Permafrost Monthly Alerts (PMAs)

14029623 Arens, V. Zh. (Russian Academy of Sciences, Moscow, Russian Federation); Khcheyan, G. Kh. and Khrulev, A. S. Skvazhinnaya gidrodobycha peskov s khozyaystvennym ispol'zovaniyem obrazovavshikhsya podzemnykh pustot v usloviyakh vechnoy merzloty [Hydraulic borehole mining of sands with practical use of underground formation voids in permafrost regions]: Gornyy Zhurnal, 2013(10), p. 79-82 (English sum.), illus., 3 ref., October 2013.

Hydraulic borehole mining of sands was proved by experimental and industrial works in middle Priobye, Tomsk Oblast and Altai Krai. Seams were developed with thickness from 8 to 44 m. The sand was raised from the depths of 15-270 m. The technology of hydraulic borehole mining of sands through inclined holes was also succesfully tested for low strength characteristics of overburden, swamped surface and small thickness of seams. Researches of hydraulic borehole mining of sands in permafrost rocks with usage of a steam-generating plant were carried out on the Yamal Peninsula by specialists of Podzemgazprom. A special well is drilled from the Earth's surface. Water is pumped into a free interval of a well by hole clearance of work strings. The pulp--a mixture of water with unfrozen sandy rock--is driven out to the surface by the central string. Hermiticity of the constructed excavation is provided by artificial cooling of casing string, and the level of water in excavation is maintained lower than the casing shoe by injection of compressed air or natural gas into it. According to the results of hydrolocation survey, the capacity of formed underground cave is 4.9 th. m3. The sufficient decreasing of cost price and higher quality of extracted solid sand (in comparison with the traditionalal method of open cast mining of sand-gravel mixtures in analogous natural-climatic conditions) is substantiated. Formed underground caves are used as reservoirs for storage of liquid hydrocarbons or burial of fine fraction mining wastes (for example, wells drilling slime).

14029527 Vincent, Warwick F. (Laval University, Centre d'Études Nordiques, Quebec City, QC, Canada); Lemay, Mickaël; Allard, Michel and Wolfe, Brent B. Adapting to permafrost change; a science framework: Eos, Transactions, American Geophysical Union, 94(42), p. 373-375, illus., 10 ref., October 15, 2013.

Permafrost is a defining feature of the circumpolar north, and with climate change already affecting its range and behavior, understanding the fate of northern environments is a pressing concern. The Canadian Arctic Development and Adaptation to Permafrost in Transition (ADAPT) project is bringing together researchers from within and outside Canada to study the mechanisms and consequences of permafrost degradation and to place this information within an interdisciplinary systems framework. Abstract Copyright (2013), . American Geophysical Union. All Rights Reserved.

DOI: 10.1002/2013EO420002

14032714 Guo Donglin (Chinese Academy of Sciences, Institute of Atmospheric Physics, Nansen-Zhu International Research Center, Beijing, China) and Wang Huijun. Simulation of permafrost and seasonally frozen ground conditions on the Tibetan Plateau, 1981-2010: Journal of Geophysical Research: Atmospheres, 118(D11), p. 5216-5230, illus. incl. 1 table, 22 ref., June 16, 2013.

Permafrost and seasonally frozen ground conditions on the Tibetan Plateau were investigated using the Community Land Model, version 4 (CLM4), forced by a suite of new, high-resolution data. This new data set was highly accurate and had an advantage in the frozen ground simulations for its fine temporal and spatial resolution. The simulated current (1981-2000) near-surface permafrost area was 151.50 ´ 10⁴ km², which is close to, but slightly larger than, the range from previous studies (111.80 ~ 150.0 ´ 10⁴ km²). The simulated current active layer thicknesses ranged from 0 to 4.74 m, with an average of 2.01 m. The other frozen ground parameters, such as the maximum freezing depths for seasonally frozen ground, the date of freeze start, the date of freeze end, and the freeze duration at 1 m depth, were also examined. Considering the issue of scale mismatch, the simulated soil temperature and other frozen ground parameters were reasonable compared to our observations. In response to the Plateau warming of approximately 0.44°C/decade from 1981 to 2010, the near-surface permafrost area decreased at a rate of 9.20 ´ 10⁴ km²/decade, and the area-mean active layer thickness increased by 0.15 m/decade. The area-mean maximum freezing depth of the seasonally frozen ground decreased by 0.34 m/decade. At a depth of 1 m, the dates of freeze start for permafrost and seasonally frozen ground delayed linearly by 3.8 and 4.0 days/decade, respectively, while the dates of freeze end for them advanced linearly by 5.9 and 4.6 days/decade, respectively. These trends in the dates of freeze start and freeze end resulted in freeze durations that were shortened by 9.7 and 8.6 days/decade for permafrost and seasonally frozen ground, respectively. These results give detailed permafrost and seasonally frozen ground states as well as their changes, which will be useful for studying frozen ground's response to climate change and frozen ground engineering stabilization. Abstract Copyright (2013), . American Geophysical Union. All Rights Reserved.

DOI: 10.1002/jgrd.50457

14031389 Beer, C. (Max Planck Institute for Biogeochemistry, Jena, Germany); Fedorov, A. N. and Torgovkin, Y. Permafrost temperature and active-layer thickness of Yakutia with 0.5-degree spatial resolution for model evaluation: Earth System Science Data (ESSD), 5(2), p. 305-310, illus. incl. sketch map, 14 ref., 2013.

Based on the map of landscapes and permafrost conditions in Yakutia (Merzlotno-landshaftnaya karta Yakutskoi0 ASSR, Gosgeodeziya SSSR, 1991), rasterized maps of permafrost temperature and active-layer thickness of Yakutia, East Siberia were derived. The mean and standard deviation at 0.5-degree grid cell size are estimated by assigning a probability density function at 0.001-degree spatial resolution. The gridded datasets can be accessed at the PANGAEA repository (doi:10.1594/PANGAEA.808240). Spatial pattern of both variables are dominated by a climatic gradient from north to south, and by mountains and the soil type distribution. Uncertainties are highest in mountains and in the sporadic permafrost zone in the south. The maps are best suited as a benchmark for land surface models which include a permafrost module.

DOI: 10.5194/essd-5-305-2013

14032689 Debol'skaya, Ye. I. (Russian Academy of Sciences, Institute for Water Problems, Moscow, Russian Federation); Debol'skiy, V. K.; Gritsuk, I. I.; Maslikova, O. Ya. and Ionov, D. N. Modelirovaniye deformatsiy rusel, slozhennykh merzlymi porodami, pri povyshenii temperatury okruzhayushchey sredy [Modeling of channel deformation in the permafrost zone under global warming]: Led i Sneg = Ice and Snow, 121, p. 104-110 (English sum.), illus., 8 ref., 2013.

This paper is devoted to investigation of the influence of river flow and of the temperature rise on the deformation of the coastal slopes composed of permafrost with the inclusion of ice layer. The method of investigation is the laboratory and mathematical modeling. The laboratory experiments have shown that an increase in water and air temperature changes in a laboratory analogue of permafrost causes deformation of the channel even without wave action, i.e. at steady-state flow and non-erosive water flow velocity. The previously developed model of the bed deformation was improved to account for long-term changes of soil structure with increasing temperature. The three-dimensional mathematical model of coastal slopes thermoerosion of the rivers flowing in permafrost regions, and its verification was based on the results of laboratory experiments conducted in the hydraulic tray. Analysis of the results of mathematical and laboratory modeling showed that bed deformation of the rivers flowing in the permafrost zone, significantly different from the deformation of channels composed of soils not susceptible to the influence of the phase transition "water-ice", and can occur even under the non-erosive velocity of the water flow.

14031390 Hugelius, G. (Stockholm University, Department of Physical Geography and Quaternary Geology, Stockholm, Sweden); Bockheim, J. G.; Camill, P.; Elberling, B.; Grosse, G.; Harden, J. W.; Johnson, K.; Jorgenson, T.; Koven, C. D.; Kuhry, P.; Michaelson, G.; Mishra, U.; Palmtag, J.; Ping, C. L.; O'Donnell, J.; Schirrmeister, L.; Schuur, E. A. G.; Sheng, Y.; Smith, L. C.; Strauss, J. and Yu, Z. A new data set for estimating organic carbon storage to 3 m depth in soils of the northern circumpolar permafrost region: Earth System Science Data (ESSD), 5(2), p. 393-402, illus. incl. 4 tables, sketch maps, 41 ref., 2013.

High-latitude terrestrial ecosystems are key components in the global carbon cycle. The Northern Circumpolar Soil Carbon Database (NCSCD) was developed to quantify stocks of soil organic carbon (SOC) in the northern circumpolar permafrost region (a total area of 18.7 ´ 10⁶ km²). The NCSCD is a geographical information system (GIS) data set that has been constructed using harmonized regional soil classification maps together with pedon data from the northern permafrost region. Previously, the NCSCD has been used to calculate SOC storage to the reference depths 0-30 cm and 0-100 cm (based on 1778 pedons). It has been shown that soils of the northern circumpolar permafrost region also contain significant quantities of SOC in the 100-300 cm depth range, but there has been no circumpolar compilation of pedon data to quantify this deeper SOC pool and there are no spatially distributed estimates of SOC storage below 100 cm depth in this region. Here we describe the synthesis of an updated pedon data set for SOC storage (kg C m^-2) in deep soils of the northern circumpolar permafrost regions, with separate data sets for the 100-200 cm (524 pedons) and 200-300 cm (356 pedons) depth ranges. These pedons have been grouped into the North American and Eurasian sectors and the mean SOC storage for different soil taxa (subdivided into Gelisols including the sub-orders Histels, Turbels, Orthels, permafrost-free Histosols, and permafrost-free mineral soil orders) has been added to the updated NCSCDv2. The updated version of the data set is freely available online in different file formats and spatial resolutions that enable spatially explicit applications in GIS mapping and terrestrial ecosystem models. While this newly compiled data set adds to our knowledge of SOC in the 100-300 cm depth range, it also reveals that large uncertainties remain. Identified data gaps include spatial coverage of deep (> 100 cm) pedons in many regions as well as the spatial extent of areas with thin soils overlying bedrock and the quantity and distribution of massive ground ice. An open access data-portal for the pedon data set and the GIS-data sets is available online at URL: http://bolin.su.se/data/ncscd/. The NCSCDv2 data set has a digital object identifier (doi:10.5879/ECDS/00000002).

DOI: 10.5194/essd-5-393-2013

14031032 Hugelius, G. (Stockholm University, Department of Physical Geography and Quaternary Geology, Stockholm, Sweden); Tarnocai, C.; Broll, G.; Canadell, J. G.; Kuhry, P. and Swanson, D. K. The Northern Circumpolar Soil Carbon Database; spatially distributed datasets of soil coverage and soil carbon storage in the northern permafrost regions: Earth System Science Data (ESSD), 5(1), p. 3-13, illus. incl. 3 tables, sketch map, 64 ref., 2013.

High-latitude terrestrial ecosystems are key components in the global carbon (C) cycle. Estimates of global soil organic carbon (SOC), however, do not include updated estimates of SOC storage in permafrost-affected soils or representation of the unique pedogenic processes that affect these soils. The Northern Circumpolar Soil Carbon Database (NCSCD) was developed to quantify the SOC stocks in the circumpolar permafrost region (18.7 ´ 10⁶ km²). The NCSCD is a polygon-based digital database compiled from harmonized regional soil classification maps in which data on soil order coverage have been linked to pedon data (n = 1778) from the northern permafrost regions to calculate SOC content and mass. In addition, new gridded datasets at different spatial resolutions have been generated to facilitate research applications using the NCSCD (standard raster formats for use in geographic information systems and Network Common Data Form files common for applications in numerical models). This paper describes the compilation of the NCSCD spatial framework, the soil sampling and soil analytical procedures used to derive SOC content in pedons from North America and Eurasia and the formatting of the digital files that are available online. The potential applications and limitations of the NCSCD in spatial analyses are also discussed. The database has the doi:10.5879/ecds/00000001. An open access data portal with all the described GIS-datasets is available online at: URL: http://www.bbcc.su.se/data/ncscd/.

DOI: 10.5194/essd-5-3-2013

14033673 Bosson, Emma (Stockholm University, Department of Physical Geography and Quaternary Geology, Stockholm, Sweden); Sabel, Ulrika; Gustafsson, Lars-Göran; Sassner, Mona and Destouni, Georgia. Influences of shifts in climate, landscape, and permafrost on terrestrial hydrology: Journal of Geophysical Research, 117(D5), Citation D05120, illus. incl. 2 tables, 34 ref., March 2012.

This study has simulated the terrestrial hydrology associated with different climate, landscape, and permafrost regime scenarios for the field case example of the relatively well characterized coastal catchment of Forsmark, Sweden. The regime scenarios were selected from long-term simulation results of climate, topographical, shoreline, and associated Quaternary deposit and vegetation development in this catchment with a time perspective of 100,000 years or more and were used as drivers for hydrological simulations with the three-dimensional model MIKE SHE. The hydrological simulations quantify the responses of different water flow and water storage components of terrestrial hydrology to shifts from the present cool temperate climate landscape regime in Forsmark to a possible future Arctic periglacial landscape regime with or without permafrost. The results show complexity and nonlinearity in the runoff responses to precipitation changes due to parallel changes in evapotranspiration, along with changes in surface and subsurface water storage dynamics and flow pathways through the landscape. The results further illuminate different possible perspectives of what constitutes wetter/drier landscape conditions, in contrast to the clearer concept of what constitutes a warmer/colder climate.

DOI: 10.1029/2011JD016429

14030021 Dury, G. H. (University of London, Department of Geography, London, United Kingdom). Theoretical implications of underfit streams: Benchmark Papers in Hydrology, 9, p. 62-76, illus. incl. 7 tables, 7 tables, 2014. Reprinted from U. S. Geological Survey Professional Paper 452-C, 43 p., 1965.

A technique of defining discharge at the natural bankfull stage, upon rivers subjected to artificial banking and dredging, is applied to extending the data available on the relation between amount of discharge and wavelength of meanders. The new data confirm that wavelength varies with the square root of discharge and support the contention that bankfull discharge of manifestly underfit streams has been reduced by the square of the reduction shown by meander wavelengths. Allowances, however, are necessary for additional changes, notably those in channel form and in downstream slope. The large channels occupied by former streams are thought to have a higher width-and-depth ratio than the present channels, thus giving, for instance, a 25:1 ratio of cross-sectional area where the bed-width ratio is 9:1 or 10:1. If velocity through the former cross section at bankfull stage were identical with present-day velocity at the corresponding stage, then the discharge ratio for highly underfit streams would be about 25:1 instead of 80:1 or 100:1 as previously suggested by the writer. But reduction to manifest underfitness involves a reduction of downstream slope on account of lengthened trace, for which infilling of headward valleys or excavation of downstream reaches do not compensate. The reduced slope, in turn, involves reduction in velocity, which considerably offsets the change in channel form. The net outcome of revised calculations is that a discharge ratio of about 50:1 or 60:1 is required where streams are highly underfit--that is, where the wavelength ratio is 9:1 or 10:1--and a discharge ratio of about 20:1 is required where the wavelength ratio is about 5:1. This last ratio is widely represented in nature. Inquiry into the possible hydrologic effects of climatic change takes into account the temperatures reconstructed for full-glacial times and applies them in transformations of the empirically determined interrelation of temperature, precipitation, and annual runoff. In conjunction with increases in total precipitation by a factor of 1.5-2.0, the inferred temperature changes are capable of increasing annual runoff by factors in the approximate range of 5.0-10.0 in a wide range of existing climates. Computed proportional increases in runoff rise toward increasingly dry and increasingly warm climates. Temperature change alone is not sufficient to explain the observed morphological effects, especially in view of the dating of certain episodes of channeling and of the assigning of initiation of valley meanders to parts of the deglacial succession when the trough of low full-glacial conditions had already been passed and when air temperatures were distinctly rising. Frozen ground, whether seasonally frozen or permafrost itself, cannot provide a general explanation of the former discharges required by underfit streams. So much, is shown by reference to the hydrologic regimens of present-day climates in Alaska and by a hypothetical translocation of seasonally cold climate from Wisconsin to the gulf coast of Texas. Manifestly underfit streams exist in this latter region, which is well beyond the extreme limit of permafrost at the last glacial maximum; similar streams in Puerto Rico are even further distant from the former lines of ice stand. Hypothetical modifications of regimens of precipitation suggest that change in total precipitation is likely to have been more influential than change in seasonal concentration. The difference between the increase effected in total runoff both by-reduced temperatures and by increased precipitation and the increase computed for momentary peak discharge is likely attributable to the short-term effects of single storms, especially those of rather high frequency and rather long duration. Their influence can readily be accommodated within the framework of a modest general increase in precipitation, and also within the framework of greatly reduced temperatures which do not prohibit the required increases either in total precipitation or in single rainfalls. The general postulate of increased precipitation in early deglacial times agrees with fluctuations of pluvial lakes; the location of the postulated increased precipitation on the time scale does not conflict with extensive and persistent continental highs, postulated for full-glacial episodes. More broadly, the climatic and meteorological demands made in connection with this general theory of underfit streams accord with reconstructions of the global weather patterns of high-glacial episodes and with observations of marked changes in rates of deep-sea sedimentation.

14031612 Rostek, Frauke (Aix-Marseille Université, Centre Européen de Recherche et d'Enseignement des Géosciences de l'Environnement, Aix-en-Provence, France) and Bard, Edouard. Hydrological changes in eastern Europe during the last 40,000 yr inferred from biomarkers in Black Sea sediments: Quaternary Research, 80(3), p. 502-509, illus. incl. sketch map, 97 ref., November 2013.

The Black Sea is connected to a large drainage area including the European Russian Plain, part of the Alps and southeastern Europe. To study the hydrological changes in this basin over the last 40,000 years, we measured specific terrigenous biomarkers for wetland vegetation in well-dated sediments from the northwestern Black Sea, spanning the last glacial period (lacustrine phase) and the Holocene (marine phase). Low abundances of these biomarkers are observed during the North Atlantic ice melting and cooling events known as Heinrich Events 4 to 2, the Last Glacial Maximum and the Younger Dryas Event. Increased biomarker inputs characterize the mild climate phases known as Dansgaard-Oeschger Interstadials, the Bolling/Allerod and Preboreal Warmings indicating increased erosion due to permafrost degradation, higher primary productivity and/or wetland extension in the drainage basin. The final retreat of the Fennoscandian Ice Sheet from the Russian Plain occurs during the early part of Heinrich Event 1 and is characterized by increased biomarker concentrations in a typical series of four deglacial clay layers. For the last glacial period, the correspondence in timing between the biomarker records and the atmospheric CH₄ record from ice cores, suggests an important CH₄ contribution due to boreal permafrost thawing and wetland emission. Abstract Copyright (2013) Elsevier, B.V.

DOI: 10.1016/j.yqres.2013.07.003

14032687 Anisimov, O. A. (State Hydrological Institute, Saint Petersburg, Russian Federation) and Kokorev, V. A. Ob optimal'nom vybore gidrodinamicheskikh modeley dlya otsenki vliyaniya izmeneniy klimata na kriosferu [Optimal hydrodynamic models for assessment of climate change impact on the cryosphere]: Led i Sneg = Ice and Snow, 121, p. 83-92 (English sum.), illus. incl. 2 tables, sketch map, 24 ref., 2013.

This study is targeted at narrowing the range of uncertainties in predictive cryospheric modeling associated with climatic projections. We used the output from 36 CMIP5 GCM runs for the period 1976-2005 and calculated trends of several climatic characteristics that largely govern the state of the cryosphere, i.e. seasonal and mean annual air temperature, thawing degree-day sums, annual and winter precipitation sums. Data from 744 weather stations were used to identify and delineate 17 regions, which demonstrate coherent temperature changes in the past decades. Results from GCMs and observations were averaged over the "coherent regions" and compared with each other. Ultimately, we evaluated the skills of individual CMIP5 GCMs, ranked them in the specific context of predictive cryospheric modeling, identified top-end models in each of the 17 regions and eliminated the outliers. Selected top-end GCMs were used to compose optimal regional ensembles that were compared with the ensemble consisting of all available models. An optimal ensemble was also constructed for the area underlain by permafrost in Russia. Results indicate that the all-model ensemble in most regions underestimates the projected temperature changes compared to the optimal ensemble. Elimination of the outliers narrows the range of uncertainty in regional climate projection by 5-20%.

14032688 Osokin, N. I. (Russian Academy of Sciences, Institute of Geography, Moscow, Russian Federation); Sosnovskiy, A. V.; Nakalov, P. R. and Nenashev, S. V. Termicheskoye soprotivleniye snezhnogo pokrova i ego vliyaniye na promerzaniye grunta [Snowpack's thermal insulation and its influence of ground freezing]: Led i Sneg = Ice and Snow, 121, p. 93-103 (English sum.), illus. incl. 3 tables, 26 ref., 2013.

Spatial and temporal variability of snow thermal resistance in some areas of Krasnoyarsk region and Yakutia has been studied. Soil freezing depth has been correlated with snow cover depth and its thermal resistance. Mathematical modeling has been applied to assess the influence of snow cover and soil parameters on depth of frost penetration. The critical thickness of snow cover that controls the development of seasonally frozen layer disconnected from underlying permafrost was found. Capabilities and efficiency of controlling the thermal resistance of snow cover required to reduce the adverse effects of climate warming on permafrost degradation have been discussed.

14030907 Jankowski, Michal (Nicolaus Copernicus University, Institute of Geography, Torun, Poland). Lateglacial soil paleocatena in inland-dune area of the Torun Basin, northern Poland: in Paleosols in soilscapes of the past and present (Sedov, Sergey, editor; et al.), Quaternary International, 265, p. 116-125, illus. incl. sects., 3 tables, sketch map, 55 ref., June 28, 2012.

The buried toposequence of soils (paleocatena) dated to the Allerod interstadial has been researched in this work. Studies were carried at the Katarzynka site located in the inland-dune area of the Torun Basin, Northern Poland. Paleosols developed on the slope dividing two glaciofluvial terraces, and were buried under dune sands during the Younger Dryas (ca 11100 BP; uncal.) The paleocatena consists of weakly developed Podzolic (Usselo) soil at the upper slope, Gley-Podzolic soil at the lower slope and humus-enriched Gleysol at the bottom of the sequence. In some parts, the paleosol also has the morphology of the 'Bwb' horizon typical for the so-called Finow soil. In the uppermost topographical position, the buried soil mantle is eroded by wind activity and shows disturbances typical for periglacial conditions. Usselo and Finow soils are usually considered to be marker stratigraphical horizons for Lateglacial aeolian landscapes of Western and Central Europe, although their genesis and paleoenvironmental significance are still controversial. The occurrence in paleocatena pattern and morphological, chemical and micromorphological features indicate their pedogenic nature. The Podzolic (Usselo) soil, Gley-Podzolic soil and Gleysol show clear effects of soil-forming and diagenetic processes varying along the buried slope. The origin of 'Bwb' Finow soil horizon seems to be a post-burial process similar to illuvial lamellae formation, masking the effects of former pedogenic features. In all probability, this process was preceded by alterations of soil morphology caused by permafrost development at the onset of the Younger Dryas, immediately before burial. The variety of soils forming the paleocatena is clear evidence of landscape diversity during the Allerod.

DOI: 10.1016/j.quaint.2012.02.006

14031615 Wang Xianyan (Nanjing University, School of Geographic and Oceanographic Sciences, Nanjing, China); Vandenberghe, Dimitri; Yi Shuangwen; Vandenberghe, Jef; Lu Huayu; van Balen, Ronald and van den Haute, Peter. Late Quaternary paleoclimatic and geomorphological evolution at the interface between the Menyuan Basin and the Qilian Mountains, northeastern Tibetan Plateau: Quaternary Research, 80(3), p. 534-544, illus. incl. sect., 2 tables, sketch map, 65 ref., November 2013.

The Tibetan Plateau is regarded as an amplifier and driver of environmental change in adjacent regions because of its extent and high altitude. However, reliable age control for paleoenvironmental information on the plateau is limited. OSL appears to be a valid method to constrain the age of deposits of glacial and fluvial origin, soils and periglacial structures in the Menyuan basin on the northeastern Tibetan Plateau. Dating results show glaciers advanced extensively to the foot of the Qilian mountains at ~21ka, in agreement with the timing of the global Last Glacial Maximum (LGM) recorded in Northern Hemisphere ice cores. Comparison with results from the eastern Tibetan Plateau suggests that the factor controlling glacial advance in both regions was decreased temperature, not monsoon-related precipitation increase. The areas of the Menyuan basin occupied by glacio-fluvial deposits experienced continuous permafrost during the LGM, indicated by large cryoturbation features, interpreted to indicate that the mean annual temperature was >&eq;7°C lower than at present. Glacio-fluvial systems in the Menyuan basin aggraded and terraces formed during cold periods (penultimate glaciation, LGM, and possibly the Younger Dryas) as a response to increased glacial sediment production and meltwater runoff then. Abstract Copyright (2013) Elsevier, B.V.

DOI: 10.1016/j.yqres.2013.08.004

14032698 Sidorova, Olga V. (Paul Scherrer Institute, Villigen, Switzerland); Saurer, Matthias; Andreev, Andrei; Fritzsche, Diedrich; Opel, Thomas; Naurzbaev, Mukhtar M. and Siegwolf, Rolf. Is the 20th century warming unprecedented in the Siberian north?: Quaternary Science Reviews, 73, p. 93-102, illus. incl. 3 tables, sketch map, 45 ref., August 1, 2013.

To answer the question "Has the recent warming no analogues in the Siberian north?" we analyzed larch tree samples (Larix gmelinii Rupr.) from permafrost zone in the eastern Taimyr (TAY) (72°N, 102°E) using tree-ring and stable isotope analyses for the Climatic Optimum Period (COP) 4111-3806 BC and Medieval Warm Period (MWP) 917-1150 AD, in comparison to the recent period (RP) 1791-2008 AD. We developed a description of the climatic and environmental changes in the eastern Taimyr using tree-ring width and stable isotope (d¹³C, d¹⁸O) data based on statistical verification of the relationships to climatic parameters (temperature and precipitation). Additionally, we compared our new tree-ring and stable isotope data sets with earlier published July temperature and precipitation reconstructions inferred from pollen data of the Lama Lake, Taimyr Peninsula, d¹⁸O ice core data from Akademii Nauk ice cap on Severnaya Zemlya (SZ) and d¹⁸O ice core data from Greenland (GISP2), as well as tree-ring width and stable carbon and oxygen isotope data from northeastern Yakutia (YAK). We found that the COP in TAY was warmer and drier compared to the MWP but rather similar to the RP. Our results indicate that the MWP in TAY started earlier and was wetter than in YAK. July precipitation reconstructions obtained from pollen data of the Lama Lake, oxygen isotope data from SZ and our carbon isotopes in tree cellulose agree well and indicate wetter climate conditions during the MWP. Consistent large-scale patterns were reflected in significant links between oxygen isotope data in tree cellulose from TAY and YAK, and oxygen isotope data from SZ and GISP2 during the MWP and the RP. Finally, we showed that the recent warming is not unprecedented in the Siberian north. Similar climate conditions were recorded by tree-rings, stable isotopes, pollen, and ice core data 6000 years ago. Abstract Copyright (2013) Elsevier, B.V.

DOI: 10.1016/j.quascirev.2013.05.015

14032500 Doxaran, D. (Centre National de la Recherche Scientifique, Laboratoire d'Océanographie de Villefranche, Villefranche, France); Ehn, J.; Bélanger, S.; Matsuoka, A.; Hooker, S. and Babin, M. Optical characterisation of suspended particles in the Mackenzie River plume (Canadian Arctic Ocean) and implications for ocean colour remote sensing: Biogeosciences, 9(8), p. 3213-3229, illus. incl. 1 table, sketch map, 57 ref., 2012.

Climate change significantly impacts Arctic shelf regions in terms of air temperature, ultraviolet radiation, melting of sea ice, precipitation, thawing of permafrost and coastal erosion. Direct consequences have been observed on the increasing Arctic river flow and a large amount of organic carbon sequestered in soils at high latitudes since the last glacial maximum can be expected to be delivered to the Arctic Ocean during the coming decade. Monitoring the fluxes and fate of this terrigenous organic carbon is problematic in such sparsely populated regions unless remote sensing techniques can be developed and proved to be operational. The main objective of this study is to develop an ocean colour algorithm to operationally monitor dynamics of suspended particulate matter (SPM) on the Mackenzie River continental shelf (Canadian Arctic Ocean) using satellite imagery. The water optical properties are documented across the study area and related to concentrations of SPM and particulate organic carbon (POC). Robust SPM and POC:SPM proxies are identified, such as the light backscattering and attenuation coefficients, and relationships are established between these optical and biogeochemical parameters. Following a semi-analytical approach, a regional SPM quantification relationship is obtained for the inversion of the water reflectance signal into SPM concentration. This relationship is reproduced based on independent field optical measurements. It is successfully applied to a selection of MODIS satellite data which allow estimating fluxes at the river mouth and monitoring the extension and dynamics of the Mackenzie River surface plume in 2009, 2010 and 2011. Good agreement is obtained with field observations representative of the whole water column in the river delta zone where terrigenous SPM is mainly constrained (out of short periods of maximum river outflow). Most of the seaward export of SPM is observed to occur within the west side of the river mouth. Future work will require the validation of the developed SPM regional algorithm based on match-ups with field measurements, then the routine application to ocean colour satellite data in order to better estimate the fluxes and fate of SPM and POC delivered by the Mackenzie River to the Arctic Ocean.

DOI: 10.5194/bg-9-3213-2012

14031391 Cresto Aleina, F. (International Max Planck Research School for Earth System Modelling, Hamburg, Germany); Brovkin, V.; Muster, S.; Boike, J.; Kutzbach, L.; Sachs, T. and Zuyev, S. A stochastic model for the polygonal tundra based on Poisson-Voronoi diagrams: Earth System Dynamics (ESD), 4(2), p. 187-198, illus., 43 ref., 2013.

Subgrid processes occur in various ecosystems and landscapes but, because of their small scale, they are not represented or poorly parameterized in climate models. These local heterogeneities are often important or even fundamental for energy and carbon balances. This is especially true for northern peatlands and in particular for the polygonal tundra, where methane emissions are strongly influenced by spatial soil heterogeneities. We present a stochastic model for the surface topography of polygonal tundra using Poisson-Voronoi diagrams and we compare the results with available recent field studies. We analyze seasonal dynamics of water table variations and the landscape response under different scenarios of precipitation income. We upscale methane fluxes by using a simple idealized model for methane emission. Hydraulic interconnectivities and large-scale drainage may also be investigated through percolation properties and thresholds in the Voronoi graph. The model captures the main statistical characteristics of the landscape topography, such as polygon area and surface properties as well as the water balance. This approach enables us to statistically relate large-scale properties of the system to the main small-scale processes within the single polygons.

DOI: 10.5194/esd-4-187-2013

14032743 Satkunas, Jonas (Lithuanian Geological Survey, Vilnius, Lithuania); Grigiene, Alma; Mikulenas, Vidas and Minkevicius, Vytautas. Gelioniu duobes paslaptis [Gelioniu Pits secrets]: Geologijos Akiraciai, 2013(2), p. 40-43, illus., 3 ref., 2013.

14032471 Cárdenes, V. (Universidad de Oviedo, Área de Petrología y Geoquímica, Asturias, Spain); Monterroso, C.; Rubio, A.; Mateos, F. J. and Calleja, L. Effect of freeze-thaw cycles on the bending strength of roofing slate tiles: Engineering Geology, 129-130, p. 91-97, illus. incl. 1 table, geol. sketch map, 10 ref., March 19, 2012.

Slate is one of the most popular natural roofing materials, because of its ability to be split into large, thin and waterproof tiles. However, while some slate roofs last up to two centuries, others disintegrate after just a few years, a fact which is closely linked to the intrinsic properties of each particular slate. The effect of these properties on durability of slates is closely related to their performance during freeze-thaw cycles, as expressed in the European Standard for Roofing Slate (EN 12326:2005), which details the tests required to market roofing slate within the European Union. This paper examines variations in the bending strength of three varieties of Spanish roofing slate tiles, upon exposure to freeze-thaw cycles. Each variety of slate was divided up into 10 groups of 3 tiles, and then subjected to freezing and thawing (from -20°C to 25°C) in a climatic chamber. Every ten cycles, a group was removed from the chamber, and its bending strength was tested according to EN 12326:2005. Petrographical characterization, porosity, water absorption and P-wave velocity tests were also conducted for each group of slate. In addition, in order to determine the environmental thermal changes that could affect the slate's integrity, the temperatures reached by a slate tile on a roof exposed to direct sunlight were measured over a period of 24 months. The results showed variations in the bending strength of the slate as well as other properties measured, including water absorption, P-wave velocity and pore size distribution. These variations are due to the formation of a new microcrack system, a process that is closely linked to the petrographical fabric of the slate. Understanding the behavior and durability of roofing slate under freeze-thaw conditions will help in determining which varieties of slate are best for roofs built in cold regions. Abstract Copyright (2012) Elsevier, B.V.

DOI: 10.1016/j.enggeo.2012.01.007

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14033249 Leblanc, Anne-Marie. Modélisation tridimensionnelle du régime thermique du pergélisol de la vallée de Salluit au Québec nordique en fonction de différents scénarios de réchauffement climatique [Three dimensional model of the thermal regime of the permafrost of Salluit Valley, northern Quebec, global warming effects]: 441 p., illus. incl. 42 tables, sketch map, 182 ref., Doctoral, 2013, Université Laval, Sainte-Foy, QC, Canada. Includes appendices.

URL: http://www.theses.ulaval.ca/2013/29687/29687.pdf

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14034212 Paytan, Adina (University of California at Santa Cruz, Santa Cruz, CA); Lecher, Alanna; Dimova, Natasha; Kessler, John and Sparrow, Kate. Methane transport and release to the atmosphere in permafrost areas via subterranean groundwater discharge [abstr.]: in Goldschmidt abstracts 2013, Mineralogical Magazine, 77(5), p. 1940, 2013. Meeting: Goldschmidt 2013, Aug. 25-30, 2013, Florence, Italy.

Methane release to the atmosphere in permafrost regions of the Arctic is exacerbated by global warming. This may result in a positive feedback effect, as methane is a powerful greenhouse gas. Accordingly, it is important to gain a good understanding of the processes that contribute methane to the atmosphere, particularly in this region. Large quantities of methane are stored in the Arctic in natural gas deposits, permafrost, and as submarine clathrates. Releases from these sources arising from warming have been reported, however, there are still considerable gaps in our understanding of the methane cycle at present and particularly how predicted climate changes will impact the methane cycle. Subterranean groundwater discharge (SGD) has been recognized as an important conduit for transport of nutrients, metals, methane and other pollutants from land to receiving water bodies throughout the world, and could be a potential important, yet not quantified, source of methane in the Arctic. SGD can be quantified using geochemical tracers such as Ra and Rn and when combined with methane measurements can elucidate the role SGD has in transporting methane form groundwater to surface water bodies such as Arctic lakes and the coastal ocean, from which this methane will be released to the atmosphere. We have used Ra and Rn along with analytical calculations and methane concentration and isotope analyses in order to determine the contribution of SGD to the methane budget in areas of different hydrological and permafrost conditions in Alaska. Our results indicate that SGD is a major conduit for methane release contributing significant amounts of methane to surface waters particularly in areas where permafrost is abundant and impacted by seasonal temperature changes.

DOI: 10.1180/minmag.2013.077.5.16

14034333 Prokushkin, A. S. (Russian Academy of Sciences, V. N. Sukachev Institute of Forest, Krasnoyarsk, Russian Federation); Mavromatis, V.; Pokrovsky, O. S. and Viers, J. Impact of basalt weathering and plant recycling on Mg transport from the soil to the river under permafrost environment; a stable Mg isotope study in central Siberia [abstr.]: in Goldschmidt abstracts 2013, Mineralogical Magazine, 77(5), p. 2000, 2013. Meeting: Goldschmidt 2013, Aug. 25-30, 2013, Florence, Italy.

To unravel the different sources of Mg generated by basalt weathering in Central Siberia under permafrost conditions and larch deciduous forest, we measured the Mg isotopic composition of large rivers (Nizhnaya Tunguska and Kochechum, tributary of Enisey) and a small stream, snow, surface flow, interstitial soil solutions, plant biomass, litter and soils. During winter baseflow, the dissolved Mg isotope composition of large rivers is significantly lighter compared to the source basaltic rocks and atmospheric deposition, suggesting a deep undergournd source such as sedimentary carbonate rocks. During spring flood and in the summer-fall season, d²⁶Mg increases by 0.3-0.2 ppm and approaches the Mg isotope composition of ground vegetation (dwarf shrubs, mosses) and soil organic horizon. Overall riverine waters are 0.6-1.0 ppm lighter than the unaltered bedrock and deep minerals soil horizon. Despite low variability of Mg isotopic composition between Larix gmelinii organs (i.e. stem wood, roots, needles etc.), there is a 0.2-0.3 ppm enrichment in d²⁶Mg of larch needles in the course of growing season, from June to September. It likely demonstrates plant uptake of isotopically heavier Mg along with the progressive thawing of mineral soil (deepen soil active layer). Taken together, Mg isotope approach indicates the important contribution of vegetation (larch needles, mosses and dwarf shrubs) in riverine Mg isotope signature and help to reveal the contribution of isotopically light carbonates or sedimentary rocks in large rivers of Central Siberian Plateau.

DOI: 10.1180/minmag.2013.077.5.16

14032597 Elwood Madden, Megan (University of Oklahoma, School of Geology and Geophysics, Norman, OK); Root, Margaret; Gainey, Seth and Leeman, John. Gas clathrate hydrate thermodynamics and kinetics; limits on near-surface volatile fluxes for cold terrestrial planetary systems through deep time [abstr.]: in Goldschmidt 2012 abstract volume, Mineralogical Magazine, 76(6), p. 1684, 2 ref., 2012. Meeting: Goldschmidt 2012, June 24-29, 2012, Montreal, QC, Canada.

Gas clathrate hydrates (a gas molecule such as CO₂, CH₄, H₂S, etc. trapped within a cage of water molecules) are thermodynamically stable at low-moderate temperatures and moderate-high pressures, conditions found near the surface of many terrestrial planetary bodies in our solar system, including Earth, Mars, Europa, Titan, Enceladus, and other icy moons. While gas hydrates are often thought of as ephemeral phases in Earth's ocean and permafrost sediments, they can serve as reservoirs for water, carbon, and other volatile phases over millions to billions of years. Hydrate stability zones (HSZ- the depth at which gas hydrates are thermodynamically stable given the P-T conditions) can extend to significant depths. In addition, gas hydrate formation and dissociation rates below the freezing point of water are transport limited, relying on solid-state diffusion of gas to or from the ice-hydrate interface. Slow gas diffusion rates through ice and hydrate at low temperatures result in geologically long-lived metastable gas hydrate reservoirs in the near subsurface. Geologic models of gas hydrates in planetary systems must therefore consider both thermodynamic and kinetic constraints on clathrate reservoirs to better understand long-term volatile fluxes in the near subsurface. Gas diffusion as well as hydrate formation and dissociation rates are needed to effectively model these complex systems. Using gas hydrate formation and dissociation rates measured in our laboratory, we have developed a coupled thermodynamic and kinetic model of obliquity-driven changes in HSZs on Mars. This model suggests that gas hydrates may provide a significant reservoir for carbon and water within the crust over 10s of km depth. In addition, these hydrate reservoirs may remain thermodynamically stable over geologic timescales, and even when preturbed, may persist as metastable bodies for thousands to millions of years, resulting in significant long-term volatile fluxes. Similar geologic models of gas hydrate reservoirs on Europa, Titan, and Enceladus are underway.

URL: http://minmag.geoscienceworld.org/content/76/6/1675.full.pdf+html

14032614 Makahnouk, W. R. M. (University of Waterloo, Earth and Environmental Sciences, Waterloo, ON, Canada); Frape, S. K.; Blyth, A. R.; Ruskeeniemi, T.; Coniglio, M. and Drimmie, R. J. Fracture mineral investigation in crystalline rock, SW Greenland [abstr.]: in Goldschmidt 2012 abstract volume, Mineralogical Magazine, 76(6), p. 2059, illus., 2012. Meeting: Goldschmidt 2012, June 24-29, 2012, Montreal, QC, Canada.

This current study is associated with the Greenland Analogue Project (GAP), an international collaboration between the Nuclear Waste Management Organization (Canada), Posiva (Finland), and SKB (Sweden). The objective of this project is to further understand groundwater evolution in bedrock as influenced by the presence of a continental ice-sheet. Physical and chemical characteristics of secondary minerals within fracture networks in the bedrock were examined to provide insights into paleo-hydrological processes (e.g. hydrothermal, metamorphic, or glacial events). Two boreholes were drilled into granitic gneiss near the margin of the Greenland ice-sheet. The first was drilled beneath a talik lake and instrumented to sample groundwater (GAP01). The second borehole was drilled to ~350 m to determine the depth of the permafrost (GAP03). Preliminary results, specifically, carbon (d¹³C) and oxygen (d¹⁸O) isotope geochemistry of carbonate fracture fillings, are now available (Fig. 1). Calcite analyses reveal a vertical d¹⁸O trend in the GAP01 borehole, indicative of hydrothermal carbonates. This is further corroborated by the ¹⁸O depleted dolomite in that borehole. Dolomite in the GAP03 borehole corresponds to a fracture filling that is coated with a thin layer of calcite (arrow identifies isotopic signature in Fig.1), indicative of two different crystallization events based on the large difference in d¹⁸O values. Ongoing fluid inclusion studies are anticipated to elucidate minimum carbonate mineral crystallization (trapping) temperatures and fluid salinities. Formation temperatures are used to calculate the isotopic composition of the parent fluids from which these carbonates precipitated. Estimates for d¹³C of DIC and d¹⁸O of paleo-fluids are powerful tools to distinguish meteoric or glacial water from fluids that have been subjected to water-rock interaction.

URL: http://minmag.geoscienceworld.org/content/76/6/2045.full.pdf+html

14032622 Mangelsdorf, K. (Helmholtz Centre Potsdam, German Research Centre for Geosciences, Potsdam, Germany); Griess, J.; Gattinger, A. and Wagner, D. Response of methanogenic communities to glacial-interglacial climate changes in the Siberian Arctic [abstr.]: in Goldschmidt 2012 abstract volume, Mineralogical Magazine, 76(6), p. 2064, 2012. Meeting: Goldschmidt 2012, June 24-29, 2012, Montreal, QC, Canada.

The Arctic has gained specific attention within the current debate on climate change. With the thawing of permafrost large amounts of stored carbon become accessible again for microbial degradation and will form a potential source for the release of CO₂ and methane to the atmosphere having a positive feedback on the global warming. Therefore, it is of specific interest to understand the microbial driven greenhouse gas dynamics of the Siberian Arctic and their response to glacial-interglacial changes in the past. Sample material was drilled on Kurungnahk Island (Russian-German expedition LENA 2002) located in the southern part of the Lena Delta and in lake El'gyggytgyn (ICDP-project) in Northeast Siberia. The Kurungnahk samples comprise Late Pleistocene to Holocene deposits, whereas the lake El'gyggytgyn samples cover Middle to Late Pleistocene sediments. Samples were investigated applying a combine biogeochemical and microbiological approach. The methane profile of the Kurungnahk core reveals highest methane contents in the warm and wet Holocene and Late Pleistocene (LP) deposits and correlates largely to the organic carbon (TOC) contents. Archaeol concentrations, being a biomarker for past methanogenic archaea, are also high during the warm and wet Holocene and LP intervals and low during the cold and dry LP periods. This indicates that part of the methane might be produced and trapped in the past. However, biomarkers for living microorgan-isms (bacteria and archaea) and microbial activity measurements of methanogens point, especially, for the Holocene to a viable archaeal community, indicating a possible in-situ methane production. Furthermore, warm/wet-cold/dry climate cycles are recorded in the archaeal diversity as revealed by genetic fingerprint analysis. In contrast to the results from the Kurungnakh core, in general the bacterial and archaeal biomarker profiles from the lake El'gygytgyn deposits reveal no distinct glacial-interglacial variability. This might be due to the fact that the overlying lake water buffers the temperature effect on the lake sediments which never became permafrost. The microbial abundance rather correlates to the TOC contents in the sediments forming the accessible carbon and energy source for the indigenous microbial communities. Also the diversity of methanogenic archaea, being still active in 400 ka old sediments, appears to vary with the organic carbon content. TOC-rich lake intervals seem to sustain a divers microbial ecosystem independent from glacial-interglacial climate cycles.

URL: http://minmag.geoscienceworld.org/content/76/6/2045.full.pdf+html

14032789 Williams, Kevin K. (State University of New York Buffalo State, Earth Sciences and Science Education, Buffalo, NY); Haltigin, Timothy W. and Pollard, Wayne H. Using ground penetrating radar to detect massive ground ice and ice wedge geometry in the Canadian Arctic [abstr.]: in Geological Society of America, Northeastern Section, 48th annual meeting, Abstracts with Programs - Geological Society of America, 45(1), p. 112, February 2013. Meeting: Geological Society of America, Northeastern Section, 48th annual meeting, March 18-20, 2013, Bretton Woods, NH.

Ground penetrating radar was used to detect massive ground ice in the western Canadian Arctic and ice wedges in the Canadian High Arctic. One goal of these studies was to use GPR and resistivity instruments to estimate volumes of ground ice, because these ice volumes are important for predicting landscape response to changing thermal conditions. The variety of locations allowed for data collection over ice bodies of different sizes and in different sediments, which leads to a larger population of examples from which to draw conclusions. In addition to ice bodies, GPR was also used to detect the base of the active layer and sedimentary structures within permafrost. Massive ground ice was detected at several locations in the Mackenzie Delta using GPR, and was confirmed with resistivity data and, in one case, a sump pit. Fieldwork there was conducted in winter, so trenching and coring by hand was not feasible. These massive ice bodies ranged in size and depth, but were mostly formed in sand. At several locations, subsurface sedimentary structures were also detected. Although not targeted specifically, two transects passed over a some small ice wedges. Ice wedges were the main target at locations on Axel Heiberg and Devon Islands in the Canadian High Arctic where subsurface material ranged from sands to cobbles. Fieldwork there was conducted during the summer when the active layer was thawing, so some of the sites contained a significant amount of water. Although the fresh water did not greatly affect the GPR data, it did complicate analysis of some resistivity data. GPR data of these ice wedges has been correlated with surface polygons, whose appearances depended on the sediment properties and wedge size. Although subsurface ice was not found beneath every trough, polygons with notable troughs contained fairly large ice wedges. These ice wedges are clearly detected in the GPR data, allowing fairly accurate width estimates for the tops of the wedges. Correlation of surface troughs with GPR-determined wedge widths shows that ice wedge volume estimates based on trough widths at the surface may be overestimated by up to 70%. Overall, GPR reveals subsurface information that will lead to a better understanding of subsurface ice volume and how that relates to surface features.

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14029943 Hu, K.; Issler, D. R.; Chen, Z. and Brent, T. A. Permafrost investigation by well logs, and seismic velocity and repeated shallow temperature surveys, Beaufort-Mackenzie Basin: Open-File Report - Geological Survey of Canada, Rep. No. 6956, 33 p., illus. incl. tables, strat. cols., 50 ref., 2013.

This report presents exploration well data and interpretations relevant for mapping the variation in the depth to the base of ice-bearing permafrost (IBPF) for the Beaufort-Mackenzie Basin. This work is part of a larger government-industry funded petroleum systems study of the Beaufort-Mackenzie region that was active from 2001-2013. Geophysical well logs, well seismic surveys, shallow repeated temperature surveys, and deeper borehole temperature-depth profiles are utilized to determine the base of IBPF for 265 wells in the basin. Composite plots of log, seismic velocity and shallow temperature data illustrate typical geophysical responses and provide multi-parameter evidence for integrated interpretations of the IBPF zone. IBPF determinations are quality-assessed in terms of their reliability using a standardised scale based on the type of methods used and the quality of data available. For many of the wells, a sharp change in electrical and acoustic properties marks the base of the interpreted fully frozen IBPF zone which may represent the base of ice-bonded permafrost. For 135 wells, there is an underlying transition zone between 7 m to 210 m in thickness that is interpreted to represent partially-frozen IBPF. The interpreted co-existence of water and ice may be the result of changes in lithology, grain size, texture and/or pore water salinity which can affect the freezing point. There is a good correlation between the geophysically-determined base of IBPF and the depth to the base of permafrost from temperature surveys. This suggests that the mapped IBPF zone is a useful thermal boundary condition for thermal modelling and heat flow studies. For most of the wells, IBPF is confined to sandstones and conglomerates within Cenozoic sediments of the post-rift succession. Beneath the Beaufort Shelf, base of IBPF occurs within highly porous sediments of the Plio-Pleistocene Iperk Sequence. For central onshore areas (Richards Island and areas to south), base of IBPF occurs in progressively older, more deeply exhumed Cenozoic strata in a southward direction. Along the southeastern basin margin on Tuktoyaktuk Peninsula, IBPF extends into the Paleocene-Eocene Aklak Sequence. In the southernmost part of the basin and in the fold belt to the west, IBPF is encountered in Lower Cretaceous syn-rift and Upper Cretaceous post-rift strata. Permafrost occurs in exhumed Paleozoic strata in the Anderson Plain southwest of Tuktoyaktuk Peninsula. Depth to the base of IBPF varies from 0 m (no IBPF) to >700 m across the study area. It is thinnest along the southern (landward) basin margin and in the deformed and exhumed western part of the basin, and is thickest in the rapidly deposited Cenozoic strata of the eastern shelf beneath the Beaufort Sea. IBPF may be absent over much of the modern delta area around Mackenzie Bay.

DOI: 10.4095/293120

14029896 Blasco, S. (Geological Survey of Canada, Canada); Bennett, R.; Brent, T. A.; Burton, M.; Campbell, P.; Carr, E.; Covill, R.; Dallimore, S.; Davies, E.; Hughes-Clarke, J.; Issler, D. R.; Leonard, L.; MacKillop, Kevin; Mazzotti, S.; Patton, E.; Rogers, G.; Shearer, J. and White, M. 2010 state of knowledge; Beaufort Sea seabed geohazards associated with offshore hydrocarbon development: Open-File Report - Geological Survey of Canada, Rep. No. 6989, 340 p., illus. incl. tables, 150 ref., 2013.

Generic exploration drilling structures include floating and bottom-founded drilling platforms. Both types of exploration drilling structures require knowledge of seabed stability conditions or geohazards to ensure safe exploration drilling. In addition, knowledge of geohazards is required for subsea pipelines. This report covers the state of knowledge of Canadian Beaufort Sea seabed stability conditions that were investigated by the Geological Survey of Canada and its partners from 1969 through 1991 and from 2001 through 2010, including seabed scouring by ice keels, foundation conditions, submarine slumping, artificial islands, seabed features, subsea permafrost, hydrates, overpressure, earthquakes and tsunamis.

DOI: 10.4095/292616

14029965 Smith, S. L. and Ednie, M. Preliminary ground thermal data from field sites established summer 2013 along the Alaska Highway easement, Yukon: Open-File Report - Geological Survey of Canada, Rep. No. 7507, 32 p., illus. incl. tables, 28 ref., 2013.

Cased boreholes along the Alaska Highway easement in the southern Yukon were acquired from TransCanada Pipelines Ltd. by the Geological Survey of Canada. Eight of the boreholes between KP1559 (near Haines Junction) and the Alaska border were instrumented for ground temperature measurement in July 2013 to provide improved information on current permafrost conditions in the highway corridor. The initial data acquired shortly after installation of thermistor cables, indicates that ground temperatures are generally higher than -1°C except at one site near the Alaska border where ground temperature is about -3°C. The instrumented sites will be maintained in collaboration with the Yukon Research Centre, Yukon Department of Highways and Public Works and the Yukon Geological Survey. Continuous data collection for at least one year will facilitate characterization of ground thermal conditions in this portion of the corridor and provide updated information to support infrastructure design and decisions regarding development projects in the region.

DOI: 10.4095/293314

14029903 Grasby, Stephen E. (Geological Survey of Canada, Calgary, AB, Canada); Majorowicz, Jacek and McCune, Gennyne. Geothermal energy potential for northern communities: Open-File Report - Geological Survey of Canada, Rep. No. 7350, 50 p., illus. incl. tables, 35 ref., 2013.

Recent studies have shown enormous geothermal energy potential spread over broad regions of Canada (Grasby et al., 2011a). This energy resource can be used to directly generate electricity with modern high efficiency heat exchangers (>90% efficiency) as well as for direct heating applications. Some northern communities are already assessing local potential for electrical generation (e.g. Fort Liard) as well as district heating (e.g. Yellowknife). The intent of this report is to examine which northern communities have the greatest geological potential for geothermal energy development to support local energy demand, along with providing an initial assessment of the economic viability of geothermal energy resources, for both: a) a realistic range of the low enthalpy heating systems, and b) electrical power generation from high temperature resources.

DOI: 10.4095/292840

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