (Observatoire pour la Mineralogie, l'Eau, les Glaces et l'Activite) imaging spectrometer aboard the Mars Express spacecraft. Recent OMEGA observations show that the WI annuli formation arises only around the retreating northern seasonal polar cap, never around the retreating southern seasonal cap. For this reason our study is confined only to the northern hemisphere. The observed relationship between the HTI and WI annuli in the northern hemisphere of Mars indicates a close physical interdependence between these two phenomena. Our results confirm that the seasonal permafrost exposed by the retreating northern polar cap (within the HTI annuli) is actively involved today in the condensation and sublimation processes in the modern water cycle on Mars. The water abundance in this annual condensation/sublimation cycle within the active layer may be an order of magnitude higher than all the annual water vapor abundance in the Martian atmosphere. Our results are consistent with existence of the positive mass balance of the northern permanent polar cap in the modern climatic period.
13019396 Mitrofanov, I. (Russian Academy of Sciences, Institute for Space Research, Moscow, Russian Federation); Litvak, M. L.; Sanin, A. B.; Malakhov, A.; Golovin, D. V.; Boynton, William V.; Droege, G.; Chin, G.; Evans, Larry G.; Harshman, K.; Fedosov, F.; Garvin, J.; Kozyrev, A.; McClanahan, T. P.; Milikh, G.; Mokrousov, M. I.; Starr, Richard D.; Sagdeev, R.; Shevchenko, V.; Shvetsov, V.; Tret'yakov, V.; Trombka, J.; Varenikov, A. and Vostrukhin, A. Testing polar spots of water-rich permafrost on the Moon; LEND observations onboard LRO: Journal of Geophysical Research, 117(E), Citation E00H27, illus. incl. 3 tables, 51 ref., 2012. Supplemental information/data is available in the online version of this article.
Results are presented for the LEND instrument onboard LRO for the detection of local spots of suppression and excess of epithermal neutron emission at the lunar poles. Twelve local Neutron Suppression Regions (NSRs) and Neutron Excess Regions (NERs) are detected. It is shown using the data from the LOLA and Diviner instruments that six NSRs have the empirical property "less local irradiation and lower temperature - fewer local neutrons." These NSRs may be identified with spots of water-ice rich permafrost on the Moon. It is shown that detected NSRs are include in both permanently shadowed and illuminated areas, and they are not coincident with Permanently Shadowed Regions (PSRs) at the bottom of polar craters, as has been commonly expected before LEND presented neutron data with high spatial resolution.
13016126 Rutty, P. C. (Mott Macdonald Group, Croydon, United Kingdom) and Johnston, T. P. Optimum use of material; selection of limits for suitable earthworks fill; Irish experience: in Earthworks in Europe (Radford, T. A., editor), Engineering Geology Special Publication, 26, p. 79-92, illus., 31 ref., 2012.
Most Irish earthworks fills consist of glacially derived soils with some excavated rock. Excavated rock and granular glacial soils will nearly always provide acceptable fill. Cohesive glacial soils are generally well-graded tills, characterized by low plasticity and relatively high undrained strength. These cohesive tills provide acceptable fills providing they can be placed and compacted to provide sufficient strength and stiffness, and achieve low air voids. In standard earthworks specifications, acceptability limits for cohesive fills may be specified by moisture content, moisture condition value or undrained shear strength. The lower limit of strength or moisture content adopted ensures acceptable trafficability, compressibility and stability. Laboratory relationship testing is carried out to establish the relationship between the various test properties. Experience has shown that simple measurements and descriptions of strength derived from data collected routinely during ground investigations are adequate for estimation at tender. For construction control, moisture condition value testing has been widely adopted, is suitable for the range of soils encountered and provides quick results allowing timely decision-making. Irish tills are moisture susceptible and on-site results allow marginal materials to be processed on site for re-use, providing care is taken to work only in dry weather and protect placed fill.
13019793 Salonen, J. Sakari (University of Helsinki, Helsinki, Finland). Fossiilit kertovat ilmaston kehityksesta [Fossils record climate change]: Geologi, 64(4), p. 104-112 (English sum.), illus. incl. sketch maps, 21 ref., 2012. Accessed on Feb. 6, 2013.
Geoscientists and biologists from two Finnish universities have undertaken studies in 1999-2010 in the northeastern part of European Russia, aiming to unravel past changes in the climate and environment of the region. These studies have examined the variability of climate, vegetation, and permafrost in the northern Russian tundra zone over the past ca. 10,000 years, based on studying fossil pollen grains and macroscopic plant remains preserved in lake sediments and peat deposits. These research efforts, funded within two European Union projects, constitute a part of an international field of palaeoclimate research that studies the natural variability of Earth's climate over geological timescales. The fossil record of the tundra zone of northeast European Russia suggests that major climatological and environmental dynamics have taken place during the past millennia. During the so-called Holocene thermal maximum (HTM), 3000-7000 years ago, summer temperatures were ca. 2.5°C above the present-day level. During this warm period the northern taiga forest had advanced by ca. 150 km into the modern tundra zone, while the extent of permafrost was significantly smaller than today. The HTM was followed by a period of cooling over the past 3000 years, during which the treeline retreated to its current position and permafrost expansion took place. These results demonstrate the overall sensitivity of the Arctic tundra environment to climatic change, as the fossil record of past environmental change shows how relatively modest temperature changes can cause major shifts in vegetation and permafrost zones.
URL: http://www.geologinenseura.fi/geologi-lehti/4-2012/4Fossiilit_kertovat_ilmaston_ ...
13019638 Yost, Cheri (Cooperative Ecosystem Studies Units, Network National Office, Washington, DC) and Janke, Jason. Hot research/cool science; an investigation of permafrost in a changing alpine environment: Park Science, 29(1), p. 19-22, illus. incl. geol. sketch map, 2012.
13013945 Zubrzycki, Sebastian (University of Hamburg, Institute of Soil Science, Hamburg, Germany). Drilling frozen soils in Siberia: Polarforschung, 81(2), p. 150-152, illus. incl. 1 table, sketch map, 6 ref., 2012.
13018791 Karpenko, L. V. (Russian Academy of Sciences, Siberian Division, Institute of Forests, Krasnoyarsk, Russian Federation) and Knorre, A. A. Rastitel'nyy pokrov i stratigrafiya torfyanoy zalezhi bolot v doline Nizhney Tunguski [Vegetation in bogs and stratigraphy of peat deposits in the Lower Tunguska Valley]: Geografiya i Prirodnyye Resursy, 2011(2), p. 97-100 (English sum.), illus. incl. table, 11 ref., June 2011.
A comprehensive investigation of a flat-raised transitional bog with an area of about 10 ha has been carried out for the first time for the valley of the middle part of the Lower Tunguska River. A brief characterization of vegetation, stratigraphy and the kinds of peat is given. The temperature of the active layer in the peat accumulation is characterized.
13018792 Vlasova, N. V. (Russian Academy of Sciences, Siberian Division, V. Sochava Institute of Geography, Irkutsk, Russian Federation). Landshaftno-geokhimicheskoye sostoyaniye tayezhnykh geosistem v basseyne Nizhney Tunguski [Landscape geochemistry of taiga geosystems in the Lower Tunguska River basin]: Geografiya i Prirodnyye Resursy, 2011(2), p. 100-107 (English sum.), 3 tables, sketch map, 20 ref., June 2011.
The soil-geochemical features of permafrost-taiga geosystems characteristic of the Yerbogachenskaya Plain are outlined. The differentiation of a number of chemical elements in soils is considered to be the result of their radial, lateral migration and accumulation on the permafrost barrier. The indicator function of some species of mosses and lichens in the assessment of changes in the biogeochemical environment is demonstrated.
13018781 Vasil'yev, I. S. (Rossiyskaya Akademiya Nauk, Sibirskoye Otdeleniye, Institut Merzlotovedeniya, Yakutsk, Russian Federation). Nuklearnost' prirodnoy sredy Tsentral'noy Yakutii [Concentric pattern of natural environments in central Yakutia]: Geografiya i Prirodnyye Resursy, 2011(1), p. 111-115 (English sum.), sketch maps, 18 ref., March 2011.
Characteristics of the main components of Central Yakutia's natural environment are examined to reveal nuclearity, i.e., one of the territorial differentiation regularities implying that on the terrestrial surface there occur geosystems with a center and periphery. The regularity of manifestation of this phenomenon is more clearly pronounced in the distribution of the precipitation amount, snow cover height, soils vegetation, cryogenic strata, and of the ice complex.
13017157 Bouchard, Frédéric (Institut National de la Recherche Scientifique, Centre-Eau Terre Environnement, Quebec, QC, Canada); Francus, Pierre; Pienitz, Reinhard and Laurion, Isabelle. Sedimentology and geochemistry of thermokarst ponds in discontinuous permafrost, subarctic Quebec, Canada: Journal of Geophysical Research, 116(G), Citation G00M04, illus. incl. 2 tables, sketch maps, 30 ref., 2011.
Thermokarst (thaw) ponds and lakes are distributed throughout arctic and subarctic regions; however their natural variability and temporal evolution recorded in the bottom sediments are poorly understood. This paper presents a multiproxy study conducted in a subarctic site with many thermokarst ponds near Kuujjuarapik-Whapmagoostui, on the eastern shore of Hudson Bay. Sedimentological, geochemical and chronological analyses have been performed on short sediment cores (10-20 cm) retrieved from limnologically contrasted ponds. Analyses revealed two distinct sedimentary facies, from bottom to top: 1) massive marine silts and clays deposited during postglacial Tyrrell Sea transgression (ca. 8000 to 6000 cal yr BP), subsequently emerged by glacio-isostatic rebound and more recently (ca. 1500 to 400 cal yr BP) affected by permafrost inception and growth; 2) laminated organic-rich lacustrine muds deposited since permafrost thawing and subsidence, i.e., since thermokarst pond inception (the last centuries). Despite displaying strikingly different water colors, the study ponds showed similar long-term developmental patterns regarding their physico-chemical properties (as recorded in the sediments), such as decreasing mineral grain size (from silts to clays), decreasing major chemical element concentrations, increasing organic matter content, and decreasing bottom water oxygen concentrations (from well-oxygenated to anoxic/hypoxic conditions).
13017154 Grosse, Guido (University of Alaska at Fairbanks, Geophysical Institute, Fairbanks, AK); Harden, Jennifer; Turetsky, Merritt; McGuire, A. David; Camill, Philip; Tarnocai, Charles; Frolking, Steve; Schuur, Edward A. G.; Jorgenson, Torre; Marchenko, Sergei; Romanovsky, Vladimir; Wickland, Kimberly P.; French, Nancy; Waldrop, Mark; Bourgeau-Chavez, Laura and Striegl, Robert G. Vulnerability of high-latitude soil organic carbon in North America to disturbance: Journal of Geophysical Research, 116(G), Citation G00K06, illus. incl. 4 tables, sketch map, 90 ref., 2011.
This synthesis addresses the vulnerability of the North American high-latitude soil organic carbon (SOC) pool to climate change. Disturbances caused by climate warming in arctic, subarctic, and boreal environments can result in significant redistribution of C among major reservoirs with potential global impacts. We divide the current northern high-latitude SOC pools into (1) near-surface soils where SOC is affected by seasonal freeze-thaw processes and changes in moisture status, and (2) deeper permafrost and peatland strata down to several tens of meters depth where SOC is usually not affected by short-term changes. We address key factors (permafrost, vegetation, hydrology, paleoenvironmental history) and processes (C input, storage, decomposition, and output) responsible for the formation of the large high-latitude SOC pool in North America and highlight how climate-related disturbances could alter this pool's character and size. Press disturbances of relatively slow but persistent nature such as top-down thawing of permafrost, and changes in hydrology, microbiological communities, pedological processes, and vegetation types, as well as pulse disturbances of relatively rapid and local nature such as wildfires and thermokarst, could substantially impact SOC stocks. Ongoing climate warming in the North American high-latitude region could result in crossing environmental thresholds, thereby accelerating press disturbances and increasingly triggering pulse disturbances and eventually affecting the C source/sink net character of northern high-latitude soils. Finally, we assess postdisturbance feedbacks, models, and predictions for the northern high-latitude SOC pool, and discuss data and research gaps to be addressed by future research.
13017156 Jones, B. M. (University of Alaska at Fairbanks, Geophysical Institute, Fairbanks, AK); Grosse, Guido; Arp, C. D.; Jones, M. C.; Walter Anthony, K. M. and Romanovsky, V. E. Modern thermokarst lake dynamics in the continuous permafrost zone, northern Seward Peninsula, Alaska: Journal of Geophysical Research, 116(G), Citation G00M03, illus. incl. 1 table, sketch map, 45 ref., 2011.
Quantifying changes in thermokarst lake extent is of importance for understanding the permafrost-related carbon budget, including the potential release of carbon via lake expansion or sequestration as peat in drained lake basins. We used high spatial resolution remotely sensed imagery from 1950/51, 1978, and 2006/07 to quantify changes in thermokarst lakes for a 700 km2 area on the northern Seward Peninsula, Alaska. The number of water bodies larger than 0.1 ha increased over the entire observation period (666 to 737 or +10.7%); however, total surface area decreased (5,066 ha to 4,312 ha or -14.9%). This pattern can largely be explained by the formation of remnant ponds following partial drainage of larger water bodies. Thus, analysis of large lakes (>40 ha) shows a decrease of 24% and 26% in number and area, respectively, differing from lake changes reported from other continuous permafrost regions. Thermokarst lake expansion rates did not change substantially between 1950/51 and 1978 (0.35 m/yr) and 1978 and 2006/07 (0.39 m/yr). However, most lakes that drained did expand as a result of surface permafrost degradation before lateral drainage. Drainage rates over the observation period were stable (2.2 to 2.3 per year). Thus, analysis of decadal-scale, high spatial resolution imagery has shown that lake drainage in this region is triggered by lateral breaching and not subterranean infiltration. Future research should be directed toward better understanding thermokarst lake dynamics at high spatial and temporal resolution as these systems have implications for landscape-scale hydrology and carbon budgets in thermokarst lake-rich regions in the circum-Arctic.
13017155 Schirrmeister, Lutz (Alfred Wegener Institute for Polar and Marine Research, Department of Periglacial Research, Potsdam, Germany); Grosse, Guido; Wetterich, Sebastian; Overduin, Pier Paul; Strauss, Jens; Schuur, Edward A. G. and Hubberten, Hans-Wolfgang. Fossil organic matter characteristics in permafrost deposits of the northeast Siberian Arctic: Journal of Geophysical Research, 116(G), Citation G00M02, illus. incl. 3 tables, sketch map, 42 ref., 2011.
Permafrost deposits constitute a large organic carbon pool highly vulnerable to degradation and potential carbon release due to global warming. Permafrost sections along coastal and river bank exposures in NE Siberia were studied for organic matter (OM) characteristics and ice content. OM stored in Quaternary permafrost grew, accumulated, froze, partly decomposed, and refroze under different periglacial environments, reflected in specific biogeochemical and cryolithological features. OM in permafrost is represented by twigs, leaves, peat, grass roots, and plant detritus. The vertical distribution of total organic carbon (TOC) in exposures varies from 0.1 wt % of the dry sediment in fluvial deposits to 45 wt % in Holocene peats. Variations in OM parameters are related to changes in vegetation, bioproductivity, pedogenic processes, decomposition, and sedimentation rates during past climate variations. High TOC, high C/N, and low d13C reflect less decomposed OM accumulated under wet, anaerobic soil conditions characteristic of interglacial and interstadial periods. Glacial and stadial periods are characterized by less variable, low TOC, low C/N, and high d13C values indicating stable environments with reduced bioproductivity and stronger OM decomposition under dryer, aerobic soil conditions. Based on TOC data and updated information on bulk densities, we estimate average organic carbon inventories for ten different stratigraphic units in northeast Siberia, ranging from 7.2 kg C m-3 for Early Weichselian fluvial deposits, to 33.2 kg C m-3 for Middle Weichselian Ice Complex deposits, to 74.7 kg C m-3 for Holocene peaty deposits. The resulting landscape average is likely about 25% lower than previously published permafrost carbon inventories.
13017153 Zona, D. (University of Antwerp, Department of Biology, Antwerp, Belgium); Lipson, D. A.; Zulueta, R. C.; Oberbauer, S. F. and Oechel, W. C. Microtopographic controls on ecosystem functioning in the Arctic Coastal Plain: Journal of Geophysical Research, 116(G), Citation G00I08, illus. incl. 4 tables, 37 ref., 2011.
The investigation of the microtopographic controls on thermal and hydrologic conditions of the soil and consequently the carbon dynamics from Arctic regions is of major importance. Ecosystem respiration (ER) between microsites of the same tundra type could differ more than ER in different tundra types even at different latitudes. In this study we investigated the microtopographic effect on soil temperature, thaw depth, pH, oxidation reduction potential (ORP), electrical conductivity (EC), dissolved CO2, vegetation types, and ER rates from different features forming the low-center polygon structure. Most of these environmental variables significantly differ particularly between areas with higher elevation (polygon rims) and with lower elevation (low-center polygons). Polygon rims presented the lowest water table and showed the lowest thaw depth and the highest ER (a seasonal average of 1 mmol CO2 m-2 s-1), almost double than the ER in the low-center polygons (a seasonal average of 0.6 mmol CO2 m-2 s-1). The microtopographic gradient from polygon rims to low-centers led to a very consistent pattern in pH, EC, ORP and dissolved CO2, with low-centers presenting the highest pH, the highest EC, the highest dissolved CO2, and the lowest ORP. Based on vegetation measurements, we also showed that microtopography controls the lateral flow of organic matter, and that vascular plant material accumulates as litter in the lower elevation areas, possibly contributing to the higher dissolved CO2 in the low-center polygons. Microtopography, and the ramifications discussed here, should be considered when evaluating landscape scale environmental controls on carbon dynamics in the Arctic.
13018773 Korotkiy, A. M. (Rossiyskaya Akademiya Nauk, Dal'nevostochnoye Otdeleniye, Tikhookeanskiy Institut Geografii, Vladivostok, Russian Federation); Korobov, V. V. and Skryl'nik, G. P. Naledi v rechnykh basseynakh Primor'ya i ikh vliyaniye na landshafty [Ice in the river basins of Primorye and their influence on landscapes]: Geografiya i Prirodnyye Resursy, 2010(4), p. 107-116 (English sum.), illus. incl. sketch map, 18 ref., December 2010.
The authors examine the types of icings in the river basins of Primorye. The conditions for their formation in autumn and winter and for their decay in the spring-summer time are assessed. Depending on the type of icings, the authors identified the character of their impact on the main components of the landscape: relief, hydrological regime of streams, soil, vegetation, etc.. The emphasis in this study is on the icing formations in the zone of seasonally frozen earth materials and, to a lesser extent, in areas of permafrost islands.
13014730 O'Connor, Fiona M. (Met Office Hadley Centre, Exeter, United Kingdom); Boucher, O.; Gedney, N.; Jones, C. D.; Folberth, G. A.; Coppell, R.; Friedlingstein, P.; Collins, W. J.; Chappellaz, J.; Ridley, J. and Johnson, C. E. Possible role of wetlands, permafrost, and methane hydrates in the methane cycle under future climate change; a review: Reviews of Geophysics, 48(4), RG4005(1-33), illus. incl. sketch maps, 264 ref., 2010.
We have reviewed the available scientific literature on how natural sources and the atmospheric fate of methane may be affected by future climate change. We discuss how processes governing methane wetland emissions, permafrost thawing, and destabilization of marine hydrates may affect the climate system. It is likely that methane wetland emissions will increase over the next century. Uncertainties arise from the temperature dependence of emissions and changes in the geographical distribution of wetland areas. Another major concern is the possible degradation or thaw of terrestrial permafrost due to climate change. The amount of carbon stored in permafrost, the rate at which it will thaw, and the ratio of methane to carbon dioxide emissions upon decomposition form the main uncertainties. Large amounts of methane are also stored in marine hydrates, and they could be responsible for large emissions in the future. The time scales for destabilization of marine hydrates are not well understood and are likely to be very long for hydrates found in deep sediments but much shorter for hydrates below shallow waters, such as in the Arctic Ocean. Uncertainties are dominated by the sizes and locations of the methane hydrate inventories, the time scales associated with heat penetration in the ocean and sediments, and the fate of methane released in the seawater. Overall, uncertainties are large, and it is difficult to be conclusive about the time scales and magnitudes of methane feedbacks, but significant increases in methane emissions are likely, and catastrophic emissions cannot be ruled out. We also identify gaps in our scientific knowledge and make recommendations for future research and development in the context of Earth system modeling.
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13019501 Goshorn-Maroney, Joseph. Thermal conditions and movement of rock glaciers in the north Cascades, Washington: 102 p., illus. incl. 7 tables, 53 ref., Master's, February 2012, Western Washington University, Bellingham, WA.
Rock glaciers are a largely unrecognized phenomenon in the North Cascades. In part this reflects their scarcity there. Additionally, because rock glaciers are widely held to be the product of permafrost conditions, the dearth of literature regarding North Cascade rock glaciers also reflects the notion that active rock glaciers should not exist at all in such temperate mountain ranges. Rock glaciers have been linked to specific air temperature conditions (<-2°C), and, based on that link, are often used as visual indications of mountain permafrost. The North Cascades, a maritime mountain range with high snowfall and relatively warm climate, are a good location to test the permafrost-rock glacier link. Review of aerial photography and satellite imagery, however, reveals at least ten morphologically active rock glaciers and even more that appear inactive. To test the activity and possible link to permafrost conditions, I selected two of the active-looking rock glaciers for movement monitoring and thermal investigation. Movement monitoring was accomplished by conducting repeat scans with a terrestrial laser scanner; this investigation represents the first attempt to use this technique on rock glaciers in North America. The Craggy Peak rock glacier was shown to be moving downslope at a rate of 5 to 10 cm per year. Movement vectors toward the top of the rock glacier suggested deflation, while vectors toward the toe indicated a slight inflation. Flow toward the top and center of the rock glacier also was faster reflecting the steeper slope while flow toward the toe slowed and vectors radiated out. Movement was not detectable on second rock glacier, Star Peak, due mainly to lack of control points located on and around the scan target. Moreover, lack of a good vantage point at the site limited the scan coverage, inhibiting data processing. Because the North Cascades are a maritime mountain range with climate conditions thought to be too warm and wet to support rock glaciers, I also deployed miniature temperature data loggers in both rock glaciers to record air temperature at the surface and within the rubble. Three logger strings were deployed with three loggers. Each string contained one surface logger, one logger of intermediate depth and one logger that was between 1.5-2.3 meters deep in the rubble (depending on the string). One year of data has revealed that average ground temperature on the rock glaciers is probably near -1 ± 1° C and modeled near-surface air temperature above them is 0.0 ± 1.6°C. Air temperature is marginally to warm to support permafrost, though a more lengthy study period is needed. Thermal exchange during the summer appears to be governed by conductive processes in the form of rain water and solar heating. Moreover, forced convection occurs when wind pumps air into the regolith. During the fall, I document at least one instance where the data loggers capture natural convection when relatively warm air evacuated the regolith. Natural convection occurs when cold air overlays warm air and the subsequent density driven inversion results in warm air escaping into the air and cold air settling into the regolith.
13018010 Makela, Jorma. Drilled well yield and hydraulic properties in the Precambrian crystalline bedrock of central Finland: Turun Yliopiston Julkaisuja, Sarja A 2, Biologica, Geographica, Geologica, 267, 356 p., Doctoral, 2012, Abo Academy University, Turku. ISBN: 978-951-29-4972-4; 978-951-29-4973-1 WWW. Accessed on Feb. 1, 2013.
The drilled well yield and hydraulic properties and their relationships to different well factors related to the location of the wells were investigated in the Precambrian crystalline bedrock of Central Finland. Data from 2,352 private wells constituted the primary study material. Additional data from 73 test wells were utilized as a support material. Based on technical well data and single well pumping tests, estimates for hydraulic parameters (normalized yield, specific capacity, well productivity, transmissivity, bulk hydraulic conductivity) were statistically determined. Nearly 60 well factors were extracted. They were divided into five groups: construction, geologic, topographic, lineament and catchment factors. In addition, the role of seismotectonics was considered. In Central Finland, drilled wells are most often used in domestic water supply by single households and farms. Some 30 villages and small towns use bedrock groundwater for their common water supply. Bedrock groundwater can provide a valuable source for water supply of large communities in various times of crisis. Hydraulic fracturing has proven to be a successful method in increasing the yield of low to medium yield wells. The median well depth and yield are 73 m and 700 Lhr-1, respectively. The median hydraulic parameters are as follows: normalized yield Q/ds 12 Lhr-1m-1, specific capacity Q/s 50 Lhr-1m-1, well productivity Qw 2,1x10-7 ms-1, transmissivity T 7,3x10-6 m2s-1, and hydraulic conductivity K 1,1x10-7 ms-1. Much the same values have been reported in most unweathered crystalline rock settings around the world despite different lithologies, climate and tectonic histories. This is suspected to be largely due to similar rock fracturing characteristics. Q/ds, Q/s and Qw can be used as estimates for bulk T and K in regional studies of fractured rock aquifers. A prerequisite for this is, however, that their mutual relations have first been statistically adjusted. The well yield and hydraulic conductivity decrease downwards in bedrock, at least to the drilled well depths. The soil type at well site and the thickness of overburden are not of any great importance to the well production properties. Lithological differences between well sites may be considered insignificant from the well production point of view. The drilled well yield and hydraulic properties are not statistically related to surface water bodies. Neither does the land uplift rate nor does the highest shore level indicate any clear trend in the well production properties. The productivity of a drilled well is clearly related to its topographic setting. Valley wells are most productive whereas hilltop wells, though deepest, yield the least amounts of water. The distance to the nearest (bedrock) hilltop and the relative height differences in a well's catchment area are statistically related to the well yield and hydraulic properties. The proximity of lineaments is considered the most important factor entity controlling the productivity of drilled wells in the study area. The most significant single lineament factors are the azimuth and prominence of lineaments and their perpendicular distance to the drilled wells. Lineament intersections have no statistical relations to the well production properties. Tectonic reactivation of faults is considered of utmost importance for groundwater flow and drilled well hydraulics. Analogously to the large postglacial faults in northern Fennoscandia, the NE-SW and NW-SE lineaments have most probably been activated in the study area during the last phases of the Weichselian deglaciation some 10,000 years BP. This well explains their higher permeability compared to other lineament sets and may be considered as an implication of postglacial faulting in Central Finland. Elevated well yields elsewhere in glaciated terrains of Fennoscandia and northern North America are possibly related to similar fault reactivation during the deglacial time. Although much has been done, a better understanding of bedrock hydrogeology and paleohydrogeology is still needed in the arrangements of the future disposal of nuclear fuel waste in Fennoscandia. High-yield well siting in crystalline rock areas should start with lineament mapping. The key point in obtaining the highest probability of success is to be able to identify those linea-ment sets, which are optimally orientated and critically stressed in a present-day stress regime and/or have been geologically recently activated. Hence, in a thrust fault regime, one should go for detecting lineaments that strike perpendicular to the maximum horizontal stress direc-tion SH. In normal fault regimes the most promising lineaments should lie parallel to the SH, while in strike-slip regimes they either coincide with the SH or diverge at various angles (< 45°) to it. Along with the lineament orientation, the prominence of lineaments must also be considered. In Central Finland, the short NW-SE and medium length to long NE-SW linea-ments should be preferred to other lineament sets. Their central parts (≤&eq; 100 m) are optimal for high-yield well drilling. Staying in low-elevation areas away from hilltops and ridges statistically increases the chances to catch a high-yield well site. The siting of high-yield wells may also benefit from previous borehole information or water well inventories to be executed in the area of interest. A conceptual hydrotectonic model was developed to guide the selection of the most favorable well sites in the study area. The lineament-stress analysis forms the fundamental basis of the model. In addition, the optimal field for bedrock seismic velocity have been included in the model. It is stressed that only the drilling and proper pumping test with water quality determinations provide the ultimate information required to decide whether a high-yield well site would suit for long-term withdrawal of groundwater.
URL: http://www.doria.fi/bitstream/handle/10024/76642/M%c3%a4kel%c3%a4_Jorma_Thesis_A ...
13019500 Larrabee, Michael Allen. Hydrologic and geomorphic assessment of Ebey's Prairie, central Whidbey Island, Washington: 29 p., illus. incl. 10 tables, 88 ref., Master's, October 2011, Western Washington University, Bellingham, WA.
Ebey's Prairie, Washington, was once bisected by a broad riparian corridor consisting of waterlogged soils, swampy areas, seasonal ponds, and intermittent flows, which helped recharge the local aquifer. By the mid-1900s, agriculture drainage tiles, drainage ditches, and fill were being installed by landowners to increase tillable acreage. The extent and location of these drainage tiles or the effects these tiles have had on surface water and subsequently on aquifer recharge in the area remains uncertain. In this study, I characterized the modern and historic surface hydrologic conditions of Ebey's Prairie and their relationship to the local geomorphology. I used the Distributed Hydrology-Soil-Vegetation Model (DHSVM) to reconstruct the pre-agricultural surface hydrology and evaluate the effects agricultural drainage tiles have had on surface hydrologic conditions and aquifer recharge. A model representing Ebey's Prairie watershed with was created, calibrated, and validated to stream discharge measured during my study. A second model was created to represent Ebey's Prairie watershed without drainage tiles. Simulations for water years 2001-2010 for each basin condition were executed and compared to quantify the influence of drainage tiles on hydrologic regimes. Additionally, I mapped the local geomorphology, relating landforms to hydrologic regimes, and used lake sediment coring to improve the understanding of the sequence of events that created the unique landscape and its paleo-environment. Average annual surface discharge for Ebey's Prairie watershed increased by 41,540 m3 (10.97 million gal.) when artificial drainage was present in the model, an increase of 163 percent over the pre-disturbance basin. The general shape of hydrographs was similar for both watersheds; however the basin with drainage tiles typically had peak flows 2-3 times larger than the basin without tiles, in addition to greater hourly baseflows and a longer recessional curve. Average recharge for the entire Ebey's Prairie watershed with drainage tiles was 19.9 cm/yr. and without tiles was 20.3 cm/yr., an increase in recharge of 41,420 m3 or 1.65 percent, which is within the margin of error for the model. It was determined that the effective drainage area of the Ebey's Prairie watershed was smaller than the watershed boundaries as delineated by DHSVM. The effective drainage area largely contained both the silty loam and loam soils or in the silty loam soil only. The silty loam is coincident with the majority of the drainage tiles network and two closed depressions identified as relict marshes. The distribution of an additional 41,418 m3 of recharge across a smaller effective drainage area would result in an increase of between 1.0 to 9.8 cm/yr., which is significant. A geomorphic map of Ebey's Landing National Historical Reserve was created, identifying 20 distinct landforms covering an area of 72.7 km2. Eighty-six percent of the map area is composed of four map units: glaciated uplands, ice-marginal deltas, marine terrace and kame-kettle topography. Two sediment cores, 6.64 m and 9.24 m long, were collected from the Lake Pondilla kettle pond. I attempted to numerically date sediments deposited after kettle collapse to constrain the timing of events associated with the formation of the local geomorphology. Lack of extension rods during coring prevented recovery of deeper sediments. The recovered cores indicated a rapid sedimentation of 1.26 - 1.37 mm/yr through the mid and late-Holocene. A tephra at 7.81 m could not be identified based on chemical analysis, however it is likely Mazama ash based on thickness, character and position within the sediment sequence.
13018135 D'Amore, David V. Hydrologic controls on carbon cycling in Alaskan coastal temperate rainforest soils: 150 p., Doctoral, 2011, University of Alaska at Fairbanks, Fairbanks, AK. ISBN: 978-1-267-04608-6 Available from: Univ. Microfilms.
13018009 Okkonen, Jarkko. Groundwater and its response to climate variability and change in cold snow dominated regions in Finland; methods and estimations: Acta Universitatis Ouluensis, Series C, Technica, 412, 78 p. (Finnish sum.), Doctoral, 2011, University of Oulu, Oulu. ISBN: 978-951-42-9700-7; 978-951-42-9701-4 WWW. Accessed on Feb. 1, 2013.
A conceptual framework was developed to assess how changes in temperature and precipitation affect sub-surface hydrology, groundwater recharge, groundwater quantity and quality. A conceptual and statistical approach was developed to predict groundwater level variations. Daily rainfall, snowmelt and evapotranspiration values were generated with a novel conceptual hydrological model developed in this study. These values were cross-correlated with observed groundwater levels to find representative time lags and significant correlations. A statistical model linking rainfall, snowmelt, evapotranspiration and groundwater level was then developed and validated. The model simulated seasonal variations in groundwater level very accurately. A sequential approach was developed to assess surface water-groundwater interactions. The simulated surface water level estimated with the WSFS model and recharge estimated with CoupModel were linked to the groundwater flow model MODFLOW. Groundwater, surface water and snow samples were collected to study the chemical composition of groundwater in an unconfined esker aquifer in Northern Finland. Concentrations of Ca2+, Cl-, NO3-N and SiO2 and electrical conductivity were determined. Water quality in the main aquifer was found to be similar to that in the perched groundwater. Solute concentrations generally decreased during and immediately after snowmelt periods, indicating the importance of snowmelt input for groundwater quality. In the perched groundwater, NO3-N concentration increased with elevated groundwater level, indicating a nitrogen source on the land surface. The Cl- concentration in groundwater decreased when the surface water level rose higher than groundwater level. According to simulation results for the A1B climate change scenario, groundwater recharge is projected to increase in winter months due to increased snowmelt and decreased soil frost depth. The spring snowmelt peak in late spring will decrease. This will reduce aquifer storage in early spring, increasing the vulnerability to summer droughts. It is projected that flow regimes between unconfined aquifers and surface water may change, affecting water quantity and possibly quality in groundwater systems.
13018141 Stroble, Shannon T. Geochemical analysis of soils from extreme environments on Earth and Mars: 349 p., Doctoral, 2011, Tufts University, Medford, MA. ISBN: 978-1-267-05887-4 Available from: Univ. Microfilms.
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13013997 Andersson, Rina A. (Stockholm University, Department of Geological Sciences, Stockholm, Sweden) and Meyers, Philip A. Effect of climate change on delivery and degradation of lipid biomarkers in a Holocene peat sequence in the Eastern European Russian Arctic: in Advances in organic geochemistry 2011; proceedings of the 25th international meeting on Organic geochemistry (van Bergen, Pim, editor; et al.), Organic Geochemistry, 53, p. 63-72, illus. incl. 2 tables, 61 ref., December 2012. Meeting: 25th international meeting on Organic geochemistry, Sept. 18-23, 2011, Interlaken, Switzerland.
Lipid biomarkers from a peat plateau profile from the Northeast European Russian Arctic were analyzed. The peat originated as a wet fen ca. 9ka BP and developed into a peat bog after the onset of permafrost ca. 2.5ka BP. The distributions and abundances of n-alkanols, n-alkanoic acids, n-alkanes, n-alkan-2-ones and sterols were determined to study the effect of degradation on their paleoclimate proxy information. Plant macrofossil analysis was also used in combination with the lipid distributions. The n-alkanol and n-alkanoic acid distributions in the upper part of the sequence generally correspond to compositions expected from plant macrofossil assemblages. Their carbon preference index (CPI) values increase with depth and age, whereas those of the n-alkanes decrease. The different CPI patterns suggest that n-alkanoic acids and n-alkanols deeper in the sequence may be produced during humification through alteration of other lipids. Excursions in the n-alkanoic acid content also suggest an important contribution of invasive roots to the lipid biomarker composition. The CPIs associated with these compounds show that under permafrost conditions organic material from Sphagnum is better preserved than material from vascular plants. Increasing stanol/stenol ratio values and decreasing n-alkane CPI values indicate progressive degradation of organic matter (OM) with depth. The n-alkan-2-one/n-alkane and n-alkan-2-one/n-alkanoic acid ratios were shown to be useful proxies that can reflect the degree of OM preservation and suggest that both microbial oxidation of n-alkanes and decarboxylation of n-alkanoic acids produce n-alkan-2-ones in this peat sequence. Abstract Copyright (2012) Elsevier, B.V.
13019757 Boman, A. (Lulea University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Lulea, Sweden); Astrom, M. E. and Ohlander, B. Can Zn isotopes be used for tracing acid sulfate soil discharge? [abstr.]: in 7th international acid sulfate soil conference; Towards harmony between land use and the environment; proceedings volume (Osterholm, Peter, editor; et al.), Opas - Geologian Tutkimuskeskus, 56, p. 24-25, 4 ref., 2012. WWW. Meeting: 7th international acid sulfate soil conference, Aug. 26-Sept. 1, 2012, Vaasa, Finland. Accessed on Feb. 6, 2013.
13013268 Hecht, M. H. (Jet Propulsion Laboratory, Pasadena, CA) and Head, J. W. Stability of shallow buried ice on Mars: in Lunar and planetary science conference XLIII; papers presented to the Forty-third lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 43, Abstract 2260, illus., 15 ref., 2012. Meeting: Forty-third lunar and planetary science conference, March 19-23, 2012, Woodlands, TX. Accessed on Nov. 16, 2012.
13019765 Hopgood, M. J. (MRM Konsult AB, Lulea, Sweden). Environmental impact of an ASS landfill on the chemical properties of a recipient river [abstr.]: in 7th international acid sulfate soil conference; Towards harmony between land use and the environment; proceedings volume (Osterholm, Peter, editor; et al.), Opas - Geologian Tutkimuskeskus, 56, p. 51-53, illus. incl. sketch map, 2012. WWW. Meeting: 7th international acid sulfate soil conference, Aug. 26-Sept. 1, 2012, Vaasa, Finland. Accessed on Feb. 6, 2013.
13019766 Jacks, G. (KTH, Department of Land and Water Resources Engineering, Stockholm, Sweden); Morth, M.; Slejkovec, Z. and Nilsson, E. Arsenic cycling in areas with sulfidic metasediments, N. Sweden [abstr.]: in 7th international acid sulfate soil conference; Towards harmony between land use and the environment; proceedings volume (Osterholm, Peter, editor; et al.), Opas - Geologian Tutkimuskeskus, 56, p. 57-59, illus. incl. 1 table, 7 ref., 2012. WWW. Meeting: 7th international acid sulfate soil conference, Aug. 26-Sept. 1, 2012, Vaasa, Finland. Accessed on Feb. 6, 2013.
13013266 Johnsson, A. (University of Gothenburg, Department of Earth Sciences, Goteborg, Sweden); Reiss, D.; Hauber, E.; Zanetti, M.; Hiesinger, H.; Johansson, L. and Olvmo, M. Periglacial mass-wasting landforms on Mars suggestive of transient liquid water in the recent past; insights from solifluction lobes on Svalbard: in Lunar and planetary science conference XLIII; papers presented to the Forty-third lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 43, Abstract 2073, illus. incl. sketch map, 15 ref., 2012. Meeting: Forty-third lunar and planetary science conference, March 19-23, 2012, Woodlands, TX. Accessed on Nov. 16, 2012.
13019767 Karjalainen, A. K. (Finnish Environmental Institute, SYKE Laboratory Centre, Research and Innovation Laboratory, Finland); Wallin, J.; Jarvisto, J.; Schultz, E. and Vuori, K. M. Ecotoxicological risk assessment of Ostrobothnian river estuaries affected by acidity and metals leached from acid sulfate soils [abstr.]: in 7th international acid sulfate soil conference; Towards harmony between land use and the environment; proceedings volume (Osterholm, Peter, editor; et al.), Opas - Geologian Tutkimuskeskus, 56, p. 60-62, illus. incl. 1 table, 5 ref., 2012. WWW. Meeting: 7th international acid sulfate soil conference, Aug. 26-Sept. 1, 2012, Vaasa, Finland. Accessed on Feb. 6, 2013.
13019768 Kosunen, M. (Finnish Environmental Institute, Helsinki, Finland); Virtanen, S. and Tattari, S. Modelling the efficiency of drainage practices at present and future climate scenarios on acid sulfate soils in Finland [abstr.]: in 7th international acid sulfate soil conference; Towards harmony between land use and the environment; proceedings volume (Osterholm, Peter, editor; et al.), Opas - Geologian Tutkimuskeskus, 56, p. 63-65, illus., 1 ref., 2012. WWW. Meeting: 7th international acid sulfate soil conference, Aug. 26-Sept. 1, 2012, Vaasa, Finland. Accessed on Feb. 6, 2013.
13019774 Nystrand, M. (Abo Akademi University, Geology and Mineralogy, Abo, Finland) and Osterholm, Peter. Metal speciation in an extreme acidic boreal river system [abstr.]: in 7th international acid sulfate soil conference; Towards harmony between land use and the environment; proceedings volume (Osterholm, Peter, editor; et al.), Opas - Geologian Tutkimuskeskus, 56, p. 80-82, illus., 3 ref., 2012. WWW. Meeting: 7th international acid sulfate soil conference, Aug. 26-Sept. 1, 2012, Vaasa, Finland. Accessed on Feb. 6, 2013.
13019776 Pousette, K. (Lulea University of Technology, Lulea, Sweden) and Knutsson, S. Study of a sulfide soil deposit at a road construction in Sunderbyn, near Lulea in the north of Sweden [abstr.]: in 7th international acid sulfate soil conference; Towards harmony between land use and the environment; proceedings volume (Osterholm, Peter, editor; et al.), Opas - Geologian Tutkimuskeskus, 56, p. 86-88, 1 table, sketch map, 3 ref., 2012. WWW. Meeting: 7th international acid sulfate soil conference, Aug. 26-Sept. 1, 2012, Vaasa, Finland. Accessed on Feb. 6, 2013.
13019779 Rosendahl, R. (Pro Agria, Rural Advisory Centre of Ostrobothnia, Vaasa, Finland); Lall, K. E.; Engblom, S.; Sten, P. and Osterholm, Peter. The Risofladan Experimental Field for chemical precision treatment of acid sulfate soils [abstr.]: in 7th international acid sulfate soil conference; Towards harmony between land use and the environment; proceedings volume (Osterholm, Peter, editor; et al.), Opas - Geologian Tutkimuskeskus, 56, p. 97-99, sketch map, 2012. WWW. Meeting: 7th international acid sulfate soil conference, Aug. 26-Sept. 1, 2012, Vaasa, Finland. Accessed on Feb. 6, 2013.
13019780 Saarinen, T. (University of Oulu, Water Resources and Environmental Engineering Laboratory, Oulu, Finland); Mohammadighavam, S.; Marttila, H. and Klove, B. Peatland forestry and sulfide-bearing sediments; how to avoid acid surges? [abstr.]: in 7th international acid sulfate soil conference; Towards harmony between land use and the environment; proceedings volume (Osterholm, Peter, editor; et al.), Opas - Geologian Tutkimuskeskus, 56, p. 100-101, sketch map, 1 ref., 2012. WWW. Meeting: 7th international acid sulfate soil conference, Aug. 26-Sept. 1, 2012, Vaasa, Finland. Accessed on Feb. 6, 2013.
13019781 Saukkoriipi, J. (Finnish Environmental Institute, Oulu, Finland); Martinmaki, K.; Marttila, H.; Heikkinen, K.; Tammela, S.; Tertsunen, J.; Tolkkinen, M.; Ihme, R. and Klove, B. Assessing the origin of the acidity in a humic boreal river draining peatlands and sulfide-bearing soil materials [abstr.]: in 7th international acid sulfate soil conference; Towards harmony between land use and the environment; proceedings volume (Osterholm, Peter, editor; et al.), Opas - Geologian Tutkimuskeskus, 56, p. 102-104, sketch map, 5 ref., 2012. WWW. Meeting: 7th international acid sulfate soil conference, Aug. 26-Sept. 1, 2012, Vaasa, Finland. Accessed on Feb. 6, 2013.
13019782 Saukkoriipi, J. (Finnish Environmental Institute, Oulu, Finland); Osterholm, Peter; Heikkinen, K.; Postila, H.; Kunnas-Hiltunen, S.; Karppinen, A.; Wichmann, A.; Klove, B. and Ihme, R. Management of sulfide-induced acidity in peat harvesting (SuHE); methods for predicting and managing acidic loads to waters from peat extraction areas [abstr.]: in 7th international acid sulfate soil conference; Towards harmony between land use and the environment; proceedings volume (Osterholm, Peter, editor; et al.), Opas - Geologian Tutkimuskeskus, 56, p. 105-106, illus., 2 ref., 2012. WWW. Meeting: 7th international acid sulfate soil conference, Aug. 26-Sept. 1, 2012, Vaasa, Finland. Accessed on Feb. 6, 2013.
13013264 Séjourné, A. (Polish Academy of Sciences, Institute of Geological Sciences, Wroclaw, Poland); Costard, F.; Gargani, J.; Soare, R. J.; Fedorov, A. and Marmo, C. Degradation of the periglacial landscape of Utopia Planitia under global warming; comparison Earth-Mars: in Lunar and planetary science conference XLIII; papers presented to the Forty-third lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 43, Abstract 1881, illus., 17 ref., 2012. Meeting: Forty-third lunar and planetary science conference, March 19-23, 2012, Woodlands, TX. Accessed on Nov. 16, 2012.
13019785 Simek, M. (Czech Academy of Sciences, Institute of Soil Biology, Veske Budejovice, Czech Republic); Virtanen, S.; Simojoki, A.; Kristufek, V. and Yli-Halla, Markku. Microbial community in boreal acid sulfate soil; vertical distribution, activity assessment, and potential for greenhouse gas emissions [abstr.]: in 7th international acid sulfate soil conference; Towards harmony between land use and the environment; proceedings volume (Osterholm, Peter, editor; et al.), Opas - Geologian Tutkimuskeskus, 56, p. 113-115, illus., 4 ref., 2012. WWW. Meeting: 7th international acid sulfate soil conference, Aug. 26-Sept. 1, 2012, Vaasa, Finland. Accessed on Feb. 6, 2013.
13019786 Simojoki, A. (University of Helsinki, Department of Food and Environmental Sciences, Helsinki, Finland); Virtanen, S. and Yli-Halla, Markku. Nitrous oxide emissions from acid sulfate soil at high and low groundwater level in a lysimeter experiment [abstr.]: in 7th international acid sulfate soil conference; Towards harmony between land use and the environment; proceedings volume (Osterholm, Peter, editor; et al.), Opas - Geologian Tutkimuskeskus, 56, p. 116-118, illus., 8 ref., 2012. WWW. Meeting: 7th international acid sulfate soil conference, Aug. 26-Sept. 1, 2012, Vaasa, Finland. Accessed on Feb. 6, 2013.
13013269 Sizemore, H. G. (Montani Consulting, Hillsboro, WV); Zent, A. P. and Rempel, A. W. Ice lens formation and unfrozen water at the Phoenix landing site: in Lunar and planetary science conference XLIII; papers presented to the Forty-third lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 43, Abstract 2397, illus., 8 ref., 2012. Meeting: Forty-third lunar and planetary science conference, March 19-23, 2012, Woodlands, TX. Accessed on Nov. 16, 2012.
13019791 Suomela, R. (Agrifood Research Finland, Ruukki, Finland); Yli-Halla, Markku; Auri, J. and Joki-Tokola, E. Subsurface irrigation and controlled drainage in reducing the acid discharge to Siikajoki River in Northern Ostrobothnia, Finland [abstr.]: in 7th international acid sulfate soil conference; Towards harmony between land use and the environment; proceedings volume (Osterholm, Peter, editor; et al.), Opas - Geologian Tutkimuskeskus, 56, p. 130-131, 2012. WWW. Meeting: 7th international acid sulfate soil conference, Aug. 26-Sept. 1, 2012, Vaasa, Finland. Accessed on Feb. 6, 2013.
13015150 Leng, M. J. (British Geological Survey, Nottingham, United Kingdom); Anderson, N. John; Wagner, B.; Bennike, O.; D'Andrea, W. J.; Liversidge, A. C. and McGowan, S. Deglaciation, lake ontogeny and organic carbon cycling in SW Greenland lakes [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract B21E-0303, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5 - 9, 2011, San Francisco, CA.
Lakes are increasingly seen as an important component of regional and global carbon cycles. The composition and concentration of lacustrine organic matter represents organic production in the lake, terrestrial production and transfer to the lake, loss processes (especially post depositional mineralization/decomposition) as well as dilution effects (by varying inorganic inputs). Interpretation of organic carbon content (usually in the form of loss on ignition (LOI) or total organic carbon (TOC) analysis) is usually described in terms of lake productivity or preservation. Productivity is often related to climate, the assumption being that temperature controls lake productivity, although this tends to ignore the role of organic matter provenance, in-lake nutrient availability as well as catchment ontogeny. These latter controls can be deciphered by using a multi-proxy approach, e.g. combining TOC, C/N, carbon isotope ratios, geochemistry, sedimentology and macrofossil analysis. We present data from a range of lakes from SW Greenland located along a climate gradient between Kangerlussuaq and Sisimiut. The sediment records reflect local, regional and global signals and we show that multiple processes are responsible for the organic records including silicate weathering, sequestering of atmospheric CO2, climate and the onset of soil development in the catchment. Carbon cycling in these lakes is complex involving multiple carbon sources as well as differential storage and loss rates.
URL: http://www.agu.org/cgi-bin/SFgate/SFgate?language=English&verbose=0&listenv=tabl ...
13015138 Loisel, J. (Lehigh University, Department of Earth and Environmental Sciences, Bethlehem, PA) and Yu, Z. Recent acceleration of carbon accumulation rates in wet boreal peatlands [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract B21D-0287, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5 - 9, 2011, San Francisco, CA.
The ongoing climate warming trend in high-latitude regions is causing rapid and irreversible changes in the structure and functioning of carbon-rich terrestrial ecosystems. The fate of peat-accumulating wetlands is particularly concerning, as these large pools of soil organic carbon could provide a significant positive feedback to warming. In subarctic peatlands, wetter conditions due to permafrost thaw are expected to substantially increase methane and nitrous oxide emissions to the atmosphere, whereas warming-induced droughts in boreal and temperate peatlands are predicted to accelerate carbon dioxide emissions through enhanced oxidation of thick peat deposits. Here we examined the response of a wet boreal peatland to global warming using empirical (peat cores) and modeling approaches. The study site is located in south-central Alaska, just south of Mt Denali (62°25'N, 150°41'W). We hypothesized that warming could enhance the carbon-sink capacity of such temperature-limited ecosystems that are not drought-sensitive by promoting biomass production. Recent peat addition rates (past 50 years) are about 20 times greater than that of the late-Holocene at our study site (600 vs. 30 g C m-2 yr-1). Even once decomposition and compaction trends were removed from the young peat profiles using three different modeling approaches, that young peat still yielded long-term peat-carbon accumulation rates that were 2 to 3 times greater than that of the past 4000 years. Our model also indicates that high peat addition rates are responsible for this rapid accumulation, suggesting that climate warming could enhance the carbon-sink capacity of wet boreal peatlands by promoting biomass productivity. This trend is further confirmed by our large-scale peatland data synthesis of recent peat-carbon accumulation (40 sites) combined with climate space analysis, which shows that our study site is characterized by unusually high recent peat addition rates given its relatively cool climate. Overall, this peatland 'greening' might partly offset peat-carbon losses to the atmosphere that are being experienced by other peatland types, such as some permafrost and temperate peatlands.
URL: http://www.agu.org/cgi-bin/SFgate/SFgate?language=English&verbose=0&listenv=tabl ...
13015169 Nakai, T. (University of Alaska Fairbanks, International Arctic Research Center, Fairbanks, AK); Kim, Y.; Busey, R. and Suzuki, R. Micrometeorological and flux measurements over a permafrost black spruce forest in interior Alaska [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract B21F-0328, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5 - 9, 2011, San Francisco, CA.
A measurement site of energy, water, and carbon fluxes was established in a black spruce forest at the center of a flat basin of Poker Flat Research Range (PFRR), University of Alaska Fairbanks (UAF), located in Interior Alaska, as a key observation site of JAMSTEC-IARC Collaboration Study (JICS). This forest is characterized by an open canopy structure of a black spruce stand with its floor covered by vegetation such as sphagnum moss, tussock sedges, shrubs, and herbs, which is typical in Interior Alaska associated with the presence of permafrost. To obtain reliable flux data for a long period with minimum data loss, an improved closed-path CO2/H2O gas analyzer LI-7200 (LI-COR) was used. In addition, to consider the effect of the angle of attack dependent errors of ultrasonic anemometer on eddy fluxes, a WindMaster Pro ultrasonic anemometer (Gill) was employed. Measurements started in October 2010. Comparing the fluxes measured on the tower (11 m) and forest floor (1.85 m), the ratio of the CO2 flux of the overstory black spruce to the total CO2 flux was almost 1 until the understory plants emerged, and gradually decreased as the understory plants grew. On the other hand, most of the evapotranspiration was explained by the forest floor, and the contribution of the overstory black spruce trees was negligibly small. The decoupling coefficient of the whole canopy was almost less than 0.1, and typically less than 0.05, indicating that the leaf and surface of this black spruce forest were strongly coupled to the prevailing weather. In fact, most of evapotranspiration was explained by the adiabatic term with saturation deficit and wind speed, and the contribution of the available energy was less important. This low decoupling coefficient may be due to the high surface roughness with the open canopy structure of the black spruce forest.
URL: http://www.agu.org/cgi-bin/SFgate/SFgate?language=English&verbose=0&listenv=tabl ...
13015175 Rogers, M. (University of Alaska Anchorage, Environment and Natural Resources Institute, Anchorage, AK); Welker, J. M. and Toohey, R. The Alaska water isotope network (AKWIN); precipitation, lake, river and stream dynamics [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract B21H-0363, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5 - 9, 2011, San Francisco, CA.
The hydrologic cycle is central to the structure and function of northern landscapes. The movement of water creates interactions between terrestrial, aquatic, marine and atmospheric processes. Understanding the processes and the spatial patterns that govern the isotopic (d18O & dD) characteristics of the hydrologic cycle is especially important today as: a) modern climate/weather-isotope relations allow for more accurate interpretation of climate proxies and the calibration of atmospheric models, b) water isotopes facilitate understanding the role of storm tracks in regulating precipitation isotopic variability, c) water isotopes allow for estimates of glacial melt water inputs into aquatic systems, d) water isotopes allow for quantification of surface and groundwater interactions, e) water isotopes allow for quantification of permafrost meltwater use by plant communities, f) water isotopes aid in migratory bird forensics, g) water isotopes are critical to estimating field metabolic rates, h) water isotopes allow for crop and diet forensics and i) water isotopes can provide insight into evaporation and transpiration processes. As part of a new NSF MRI project at the Environment and Natural Resources Institute (ENRI) at the University of Alaska Anchorage and as an extension of the US Network for Isotopes in Precipitation (USNIP); we are forming AKWIN. The network will utilize long-term weekly sampling at Denali National Park and Caribou Poker Creek Watershed (USNIP sites-1989 to present), regular sampling across Alaska involving land management agencies (USGS, NPS, USFWS, EPA), educators, volunteers and citizen scientists, UA extended campuses, individual research projects, opportunistic sampling and published data to construct isoscapes and time series databases and information packages. We will be using a suite of spatial and temporal analysis methods to characterize water isotopes across Alaska and will provide web portals for data products. Our network is designed to interface with the existing USNIP and will provide a research and data platform that will assist with answering the core questions of NEON addressing climate and land use change in Alaska, in the north and across the US.
URL: http://www.agu.org/cgi-bin/SFgate/SFgate?language=English&verbose=0&listenv=tabl ...
13017550 Cordua, William S. (University of Wisconsin-River Falls, Department of Plant and Earth Science, Wisconsin, WI). Geological destinies of nations; a multidisciplinary course for upper level undergraduates [abstr.]: in Geological Society of America, 2011 annual meeting, Abstracts with Programs - Geological Society of America, 43(5), p. 253, October 2011. Meeting: Geological Society of America, 2011 annual meeting, Oct. 9-12, 2011, Minneapolis, MN.
Geology 350-Geological Destinies of Nations was developed and first offered at the University of Wisconsin-River Falls in Spring, 2010 in order to bring geology to a new student audience--the junior and senior non-major. It combines geology with history, political science, geography and economics to offer a view of the effects of the epic quest for non-renewable resources on national development and interactions. Although the course is taught primarily to juniors and seniors, it has no prerequisites. It has been approved to fulfill both a multicultural and global perspective requirement in the university's general education program. It begins with a section on personal resource use. It then presents an overview of plate tectonics, ore-forming processes and fossils fuels. Next it looks at many examples of resource use and conflicts from past and present. This includes metallic and non-metallic resources, fossil fuels, soils and water. It concludes with predictions for the future, including possible sea floor, Antarctic and space-based resources. The course has been well received by students and may be looked at as an additional way to reach non-geologists with pertinent information on the impact of geology on society.
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13015630 Jepsen, Steven M. (U. S. Geological Survey); Koch, Joshua C.; Rose, Joshua R.; Voss, Clifford I. and Walvoord, Michelle A. Thermal and hydrological observations near Twelvemile Lake in discontinuous permafrost, Yukon Flats, interior Alaska, September 2010-August 2011: Open-File Report - U. S. Geological Survey, Rep. No. OF 2012-1121, 25 p., illus. incl. 3 tables, sketch maps, 5 ref., 2012. Accessed on Aug. 3, 2012; includes appendices.
A series of ground-based observations were made between September 2010 and August 2011 near Twelvemile Lake, 19 kilometers southwest of Fort Yukon, Alaska, for use in ongoing hydrological analyses of watersheds in this region of discontinuous permafrost. Measurements include depth to ground ice, depth to water table, soil texture, soil moisture, soil temperature, and water pressure above the permafrost table. In the drained basin of subsiding Twelvemile Lake, we generally find an absence of newly formed permafrost and an undetectable slope of the water table; however, a sloping water table was observed in the low-lying channels extending into and away from the lake watershed. Datasets for these observations are summarized in this report and can be accessed by clicking on the links in each section or from the Downloads folder of the report Web page.
13015763 Huntley, David H. (Geological Survey of Canada, Vancouver, BC, Canada); Hickin, Adrian S. and Ferri, Filippo. Provisional surficial geology, glacial history and paleogeographic reconstructions of the Toad River (NTS 094N) and Maxhamish Lake map areas (NTS 094O), British Columbia: in Oil and gas geoscience report 2011 (British Columbia Ministry of Energy and Mines, Geoscience and Natural Gas Development Branch), Oil and Gas Geoscience Reports, Rep. No. 2011, p. 37-56, illus., 2 p. ref., 2011. WWW.
The Geological Survey of Canada (GSC) and British Columbia Ministry of Energy and Mines (BC MEM) are collaborating to provide new insight into surficial and applied geology of northeastern British Columbia as part of the Geo-mapping for Energy and Minerals (GEM-Energy) Program Yukon Basins Project. Remote predictive digital terrain mapping and field-based reconnaissance studies are leading to a better understanding of the regional distribution of surficial deposits, permafrost, landslides and other geomorphic processes in the Toad River (NTS 094N) and Maxhamish Lake (NTS 094O) map areas. This work is improving our knowledge of the limits of glaciation, the range of subglacial processes, the patterns of ice flow, and the history of ice retreat and glacial lake formation during a dynamic period of climate change and geomorphic adjustment in the region. From an applied perspective, our work aims to encourage new investment in northern Canada by reducing the future risks for exploration, sustainable development and management of energy and mineral resources.
URL: http://www.empr.gov.bc.ca/Mining/Geoscience/PublicationsCatalogue/OilGas/OGRepor ...
13015772 Johnson, Elizabeth (British Columbia Ministry of Energy, Mines and Petroleum Resources, Victoria, BC, Canada). Conceptual water model for the Horn River basin, northeast British Columbia (parts of NTS 094I, J, O, P): in Oil and gas geoscience report 2010 (British Columbia Ministry of Energy, Mines and Petroleum Resources, Resource Development and Geoscience Branch), Oil and Gas Geoscience Reports, Rep. No. 2010, p. 99-121, illus. incl. 5 tables, 3 p. ref., 2010. WWW.
Work was undertaken to develop a conceptual water model for the Horn River Basin (HRB). Water models are needed for resource management because of a rapidly growing water demand associated with shale gas development in northeast British Columbia. Lumped-parameter models are easier to generate, but for the scale of watersheds in the HRB, distributed-parameter models are more appropriate. A representative distributed-parameter model already exists for the Liard Basin. Modeling the spatial distribution and interrelationship between evapotranspiration, permafrost and muskeg is challenging in this relatively flat-lying region of forests, fens, bogs, numerous small and shallow lakes and discontinuous permafrost. Groundwater represents the mechanism by which peatlands retain water, lakes and uplands exchange water, and streamwater quality and quantity is maintained. Information gaps were also identified.
URL: http://www.empr.gov.bc.ca/Mining/Geoscience/PublicationsCatalogue/OilGas/OGRepor ...
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