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14021729 Zech, Michael (University of Bayreuth, Department of Soil Physics, Bayreuth, Germany); Tuthorn, Mario; Detsch, Florian; Rozanski, Kazimierz; Zech, Roland; Zöller, Ludwig; Zech, Wolfgang and Glaser, Bruno. A 220 ka terrestrial d18O and deuterium excess biomarker record from an eolian permafrost paleosol sequence, NE Siberia: Chemical Geology, 360-361, p. 220-230, illus. incl. sketch map, 83 ref., December 18, 2013. Includes appendices.
The natural abundances of stable oxygen (18O/16O) and hydrogen isotopes (2H/1H) are valuable proxies of climate changes in the past. Yet, to date no continuous d18O and only few d2H records are available from loess-paleosol sequences. Taking advantage of a recently developed method based on compound-specific d18O analyses of hemicellulose sugar biomarkers in soils (Zech and Glaser, 2009. RCM 23, 3522-3532), we here present a first terrestrial d18O biomarker record from an eolian permafrost paleosol sequence in NE-Siberia that covers the last ~220 ka. The d18O values of the hemicellulose biomarkers arabinose and xylose range from 22.5 to 32.8 ppm and from 21.3 to 31.9 ppm, respectively, and reveal systematic glacial-interglacial shifts. The modern topsoil and the interglacial paleosols exhibit more positive d18O values, whereas the glacial paleosols are characterized by more negative d18O values. This is in agreement with the d2H record obtained for sedimentary n-alkane leaf wax biomarkers. We present a conceptual model for interpreting the combined d18O and d2H biomarker record. Based on this model, we suggest that both our d18O and the d2H records primarily reflect the temperature-controlled isotopic composition of paleoprecipitation modified by evaporative isotope enrichment of leaf water during transpiration. Considering fractionation factors during sugar and n-alkane biomarker biosynthesis allows reconstructing the leaf water isotopic composition and the deuterium excess of the leaf water. The deuterium excess may serve as proxy for evaporative enrichment and allows calculating relative humidity using a Craig-Gordon model. Accordingly, relative humidity in NE-Siberia was higher during marine isotope stage (MIS) 6 compared to MIS 2, 4 and 5d and thus could help explaining the much larger extent of the Late Saalian glaciation compared to the Weichselian glaciations. Using the Craig-Gordon model, we also calculated d18O of the plant source water (d18Osource water), which can be assumed to primarily reflect d18O of paleoprecipitation. Our 220 ka d18Osource water record is well in agreement with the d18Odiatom record from Crater Lake El'gygytgyn in NE-Siberia and enables a regional paleoclimate reconstruction and interpretation. Accordingly, summer temperature was periodically warmer than at present during the Weichselian glacial period and there is a strong July insolation forcing of the summer temperature in the extremely continental study area. Overall, our study highlights the great potential of the novel hemicellulose biomarker d18O method for paleoclimate reconstructions, especially when combined with d2H analyses of n-alkane lipid biomarkers. Abstract Copyright (2013) Elsevier, B.V.
DOI: 10.1016/j.chemgeo.2013.10.023
14020152 Zheleznyak, M. N. (Rossiyskaya Akademiya Nauk, Sibirskoye Otdeleniye, Institut Merzlotovedeniya, Yakutsk, Russian Federation); Misaylov, I. Ye. and Krinin, V. A. Geotemperaturnoye pole i moshchnost' kriogennoy tolshchi v zone sochleneniya Yenisey-Khatangskogo progiba s Tungusskoy sineklizoy [Geothermal field and permafrost thickness in zones connecting the Yenisei-Khatanga Basin with the Tunguska Syneclise]: Kriosfera Zemli = Earth Cryosphere, 17(4), p. 22-29 (English sum.), illus. incl. 2 tables, sect., sketch maps, 13 ref., December 2013.
Based on the geothermal measurements in deep boreholes, this study provides the first characterization of the subsurface temperature field and the permafrost thickness in the geologically and tectonically complicated, transitional zone extending from the Yenisei-Khatanga trough to the Tunguska Basin. The laboratory determinations of thermophysical properties for the main types of rocks, as well as the estimation of geothermal heat fluxes in and below the permafrost are presented. Based on the cycle of repeated geothermal measurements, the time of recovery of the temperature regime in the boreholes after drilling has been assessed. The data obtained in 2010-2013 have been used for constructing the geothermal profile up to the depth of 1500 m characterizing peculiarities of the subsurface temperature field in the region.
14020941 Zollinger, Barbara (University of Zurich, Department of Geography, Zurich, Switzerland); Alewell, Christine; Kneisel, Christof; Meusburger, Katrin; Gärtner, Holger; Brandová, Dagmar; Ivy-Ochs, Susan; Schmidt, Michael W. I. and Egli, Markus. Effect of permafrost on the formation of soil organic carbon pools and their physical-chemical properties in the Eastern Swiss Alps: Catena (Giessen), 110, p. 70-85, illus. incl. 6 tables, sketch map, 78 ref., November 2013.
Current climatic conditions and the occurrence of discontinuous and sporadic permafrost in the Alps result in a low turnover rate and therefore accumulation of organic matter (OM) in soils. Alpine soils are thus highly sensitive to global warming that potentially promotes the mineralisation of soil organic matter (SOM). This process might increase the release of CO2 to the atmosphere. Our aim was to investigate the potential effect of permafrost thawing by the analysis of the physical-chemical soil properties of permafrost versus non-permafrost sites. Specifically, we i) quantified the SOM stocks at such sites, ii) characterized SOM and its physical and chemical fractions and iii) estimated the age range of the bulk soil and stable C-fraction (radiocarbon dating). In south-eastern Switzerland, two areas above the timberline and one below the timberline (where isolated permafrost was verified) were investigated in detail. At each site, the experimental set-up consisted in the comparison of nearby soils that were either influenced or not by permafrost. The C-stocks (down to the C horizon or rock surface) did not show a significant difference between permafrost and non-permafrost soils and were in the same range of 10-15kg/m2 in alpine (grassland) and subalpine (forest) sites. Above the timberline, the bulk SOM showed a distinct higher age at permafrost sites compared to non-permafrost sites. This higher age was even more evident in the stable C-fraction (resistant to an H2O2 treatment), where ages of up to 11ky in permafrost soils were recorded. The highest age obtained in the stable C-fraction in non-permafrost soils was around 4ky. Consequently, climatic conditions and the occurrence of discontinuous permafrost resulted in a very low turnover rate of SOM. At the subalpine site, the difference between permafrost and non-permafrost sites was less. At both sites (alpine and subalpine), DRIFT (Diffuse Reflection Infrared Fourier Transform) was used to determine the functional groups in the bulk soil and in the stable C-fraction. In general, the stable C-fraction had a different composition compared to the bulk SOM at non-permafrost sites; this was mostly not the case at the permafrost sites. This confirms that different decomposition processes occur between permafrost and non-permafrost sites. Furthermore, permafrost sites accumulated more the low-density physical fractions of SOM that are potentially easily degradable. The obtained results suggest that a warmer climate may not necessarily lead to an increased CO2 release from SOM-degradation in permafrost soils compared to non-permafrost soils. High-alpine soils and OM furthermore integrate a multi-faceted response to the past and ongoing surrounding conditions. The melting of permafrost will most likely enhance vegetation growth, which to a certain degree will probably compensate for carbon losses on the long-term. Abstract Copyright (2013) Elsevier, B.V.
DOI: 10.1016/j.catena.2013.06.010
14020142 Shmelev, D. G. (Rossiyskaya Akademiya Nauk, Institut Fiziko-Khimicheskikh i Biologicheskikh Problem Pochvovedeniya, Pushchino, Moscow region, Russian Federation); Krayev, G. N.; Veremeyeva, A. A. and Rivkina, Ye. M. Soderzhaniye ugleroda v merzlykh otlozheniyakh severo-vostoka Yakutii [Carbon pool in permafrost deposits of northeastern Yakutia]: Kriosfera Zemli = Earth Cryosphere, 17(3), p. 50-59 (English sum.), illus. incl. 3 tables, sketch maps, 44 ref., September 2013.
The volume and carbon storage of the main regional Quaternary formations at the Kolyma-Indigirka lowland have been estimated by using the State Geological Map of Quaternary Deposits and database of the Laboratory of Soil Cryology on carbon concentration, density and moisture in permafrost deposits of different age and genesis. Total carbon storage for the upper 25 m have been presented. The total carbon pool of the upper Neopleistocene ice complex (Yedoma subhorizon) has been found to be lower than it had been thought previously. The pioneer data change the concept of carbon storage in the Arctic permafrost.
14020116 Gorbunov, A. P. (Rossiyskaya Akademiya Nauk, Sibirskoye Otdeleniye, Institut Merzlotovedeniya, Kazakhstanskaya Vysokogornaya Geokriologicheskaya Laboratoriya, Almaty, Kazakhstan). Kamennyye gletchery, ledniki i vechnaya meerzlota v Irane [Rock glaciers, glaciers and permafrost in Iran]: Kriosfera Zemli = Earth Cryosphere, 17(1), p. 28-34 (English sum.), illus. incl. table, 11 ref., March 2013.
Analysis of satellite imagery of Google Earth has revealed the active, inactive and fossil rock glaciers, glaciers and areas with permafrost in Iran mountains. The total number of rock glaciers is 355-360, and 70 of them are active. The active and inactive forms occur mainly in the altitudinal range from 4400 to 2700 m. The fossil rock glaciers are sometimes recorded even at the altitude of 2450 m. The length of the largest fossil rock glaciers reaches 5 km. The length of the largest active and inactive rock glaciers ranges within 2.4 and 3.4 km. Small cirque glaciers predominate in the mountains of Iran. The largest debris-covered rock glacier reaches the length of 4 km, whereas their usual length is 200-300 m. The total number of glaciers does not exceed 30. They are confined to 5 mountain massifs. Permafrost is spread at least in the 30 mountain regions.
14020119 Kunitskiy, V. V. (Rossiyskaya Akademiya Nauk, Sibirskoye Otdeleniye, Institut Merzlotovedeniya, Yakutsk, Russian Federation); Syromyatnikov, I. I.; Shirrmeyster, L.; Skachkov, Yu. B.; Grosse, G.; Vetterikh, S. and Grigor'yev, M. N. L'distyye porody i termonudatsiya v rayone poselka Batagay (Yanskoye ploskogor'ye, Vostochnaya Sibir') [Ice-rich permafrost and thermal denudation in the Batagay area (Yana Upland, eastern Siberia)]: Kriosfera Zemli = Earth Cryosphere, 17(1), p. 56-68 (English sum.), illus. incl. 2 tables, sketch map, 38 ref., March 2013.
Ice-rich permafrost in the Yana Upland has been investigated. The composition and structure of the permafrost have been determined. Their role in thermal denudation processes has been examined. The response of the ice-rich permafrost to recent climate change has been assessed.
14020115 Vasil'chuk, Yu. K. (Moskovskiy Gosudarstvennyy Universitet, Moscow, Russian Federation). Sovremennoye polozheniye yuzhnoy granitsy zony mnogoletnemerzlykh porod Zapadno-Sibirskoy nizmennosti [Modern southern limit of permafrost in the West Siberian Lowland]: Kriosfera Zemli = Earth Cryosphere, 17(1), p. 17-27 (English sum.), illus. incl. sketch maps, 36 ref., March 2013.
The location of the modern southern limit of permafrost has been elaborated. The southern boundary of the upper layer of permafrost coincides with the southern limit of the palsa areal in the northern part of West Siberia. The southern limit of permafrost extends to 60 ° N in the western part, south to the latitude part of the Ob River valley, and about 57 ° N in the eastern part of the region.
14019273 Wang Xianwei (Chinese Academy of Sciences, Northeast Institute of Geography and Agricultural Ecology, Changchun, China); Song Changchun; Sun Xiaoxin; Wang Jiaoyue; Zhang Xinhou and Mao Rong. Soil carbon and nitrogen across wetland types in discontinuous permafrost zone of the Xiao Xing'an Mountains, northeastern China: Catena (Giessen), 101, p. 31-37, illus. incl. 3 tables, sketch map, 52 ref., February 2013.
Soil organic carbon (SOC) in high latitude ecosystems is potentially vulnerable to global climate change. However, the distribution of SOC and total nitrogen (N) is still unknown for the boreal wetlands. In this study, we collected soil samples from different wetlands in the discontinuous permafrost zone of the Xiao Xing'an Mountains, northeastern China. Permafrost was only present in the bogs and fens in this zone. Soil C concentrations were significantly correlated with total N concentrations and bulk density (P<0.001). Wetland type, soil depth, and incidence of fire affected soil C and total N concentrations, suggesting that vegetation changes in wetlands could alter the soil C and nutrient sequestration processes under future global warming scenarios. However, soil C and total N storage in the 40 cm depth was not significantly different between wetland types (P>0.05), suggesting that future global warming and vegetation change would not significantly affect soil C and total N storage in upper soil layers in wetlands. However, vegetation changes are likely to increase the depth of the permafrost active layer under permafrost degradation, release deep soil C, and add C to the atmosphere over the coming decades. Abstract Copyright (2013) Elsevier, B.V.
DOI: 10.1016/j.catena.2012.09.007
14021986 Vonk, Jorien E. (Utrecht University, Department of Earth Sciences, Utrecht, Netherlands) and Gustafsson, Orjan. Permafrost-carbon complexities: Nature Geoscience, 6(9), p. 675-676, illus., 17 ref., September 2013.
DOI: 10.1038/ngeo1937
14016556 Klein, Eric S. (Lehigh University, Department of Earth and Environmental Sciences, Bethlehem, PA); Yu, Zicheng and Booth, Robert K. Recent increase in peatland carbon accumulation in a thermokarst lake basin in southwestern Alaska: Palaeogeography, Palaeoclimatology, Palaeoecology, 392, p. 186-195, illus. incl. charts, 2 tables, sketch map, 60 ref., December 15, 2013.
Drained thermokarst lake basins cover large areas of northern high latitude lowlands. However, the importance of peat accumulated in these drained basins to carbon (C) cycling is poorly understood. Results are presented here from a permafrost sediment core aimed at investigating site history, lake drainage, apparent carbon accumulation, and paleohydrology in a thermokarst basin on the Yukon Kuskokwim Delta in southwestern Alaska. The results show that a thermokarst lake existed for about 2300 years before it drained and a peatland established in the early 1600s. Average apparent C accumulation rate (CAR) was 12 gC/m2/yr over the 2300 years before lake drainage, but increased to 120 gC/m2/yr following peatland initiation. After transitioning to a Sphagnum-dominated peatland at ~1700 AD, CAR reduced gradually before more than doubling from the mid-1970s to the early 1980s. This abrupt increase in CAR was possibly in response to a Pacific climate regime shift in the late 1970s, a transition characterized by a nearly 1.5°C increase in regional average annual temperature. Even after considering the differential decay of recent peat, there was an increase in C accumulation after 1977. Reconstructed water-table depths from subfossil testate amoebae show little change throughout the past three centuries, but there was a pronounced shift in testate amoeba composition after the 1977 temperature change (e.g., absence of Phryganella acropodia type and increase in Hyalosphenia elegans). If the results from peatlands in other drained thermokarst lake basins are consistent with the results from this study, then the C accumulated in these vegetated drained basins under current warming might help offset some of the C released from thawing permafrost and thermokarst features in northern regions. Abstract Copyright (2013) Elsevier, B.V.
DOI: 10.1016/j.palaeo.2013.09.009
14020150 Semenov, V. P. (Rossiyskaya Akademiya Nauk, Sibirskoye Otdeleniye, Institut Merzlotovedeniya, Yakutsk, Russian Federation). Geotermicheskiye usloviya Vilyuyskoy sineklizy [Geothermal conditions of the Vilyuy Syneclise]: Kriosfera Zemli = Earth Cryosphere, 17(4), p. 3-10 (English sum.), illus. incl. 3 tables, sketch map, 11 ref., December 2013.
The characteristics of the geothermal conditions in the Vilyuy Basin have been adduced. The Vilyuy Basin is located within the Siberian Platform and contains disequilibrium permafrost. Recently obtained data on permafrost thickness and temperature distribution for geological units of the Vilyuy Basin have been presented. Estimates of geothermal heat fluxes and below temperature distribution for geological units of the Vilyuy Basin have been presented. Estimates of geothermal heat fluxes in and below the permafrost are given. It has been determined that the heat flux in the permafrost is 30-34mW/m2 lower than in the subpermafrost zone. Four intervals are identified on the temperature curves differing in geothermal gradient and indicating different paleoclimatic conditions in the course of permafrost development. Based on the obtained data, a 2000 m depth geothermal profile characterizing the geothermal field in the region has been plotted.
14020140 Osadchaya, G. G. (Institut Upravleniya, Informatsii i Biznesa, Ukhta, Russian Federation) and Khokhlova, Ye. S. Optimizatsiya prirodopol'zovaniya pri osvoyenii territorial'nykh resursov yuzhnoy kriolitozony Bol'shezemel'skoy tundry [Optimization of natural management during the industrial exploration of territorial resources of southern cryolithozone of Bolshezemelskaya Tundra]: Kriosfera Zemli = Earth Cryosphere, 17(3), p. 35-43 (English sum.), illus. incl. table, sketch maps, 25 ref., September 2013.
Limitations for nature management have been determined for local landscapes of the southern cryolithozone of Bolshezemelskaya Tundra. It will allow optimization of the territory planning without loss of biosphere and social functions of territory. Zone and regional regularities of the variability of these limitations have been revealed for the subzones of insular and massive-insular permafrost.
14020141 Skryabin, P. N. (Rossiyskaya Akademiya Nauk, Sibirskoye Otdeleniye, Institut Merzlotovedeniya, Yakutsk, Russian Federation) and Varlamov, S. P. Termicheskiy rezhim gruntov narushennykh landshaftov Tsentral'noy Yakutii [Ground thermal regime in disturbed landscapes of central Yakutia]: Kriosfera Zemli = Earth Cryosphere, 17(3), p. 44-49 (English sum.), illus. incl. table, 13 ref., September 2013.
The results of long-term geothermal investigations in disturbed landscapes along the railway, water line and gas pipeline are presented. Human-induced changes in the ground thermal state are analyzed. The study has shown significant increases in mean annual temperature of the upper permafrost layers, as well as in seasonal thaw depth in inter-layer type of terrain after the removal of trees, ground surface stripping and post-fire clearing. Quantitative estimates are given for the dynamics of mean annual ground temperatures on cuts and burns in relation to vegetation succession.
14018196 Kuipers, Gerrit (Vrije University, Department of Petrology, Faculty of Earth and Life Sciences, Amsterdam, Netherlands); Beunk, Frank F. and van der Wateren, Frederik M. Periglacial evidence for a 1.91-1.89 Ga old glacial period at low latitude, central Sweden: Geology Today, 29(6), p. 218-221, illus. incl. geol. sketch maps, December 2013.
Cryoturbation and slump fold-like sedimentary structures in ca. 1.9 Ga old dacitic metavolcanic sediments in West Bergslagen, Central Sweden, are recognized as a lowland periglacial environment. This type of environment is comparable with present day tundra in Siberia. Ice-wedge casts and cryoturbation, together with polygonal frost patterns, are typical geomorphological structures above permafrost in this type of environment. The sedimentary environment could be interpreted as periglacial, broadly comparable to present day tundras. Intensive cryoturbation of the formation and close structural analogy with Quaternary ice-wedges suggests a cold and humid environment. This discovery is corroborated by a previous report of glacial sediments and structures from NW Australia of ca. 1.8 Ga age. Both occurrences developed at low geographical latitudes, at locations far apart in the Late Palaeoproterozoic supercontinent Columbia. Either suggest the existence of a ca. 100 Ma long epoch of extreme, though possibly intermittent glaciations during the ca. 1.4 Ga long 'Proterozoic gap' (~2.2-0.77 Ga) from which no convincing glacial deposits were previously known. Abstract Copyright (2013), Blackwell Publishing Ltd, The Geologists' Association & The Geological Society of London.
DOI: 10.1111/gto.12027
14016602 Ballantyne, Colin K. (University of Saint Andrews, School of Geography and Geosciences, Saint Andrews, United Kingdom); Wilson, Peter; Schnabel, Christoph and Xu, Sheng. Lateglacial rock slope failures in north-west Ireland; age, causes and implications: JQS. Journal of Quaternary Science, 28(8), p. 789-802, illus. incl. 3 tables, geol. sketch map, 115 ref., November 2013.
Nine postglacial quartzite rock slope failures (RSFs) in north-west Ireland were dated using cosmogenic 10Be. Weighted mean RSF ages range from 17.7±0.9 to 12.5±0.7 ka or 16.6±0.7 to 11.7±0.5 ka, depending on assumed 10Be production rate. All dated RSFs occurred within ~5000 years following ice-sheet deglaciation at ~17.4 ka (~16.3 ka) and all but two occurred within 2000 years after deglaciation. The timing of RSFs rules out glacial 'debuttressing', permafrost degradation and enhanced deglacial cleft-water pressures as triggers of failure in most cases. We infer that paraglacial stress release and associated fracture propagation were critical in reducing rock masses to critical stability, although earthquakes caused by Lateglacial glacio-isostatic rebound and/or release of stored tectonic stresses may have triggered failure in some or all cases. In conjunction with data from related studies, our results imply that most undated RSFs outside the limit of Younger Dryas glaciation in the British Isles are of Lateglacial age, and that numerous Lateglacial RSFs occurred inside these limits, with subsequent removal of debris by glaciers. They support the view that paraglacial RSF activity in tectonically stable intraplate terrains was concentrated within a few millennia following deglaciation. Abstract Copyright (2010), John Wiley & Sons, Ltd.
DOI: 10.1002/jqs.2675
14020155 Gubin, S. V. (Rossiyskaya Akademiya Nauk, Institut Fiziko-khimicheskikh i Biologicheskikh Problem Pochvovedeniya, Pushchino, Russian Federation) and Zanina, O. G. Izmeneniye pochvennogo pokrova v khode formirovaniya otlozheniy ledovogo kompleksa na Kolymskoy nizmennosti (chast' 1) [Variation of soil cover during the formation of ice complex deposits in the Kolyma Lowland (Part 1)]: Kriosfera Zemli = Earth Cryosphere, 17(4), p. 48-56 (English sum.), illus. incl. table, sketch map, 17 ref., December 2013.
Soils formed within the late Pleistocene polygons of the Ice Complex have been studied. Significant data on the structure and distribution of epigenetic buried soils of Kolyma Lowland have been obtained. Periods of well-expressed soil zonal sequence took place of the beginning of Marine Isotope Stage 3. In later periods the evidence for this zonality gradually decreases.
14018204 Zhou, M. M. (Ruhr-University Bochum, Institute for Structural Mechanics, Bachum, Germany) and Meschke, G. A three-phase thermo-hydro-mechanical finite element model for freezing soils: International Journal for Numerical and Analytical Methods in Geomechanics, 37(18), p. 3173-3193, illus. incl. 4 tables, 43 ref., December 25, 2013.
Artificial ground freezing (AGF) is a commonly used technique in geotechnical engineering for ground improvement such as ground water control and temporary excavation support during tunnel construction in soft soils. The main potential problem connected with this technique is that it may produce heave and settlement at the ground surface, which may cause damage to the surface infrastructure. Additionally, the freezing process and the energy needed to obtain a stable frozen ground may be significantly influenced by seepage flow. Evidently, safe design and execution of AGF require a reliable prediction of the coupled thermo-hydro-mechanical behavior of freezing soils. With the theory of poromechanics, a three-phase finite element soil model is proposed, considering solid particles, liquid water, and crystal ice as separate phases and mixture temperature, liquid pressure, and solid displacement as the primary field variables. In addition to the volume expansion of water transforming into ice, the contribution of the micro-cryo-suction mechanism to the frost heave phenomenon is described in the model using the theory of premelting dynamics. Through fundamental physical laws and corresponding state relations, the model captures various couplings among the phase transition, the liquid transport within the pore space, and the accompanying mechanical deformation. The verification and validation of the model are accomplished by means of selected analyses. An application example is related to AGF during tunnel excavation, investigating the influence of seepage flow on the freezing process and the time required to establish a closed supporting frozen arch. Abstract Copyright (2010), John Wiley & Sons, Ltd.
DOI: 10.1002/nag.2184
14017904 Lacelle, Denis (University of Ottawa, Department of Geography, Ottawa, ON, Canada); Lauriol, Bernard; Zazula, Grant; Ghaleb, Bassam; Utting, Nicholas and Clark, Ian D. Timing of advance and basal condition of the Laurentide ice sheet during the last glacial maximum in the Richardson Mountains, NWT: Quaternary Research, 80(2), p. 274-283, illus. incl. 3 tables, sketch map, 57 ref., September 2013.
This study presents new ages for the northwest section of the Laurentide Ice Sheet (LIS) glacial chronology from material recovered from two retrogressive thaw slumps exposed in the Richardson Mountains, Northwest Territories, Canada. One study site, located at the maximum glacial limit of the LIS in the Richardson Mountains, had calcite concretions recovered from aufeis buried by glacial till that were dated by U/Th disequilibrium to 18,500 cal yr BP. The second site, located on the Peel Plateau to the east yielded a fossil horse (Equus) mandible that was radiocarbon dated to ca. 19,700 cal yr BP. These ages indicate that the Peel Plateau on the eastern flanks of the Richardson Mountains was glaciated only after 18,500 cal yr BP, which is later than previous models for the global last glacial maximum (LGM). As the LIS retreated the Peel Plateau around 15,000 cal yr BP, following the age of the Tutsieta phase, we conclude that the presence of the northwestern margin of the LIS at its maximum limit was a very short event in the western Canadian Arctic. Abstract Copyright (2013) Elsevier, B.V.
DOI: 10.1016/j.yqres.2013.06.001
14018379 Zhao Xiaodong (China University of Mining and Technology, State Key Laboratory for Geomechanics and Deep Underground Engineering, Jiangsu, China); Zhou Guoqing and Wang Jianzhou. Deformation and strength behaviors of frozen clay with thermal gradient under unixial compression: Tunnelling and Underground Space Technology, 38, p. 550-558, illus. incl. 3 tables, 25 ref., September 2013.
DOI: 10.1016/j.tust.2013.09.003
14019413 Shi, Mingjie (University of Texas at Austin, Department of Geological Sciences, Austin, TX); Yang, Zong-Liang and Landerer, Felix W. Representing and evaluating the landscape freeze/thaw properties and their impacts on soil impermeability; hydrological processes in the Community Land Model Version 4: Journal of Geophysical Research: Atmospheres, 118(D14), p. 7542-7557, illus., 30 ref., July 27, 2013.
Snow cover at high latitudes is an excellent natural insulator that can maintain the underlying ground at a higher temperature than the overlying atmosphere. Soil impermeability usually varies when snow cover accumulates, which is closely related to soil and landscape freeze/thaw status. How snow cover affects the landscape frozen fraction and soil impermeability and how this impermeability regulates hydrological processes in cold regions have not been fully assessed and quantified. In order to understand these processes, this study performed a series of experiments by using the Community Land Model version 4 (CLM4). We first simulated the top-soil-layer ice, snow ice, and canopy ice to calculate the landscape frozen fraction, which was evaluated based on the Special Sensor Microwave/Imager (SSM/I) observed landscape freeze/thaw earth system data record (FT-ESDR) in two selected regions at high latitudes. Then two soil impermeability parameterizations ere validated against various in situ and satellite observations. The results suggest the following: (1) compared to SSM/I FT-ESDR, CLM4 can capture the overall landscape freeze/thaw status in the regions north of 60°N in boreal winter and spring; (2) as the snow cover fraction approaches unity, the CLM4-simulated landscape frozen fraction is mainly controlled by the snow ice amount, resulting in step changes between SSM/I FT-ESDR observed and CLM4-simulated landscape frozen fractions; and (3) in most of the cold regions, the timing of the boreal spring runoff simulations is improved by reducing the impermeable area in high landscape frozen fraction regions. Abstract Copyright (2013), American Geophysical Union. All Rights Reserved.
DOI: 10.1002/jgrd.50576
14020760 Kim, D. G. (Landcare Research, Palmerston North, New Zealand); Vargas, R.; Bond-Lamberty, B. and Turetsky, M. R. Effects of soil rewetting and thawing on soil gas fluxes; a review of current literature and suggestions for future research: Biogeosciences, 9(7), p. 2459-2483, 267 ref., 2012.
The rewetting of dry soils and the thawing of frozen soils are short-term, transitional phenomena in terms of hydrology and the thermodynamics of soil systems. The impact of these short-term phenomena on larger scale ecosystem fluxes is increasingly recognized, and a growing number of studies show that these events affect fluxes of soil gases such as carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), ammonia (NH3) and nitric oxide (NO). Global climate models predict that future climatic change is likely to alter the frequency and intensity of drying-rewetting events and thawing of frozen soils. These future scenarios highlight the importance of understanding how rewetting and thawing will influence dynamics of these soil gases. This study summarizes findings using a new database containing 338 studies conducted from 1956 to 2011, and highlights open research questions. The database revealed conflicting results following rewetting and thawing in various terrestrial ecosystems and among soil gases, ranging from large increases in fluxes to non-significant changes. Studies reporting lower gas fluxes before rewetting tended to find higher post-rewetting fluxes for CO2, N2O and NO; in addition, increases in N2O flux following thawing were greater in warmer climate regions. We discuss possible mechanisms and controls that regulate flux responses, and recommend that a high temporal resolution of flux measurements is critical to capture rapid changes in gas fluxes after these soil perturbations. Finally, we propose that future studies should investigate the interactions between biological (i.e., microbial community and gas production) and physical (i.e., porosity, diffusivity, dissolution) changes in soil gas fluxes, apply techniques to capture rapid changes (i.e., automated measurements), and explore synergistic experimental and modelling approaches.
URL: http://www.biogeosciences.net/9/2459/2012/bg-9-2459-2012.pdf
14018602 Overduin, P. P. (Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Potsdam, Germany); Strzelecki, M. C.; Grigoriev, M. N.; Couture, N.; Lantuit, H.; St-Hilaire-Gravel, D.; Günther, F. and Wetterich, S. Coastal changes in the Arctic: in Sedimentary coastal zones from high to low latitudes; similarities and differences (Martini, I. P., editor; et al.), Special Publication - Geological Society of London, 388, illus. incl. 1 table, sketch maps, 127 ref., February 12, 2014. (Online First).
The arctic environment is changing: air temperatures, major river discharges and open water season length have increased, and storm intensities and tracks are changing. Thirteen quantitative studies of the rates of coastline position change throughout the Arctic show that recently observed environmental changes have not led to ubiquitously or continuously increasing coastal erosion rates, which currently range between 0 and 2 m/yr when averaged for the arctic shelf seas. Current data is probably insufficient, both spatially and temporally, however, to capture change at decadal to sub-decadal time scales. In this context, we describe the current understanding of arctic coastal geomorphodynamics with an emphasis on erosional regimes of coasts with ice-rich sedimentary deposits in the Laptev, East Siberian and Beaufort seas, where local coastal erosion can exceed 20 m/yr. We also examine coasts with lithified (rocky) substrates where geomorphodynamics are intensified by rapid glacial retreat. Coastlines of Svalbard, Greenland and the Canadian Archipelago are less frequently studied than ice-rich continental coasts of North America and Siberia, and studies often focus on coastal sections composed of unlithified material. As air temperature and sea ice duration and extent change, longer thaw and wave seasons will intensify coastal dynamics in the Arctic.
DOI: 10.1144/SP388.13
14020156 Cheverov, V. G. (Moskovskiy Gosudarstvennyy Universitet, Moscow, Russian Federation); Burnayev, R. S.; Gagarin, V. Ye. and Safronov, Ye. F. Vliyaniye vneshney nagruzki na stepen' moroznogo pucheniya glinistykh gruntov [Influence of external pressure on the degree of frost heaving of clay soils]: Kriosfera Zemli = Earth Cryosphere, 17(4), p. 57-62 (English sum.), illus., 10 ref., December 2013.
The method for the laboratory determination of the characteristics of ground frost heaving has been described. The complex nature of the correlation between relative frozen silt clay heaving and the external load in consolidated and non-consolidated conditions has been demonstrated.
14020154 Kizyakov, A. I. (Moskovskiy Gosudarstvennyy Universitet, Moscow, Russian Federation); Zimin, M. V.; Leybman, M. O. and Pravikova, N. V. Monitoring skorosti termodenudatsii i termoabrazii na zapadnom poberezh'ye ostrova Kolguyev s ispol'zovaniyem materialov kosmicheskoy s"yemki vysokogo razresheniya [Monitoring the rate of thermal denudation and thermal abrasion on the western coast of Kolguyev Island using high resolution satellite images]: Kriosfera Zemli = Earth Cryosphere, 17(4), p. 36-47 (English sum.), illus. incl. 5 tables, sketch maps, 29 ref., December 2013.
New data on thermocirque and coastal bluff retreat rates within a key site on Kolguyev Island have been obtained using high resolution satellite images covering the period of 2002 to 2012. It was revealed that the modern (2002-2012) thermocirque retreat rates (thermal denudation of frozen steep slopes with tabular ground ice exposures) amount to an average of 2.6 m/year, which is close to the rates established for the period of 1948 to 2002 (2.4 m/year). Modern maximum retreat rates have reached up to 14.5-15.1 m/year. During the period of 1948-2012 the maximum coastal bluff retreat rates (thermal abrasion) 4 m/year.
14020153 Roman, L. T. (Moskovskiy Gosudarstvennyy Universitet, Moscow, Russian Federation) and Kotov, P. I. Opredeleniye vyazkosti merzlykh gruntov sharikovym shtampom [Determination of the viscosity of frozen ground using the method of sphere punch]: Kriosfera Zemli = Earth Cryosphere, 17(4), p. 30-35 (English sum.), illus. incl. 2 tables, 17 ref., December 2013.
A method for obtaining rheological curves of frozen ground by sphere punch has been suggested. This method gives a possibility for determining the dynamic viscosity of frozen ground by Stoke's equation together with determining strength characteristic--equivalent cohesion. The results of investigation into the dependence of dynamic viscosity of various frozen soils on temperature, granulometric composition, and salinity have been presented.
14020161 Shirshova, L. T. (Rossiyskaya Akademiya Nauk, Institut Fiziki-khimicheskikh i Biologicheskikh Problem Pochvovedeniya, Pushchino, Russian Federation); Gilichinskiy, D. A.; Ostroumova, N. V. and Yermolayev, A. M. Primeneniye metodov opticheskoy spektroskopii dlya issledovaniya guminovykh veshchestv merzlykh tolshch [Investigation of humic substances from frozen ground using the method of optical spectroscopy]: Kriosfera Zemli = Earth Cryosphere, 17(4), p. 94-104 (English sum.), illus. incl. table, 31 ref., December 2013.
The results of optical spectroscopy (absorbance, emission and synchronous spectra) applied to the study of humic substances gained from permanently frozen sediments of different ages were examined. In accordance with the spectroscopy-produced data, the humic substances of examined sediments are enriched by low-humified compounds. It was found that the optical characteristics of certain humic fractions isolated from a freshly defrosted sample differ from the corresponding characteristics of corresponding fractions obtained from air-dried sample incubated at room temperature. Spectroscopic parameters for characterization of the state of humic substances stored in frozen strata are suggested.
14020151 Slagoda, Ye. A. (Rossiyskaya Akademiya Nauk, Sibirskoye Otdeleniye, Institut Kriosfery Zemli, Tyumen, Russian Federation); Leybman, M. O.; Khomutov, A. V. and Orekhov, P. T. Kriolitologicheskoye stroyeniye pervoy terrasy ostrova Belyy v Karskom more (chast' 1) [Cryolithologic reconstruction of the first terrace at Belyy Island, Kara Sea (Part 1)]: Kriosfera Zemli = Earth Cryosphere, 17(4), p. 11-21 (English sum.), illus. incl. sects., sketch map, 20 ref., December 2013.
New data on the cryolithologic construction of the marine terrace on Belyy Island in the Kara Sea were obtained in 2009-2012. Cryogenic structure, soluble salt concentration, structure and texture of deposits are described and sampled in four boreholes. The data obtained allow subdividing three types of geological section of coastal-marine deposits of the first terrace which differ in the presence of polygonal ice wedges, salinity and deformation of stratification in deposits.
14020146 Altunina, L. K. (Rossiyskaya Akademiya Nauk, Sibirskoye Otdeleniye, Institut Khimii Nefti, Tomsk, Russian Federation); Fufayeva, M. S.; Filatov, D. A.; Svarovskaya, L. I. and Gam-Erdene, T. Primeneniye kriogelya dlya stabilizatsii pochv, podverzhennykh deflyatsii [Application of cryogel for stabilizing soils under deflation]: Kriosfera Zemli = Earth Cryosphere, 17(3), p. 83-88 (English sum.), illus. incl. 3 tables, 17 ref., September 2013.
It has been demonstrated that being absorbed by soil, the cryogeol obtained by the method of freezing-thawing with the use of polyvinyl alcohol solution has a positive effect on the size of indigenous microflora, soil enzyme activity, and growth of perennial grasses. A new chemical-biological method has been suggested to prevent wind erosion (deflation) of soil using cryogel combined with sowing of perennial grasses, which promote the formation of a soddy horizon. The prepared cryogeo-coil particle system is strong enough to withstand the impact of erosion processes, and it is elastic enough not to interfere with the growth of plants. The seeds germinated through a cryogel layer form a stable vegetable cover. Cryogeol are harmless to humans and the environment.
14020138 Streletskaya, I. D. (Moskovskiy Gosudarstvennyy Universitet, Moscow, Russian Federation); Gusev, Ye. A.; Vasil'yev, A. A.; Oblogov, G. Ye.; Anikina, N. Yu.; Arslanov, Kh. A.; Derevyanko, L. G. and Pushina, Z. V. Geokriologicheskoye stroyeniye chetvertichnykh otlozhdeniy beregov Zapadnogo Taymyra [Geocryologic structure of Quaternary sediments from the western Taymyr coast]: Kriosfera Zemli = Earth Cryosphere, 17(3), p. 17-26 (English sum.), illus. incl. sects., sketch map, 29 ref., September 2013.
This paper summarizes the new analytical studies of the Quaternary deposits of West Taymyr and presents the results of spore-pollen, fauna, grain-size and mineralogical, geochemical, isotopic and other analyses. Latest dating for the supporting geocryological transects enables us to refine the stratigraphy and paleogeographical reconstruction of depositional environments and the late Pliocene-Holocene freezing sediments in West Taymyr. The long marine sedimentation in the late Kargino time (MIS 3) gives the direction toward continental conditions. Marine sediments were frozen syngenetically and epigenetically with formation of cryostructure and ground ice. Polygonal vein ice formed in the late Pliocene (MIS 2) and is characterized by values of the stable isotopes of oxygen (d18O) - 26ppm...-23ppm and hydrogen (dD) - 198ppm... - 172 ppm, and predominance of HCO3- and Ca2+ ions in the ice. Holocene (MIS 1) polygonal vein ice is characterized by values of the oxygen (d18O) - 20ppm... -17ppm and hydrogen (dD) - 160ppm... - 126ppm and prevalence of Cl- and Na+ ions in the ice.
14020149 Tentyukov, M. P. (Rossiyskaya Akademiya Nauk, Ural'skoye Otdeleniye, Komi Nauchnyy Tsentr, Institut Biologii, Syktyvkar, Russian Federation). Osobennosti raspredeleniya khimicheskikh elementov v merzlykh pochvakh [Features of distribution of chemical elements in frozen soils]: Kriosfera Zemli = Earth Cryosphere, 17(3), p. 100-107 (English sum.), illus. incl. table, 26 ref., September 2013.
The results of geocryological and landscape-geochemical studies of frozen peat soils developed on the relic peat in the southern part of the Bolshezemelskaya tundra have been presented. The influence of snow cover on the feature of trace elements distribution in the frozen soil profile has been considered. The formation conditions of cryogenic zone desalination in frozen soils have been analyzed. Indicator geochemical features of cryogenic desalination zone in winter conditions have been determined, and their informative degree in the thawed soils profile has been evaluated. The need for studying seasonal migration of chemical elements in the tundra landscape has been pointed out, taking into account the fact that the winter processes in frozen soil profile affect the soil geochemical characteristics even in the summer period.
14020118 Anikin, G. V. (Rossiyskaya Akademiya Nauk, Sibirskoye Otdeleniye, Institut Kriosfery, Tyumen, Russian Federation); Plotnikov, S. N. and Spasennikova, K. A. Raschet dinamiki promerzaniya grunta pod vozdeystviyem odinochnogo termosifona [Calculation of soil freezing rate under the influence of a solitary thermosyphon]: Kriosfera Zemli = Earth Cryosphere, 17(1), p. 51-55 (English sum.), illus. incl. table, 5 ref., March 2013.
The analytic approach to the solution of the problem of freezing of soil under the influence of a vertical vapor-liquid thermosyphon has been proposed. The analytic approach was compared with a similar solution obtained with the help of numerical methods. It has been demonstrated that the calculation results obtained using these methods are very similar, which allows one to utilize the obtained analytical expressions for practical calculations.
14020120 Chuvilin, Ye. M. and Bukhanov, B. A. Eksperimental'noye izucheniye teploprovodnosti merzlykh gidratosoderzhashchikh gruntov pri atmosfernom davlenii [Experimental study of the thermal conductivity of frozen hydrate-saturated sediments during atmospheric pressure]: Kriosfera Zemli = Earth Cryosphere, 17(1), p. 69-79, illus. incl. 6 tables, 39 ref., March 2013.
14019299 Kadereit, Annette (Universität Heidelberg, Geographisches Institut, Heidelberg, Germany); Kind, Claus-Joachim and Wagner, Günther A. The chronological position of the Lohne soil in the Nussloch loess section; re-evaluation for a European loess-marker horizon: Quaternary Science Reviews, 59, p. 67-86, illus. incl. sects., 1 table, geol. sketch map, 136 ref., January 3, 2013.
The loess section of Nussloch in southwestern Germany is a key profile for the reconstruction of the terrestrial palaeo-environment of central Europe at the time of the Last Glacial and Interglacial. Recently, the significance of the site for palaeo-environmental and geoarchaeological research increased additionally, with the discovery of unique Palaeolithic cultural remains from anatomically and culturally modern humans that invaded southwestern Germany during the Weichselian (Wurmian) Pleniglacial period. At Nussloch, a chrono-stratigraphical key position is taken by a Middle Pleniglacial Cambisol remain which, under the designation Lohne Soil, serves as an important pedostratigraphic marker horizon for the greater area. Repeatedly, Greenland interstadial (GIS) 8 was suggested as a likely period of soil formation for the Lohne Soil. This interpretation is yet not justified on the basis of published chronometric data. Critical assessment of the data points to a later period of soil formation, likely during GIS7 to GIS5. This conclusion is supported by a new set of radiocarbon ages for the Nussloch site which are presented here for the first time. Consequences of a revised chronology for correlations of Pleniglacial Cryosols below and above the Lohne Soil with Greenland interstadials are discussed. The implications are important for European loess research as the Nussloch section serves as a reference base for loess sections throughout Europe. Abstract Copyright (2013) Elsevier, B.V.
DOI: 10.1016/j.quascirev.2012.10.026
14021257 Hammer, Jörg (Bundesanstalt für Geosissenschaften und Rohstoffe, Hanover, Germany); Fleig, Stephanie; Mingerzahn, Gerhard; Kühnlenz, Tatjana; Mertineit, Michael; Pusch, Maximilian; Schramm, Michael; Behlau, Joachim; Zaretzki, Britta; Hesser, Jürgen; Shao, Hua; Köthe, Angelika and Vogel, Peter. Salzgeologische Bewertung des Einflusses von "kryogenen Klüften" und halokinetischen Deformationsprozessen auf die Integrität der geologischen Barriere des Salzstocks Gorleben; Bericht zum Arbeitspaket 2; vorläufige Sicherheitsanalyse für den Standort Gorleben [Salt geology assessment of the effects of "cryogenic fissures" and halokinetic deformation processes on the integrity of geological barriers of the Gorleben salt dome; report on the working packet 2; preliminary safety analysis for the Gorleben site]: GRS - Berichte, 273, 86 p., illus. incl. sects., sketch maps, 80 ref., 2012. ISBN: 978-3-939355-49-6.
URL: http://www.grs.de/sites/default/files/pdf/GRS-273.pdf
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