Permafrost Monthly Alerts (PMAs)

13086814 Pokrovsky, O. S. (University of Toulouse, Géosciences Environment Toulouse, Toulouse, France); Reynolds, B. C.; Prokushkin, A. S.; Schott, J. and Viers, J. Silicon isotope variations in central Siberian rivers during basalt weathering in permafrost-dominated larch forests: Chemical Geology, 355, p. 103-116, illus. incl. 2 tables, sketch map, 80 ref., September 26, 2013.

This work is devoted to the characterization of natural mechanisms of silicon isotope fractionation within Siberian watersheds and predicting the climate warming effect on Si fluxes from the land to the Arctic Ocean. To unravel the different sources of silica generated by basalt weathering in Central Siberia under permafrost and larch deciduous forest conditions, we measured the Si isotopic composition of large and small rivers, surface flow, interstitial soil solutions, plant litter and soils. The average annual discharge-weighted d³⁰Si values of the second largest tributary of the Yenissei River, Nyzhnaya Tunguska and its main northern tributary (Kochechum) are equal to 1.08±0.10 ppm and 1.67±0.15 ppm, respectively, while their average annual Si concentrations are very similar (3.46 and 3.50 mg/L, respectively). During summer baseflow, the dissolved Si isotope composition of both large rivers and a small stream ranges between 1.5 and 2.5 ppm. This is much heavier compared to the source basaltic rocks but similar to the fresh litter of Larix gmelinii, the dominating tree species in this region. It could be consistent with litter degradation in the uppermost soil horizons being the dominant source of solutes annually exported by Central Siberian rivers. During spring flood, accounting for 60-80% of annual Si flux, the d³⁰Si of the large rivers' dissolved load decreases by 1-1.5 ppm, thus approaching the value of the bedrock and the silicate suspended matter of the rivers (RSM). This may reflect the dissolution of the silicate suspended load at high water/mineral ratio. The winter d³⁰Si values of the large river dissolved load range between 1.0 and 2.5 ppm. During this period, contributing to ≤&eq;10% of the annual Si chemical flux, the interaction between bedrock (porous tuffs) and deep ground waters occurs at a very high solid/solution ratio, leading to the precipitation of isotopically light secondary minerals and enrichment of ³⁰Si in the fluids that feed the river through the unfrozen flowpaths. Results of this study imply that more than a half of the silica transported by Siberian rivers may transit through the biogenic pool and that, like in other stable basaltic regions, bedrock-water interactions account for a lesser fraction of the silica flux. As a result of projected future climate warming and weathering increases in boreal regions, the d³⁰Si isotopic composition of large Siberian rivers is likely to shift towards less positive values. Abstract Copyright (2013) Elsevier, B.V.

DOI: 10.1016/j.chemgeo.2013.07.016

13084776 Arzhanov, M. M. (Russian Academy of Sciences, Obukhov Institute of Atmospheric Physics, Moscow, Russian Federation) and Mokhov, I. I. Temperature trends in the permafrost of the Northern Hemisphere; comparison of model calculations with observations: Doklady Earth Sciences, 449(1), p. 319-323, illus., 15 ref., March 2013. Original Russian Text: M.M. Arzhanov, I.I. Mokhov, 2013, published in Doklady Akademii Nauk, 2013, Vol. 449, No. 1, pp. 87-92.

We present the results of analysis of numerical calculations of the thermal state of permafrost grounds at different depths using a model of heat and moisture transport in the ground developed at the Oboukhov Institute of Atmospheric Physics, Russian Academy of Sciences (IAP RAS). For high-latitude regions of Russia, the model-estimated temperature trends in grounds (around 0.3°C/10 years at a depth of 3 m) are quite consistent with empirical estimates for the past few decades. Copyright 2013 Pleiades Publishing, Ltd.

DOI: 10.1134/S1028334X1303001X

13085604 Janke, Jason R. (Metropolitan State College of Denver, Denver, CO); Williams, Mark W. and Evans, Andrew. A comparison of permafrost prediction models along a section of Trail Ridge Road, Rocky Mountain National Park, Colorado, USA: Geomorphology, 138(1), p. 111-120, illus. incl. 5 tables, sketch maps, 58 ref., February 2012.

The distribution of mountain permafrost along Trail Ridge Road (TRR) in Rocky Mountain National Park, Colorado, was modeled using 'frost numbers' and a 'temperature of permafrost model' (TTOP) in order to assess the accuracy of prediction models. The TTOP model is based on regional observations of air temperature and heat transfer functions involving vegetation, soil, and snow; whereas the frost number model is based on site-specific ratios of ground temperature measurements of frozen and thawed degree-days. Thirty HOBO(C) temperature data loggers were installed near the surface as well as at depth (30 to 85 cm). From mid-July 2008 to 2010, the mean annual soil temperature (MAST) for all surface sites was -1.5°C. Frost numbers averaged 0.56; TTOP averaged -1.8°C. The MAST was colder on western-facing slopes at high elevations. Surface and deeper probes had similar MASTs; however, deeper probes had less daily and seasonal variation. Another model developed at the regional scale based on proxy indicators of permafrost (rock glaciers and land cover) classified 5.1 km² of permafrost within the study area, whereas co-kriging interpolations of frost numbers and TTOP data indicated 2.0 km² and 4.6 km² of permafrost, respectively. Only 0.8 km² were common among all three models. Three boreholes drilled within 2 m of TRR indicate that permafrost does not exist at these locations despite each borehole being classified as containing permafrost by at least one model. Addressing model uncertainty is important because nutrients stored within frozen or frost-affected soils can be released and impact alpine water bodies. The uncertainty also exposes two fundamental problems: empirical models designed for high latitudes are not necessarily applicable to mountain permafrost, and the presence of mountain permafrost in the alpine tundra of the Colorado Front Range has not been validated. Abstract Copyright (2012) Elsevier, B.V.

DOI: 10.1016/j.geomorph.2011.08.029

13084768 Lobkovskii, L. I. (Russian Academy of Sciences, Shirshov Institute of Oceanology, Moscow, Russian Federation); Nikiforov, S. L.; Shakhova, N. E.; Semiletov, I. P.; Libina, N. V.; Anan'ev, R. A. and Dmitrevskii, N. N. Mechanisms responsible for degradation of submarine permafrost on the eastern Arctic shelf of Russia: Doklady Earth Sciences, 449(1), p. 280-283, illus. incl. sketch map, 12 ref., March 2013.

DOI: 10.1134/S1028334X13030124

13086241 Bodin, Xavier (Université de Savoie, EDYTEM, Le Bourget du Lac, France). Present status and development of rock glacier complexes in south-faced valleys (45°N, French Alps): in Environmental geography; from field observations to mapping, from processes to risk management; a tribute to Prof. Monique Fort (University of Paris-Diderot) (Arnaud-Fassetta, Gilles, prefacer; et al.), Geografia Fisica e Dinamica Quaternaria (Testo Stampato), 36(1), p. 27-38, illus. incl. sketch maps, 36 ref., 2013.

The landscapes of the Vallon de la Route and Vallon de Pradieu (France) display typical geomorphological features of the Southern French Alps, with very few or no glaciers but a wide periglacial belt that extends from 2500 to 3100 m a.s.l. These valleys are unusual in that they contain several generations of rock glaciers that, from their rooting zone to their front, have developed in a topoclimatic setting characterised by high mean insolation (southerly aspect) and relatively low altitude. In this work, we determined the present status of these landforms, and more precisely the characteristics of the icy layers within the rock glaciers, via electrical soundings and thermal measurements, which we then combined with field observations. The permafrost zones in both areas are highly fragmented, whereas ground-ice can be present in landforms previously assumed as relict on the basis of their geomorphological characteristics alone. We used an empirical relationship between rock glacier flow velocity and terrain slope to estimate the time needed for both rock glacier assemblages to reach their present size. Our analyses therefore provide at the same time a broad relative chronological framework of the landscape setting up together with an overview of the spatial patterns of ice-rich permafrost features. It also suggests a number of hypotheses for the development of these landforms; however, further work involving more accurate dating methods is required to constrain these hypotheses.

DOI: 10.4461/GFDQ.2013.36.2

13088292 Onaca, Alexandru (West University of Timisoara, Department of Geography, Timisoara, Romania); Urdea, Petru; Ardelean, Adrian and Serban, Raul. Assessment of internal structure of periglacial landforms from Southern Carpathians (Romania) using DC resistivity tomography: Carpathian Journal of Earth and Environmental Sciences, 8(2), p. 113-122, illus. incl. sketch map, 34 ref., 2013.

This study presents the use of DC resistivity tomography for the detection of periglacial landforms structure from Southern Carpathians. Direct-current (DC) resistivity tomography has been applied to six periglacial landforms from the alpine domain of Southern Carpathians for the first time in Romania. Due to important differences in the electrical resistivity of the subsurface materials it was possible to determine the internal structure and the thickness of the periglacial landforms. A rock glacier (Rosiile) from Parang Mountains, two patterned ground sites from Tarcu Mountains, as well as two solifluction phenomena and a scree slope from the central part of Fagaras Mountains were investigated by means of 2D resistivity imaging. The electrical resistivity measurements indicated the presence of sediments cemented by ice and ice lenses in Rosiile rock glacier. The large depth of the active layer and the low content of ice suggest that the permafrost exists in marginal condition and is not in equilibrium with the present climate. A chaotic structural pattern characteristic for the near-surface layer of the patterned ground was interpreted as the result of actual frost heaving. The solifluction lobe and terraces were analyzed comparatively displaying a relatively thin mixture of unconsolidated unfrozen sediments affected by seasonally frozen ground. One scree slope from Vaiuga glacial cirque was investigated in a similar manner revealing a thick mantle of unconsolidated stratified periglacial deposits

13086251 Ravanel, Ludovic (Université de Savoie, EDYTEM, Le Bourget du Lac, France) and Deline, Philip. A network of observers in the Mont Blanc Massif to study rockfall from high Alpine rockwalls: in Environmental geography; from field observations to mapping, from processes to risk management; a tribute to Prof. Monique Fort (University of Paris-Diderot) (Arnaud-Fassetta, Gilles, prefacer; et al.), Geografia Fisica e Dinamica Quaternaria (Testo Stampato), 36(1), p. 151-158, illus. incl. sketch map, 34 ref., 2013.

The study of rockfall (volume >100 m³) in high mountain is essential to understand landscape evolution and to evaluate natural hazards. The number of rockfalls is presently rising in the Alps, while vulnerability is increasing at high elevation and in valleys. Due to the lack of systematic observations, frequency and volume of rockfalls, as well as their triggering factors remain poorly understood. Until today, most of the studies on rockfall carried out in high Alpine rockwalls were indeed devoted to individual events, while systematic surveys are needed to clarify the role of regional factors such as permafrost degradation. Here we present the network of observers (guides, hut keepers, mountaineers) which sets aside the documentation of all the rockfall events that occur in the central part of the Mont-Blanc massif. Operational since 2007, this network allowed identifying and documenting 251 rockfalls between 2007 and 2011. Checked and completed each year by extensive field work, data from the network are then analysed through a Geographic Information System to statistically characterise these rockfalls. The results of the first five years of survey indicate that permafrost degradation is the main rockfall triggering factor.

DOI: 10.4461/GFDQ.2013.36.12

13085596 Jones, Benjamin M. (U. S. Geological Survey, Anchorage, AK); Grosse, Guido; Hinkel, Kenneth M.; Arp, Christopher D.; Walker, Shane; Beck, Richard A. and Galloway, John P. Assessment of pingo distribution and morphometry using an IfSAR derived digital surface model, western Arctic Coastal Plain, northern Alaska: Geomorphology, 138(1), p. 1-14, illus. incl. 2 tables, sketch maps, 59 ref., February 2012.

Pingos are circular to elongate ice-cored mounds that form by injection and freezing of pressurized water in near-surface permafrost. Here we use a digital surface model (DSM) derived from an airborne Interferometric Synthetic Aperture Radar (IfSAR) system to assess the distribution and morphometry of pingos within a 40,000 km² area on the western Arctic Coastal Plain of northern Alaska. We have identified 1247 pingo forms in the study region, ranging in height from 2 to 21 m, with a mean height of 4.6 m. Pingos in this region are of hydrostatic origin, with 98% located within 995 drained lake basins, most of which are underlain by thick eolian sand deposits. The highest pingo density (0.18 km^-2) occurs where streams have reworked these deposits. Morphometric analyses indicate that most pingos are small to medium in size (<200 m diameter), gently to moderately sloping (<30°), circular to slightly elongate (mean circularity index of 0.88), and of relatively low height (2 to 5 m). However, 57 pingos stand higher than 10 m, 26 have a maximum slope greater than 30°, and 42 are larger than 200 m in diameter. Comparison with a legacy pingo dataset based on 1950s stereo-pair photography indicates that 66 may have partially or completely collapsed over the last half-century. However, we mapped over 400 pingos not identified in the legacy dataset, and identified only three higher than 2 m to have formed between ca. 1955 and ca. 2005, indicating that caution should be taken when comparing contemporary and legacy datasets derived by different techniques. This comprehensive database of pingo location and morphometry based on an IfSAR DSM may prove useful for land and resource managers as well as aid in the identification of pingo-like features on Mars. Abstract Copyright (2012) Elsevier, B.V.

DOI: 10.1016/j.geomorph.2011.08.007

13084892 Carvajal-Ortiz, Humberto (Indiana University, Department of Geological Sciences, Bloomington, IN) and Pratt, Lisa M. Influences of salinity and temperature on the stable isotopic composition of methane and hydrogen sulfide trapped in pressure vessel hydrates: Geochimica et Cosmochimica Acta, 118, p. 72-84, illus. incl. 1 table, 69 ref., October 1, 2013.

The stable isotopic composition of carbon (d¹³C_CH4) and hydrogen (d²H_CH4) in methane and sulfur (d³⁴S_H2S) in hydrogen sulfide can be used to infer the source of volatile molecules encaged in gas hydrates. Differentiation of methane and hydrogen sulfide from microbial and thermal origins provides valuable information for hydrocarbon exploration and for climatic models assessing the role of gas hydrates during climate change. In astrobiological studies, d¹³C_CH4, d²H_CH4, and d³⁴S_H2S values will be critical in deciphering the origin of methane and hydrogen sulfide molecules if gas hydrates are detected within the cryosphere of Mars or associated with ice-covered oceans on Europa or Enceladus. It is challenging, however, to apply isotope systematics to hydrate-forming systems due to complex influences on nucleation and decomposition under varying conditions of salinity, pressure, and temperature. Few laboratory studies have evaluated the effect of hydrate formation, on isotopic composition of free, encaged, and dissolved gas molecules. In this study, pressure-vessel hydrates were nucleated under conditions inferred for marine continental margins and terrestrial permafrost: low temperatures, moderate pressures, saturation of methane and/or hydrogen sulfide saturation, and varying concentration of sodium chloride (NaCl) and magnesium sulfate heptahydrate (MgSO₄.7H₂O). Methane experiments show less than 1 ppm differences in values of d¹³C_CH4 between free and encaged molecules and up to 6.5 ppm variations in values of d²H_CH4 between free and encaged molecules. In hydrogen-sulfide hydrates, d³⁴S_H2S values show less than 4 ppm differences between free and encaged molecules, but up to 14 ppm differences between dissolved and free molecules and between dissolved and encaged molecules. Results presented here indicate that shifts found for free and encaged values of d¹³C_CH4 and d²H_CH4 are small and do not complicate interpretation of gas provenance. Conversely, in hydrate systems containing H₂S molecules values of d³⁴S_H2S need to be interpreted with caution. Although isotopic fractionation between free- and encaged-sulfur molecules is mild during hydrate formation, values of dissolved d³⁴S_H2S are substantially fractionated and necessitate careful examination of sulfur isotopic values. Because dissolved H₂S could potentially be recycled by oxidation and reduction processes during hydrate formation events, use of d³⁴S_H2S values might complicate assessment of biosignatures for other planetary bodies. Abstract Copyright (2013) Elsevier, B.V.

DOI: 10.1016/j.gca.2013.05.013

13088911 Svensson, Per Daniel (Swedish Nuclear Fuel and Waste Management Company, Oskarshamn, Sweden) and Hansen, Staffan. Combined salt and temperature impact on montmorillonite hydration: Clays and Clay Minerals, 61(4), p. 328-341, illus. incl. 1 table, 39 ref., October 2013.

Bentonite is to be used as a sealing material for long-term storage of radioactive waste. During permafrost periods the buffer may freeze, causing the following: montmorillonite dehydration, ice formation, and pressure build-up that may fracture the surrounding rock. No previous study has been done on freezing of bentonite in saline water. Using small and wide angle X-ray scattering, the present study aimed to increase understanding of the combined impact of salt and temperature on the hydration (swelling) of Wyoming montmorillonite. The basal spacing of the Na-montmorillonite was very dependent on the water content, while this was not the case for the Ca-montmorillonite (after reaching 19 Å). The basal spacing of the free-swelling Na-montmorillonite (34-280 Å) was estimated successfully using simple calculations. During freezing of Na-montmorillonite in NaCl solution, both ice and hydrohalite formed (at -50 and -100°C). At starting concentrations >&eq;1.5 M the basal spacing was not affected by freezing. During freezing of Ca-montmorillonite in CaCl₂ solution, ice formed; antarcticite formed only sporadically. The basal spacing of the Ca-montmorillonite at high NaCl concentrations (>1 M) was greater at -50 and -100°C (18 Å) than at 20°C (16 Å). The opposite was observed at low concentrations. This change was attributed to small amounts of salts introduced into the montmorillonite interlayer, hence changing the interlayer water properties. The montmorillonite hydration was also temperature dependent; decreasing temperature increased the hydration (as long as no ice was formed) and increasing the temperature decreased the hydration. This was attributed to the temperature impact on the entropy of the hydration reaction. This observation was also reproduced in an experiment up to 90°C. A small amount of salt in the groundwater was noted to reduce significantly the potential problem of ice formation in bentonite sealings.

DOI: 10.1346/CCMN.2013.0610412

13084383 Mahaney, William C. (Quaternary Surveys, Thornhill, ON, Canada) and Kalm, Volli. Topographic and bioclimatic controls on soil/paleosol morphogenesis in the Norra Storfjallet Mountains, Sweden: Geomorphology, 173-174, p. 43-51, illus. incl. 4 tables, sketch map, 58 ref., November 1, 2012.

Retreat of the Stabre Glacier in the Norra Storfjallet Mountains of northern Sweden led to the emplacement of a broad expanse of glaciofluvial sediment, a virtual blanket of debris interspersed with recessional and push moraines. Episodic mass wasting of the glaciofluvial, moraine and loessic deposits yielded a pedostratigraphic succession of ¹⁴C-dated sub-Boreal and sub-Atlantic Cryosols in soliflucted sediment that provide weathering data related to Neoglacial perturbations, whereas weathering within polygonal complexes yielded single profile, one event, Cryosolic Gleysols of similar age. Both provide a database of paleosol extremes controlled by topography and bioclimate. Together, the paleosols provide a database of weathering of mixed amphibolitic gneiss, trachytic lavas and granite weathering under two variable redox conditions, one (soliflucted sediment) fully or partially aerated and free draining under a subaerial atmosphere with high redox potential; the other (polygonal soil) partly reduced under the influence of an active layer of sporadic permafrost. Paleosols dated to the Early Neoglacial (~3600-4200 cal¹⁴CyrBP) have variable horizon development dependent upon landform associations, and provide maximum ages for the second oldest moraine stillstand of ice retreat into the highlands on the Arctic Circle of Sweden. The Cryosolic Gleysol yields surprisingly high extractable Fe and Al suggestive of considerable redox fluctuations over the time of morphogenesis.

DOI: 10.1016/j.geomorph.2012.05.025

13085893 Amundsen, Lasse (Norwegian University of Science and Technology, Trondheim, Norway) and Landro, Martin. Gas hydrates; Part 1, Burning ice: GEO ExPro, 9(3), p. 68-72, 2012. Accessed on Oct. 30, 2013.

URL: http://www.geoexpro.com/article/Gas_Hydrates_Part_I_Burning_Ice/69fe2a11.aspx

13086680 Zech, Roland (Brown University, Geological Sciences, Providence, RI); Zech, Michael; Markovic, Slobodan; Hambach, Ulrich and Huang, Yongsong. Humid glacials, arid interglacials; critical thoughts on pedogenesis and paleoclimate based on multi-proxy analyses of the loess-paleosol sequence Crvenka, northern Serbia: Palaeogeography, Palaeoclimatology, Palaeoecology, 387, p. 165-175, illus. incl. sketch maps, 97 ref., October 1, 2013.

Loess-paleosol sequences (LPS) provide unique terrestrial archives for past environmental and climate changes. The loess units are generally interpreted to reflect more arid conditions, whereas paleosols are thought to document more humid conditions. This paradigm may, however, deserve to be challenged in some regions, because it does not take into account past changes in dust accumulation rates. Here we present a multi-proxy sedimentological and geochemical characterization of the LPS Crvenka, Serbia, spanning the last ~140 ka. Commonly used analyses, such as magnetic susceptibility, organic carbon content, grain size and weathering indices, allow the quantification of the intensity of pedogenesis. However, loess accumulation rates were much higher during glacials than during interglacials, so that it is not trivial to infer past rates of pedogenesis and related paleoclimate conditions. Novel proxies, based for example on lipid biomarkers and their isotopic composition, are not so directly affected by changes in loess accumulation rates and might provide interesting new insights. Long-chain, plant-derived n-alkanes in the LPS Crvenka suggest a minor, but non-negligible contribution of deciduous trees and shrubs (C₂₇ and C₂₉) during MIS 1, 2, 4 and 6, whereas grasses and herbs (C₃₁ and C₃₃) dominate the alkane input during MIS 3 and 5. This is in agreement with the notion that parts of southeast Europe served as refugia for deciduous trees during glacials. On the other hand, edaphic conditions on the drought-prone loess plateaus seem to have been more arid during MIS 3 and 5. Compound-specific dD analyses on the alkanes show only little changes on glacial-interglacial timescale. When compared with the isotopic enrichment of the Mediterranean Sea during the last glacial, this likely indicates a complex combination of reduced temperatures, increased rainfall, reduced evapotranspiration and more advection of North Atlantic moisture. Although disentangling these factors is difficult, interpretation in terms of humid glacials and more arid interglacials seems to be supported also by other novel lipid biomarkers, so-called GDGTs (glycerol dialkyl glycerol tetraethers). Abstract Copyright (2013) Elsevier, B.V.

DOI: 10.1016/j.palaeo.2013.07.023

13086791 Andersen, Morten B. (University of Bristol, School of Earth Sciences, Bristol, United Kingdom); Vance, D.; Keech, A. R.; Rickli, J. and Hudson, G. Estimating U fluxes in a high latitude, boreal post-glacial setting using U-series isotopes in soils and rivers: Chemical Geology, 354, p. 22-32, illus. incl. 3 tables, sketch map, 93 ref., September 16, 2013.

This study reports U-series activity ratios from river waters and six soil profiles across a soil chronosequence formed since the last glacial retreat, in Glen Feshie, Scotland. The overall aim is to examine the geochemical behaviour of the U-series nuclides in a boreal climate setting. The U-series data show that U is being both added to and leached out of the soils, to varying degrees. The U addition elevates the (²³⁴U/²³⁸U) of the bulk soils (up to 1.25), which is most pronounced in the youngest and the upper organic-rich soil horizons. The U addition appears to be linked to U adsorption, controlled by the degree of flooding by the Feshie River. The Feshie River has a high (²³⁴U/²³⁸U) ratio (~1.7), a feature shared with most high-latitude Northern Hemisphere rivers. For the soil profiles with no significant U addition, U-series nuclide modelling suggests U leaching rates on the order of 0.5-2´10^-5y^-1, a similar range to other Northern Hemisphere high-latitude areas affected by the last glaciation, e.g. Mackenzie Basin, Canada. These two observations suggest a link between weathering rates and riverine (²³⁴U/²³⁸U) for areas that have been glaciated recently. A global compilation of major rivers shows that high-latitude Northern Hemisphere rivers comprise a significant U flux to the ocean with high (²³⁴U/²³⁸U). Thus, past changes in this Northern Hemisphere high-latitude U flux may have played a major role in oceanic (²³⁴U/²³⁸U) variation over glacial-interglacial cycles. Abstract Copyright (2013) Elsevier, B.V.

DOI: 10.1016/j.chemgeo.2013.06.021

13086859 Tinker, Scott W. (University of Texas at Austin, Bureau of Economic Geology, Austin, TX); Lynch, Harry; Carpenter, Mark and Hoover, Matthew. Global energy and the role of geosciences; a North American perspective: in The impact of the geological sciences on society (Bickford, Marion E., editor), Special Paper - Geological Society of America, 501, p. 21-51, illus. incl. sketch map, 95 ref., September 2013.

The world contains abundant energy resources. The challenge is extracting and utilizing these resources affordably, in an environmentally responsible way, and in a dense enough form to be useful to humans. The link between energy, the environment, and the economy is unavoidable and involves the geosciences at its core. Carbon-based fuels such as wood, hay, and coal powered human society for millennia. Then, in the early twentieth century, petroleum in various refined forms came into use for lighting, heating, and early combustion engines. Today, fossil fuels--coal, petroleum products, and natural gas--represent an important 85% of the global energy mix, but they are not without challenges. Coal's greatest challenges are environmental: the impact of surface mining; water contamination; discharge of airborne pollutants including sulfur, nitrogen, and mercury; and the emission of CO₂. The emerging technologies of carbon capture and sequestration may offer the prospect (such as coal-fired of solving one of coal's problems; large, stationary sources of CO₂ power plants) are the most efficient targets for carbon capture. However, capturing CO₂ is expensive. Oil and, to a much lesser degree, natural gas also produce CO₂ and other emissions when combusted. Oil and natural gas require drilling, entailing the associated environmental impacts of oil-field operations; yet there remain considerable global oil and natural gas resources. The current frontiers for conventional oil and natural gas production include ultra-deep water, the Arctic, sediments deposited beneath major salt formations, and other extreme operational environments. As existing and new conventional oil and natural gas reserves decline, unconventional reservoirs--shale gas, coal bed natural gas, tight gas, shale oil, oil shale, oil sands, and perhaps eventually natural gas hydrates--will represent a growing part of the fossil-fuel mix. Nuclear energy--today fission, and tomorrow, perhaps, fusion--is very dense, has no emissions, is highly efficient, and is very affordable on a kilowatt-hour basis. Adoption of nuclear energy is limited by the high initial cost of building a power plant, public perception, issues of waste handling, the fear of proliferation, and the very real need to make reactors safe from natural and human-caused disasters. "Renewable" forms of energy--those that are generated by "renewable" motion such as wind and moving water; or "renewable" sources of heat such as geothermal and solar; or those that are grown such as biofuels--will increase as a proportion of the energy mix. These sources are currently limited in growth rate by their lower energy density and, for some, their intermittency. Intermittency--the wind does not always blow and the sun does not always shine--must be addressed by significant improvements in energy storage technologies: in chemical batteries; as pumped water or compressed air; as heat stored in molten salt, buildings, and other forms; as kinetic energy in flywheels; as electrons in advanced capacitors; or by various other technologies. But these energy storage technologies need to be made efficient, affordable, and scalable before they will be deployed broadly. Because the transition from a fossil-energy present to an alternate-energy future involves the interplay between energy, environment, economy, and policy, almost without exception all forms of energy involve the geosciences. Coal mining requires geologic understanding. Large-scale geologic carbon sequestration, which might someday make coal more environmentally friendly, will rely on a whole new discipline involving advanced subsurface characterization and monitoring. The subsurface understanding and technology required for conventional and unconventional oil and gas exploration and extraction are substantial. From the scale of nanopores to tectonic plates, the use of advanced seismic imaging, ever more-quantified field and laboratory experimentation, airborne remote sensing, and much more is required to unlock the fossil-fuel resources that remain trapped in the Earth. Nuclear energy relies on sources of uranium, plutonium, thorium, and many other mined products. And eventually, geologic repositories will be required to store the waste products of nuclear power generation. In terms of renewable energy, production of biofuels involves soil science, hydrogeology, fertilizers, weather, and climate. Harnessing geothermal energy involves the ability to characterize the subsurface geothermal resource. Generating power from tides and waves involves oceanography and analysis of coastal change. Utilizing wind depends on weather pattern studies and geomorphology for the siting of turbines, as well as the mining of copper, carbon, and other materials. Producing solar energy involves the geosciences, with the need for silicon, gallium, cadmium, copper, and other materials. As large-scale energy-storage solutions become necessary, input from the geosciences will range from characterizing the subsurface for compressed-air storage to mining rare-earth elements for chemical batteries. The involvement of geosciences in energy does not stop with subsurface understanding or the construction of a power plant. "Above-ground" environmental and policy challenges covering the full lifecycle of any form of energy are as great as the "below-ground" technical challenges. Environmental geologists, biologists, energy economists, and policymakers must come together to develop sensible policies and regulatory rules that make it possible for industry, government, academe, and nongovernmental organizations (NGOs) to work together to deliver balanced solutions.

DOI: 10.1130/2013.2501(02)

13088381 Travis, Bryan J. (Los Alamos National Laboratory, Computational Earth Science Group, Los Alamos, NM); Feldman, William C. and Maurice, Sylvestre. A mechanism for bringing ice and brines to the near surface of Mars: Journal of Geophysical Research: Planets, 118(E5), p. 877-890, illus. incl. 1 table, 82 ref., May 2013.

Recent discovery of transient ice deposits uncovered by five small craters between 40 and 55°N latitude, reinterpretation of MONS neutron data that indicate the wide-spread presence of ice within 1 m of the surface at midlatitudes (down to 30°N) of Mars, and evidence of recent periglacial activity within 10°N of the equator, all suggest ice may be or recently was present at latitudes where it is not expected and at unexplained abundance. As ice may be unstable under present Mars climatic conditions, a mechanism may be needed to explain the presence of ice in the near surface at these latitudes. Water release history, chemical composition, and heat fluxes are variable over the surface of Mars, and there could be more than one mechanism responsible for near-surface ice. The purpose of this study is to show that hydrothermal circulation of brines in the subsurface of Mars is a possible mechanism that can deposit ice and brine, close to, or even at, the surface of Mars. Furthermore, the action of brine convection can be related to some of the surface features associated with subsurface water during previous or even present epochs, such as polygonal ground and sorted stone circles. Abstract Copyright (2013). American Geophysical Union. All Rights Reserved.

DOI: 10.1002/jgre.20074

13084816 Becher, Marina (Umea University, Department of Ecology and Environmental Sciences, Umea, Sweden); Olid, Carolina and Klaminder, Jonatan. Buried soil organic inclusions in non-sorted circles fields in northern Sweden; age and paleoclimatic context: Journal of Geophysical Research: Biogeosciences, 118(G1), p. 104-111, illus. incl. 1 table, sketch map, 40 ref., March 2013.

Although burial of surface organic soil horizons into deeper mineral soil layers helps drive the long-term buildup of carbon in arctic soils, when and why buried horizons formed as result of cryoturbation in northern Sweden remain unclear. In this study, we used ¹⁴C and ²¹⁰Pb dating to assess when organic matter was buried within non-sorted circles fields near Abisko in northern Sweden. In addition, we used aerial photos from 1959 and 2008 to detect eventual trends in cryogenic activities during this period. We found that organic matter from former organic horizons (stratigraphically intact or partly fragmented) corresponds to three major periods: 0-100 A.D., 900-1250 A.D., and 1650-1950 A.D. The latter two periods were indicated by several dated samples, while the extent of the oldest period is more uncertainty (indicated by only one sample). The aerial photos suggest a net overgrowth by shrub vegetation of previously exposed mineral soil surfaces since 1959. This overgrowth trend was seen in most of the studied fields (92 out of 137 analyzed fields), indicating that the cryogenic activity has mainly decreased in studied non-sorted circles fields since the 1950s. This latter interpretation is also supported by the absence of buried organic layers formed during the last decades. We suggest that the organic matter was buried during the transition from longer cold periods to warmer conditions. We believe these climatic shifts could have triggered regional scale burial of soil organic matter and thus affected how these soils sequestered carbon. Abstract Copyright (2013), . American Geophysical Union. All Rights Reserved.

DOI: 10.1002/jgrg.20016

13088378 Hirmas, Daniel R. (University of Kansas, Department of Geography, Lawrence, KS). A simple method for removing artifacts from moist fine-textured soil faces: Soil Science Society of America Journal, 77(2), p. 591-593, illus., 14 ref., March 2013.

Smearing of soil faces during preparation of soil excavation walls for detailed imaging, analyses, and description tends to be a problem in moist, fine-texture soils. The artifacts left behind on faces of soil in these conditions is also a problem when preparing monolith surfaces for preservation and when working with significantly moist soil aggregates meant to be kept intact. This paper describes a simple method of using 1,1-difluoroethane (DFE) to flash freeze the surface of significantly moist soils and peel the resulting frozen layers away to expose a relatively smooth, intact soil face. The method works well when compared to traditional methods of using hand tools such as soil knives or trowels. When handled carefully, exposure risks to DFE are minimal. There are, however, potential dangers associated with DFE. These should be made known to users of the method and precautions taken as appropriate.

DOI: 10.2136/sssaj2012.0418n

13088376 Knadel, Maria (Arhus University, Department of Agroecology, Tjele, Denmark); Viscarra Rossel, Raphael A.; Deng, Fan; Thomsen, Anton and Greve, Mogens Humlekrog. Visible-near infrared spectra as a proxy for topsoil texture and glacial boundaries: Soil Science Society of America Journal, 77(2), p. 568-579, illus. incl. 4 tables, geol. sketch map, 73 ref., March 2013.

Spectroscopy is widely recognized as an effective tool for the analysis of soil properties. The majority of studies on the use of spectroscopy have focused on spectroscopic modeling to predict these properties. Information derived from spectra, however, can also be used to describe the soil type and how it varies across landscapes because spectra contain information on the fundamental composition of soil: its organic matter, and Fe oxide, clay and carbonate minerals, as well as on water and particle size. In this study, we used visible-near infrared (vis-NIR) spectra to describe topsoils across Denmark. We used 693 agricultural topsoil samples (0-20 cm) from the Danish soil collection and measured them with a vis-NIR spectrometer covering the spectral range between 350 and 2500 nm. We interpreted the soils by deriving the organic and texture information from the spectra. To summarize the information content in the spectra, we performed a principal component analysis (PCA). The first three principal components explained 94% of the variability in the spectra. The scores from the PCA were clustered using k-means to help with interpretation. Soil properties of the clusters were described using the mean spectrum of each class. We mapped the scores of the first three principal components and the clustered scores using ordinary kriging. Both the score maps and the spectroscopic k-means cluster map clearly reflected the general pattern of soil variability in Denmark, including the soil texture classes and the glacial origin of the landscape.

DOI: 10.2136/sssaj2012.0093

13088370 Saey, Timothy (Ghent University, Department of Soil Management, Gent, Belgium); de Smedt, Philippe; de Clercq, Wim; Meerschman, Eef; Monirul Islam, Mohammad and van Meirvenne, Marc. Identifying soil patterns at different spatial scales with a multi-receiver EMI sensor: Soil Science Society of America Journal, 77(2), p. 382-390, illus. incl. 1 table, sketch map, 37 ref., March 2013.

Multi-receiver electromagnetic induction (EMI) sensors are increasingly being used to map soil spatial variability by measuring the apparent electrical conductivity (ECa) of multiple soil volumes. We present a procedure to process such measurements to identify both large-scale soil variability patterns and small-scale features such as archaeological traces. A 2.6-ha arable field in Belgium was selected since aerial surveys indicated the presence of fine archaeological traces being masked partly by what appeared to be a trend in the soil composition. A survey with a DUALEM-21S EMI sensor provided four co-located ECa measurements of varying soil volumes, which were combined in a two-step inversion procedure. Our procedure enhanced the distinction between the archaeological traces and probable ice-wedge casts, with a small lateral and vertical extent, and the large-scale trend of natural soil variability, identified as the varying depth to the interface between two contrasting soil layers.

DOI: 10.2136/sssaj2012.0276

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13086601 Gusev, Yeugeniy M. (Russian Academy of Sciences, Institute of Water Problems, Moscow, Russian Federation) and Nasonova, Olga N. Modelling snowpack formation processes and meltwater runoff using the LSM SWAP under permafrost and highland conditions: in Cold and mountain region hydrological systems under climate change; towards improved projections (Gelfan, Alexander, editor; et al.), IAHS-AISH Publication, 360, p. 93-98, illus. incl. sketch map, 14 ref., 2013. Meeting: IAHS-IAPSO-IASPEI assembly, symposium H02 on Cold and mountain region hydrological systems under climate change; towards improved projections, July 22-26, 2013, Gothenburg, Sweden.

An ability of a physically-based land surface model SWAP, which describes heat and water exchange processes in a soil-vegetation-(snow cover)-atmosphere system, to reproduce snow formation processes and meltwater runoff at small watersheds under permafrost and highland conditions is investigated. Model simulations were performed for a 10-year period (1969-1978) using observations from the Kolyma Water Balance Station (KWBS), located within the permafrost zone of the Kontaktovyi Creek basin (the upper course of the Kolyma River, Russia). The model was validated against available observations of snow depth; soil thawing/freezing depth; soil and snow surface temperatures; snow evaporation; runoff from different river basins located within the KWBS. The validation results demonstrated the ability of the SWAP model to reproduce heat and water exchange processes under permafrost and highland conditions quite reasonable.

13086602 Lebedeva, Lyudmila (Nansen Environmental and Remote Sensing Centre, St. Petersburg, Russian Federation) and Semenova, Olga. Coupled modelling of soil thaw/freeze dynamics and runoff generation in permafrost landscapes, Upper Kolyma, Russia: in Cold and mountain region hydrological systems under climate change; towards improved projections (Gelfan, Alexander, editor; et al.), IAHS-AISH Publication, 360, p. 118-124, illus. incl. 2 tables, sketch map, 31 ref., 2013. Meeting: IAHS-IAPSO-IASPEI assembly, symposium H02 on Cold and mountain region hydrological systems under climate change; towards improved projections, July 22-26, 2013, Gothenburg, Sweden.

The distributed process-based runoff formation hydrograph model was applied and tested against soil thaw/freeze depth and runoff data in several permafrost landscapes of the Kolyma Water Balance Station (KWBS). The parameterization describing different permafrost conditions was elaborated. Soil thaw/freeze depths were simulated for three sites comprising rocky talus, mountainous tundra and larch forest landscapes. The runoff model was applied and calibrated for three plot-scale homogenous watersheds related to certain landscapes and one larger Kontaktovy Creek basin enclosing the mentioned land surface types (21.2 km₂). The hydrograph model proved its capability to simulate both surface and subsurface processes of runoff formation in different permafrost landscapes.

13086600 Quinton, William L. (Wilfrid Laurier University, Centre for Cold Regions and Water Science, Waterloo, ON, Canada) and Baltzer, Jennifer L. Changing surface water systems in the discontinuous permafrost zone; implications for streamflow: in Cold and mountain region hydrological systems under climate change; towards improved projections (Gelfan, Alexander, editor; et al.), IAHS-AISH Publication, 360, p. 85-92, illus. incl. sketch map, 20 ref., 2013. Meeting: IAHS-IAPSO-IASPEI assembly, symposium H02 on Cold and mountain region hydrological systems under climate change; towards improved projections, July 22-26, 2013, Gothenburg, Sweden.

This study was conducted in the wetland-dominated, southern margin of continental permafrost at Scotty Creek, NWT, Canada over the period 2001-2010. In this region permafrost is discontinuous and occurs predominately below tree-covered peat plateaus. The southern margin of continental permafrost is experiencing unprecedented rates of permafrost thaw, yet the effect of this thaw and the resulting ecosystem changes on northern water resources is poorly understood. A distinction between primary and secondary runoff pathways that supply basin drainage networks was identified and incorporated into a new conceptual model that describes the flow and storage of water in the wetland-dominated terrains that dominate the southern margin of permafrost. The objectives of this study were to: (a) estimate primary runoff from the plateaus using the Cold Regions Hydrological Model and relate to basin runoff; and (b) evaluate the impact of changing primary runoff on basin discharge. A strong, positive correlation between primary runoff from plateaus and basin discharge was demonstrated, indicating that with the representation of other flow and storage processes, such as secondary runoff and the routing of water through connected bogs and channel fens, hydrograph simulation for basins with thawing permafrost plateaus is attainable.

13085841 Singh, Shiv Mohan (National Centre for Antarctic and Ocean Research, Goa, India); Sharma, Jagdev; Gawas-Sakhalkar, Puja; Upadhyay, Ajay K.; Naik, Simantini; Bande, Dnyanesh and Ravindra, Rasik. Chemical and bacteriological analysis of soil from the middle and late Weichselian from western Spitsbergen, Arctic: in The environment and chronology of the earliest occupation of north-west Europe; current knowledge, problems and new research directions (MacDonald, Katharine, editor; et al.), Quaternary International, 271, p. 98-105, illus. incl. sketch map, 28 ref., August 31, 2012. Meeting: International conference on the Enivronment and chronology of the earliest occupation of north-west Europe, 2009, Leiden, Netherlands.

This paper discusses temporal variability in the biogeochemical properties of the deeper permafrost soils of Western Spitsbergen, Arctic, that dates back up to the Middle Weichselian period (44.8ka BP). Results indicate that during the mid of the last interstadial (»37ka BP) the chemical and biological properties of the soils were different from the stadial period that followed. Trace element concentration during the period remained low. Electrical conductivity along with K, Mg, Na, SO₄^-2, Cl^- and HCO₃^- content of the soils during this period was high. Mineralizable nitrogen, organic carbon, biomass nitrogen and total bacterial counts were also high. These observations concurrently lead to a conclusion that the soils of Western Spitsbergen during the interstadial period were under marine influence. The culturability of bacterial cells was low which increased later with the onset of the stadial.

DOI: 10.1016/j.quaint.2012.03.008

13086355 Matzke, Jeffrey A. (University of Iowa, Department of Geoscience, Iowa City, IA); Bettis, E. Arthur, III; Weirich, Frank and Vogelgesang, Jason. A new view of the stone zone on the Iowa erosion surface [abstr.]: in Geological Society of America, North-Central Section, 47th annual meeting, Abstracts with Programs - Geological Society of America, 45(4), p. 17, April 2013. Meeting: Geological Society of America, North-Central Section, 47th annual meeting, May 2-3, 2013, Kalamazoo, MI.

The processes that generated the distinctive landscape of the Iowa Erosion Surface (IES) of northeastern Iowa have been debated for over a century. A number of researchers have concluded that the IES experienced a periglacial environment and was underlain by continuous permafrost during the last glacial maximum. Ubiquitous throughout the IES is a stone zone that lies 60-100 cm below the surface. Several explanations for the genesis of the stone zone have been proposed, including a lag concentrate, biomantle processes, and cryogenesis. We utilized a combination of coring and trenching, ground penetrating radar and resistivity to investigate the 3D distribution of the stone zone, overlying "pedisediment" and the underlying contact with dense till across a 100 m² area on a typical IES hillslope in east-central Iowa . Our preliminary results indicate that the stone zone occurs in the basal few decimeters of pedisediment that rests uncomformably and abruptly on eroded, dense till. Ice wedge casts extend from the stone zone into the underlying till. The depth of the stone zone below the modern surface increases downslope and the stone zone dissipates and eventually is replaced by relatively thick loamy sand beneath the footslope. These relationships argue against the stone zone being of biogenic origin. The occurrence of ice wedge casts associated with the stone zone and systematic changes in the thickness and texture of the pedisediment suggest to us that stone zone on the IES was formed by a combination of cryogenic and active zone erosive processes during the full glacial period.

13086571 Magritsky, Dmitry (Moscow State University, Faculty of Geography, Moscow, Russian Federation); Mikhailov, Vadim; Korotaev, Vladislav and Babich, Dmitry. Changes in hydrological regime and morphology of river deltas in the Russian Arctic: in Deltas; landforms, ecosystems and human activities (Young, Gordon; et al.), IAHS-AISH Publication, 358, p. 67-79, illus. incl. 2 tables, 35 ref., 2013. Meeting: IAHS-IAPSO-IASPEI joint assembly, symposium HP1 on Deltas; landforms, ecosytems and human activities, July 22-26, 2013, Gothenburg, Sweden.

This paper provides information on the current regime and morphological processes in the river deltas of the Northern Dvina, Pechora, Ob, Pur, Taz, Yenisey, Olenek, Lena, Yana, Indigirka and Kolyma, and their possible changes in the 21st century. This article contains data on morphological type, structure and size of the major deltas, about the current state and changes of the main river (water and sediment river runoff) and marine factors of delta formation processes.

13086416 Baratta, Vanessa M. (University of Iowa, Department of Geosciences, Iowa City, IA); Bettis, E. Arthur, III; Ward, Adam S. and Weirich, Frank. The effects of freeze-thaw cycles and stormwater runoff input on three bioswale soil mixtures [abstr.]: in Geological Society of America, North-Central Section, 47th annual meeting, Abstracts with Programs - Geological Society of America, 45(4), p. 51, April 2013. Meeting: Geological Society of America, North-Central Section, 47th annual meeting, May 2-3, 2013, Kalamazoo, MI.

Urbanization and the growth of suburbs are world-wide phenomena. One product of this development is a dramatic increase in impermeable surfaces and a consequent increase in stormwater runoff. Bioretention cells (biocells) are one best management practice frequently used to mitigate the impacts of urban stormwater runoff. To ensure that a biocell will continue to perform adequately in the long term, it is imperative that the varieties of conditions it will sustain through time are considered during its initial design. Although biocells are frequently used for stormwater management, very few quantitative data exist on how they perform through time and in varied physical environments. In regions with seasonal freeze-thaw cycles, it is important to understand the physical effects of freeze-thaw cycles on biocell materials so that the integrity of the design will not be compromised by seasonal change. This project utilizes manufactured laboratory columns to investigate the effects of freeze-thaw cycles and runoff sediment input on the infiltration capacity of three different biosoil mixtures. These tests will provide an analog for long-term changes in biocell infiltration rates due to seasonal variations, which will provide critical data on which soil mixture would be best implemented in geographic regions susceptible to freeze-thaw activity. Furthermore these results will inform design standards for biocells to insure their long-term use.

13086414 Bouali, El Hachemi Y. (Western Michigan University, Department of Geosciences, Kalamazoo, MI); Kaunda, Rennie B.; Chase, Ronald B. and Kehew, Alan E. The stability of the Lake Michigan bluffs in Allegan County, Michigan, and the relationships between air temperature, groundwater levels, and downslope displacement [abstr.]: in Geological Society of America, North-Central Section, 47th annual meeting, Abstracts with Programs - Geological Society of America, 45(4), p. 51, April 2013. Meeting: Geological Society of America, North-Central Section, 47th annual meeting, May 2-3, 2013, Kalamazoo, MI.

Unstable bluffs composed of heterogeneous glacial sediments account for approximately 60 percent of the Great Lakes shoreline. This instability has been attributed to toe erosion, soil saturation, surface water flow, and/or misguided human intervention. The U.S. Army Corps of Engineers and Western Michigan University conducted a joint study between 1996 and 2008 that resulted in a temporal dataset allowing significant insight into the causes of bluff failure. Electronic instrumentation, installed in 2003 within the bluffs of Lake Michigan, north of South Haven, MI, has led to data that grants explanations for the mechanisms and causes of failure. Instruments include subsurface arrays of in-situ inclinometers, vibrating wire piezometers, thermistors, and weather stations. Over the 12-year acquisition of displacement, groundwater, wave, precipitation, and temperature data, the damaging effects of groundwater activity, especially during times of freeze/thaw cycles, have been adequately observed. Groundwater was also discharged from vertical pumping wells during the winter seasons of 2003 and 2005. The vertical pumping wells were located in a dewatering site next to a (non-dewatered) control site. Downslope displacements were reduced by as much as 400 percent when compared to the control zone displacements during the dewatering times. Statistical evaluation of the data has emphasized the erosional effects during freeze/thaw cycles. Correlation and kernel density studies of: (1) air temperature versus downslope rotational displacement, (2) air temperature versus perched ground water potentiometric surface elevations, and (3) groundwater-level fluctuations verses downslope rotational displacements, have demonstrated instantaneous displacement activity when air temperatures cross 0° Celsius. The freezing of bluff surfaces produces a barrier to perched water discharge, which then raises pore pressures to produce a factor of safety of less than one; this results in simple shear displacement within the bluff. As the frozen bluffs thaw there is a rapid discharge of stored groundwater, which creates an additional lagged downslope displacement that accompanies the increase of flow pressure. The second pulse of displacements tends to be back rotations that accompany block movements of coherent soil.

13086337 Bruegger, Alison (University of Illinois at Urbana-Champaign, Illinois State Geological Survey, Champaign, IL); Curry, B. Brandon and Grimley, David A. Ice-walled lake plains highlighted on new surficial geology map of Kane County, Illinois [abstr.]: in Geological Society of America, North-Central Section, 47th annual meeting, Abstracts with Programs - Geological Society of America, 45(4), p. 14, April 2013. Meeting: Geological Society of America, North-Central Section, 47th annual meeting, May 2-3, 2013, Kalamazoo, MI.

A 1:62,500-scale surficial geology map of Kane County, a western collar county of suburban Chicago, has recently been digitally compiled from published and unpublished 1:24,000 maps. The map's digital database includes information from more than 200 borings and outcrops sampled over the past 45 years by the Illinois State Geological Survey (ISGS). Many include down-hole natural gamma-ray logs, and core subsample analyses of clay minerals and particle-size distribution. Mapping in the digital environment has benefited from new base maps of shaded relief from LiDAR-based DEMs. Our new map highlights the distribution of ice-walled lake plains which occur primarily between the Arlington and Bloomington moraines, and between the St. Charles and Marengo moraines. Mapped as a facies of the silty and clayey surficial lacustrine/glaciolacustrine unit (the Equality Formation), ice-walled lake plains (IWLPs) include deposits of sand and gravel that occur, relative to the core of laminated silty lake sediment at the base (as a lag), on the sides (as ice-contact deltas), and in the sub-loess mantle (as solifluction deposits). The total facies package is typically 4 to 8 m thick. IWLPs rise 1 to 3 m above the surrounding landscape which may include deposits of diamicton or younger terraces underlain by younger glaciolacustrine deposits. Glacial Lake Pingree, a large proglacial lake mapped originally by Willman and Frye (1970), is a complex of IWLPs encased in younger lake sediment. Some lower level terraces may reflect stepwise lowering of base level, and could be interpreted as IWLPs. Notable features in Kane County include: 1) Seventy-meter thick deposits of clay loam diamicton of the Tiskilwa Formation (Wedron Group) forming the Marengo Moraine, 2) High-level terraces along the Fox River formed during by catastrophic overflow ("Fox Torrent" of Alden) of a proglacial lake dammed by the Woodstock Moraine, 3) Deep bedrock valleys with glaciofluvial fills of Illinois Episode sand and gravel, that contain important regional aquifers, and 4) An outstanding array of data characterizing Quaternary deposits. Data density is especially high at the former Fermi Accelerator Laboratory, which allowed differentiation of three facies of the Yorkville Member and the Batestown Member of the Lemont Formation.

13086278 Curry, B. Brandon (Illinois State Geological Survey, Prairie Research Institute, Champaign, IL). Superposed ice-walled lake deposits, northeastern Illinois [abstr.]: in Geological Society of America, North-Central Section, 47th annual meeting, Abstracts with Programs - Geological Society of America, 45(4), p. 4, April 2013. Meeting: Geological Society of America, North-Central Section, 47th annual meeting, May 2-3, 2013, Kalamazoo, MI.

A complex of ice-walled lake plains occurs in and around Woodstock, Illinois. One ice-walled lake plain stands out from the rest (-88.4113°W, 42.2571°N). It is nearly circular, about 1.1 km across, with an unusual central kettle about 0.4 km across. Five cores of this landform have been sampled. Facies architecture, radiocarbon ages of entombed tundra plants, and geomorphology collectively indicate two stages of ice-walled lake development. Gray, silty clay diamicton of the Yorkville Member (Lemont Formation; Livingston Phase) underlies the glaciolacustrine complex forming the ice-walled lake plain, but sediment cores sampled adjacent to the landform reveal patches of dolomite-rich, pebbly sandy loam diamicton of the Haeger Member (Lemont Formation; Woodstock Phase) that cover the fine-grained Yorkville unit. The margin of the ice-walled lake plain is covered by about 1.7 m of well-sorted, fining-upward medium sand. The sand pinches out approaching the kettle's edge. The underlying fossiliferous lacustrine sediment is as much as 7.5 m thick. The two stages of development are reflected in five radiocarbon ages (each with < 30 yrs sigma-one error) of Dryas integrifolia found in the lacustrine faces. The first stage lasted from about 21,870 to 21,460 cal yr BP during deglaciation of the Livingston Phase. The second stage occurred from about 18,720 to 17,870 cal yr BP during deglaciation of the Woodstock Phase. The lack of ¹⁴C ages spanning from about 21,460 to 18,720 cal yr BP also is observed from the composite of more than 40 radiocarbon ages associated with ice-walled lakes in Illinois. The hiatus is also observed in 15 ¹⁴C ages of plant fossils from the nearby De Kalb mounds. The lack of physical evidence for the nonconformity in sediment cores such as clay mineral alteration or changes in bedding or grain-size suggests that the active layer did not thaw; the landscape was physically and chemically inert during this time of extremely cold summer temperatures.

13086431 Lemke, Lawrence D. (Wayne State University, Department of Geology, Detroit, MI); Frahm, Andrew L. and Pappas, Lena K. Drawing the dog; deterministic hydrostratigraphic modeling of a complex glacial aquifer system using an allostratigraphic approach [abstr.]: in Geological Society of America, North-Central Section, 47th annual meeting, Abstracts with Programs - Geological Society of America, 45(4), p. 53-54, April 2013. Meeting: Geological Society of America, North-Central Section, 47th annual meeting, May 2-3, 2013, Kalamazoo, MI.

Complexity and glacial sediments go hand in hand. Consequently, modeling three-dimensional variability in glacial aquifer systems can require considerable experience, perseverance, and imagination, even when abundant subsurface data are readily available. In practice, subsurface information is usually sparse, and evaluating model uncertainty constitutes a significant challenge. This study employs hybrid models incorporating stochastic variability within a deterministic hydrostratigraphic framework to model spatial variability of physical hydrogeologic properties and assess contaminant transport prediction uncertainty in a complex glacial aquifer system. The approach is illustrated with a case study in Ann Arbor, Michigan, USA, where plumes of groundwater containing 1,4-dioxane have migrated several kilometers in different directions through 80m of underlying glacial drift. The deepest known plume appears to be advancing toward the Huron River beneath a groundwater Prohibition Zone established in 2005. 1,4-Dioxane is readily soluble in water but resistant to microbial degradation and adsorption to soil particles. Thus, it provides a tracer-like record of solute transport. More than 130 monitoring wells and 20 extraction wells have been drilled to detect, trace, and remediate 1,4-dioxane in the area. These wells form the basis of an allostratigraphic interpretation of the three-dimensional distribution of aquifer and aquitard units, constrained by available hydraulic head and contaminant concentration data, that is described in this presentation. Stochastic modeling of aquifer and aquitard properties within that deterministic hydrogeologic framework is described in a companion presentation.

13086542 Naylor, Shawn (Indiana Geological Survey, Center for Geospatial Data Analysis, Bloomington, IN); Gustin, Andrew R.; Letsinger, Sally L.; Ellett, Kevin and Olyphant, Greg A. Quantifying hydrologic budget components in Indiana using a network of meteorological and vadose-zone instrument arrays [abstr.]: in Geological Society of America, North-Central Section, 47th annual meeting, Abstracts with Programs - Geological Society of America, 45(4), p. 71, April 2013. Meeting: Geological Society of America, North-Central Section, 47th annual meeting, May 2-3, 2013, Kalamazoo, MI.

Weather stations in the United States that collect reliable, long-term meteorological data sets are now widely distributed owing to advances in both instrumentation and remote data-server technology. However, with the exception of Illinois, sites collecting soil-moisture and soil-temperature data remain sparse in the Midwest, and fewer locations exist where complete meteorological data are collected along with vadose-zone data. Coupled monitoring networks are important for establishing reliable land surface water and energy budgets and estimating deep drainage in the soil profile. They also provide essential data for expanding our understanding of soil moisture-climate coupling. Accordingly, a network of 11 monitoring stations has been developed in Indiana. Nine of the stations are located in glaciated environments including: ground moraine, moraine crest, outwash terrace, and alluvial terrace settings with the remaining two sites situated in reclaimed-mine and unglaciated highland settings. Each instrument array employs standard meteorological sensors, including pyranometers used to measure incoming shortwave solar radiation at seven of the sites and net radiometers at four of the sites. The resulting data are used to calculate potential evapotranspiration (PET) using standard methods by the Food and Agriculture Organization (FAO) of the United Nations. Vadose-zone instrumentation is installed at six of the glaciated sites and includes time-domain reflectometry soil-moisture and temperature sensors at 0.3-m depth intervals down to a depth of 1.8 m, in addition to matric-potential sensors at 0.15, 0.3, 0.6, and 1.2 m. Shallow water-table aquifers are present at three of the sites, and piezometers are used to measure water-table fluctuations. Beyond providing PET estimates using the FAO guidelines, the data will be used to determine groundwater recharge using the soil-water-balance approach. The significance of quantifying these hydrosphere components is especially important with more frequent drought conditions creating increasing stresses on groundwater resources and agriculture in Indiana. Future land-based modeling efforts aimed at improving our understanding of soil-moisture and recharge distribution will also benefit from having an established empirical data network.

13086300 Zmijewski, Kirk A. (University of Toledo, Department of Environmental Sciences, Toledo, OH) and Becker, Richard H. Using GRACE data to monitor effects of anthropogenic modification and climate change on groundwater in the Aral Sea region; 2002-2012 [abstr.]: in Geological Society of America, North-Central Section, 47th annual meeting, Abstracts with Programs - Geological Society of America, 45(4), p. 8, April 2013. Meeting: Geological Society of America, North-Central Section, 47th annual meeting, May 2-3, 2013, Kalamazoo, MI.

The Aral Sea watershed located in central Asia has seen significant anthropogenic modification since the mid 20^th century, leading to a decrease in size of the sea by almost 90%. The watershed is a closed basin with an area of almost 2 million square kilometers which includes both the Amu Darya and Syr Darya river systems. A network of canals and channels has diverted a significant amount of flow from both rivers into various agricultural areas and reservoirs. Groundwater is an extremely important resource in the region providing the majority of river flow during winter months, while glacial melt provides up to 70% during the summer months in hot years. GRACE (Gravity and Climate Experiment) data from 2002-2012 was used to monitor total water storage trends within the basin using a linear model. The data was normalized with an annual periodic function to remove seasonality. The GLDAS (Global Land Data Assimilation Systems) model was used to estimate the monthly mass of soil moisture and snow cover. Total surface water mass was estimated using satellite imagery and historical topographic maps. Much of the water diverted from the Syr Darya and Amu Darya remains stored as groundwater recharge and growing artificial lakes which supports the regions agriculture. However, the water balance of the whole watershed shows an overall negative trend in water storage due to evaporative losses from these diversions. A positive trend in groundwater storage mass was observed in agricultural areas and in the vicinity of the reservoirs in the central part of the basin. Opposite trends were observed in the headwaters of both glacial-fed rivers within the Aral Sea basin. Total summer time snow cover area was determined for both rivers using Landsat imagery. An increase in total snow/ice cover in the Amu Darya headwaters was observed and a decrease in total snow/ice in the Syr Darya. The Amu Darya receives precipitation from the South Asian Monsoon which has increased in the last decade. The more northern headwaters of the Syr Darya River receive continental precipitation of which previous studies have shown no significant trends, but an increase of 1-2 degrees C over the past century may explain loss in mass due to glacial ablation. Future water and food security in the region depends on accurate monitoring and predictions of water resources in the future.

13085843 Yanina, Tamara A. (Moscow State University, Faculty of Geography, Moscow, Russian Federation). Correlation of the late Pleistocene paleogeographical events of the Caspian Sea and Russian Plain: in The environment and chronology of the earliest occupation of north-west Europe; current knowledge, problems and new research directions (MacDonald, Katharine, editor; et al.), Quaternary International, 271, p. 120-129, illus. incl. 2 tables, sketch map, 103 ref., August 31, 2012. Meeting: International conference on the Enivronment and chronology of the earliest occupation of north-west Europe, 2009, Leiden, Netherlands.

The present work shows the author's concept of paleogeographic development of the Caspian Sea in the Late Pleistocene, based on the comprehensive analysis of the Caspian deposits and their relation and synchronization with glacial-interglacial cycles on the Russian Plain, based on published materials. Global climate changes were fundamental for both the transgressive-regressive state of the Caspian basins, as well as for glacier formation and retreat on the Russian Plain. At the same time, glaciers influenced the Caspian basin development on a regional level. The long-term low Caspian Sea level, complicated by the double-stage "minor" Late Khazar transgression, corresponded to the Mikulino (Eemian) interglacial with two endothermals. This warm stage in the Caspian history encompassed the interval corresponding to Marine Isotope Stage (MIS) 5. This is in agreement with the point of view of researchers who correlate the Mikulino interglacial with the entire MIS 5. The "cold" vast Khvalynian transgression and preceding to it the Atel regression developed during the Valday glaciation (MIS 4-2). The Atel regression corresponds to cold MIS 2 and the beginning of MIS 3. Its lower boundary in the Lower Volga region is marked with ice wedges. A transgressive tendency began to show in the second half of the interstadial (second half of MIS 3) and continued into early stages of the Late Valdai cooling, but it was interrupted during the dry and cold Glacial Maximum (peak of MIS 2) by the regressive stage. Further transgression development occurred during the degradation of the glaciation. Its course was impacted by transgressive-regressive events of lower magnitude linked to oscillations of climatic parameters: i.e., cold dry conditions of the Middle Dryas by the Enotaevka regression, and the continentalization of the Boreal period of the Holocene by the Mangyshlak regression.

DOI: 10.1016/j.quaint.2012.06.003

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