Permafrost Monthly Alerts (PMAs)

2016086722 Cao Wei (Chinese Academy of Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, Lanzhou, China); Sheng Yu; Wu Jichun; Li Jing; Li Jinping and Chou Yaling. Simulation analysis of the impact of excavation backfill on permafrost recovery in an opencast coal-mining pit: Environmental Earth Sciences, 75(9), Article 837, illus. incl. 2 tables, 21 ref., May 2016.

The article attempts to investigate the status of permafrost recovery after excavation backfill in an opencast coal mine. To do that, we forecast the permafrost recovery under certain initial temperatures and different boundary conditions by using the numerical simulation method. The results show that the filling temperature significantly influences permafrost recovery after backfilling. When the filling temperature decreases from +2.0 to -2.0 °C, the permafrost recovery rate will greatly accelerate, and the permafrost thickness will significantly increase. When the surface temperature of the filling is positive, the permafrost recovery at the bottom of the excavation will be more difficult than when the temperature is negative. The permafrost recovery rate will be slow, and the permafrost thickness will be thin. The permafrost recovery also gradually speeds up the thickening with decreasing natural surface temperature. Thus, backfilling should be conducted in the cold season, and cooling treatment should be applied to the filling before backfilling. The treatment will ensure that the permafrost recovery is faster and more stable. This measure is also conducive to the recovery of the ecological environment of the mine. Copyright 2016 Springer-Verlag Berlin Heidelberg

DOI: 10.1007/s12665-016-5659-5

2016084645 Zhang, Yu (Natural Resources Canada, Canada Centre for Mapping and Earth Observation, Ottawa, ON, Canada); Wolfe, Stephen A.; Morse, Peter D.; Olthof, Ian and Fraser, Robert H. Spatiotemporal impacts of wildfire and climate warming on permafrost across a subarctic region, Canada: Journal of Geophysical Research: Earth Surface, 120(11), p. 2338-2356, illus. incl. 1 table, sketch maps, 60 ref., November 2015.

Field observations show significant impacts of wildfires on active layer thickness and ground temperatures. However, the importance of fires to permafrost conditions at regional scales remains unclear, especially with climate warming. This study evaluated the regional impacts of fire on permafrost with climate change from 1942 to 2100 using a process-based model in a large subarctic region in the Northwest Territories, Canada. Climate warming is shown to be the dominant factor for permafrost reduction. The warming trend of climate reduces permafrost extent in this region from 67% at present to 2% by 2100. For burned areas, fire increases the reduction of permafrost extent by up to 9% on average, with up to 16% for forest, 10% for tundra and bogs, and 4% for fens. Fire accelerates permafrost disappearance by 5 years on average. The effects of fire on active layer thickness and permafrost extent are much larger in forest areas than in tundra, bogs, and fens. Since active layer is thicker after a fire and cannot recover in most of the areas, the fire effects on active layer are widespread. On average, fires thickens active layer by about 0.5 m. The fire effects on active layer increased significantly after 1990 due to climate warming. Abstract Copyright (2015), Her Majesty the Queen in Right of Canada.

DOI: 10.1002/2015JF003679

2016082076 Kneisel, Christof (University of Würzburg, Institute of Geography and Geology, Wurzburg, Germany); Emmert, Adrian; Polich, Pascale; Zollinger, Barbara and Egli, Markus. Soil geomorphology and frozen ground conditions at a subalpine talus slope having permafrost in the Eastern Swiss Alps: Catena (Giessen), 133, p. 107-118, illus. incl. 2 tables, sketch maps, 55 ref., October 2015.

At a subalpine site with permafrost below the timberline in the eastern Swiss Alps the complex interrelationship between different environmental factors was investigated by applying an integrated approach that combines soil mapping, 3D near-surface geophysics and surface and subsurface temperature monitoring. The objectives of this approach were to explore the 3D extension of isolated permafrost bodies and to relate this to surface parameters such as soils and humus forms and other extrinsic factors. Using this procedure, interdependencies between surface (soil properties and humus forms) and subsurface factors (ground thermal regime and frozen ground conditions) could be independently analysed. Although time-consuming, 3D ERI (electrical resistivity imaging) demonstrated its ability for precise permafrost mapping. Despite climate warming, super-cooling in winter along the investigated scree slopes is still efficient enough for establishing permafrost conditions. By comparing the spatial dimensions of the permafrost bodies with surface conditions, we found that thick moss or organic litter layers had an insulating effect and prevented the permafrost from melting. However, the comparison of soil units and soil thickness with the permafrost distribution did not always show an obvious relationship. This indicates that there is a complex evolution and behavior of soils and permafrost at such sites. Abstract Copyright (2015) Elsevier, B.V.

DOI: 10.1016/j.catena.2015.05.005

2016087743 Ma Yingzhao (Chinese Academy of Sciences, Institute of Tibetan Plateau Research, Beijing, China); Zhang Yinsheng; Zubrzycki, Sebastian; Guo Yanhong and Bin Farhan, Suhaib. Hillslope-scale variability in seasonal frost depth and soil water content investigated by GPR on the southern margin of the sporadic permafrost zone on the Tibetan Plateau: Permafrost and Periglacial Processes, 26(4), p. 321-334, illus. incl. 2 tables, sketch map, 34 ref., October 2015.

Ground temperature data show that permafrost has recently been absent at a site on the southern edge of the sporadic permafrost zone on the Tibetan Plateau (TP). A detailed survey of seasonal frost depth (SFD) and soil water content (SWC) here is significant for understanding the hydrological response to thawing permafrost. However, little is known about the spatial heterogeneity of SFD and SWC at the hillslope scale in this vulnerable permafrost region. Thus, high-frequency ground-penetrating radar (GPR) was applied to a field site that varied in terms of topography (slope, aspect and elevation) and surface environments (vegetation cover and stream presence). The GPR data and accompanying field observations of gravimetric water content and frost depth revealed a spatial variation at the hillslope scale in SFD and SWC, and indicated that topography, vegetation and stream distribution significantly influence the patterns observed. The average SFD was much deeper along the north-facing slope, compared to the south-facing slope in early May, and its thickness varied considerably with altitude along each slope. An increase in the extent of vegetation cover correlated with decreasing SFD. The SWC at shallow depth was higher along the south-facing slope than along the north-facing slope at the beginning of the thawing period. For slopes of both aspects, the SWC vertical profiles exhibited a similar variability, with SWC decreasing with depth, but at different rates. This study demonstrates that GPR provides an appropriate method for quantifying SWC at the hillslope scale on the TP. Copyright Copyright 2015 John Wiley & Sons, Ltd.

DOI: 10.1002/ppp.1844

2016087741 Smith, Sharon L. (Natural Resources Canada, Geological Survey of Canada, Ottawa, ON, Canada); Riseborough, Daniel W. and Bonnaventure, Philip P. Eighteen year record of forest fire effects on ground thermal regimes and permafrost in the central Mackenzie Valley, NWT, Canada: Permafrost and Periglacial Processes, 26(4), p. 289-303, illus. incl. 3 tables, sketch map, 49 ref., October 2015. Natural Resources Canada, Earth Science Sector Contrib. No. 20140259.

Ground thermal conditions following a forest fire in 1994 were investigated along a hillslope transect in the discontinuous permafrost zone adjacent to a pipeline right of way in the central Mackenzie Valley, NWT, Canada. The intensity of the burn and damage to the forest and organic layer were more severe in the upper part of the slope than the bottom. Analysis of ground temperature records between 1995 and 2012 indicates that post-fire changes to the surface altered the ground temperature regime, likely by allowing more snow to accumulate on the ground in winter (as interception by coniferous trees ceased) and decreasing albedo and evapotranspiration in summer. Active layer thickness at the affected site doubled between 1995 and 1998, before stabilising. Permafrost degradation likely occurred at the top of the slope, where burning was most severe. Towards the end of the study period, ground surface temperatures in the upper portion of the slope were lower than they were post fire (1997), whereas the surface temperatures were higher in the lower portion of the slope. In contrast, little to no change in surface temperature was observed for the Unburnt site. These changes in the burned sites are attributed to the increased re-establishment of aspen, willow and tamarack in the upper part of the transect. Permafrost appears to be recovering at all burned sites in response to ongoing vegetation succession (except at the top of the slope), which is important for maintaining permafrost under conditions of projected climate warming in this boreal environment. Copyright Copyright 2015 John Wiley & Sons, Ltd.

DOI: 10.1002/ppp.1849

2016081907 Wang Jiaoyue (Chinese Academy of Sciences, Northeast Institute of Geography and Agroecology, Changchun, China); Song Changchun; Zhang Jing; Wang Lili; Zhu Xiaoyan and Shi Fuxi. Temperature sensitivity of soil carbon mineralization and nitrous oxide emission in different ecosystems along a mountain wetland-forest ecotone in the continuous permafrost of northeast China: Catena (Giessen), 121, p. 110-118, illus. incl. 5 tables, 70 ref., October 2014. Includes appendices.

Soil organic matter decomposition under global warming has a potential to alter soil carbon and nitrogen storages in permafrost. The objectives of this study were to investigate the temperature sensitivity of greenhouse gas emissions from soil samples along a mountain wetland-forest ecotone in the continuous permafrost and determine its influencing mechanisms. The CO₂, N₂O and carbon, nitrogen substrates were measured at 5, 15 and 25 °C. The relation between greenhouse gas emission rates and temperature depended on substrate quality in the three ecosystems. Soil DOC, MBC, NH₄⁺ and NO₃^- concentrations determined the higher CO₂ and N₂O emission rates in the thicket peatland and the surface soil layer. During the incubation period, the degrees of soil carbon and nitrogen losses in the thicket peatland were 0.6-4.7% and 1.0-14.3 (1000 ´ %), approximately 1.6 and 1.2 times higher than those in the forest and fen, respectively. The highest degrees of soil carbon and nitrogen losses in the thicket peatland indicated that more greenhouse gases would emit from soils when permafrost degradation induced the succession from wetlands or forest to the wetland-forest ecotone. Although the gas emission rates presented significant differences in the three ecosystems, the Q₁₀ values with 2.0 to 2.2 for CO₂ and 2.4 to 3.0 for N₂O, did not change significantly, indicating that the temperature sensitivity of gas emissions would not fluctuate much in the ecosystems along the mountain wetland-forest ecotone. However, the higher Q₁₀ values in the deeper soil layer in our study indicated that the decomposition of soil C and N in the deeper active layer of the permafrost region is more impressionable to global warming. As laboratory results could not actually reflect the situation in the field, more field work about temperature sensitivity of soil organic matter decomposition in different ecosystems should be encouraged in the future. Abstract Copyright (2014) Elsevier, B.V.

DOI: 10.1016/j.catena.2014.05.007

2016087315 Anthony, Katey Walter (University of Alaska at Fairbanks, Water and Environmental Research Center, Fairbanks, AK); Daanen, Ronald; Anthony, Peter; von Deimling, Thomas Schneider; Ping, Chien-Lu; Chanton, Jeffrey P. and Grosse, Guido. Methane emissions proportional to permafrost carbon thawed in Arctic lakes since the 1950s: Nature Geoscience, 9(9), p. 679-682, illus., 30 ref., September 2016.

DOI: 10.1038/NGEO2795

2016087316 Crichton, K. A. (Centre National de la Recherche Scientifique, Laboratoire de Glaciologie et Géophysique de l'Environnement, Grenoble, France); Bouttes, N.; Roche, D. M.; Chappellaz, J. and Krinner, G. Permafrost carbon as a missing link to explain CO₂ changes during the last deglaciation: Nature Geoscience, 9(9), p. 683-686, illus., 29 ref., September 2016.

DOI: 10.1038/NGEO2793

2016087358 Roy-Léveillée, Pascale (Laurentian University, School of Northern and Community Studies, Sudbury, ON, Canada) and Burn, Christopher R. A modified landform development model for the topography of drained thermokarst lake basins in fine-grained sediments: Earth Surface Processes and Landforms, 41(11), p. 1504-1520, illus. incl. sects., strat. cols., 3 tables, sketch maps, 58 ref., September 15, 2016.

Permafrost degradation associated with the expansion of thermokarst lakes is commonly interrupted by catastrophic drainage. Subsequently, in tundra areas, permafrost aggradation in drained basins leads to uneven topography characterized by raised centres and wet, depressed margins. The genesis of such topography has been investigated in Old Crow Flats (OCF), a glaciolacustrine plain in the continuous permafrost of northern Yukon. The thermokarst lakes of OCF have a mean depth of only 1.5 m because excess ice is dominantly found only in the uppermost 10 m of the ground. Surface conditions were measured in three drained thermokarst lake basins, including relief, snow conditions, ground temperatures, near-surface ground ice, and sediment stratigraphy. Four nearby lakes provided information on wave base, shore recession patterns, and bathymetry before drainage: the bottoms of these lakes were not raised in the centre. An elevation difference of up to 2 m was recorded between drained basin margins and centres but was not associated with variations in ice-wedge density or segregated ice content. Hence basin topography was not controlled by differences in volumetric ground-ice content between margins and centres. We propose that transport of fine sediment away from eroding lake margins during lake development is the primary mechanism for the genesis of depressed margins and raised centres in drained basins of OCF. Over time, the transport results in the deposition of more and finer sediment in the central parts of lakes, where the lake bottom has subsided below wave base, than at the shallow margins, where resuspension by wave action occurs frequently. This difference in sediment volume is revealed in the topography after drainage, when permafrost aggrades in the lake-bottom sediment and underlying talik. Copyright Copyright 2016 John Wiley & Sons, Ltd.

DOI: 10.1002/esp.3918

2016086711 Qin Yanhui (Chinese Academy of Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, Lanzhou, China); Wu Tonghua; Li Ren; Yu Wenjun; Wang Tianye; Zhu Xiaofan; Wang Weihua; Hu Guojie and Tian Liming. Using ERA-Interim reanalysis dataset to assess the changes of ground surface freezing and thawing condition on the Qinghai-Tibet Plateau: Environmental Earth Sciences, 75(9), Article 826, illus. incl. 1 table, sketch maps, 70 ref., May 2016.

It is important to assess the freezing and thawing condition of ground surface for understanding the impacts of frozen ground on surface and subsurface hydrology, the surface energy and moisture balance, ecosystem conservation, and engineering construction on the Qinghai-Tibet Plateau (QTP). However, assessing the changes of ground surface freezing and thawing condition on the QTP still remains a challenge owing to data sparseness and discontinuous observations. The annual ground surface freezing index (GFI) and ground surface thawing index (GTI) could be used to predict changes of the thermal regime of permafrost and can be good indicators of climate change on the QTP, which has important engineering applications. In this study, we first calibrated the reanalysis ground surface temperature (GST) data using the methods of elevation correction on the QTP. After calibration, the quality of reanalysis data has been improved significantly. For the annual time series, the root mean square error decreased from 7.7 to 1.6 °C, the absolute value of mean bias error decreased from 7.5 to 0.0 °C, and the correlation coefficient increased from 0.62 to 0.86. Second, we estimated the annual and seasonal spatial distributions of GST. The spatial distribution of spring and autumn GST closely resembled the annual mean pattern. The long-term mean GFI and GTI from the calibrated reanalysis dataset were 1322.3 and 2027.9 °C/day, respectively. The GFI and GTI were presented as latitude and elevation zonation; it can also be seen that permafrost mostly occurred in the high GFI and low GTI regions. Estimating the GFI and GTI precisely will be utilized to model the permafrost distribution and estimate active layer thickness in the future. Copyright 2016 Springer-Verlag Berlin Heidelberg

DOI: 10.1007/s12665-016-5633-2

2016086705 Qin Yinghong (Guangxi University, College of Civil Engineering and Architecture, China); Tan Kanghao; Liang Jia; Li Yunfeng and Li Fanghua. Experimental study on the solar reflectance of crushed rock layer with different sizes: Environmental Earth Sciences, 75(9), Article 817, illus., 29 ref., May 2016.

A crushed rock layer is often reveted on a cold-region embankment side slope to keep the underlying permafrost layer cool. However, its cooling effect is strongly affected by the solar absorption of this layer. This study proposes a procedure for measuring the albedo of a heterogeneous surface like a crushed rock layer. The albedo of crushed rock layers with different aggregate sizes is measured. It is found that the albedo of the crushed rock layer decreases with the aggregate size and that the albedo of the crushed rock layer is 0.1-0.2 lower than the albedo of the fresh flat rock. This is because the multiple reflections in the inter-aggregate cavity increase the solar absorption of the layer. Painting the crushed rock layer with high-reflective pigments can increase the albedo of the layer about 0.10-0.20, with the greater increase for the layer with the larger aggregate size. Copyright 2016 Springer-Verlag Berlin Heidelberg

DOI: 10.1007/s12665-016-5609-2

2016084642 Jorgenson, M. T. (Alaska Ecoscience, Fairbanks, AK); Kanevskiy, M.; Shur, Y.; Moskalenko, N.; Brown, D. R. N.; Wickland, K.; Striegl, R. and Koch, J. Role of ground ice dynamics and ecological feedbacks in recent ice wedge degradation and stabilization: Journal of Geophysical Research: Earth Surface, 120(11), p. 2280-2297, illus. incl. sects., 1 table, sketch maps, 69 ref., November 2015.

Ground ice is abundant in the upper permafrost throughout the Arctic and fundamentally affects terrain responses to climate warming. Ice wedges, which form near the surface and are the dominant type of massive ice in the Arctic, are particularly vulnerable to warming. Yet processes controlling ice wedge degradation and stabilization are poorly understood. Here we quantified ice wedge volume and degradation rates, compared ground ice characteristics and thermal regimes across a sequence of five degradation and stabilization stages and evaluated biophysical feedbacks controlling permafrost stability near Prudhoe Bay, Alaska. Mean ice wedge volume in the top 3 m of permafrost was 21%. Imagery from 1949 to 2012 showed thermokarst extent (area of water-filled troughs) was relatively small from 1949 (0.9%) to 1988 (1.5%), abruptly increased by 2004 (6.3%) and increased slightly by 2012 (7.5%). Mean annual surface temperatures varied by 4.9°C among degradation and stabilization stages and by 9.9°C from polygon center to deep lake bottom. Mean thicknesses of the active layer, ice-poor transient layer, ice-rich intermediate layer, thermokarst cave ice, and wedge ice varied substantially among stages. In early stages, thaw settlement caused water to impound in thermokarst troughs, creating positive feedbacks that increased net radiation, soil heat flux, and soil temperatures. Plant growth and organic matter accumulation in the degraded troughs provided negative feedbacks that allowed ground ice to aggrade and heave the surface, thus reducing surface water depth and soil temperatures in later stages. The ground ice dynamics and ecological feedbacks greatly complicate efforts to assess permafrost responses to climate change. Abstract Copyright (2015), . American Geophysical Union. All Rights Reserved.

DOI: 10.1002/2015JF003602

2016083351 Belshaw, R. K. (6a Ipswich Road, Norwich, United Kingdom); Gibbard, P. L.; Murton, J. B. and Murton, D. K. Early-middle Pleistocene drainage in southern-central England: Geologie en Mijnbouw. Netherlands Journal of Geosciences, 93(4), p. 135-145, illus. incl. sketch maps, 63 ref., December 2014.

The fluvial sequences of the Milton and the Letchworth formations in the south Midlands of England and neighbouring regions represent at least two pre-existing rivers, the Milton and Brigstock streams, underlying Middle Pleistocene glacial sediments. The Milton Formation includes sand sourced from the Midlands bedrock. This implies that both streams were aligned in a northwest to southeast direction. This direction parallels the contemporaneous courses of the rivers Thames and Trent, the former turning towards the east and northeast to enter the North Sea. Their alignments indicate that the Milton and Letchworth streams formed left-bank tributaries of the Thames, joining the river in Hertfordshire and Essex, as illustrated in the article. This reconstruction has important implications for the interpretation of the proto-Soar river of the south Midlands, represented by the Baginton Formation. Although originally thought to represent a late Middle Pleistocene line, this southwest to northeast aligned system was reinterpreted as the headwaters of a pre-Anglian 'Bytham river', alligned towards East Anglia. However, recent work has shown that this river could not have existed in the pre-Anglian since there is no link between the Midlands and East Anglian spreads. Recent re-recognition that the Baginton Formation deposits do represent a later, post-Anglian drainage line is reinforced by the identification of the Milton and Letchworth streams, whose catchments occupied the area later drained by the proto-Soar. Overall, the main drainage alignment in southern England during the pre-Anglian period was dominated by northwest-southeast-draining consequent rivers adjusted to the regional geological dip. After widespread drainage disruption caused by the Anglian glaciation, northeast-southwest-orientated subsequent streams eroded frost-susceptible clay bedrock under periglacial and permafrost conditions, and beheaded the courses of some of the older consequent streams.

DOI: 10.1017/njg.2014.25

2016085578 Luo Dongliang (Chinese Academy of Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, State Key Laboratory of Frozen Soils Engineering, Lanzhou, China); Jin Huijun; Lü Lanzhi and Wu Qingbai. Spatiotemporal characteristics of freezing and thawing of the active layer in the source areas of the Yellow River (SAYR): Chinese Science Bulletin, 59(24), p. 3034-3045, 34 ref., August 2014. Based on Publisher-supplied data.

Based on the analysis of data on temperatures and moisture of soils in the active layer at four different permafrost sites in the source areas of the Yellow River (SAYR) in 2010-2012, the freeze-thaw processes of soils in the active layer were compared and contrasted for understanding the spatiotemporal variations. At the four studied sites, the thickness and mean annual temperature of permafrost are different. The temperatures at the top of permafrost (TTOP), i.e., the maximum depth(s) of seasonal frost and/or thaw penetration, are -1.9 °C at the Chalaping site (CLP), -0.9 °C at the site on the southern bank of the Zhaling Lake (ZLH), -0.4 °C at the Maduo Town site (MDX), and 1.1 °C at the site on the northern bank of the Eling Lake (ELH). Differences in the mean annual ground temperature of permafrost and TTOPs may be responsible for the differentiations in the freeze-thaw processes of soils in the active layer. With rising TTOPs, the ground thawing started earlier: CLP in early June, ZLH in late May, MDX in early May, and ELH in mid-April, while the freezing began later: CLP in early October, ZLH in early to mid-October, MDX in mid-October, and ELH in the mid- to late October. With increasing TTOPs, the freeze-up periods for permafrost sites were shortened: 202 days at CLP, 130 days at ZLH, 100 days at MDX, and the period of complete thaw was 89 days at ELH. At the CLP and ZLH sites, the two-directional ground freezing (downwards from ground surfaces and upwards from the permafrost table) and thawing finished in the same year, but the ground freezing at the MDX continued to the end of the next January, with very slow freezing rates in the end. At the ELH site, ground freezing kept on until early May when thawing began on the surface, and upward and downward thawing became increasingly stable in late June to early July. At each site, with rising TTOPs, the downward freezing accelerated in comparison with the upward freezing, and with an increasing proportion of downward frozen depth, and with the larger ratios of freezing to thawing duration. In summary, the patterns of thawing and freezing processes in the active layer in the SAYR differ from those in other parts of the Qinghai-Tibet Plateau to a noticeable extent. Copyright 2014 Science China Press and Springer-Verlag Berlin Heidelberg

DOI: 10.1007/s11434-014-0189-6

2016087742 Jaworski, Tomasz (Nicolaus Copernicus University in Torun, Department of Geomorphology and Palaeogeography of the Quaternary, Torun, Poland) and Chutkowski, Karol. Genesis, morphology, age and distribution of cryogenic mounds on Kaffioyra and Hermansenoya, northwest Svalbard: Permafrost and Periglacial Processes, 26(4), p. 304-320, illus. incl. sect., 1 table, geol. sketch maps, 81 ref., October 2015.

Three main types of cryogenic mounds on the coastal plains (strandflats) of Kaffioyra and Hermansenoya on northwest Svalbard are distinguished according to their distribution, morphology, internal structure, genesis and age. The mounds include aggradational forms: a previously unrecognised hydraulic pingo, frost peat mounds with either a minerogenic core (mineral palsas) or an ice/ice-peat core, and earth hummocks. Previously unrecognised degradational features represent thermokarst mounds. Individual types of mounds have developed in different geomorphological locations: (i) in the forefield of a retreating subpolar glacier over fault zones (hydraulic pingo 7.8 m high); (ii) on peat bogs (two types of frost peat mounds 0.7-1.3 m high and thermokarst mounds 0.5-0.8 m high); (iii) on raised beaches (high earth hummocks 0.5-1.0 m high); and (iv) on flat and wet tundra surfaces (miniature earth hummocks 0.2-0.3 m high). Although large, pingo-type mounds are typical on Svalbard, only one pingo occurs in the study area because of lithological, hydrological and geomorphological conditions of the area. These conditions, together with thick permafrost, do not allow the outflow of sub- and intra-permafrost water to the surface. Some cryogenic mounds are the result of climate fluctuations in the recent part of the Holocene (Little Ice Age). The oldest frost peat mounds from Hermansenoya developed 3.0-2.5 kyr BP, while the pingo is still growing. Copyright Copyright 2015 John Wiley & Sons, Ltd.

DOI: 10.1002/ppp.1850

2016087510 Coronato, Andrea (Consejo Nacional de Investigaciones Científicas y Técnicas, Centro Austral de Investigaciones Científicas, Ushuaia, Argentina); Ercolano, Bettina; Corbella, Hugo and Tiberi, Pedro. Glacial, fluvial and volcanic landscape evolution in the Laguna Potrok Aike maar area, southern Patagonia, Argentina: in Potrok Aike maar lake Sediment Archive Drilling prOject (PASADO) (Zolitschka, Bernd, editor; et al.), Quaternary Science Reviews, 71, p. 13-26, illus. incl. geol. sketch maps, 68 ref., July 1, 2013.

We describe the Pleistocene evolution of the landscape in the Laguna Potrok Aike area in southern Patagonia, Argentina, based on a geomorphological survey. Basaltic eruptions generated tablelands and scoria cones between the Late Miocene and Middle Pleistocene, and phreatomagmatic eruptions produced maars during Middle and Late Pleistocene time. The first glaciations during the Early Pleistocene generated a gently undulating to flat landscape that was affected by cryogenic processes; they are documented but not dated. Outwash surfaces indicate that the Greatest Patagonian Glaciation was multi-phased. The eruption that produced Potrok Aike maar truncated terrace levels dating to a Middle Pleistocene glaciation. The abundance of maars dating to this time may be linked to large amounts of water associated with meltwater streams and permafrost. The landscape in the Potrok Aike area has changed little since the Middle Pleistocene and only minor modifications of landforms have occurred due to cryogenesis, moderate fluvial incision, mass wasting and eolian activity. Abstract Copyright (2013) Elsevier, B.V.

DOI: 10.1016/j.quascirev.2012.06.019

2016087521 Hahn, Annette (University of Bremen, Institute of Geography, Bremen, Germany); Kliem, P.; Ohlendorf, Christian; Zolitschka, Bernd and Rosén, P. Climate induced changes as registered in inorganic and organic sediment components from Laguna Potrok Aike (Argentina) during the past 51 ka: in Potrok Aike maar lake Sediment Archive Drilling prOject (PASADO) (Zolitschka, Bernd, editor; et al.), Quaternary Science Reviews, 71, p. 154-166, illus. incl. sketch map, 116 ref., July 1, 2013.

Total organic carbon, total inorganic carbon, biogenic silica content and total organic carbon/total nitrogen ratios of the Laguna Potrok Aike lacustrine sediment record are used to reconstruct the environmental history of south-east Patagonia during the past 51 ka in high resolution. High lake level conditions are assumed to have prevailed during the Last Glacial, as sediments are carbonate-free. Increased runoff linked to permafrost and reduced evaporation due to colder temperatures and reduced influence of Southern Hemispheric Westerlies (SHW) may have caused these high lake levels with lake productivity being low and organic matter mainly of algal or cyanobacterial origin. Aquatic moss growth and diatom blooms occurred synchronously with southern hemispheric glacial warming events such as the Antarctic A-events, the postglacial warming following the LGM and the Younger Dryas chronozone. During these times, a combination of warmer climatic conditions with related thawing permafrost could have increased the allochthonous input of nutrients and in combination with warmer surface waters increased aquatic moss growth and diatom production. The SHW were not observed to affect southern Patagonia during the Last Glacial. The Holocene presents a completely different lacustrine system because (a) permafrost no longer inhibits infiltration nor emits meltwater pulses and (b) the positioning of the SHW over the investigated area gives rise to strong and dry winds. Under these conditions total organic carbon, total organic carbon/total nitrogen ratios and biogenic silica cease to be first order productivity indicators. On the one hand, the biogenic silica is influenced by dissolution of diatoms due to higher salinity and pH of the lake water under evaporative stress characterizing low lake levels. On the other hand, total organic carbon and total organic carbon/total nitrogen profiles are influenced by reworked macrophytes from freshly exposed lake level terraces during lowstands. Total inorganic carbon remains the most reliable proxy for climatic variations during the Holocene as high precipitation of carbonates can be linked to low lake levels and high autochthonous production. The onset of inorganic carbon precipitation has been associated with the southward shift of the SHW over the latitudes of Laguna Potrok Aike. The refined age-depth model of this record suggests that this shift occurred around 9.4 cal. ka BP. Abstract Copyright (2013) Elsevier, B.V.

DOI: 10.1016/j.quascirev.2012.09.015

2016087519 Kliem, Pierre (University of Bremen, Institute of Geography, Bremen, Germany); Buylaert, J. P.; Hahn, Annette; Mayr, Christoph; Murray, A. S.; Ohlendorf, Christian; Veres, D.; Wastegard, Stefan and Zolitschka, Bernd. Magnitude, geomorphologic response and climate links of lake level oscillations at Laguna Potrok Aike, Patagonian steppe (Argentina): in Potrok Aike maar lake Sediment Archive Drilling prOject (PASADO) (Zolitschka, Bernd, editor; et al.), Quaternary Science Reviews, 71, p. 131-146, illus. incl. 2 tables, sketch map, 93 ref., July 1, 2013.

Laguna Potrok Aike is a large maar lake located in the semiarid steppe of southern Patagonia known for its Lateglacial and Holocene lake level fluctuations. Based on sedimentary, seismic and geomorphological evidences, the lake level curve is updated and extended into the Last Glacial period and the geomorphological development of the lake basin and its catchment area is interpreted. Abrasion and lake level oscillations since at least »50 ka caused concentric erosion of the surrounding soft rocks of the Miocene Santa Cruz Formation and expanded the basin diameter by approximately 1 km. A high lake level and overflow conditions of the lake were dated by luminescence methods and tephra correlation to the early Lateglacial as well as to »45 ka. The lowest lake level of record occurred during the mid-Holocene. A further lake level drop was probably prevented by groundwater supply. This low lake level eroded a distinct terrace into lacustrine sediments. Collapse of these terraces probably caused mass movement deposits in the profundal zone of the lake. After the mid-Holocene lake level low stand a general and successive transgression occurred until the Little Ice Age maximum; i.e. ca 40 m above the local groundwater table. Frequent lake level oscillations caused deflation of emerged terraces only along the eastern shoreline due to prevailing westerly winds. Preservation of eolian deposits might be linked to relatively moist climate conditions during the past 2.5 ka. Precisely dated lake level reconstructions in the rain-shadow of the Andes document high Last Glacial and low Holocene lake levels that could suggest increased precipitation during the Last Glacial period. As permafrost in semiarid Patagonia is documented and dated to the Last Glacial period we argue that the frozen ground might have increased surficial runoff from the catchment and thus influenced the water balance of the lake. This is important for investigating the glacial to Holocene latitudinal shift and/or strengthening of the Southern Hemispheric Westerlies by using lake level reconstructions as a means to assess the regional water balance. Our interpretation explains the contradiction with investigations based on pollen data indicating drier climatic conditions for the Last Glacial period. Abstract Copyright (2013) Elsevier, B.V.

DOI: 10.1016/j.quascirev.2012.08.023

2016087361 Wilhelm, Kelly (University of Wisconsin at Madison, Department of Soil Science, Madison, WI) and Bockheim, James. Influence of soil properties on active layer thermal propagation along the western Antarctic Peninsula: Earth Surface Processes and Landforms, 41(11), p. 1550-1563, illus. incl. 7 tables, sketch maps, 44 ref., September 15, 2016.

The rate of energy transfer through soils is an important factor governing the active layer (seasonal thaw layer) in polar regions. Energy is transferred through conductive and convective means, which are primarily influenced by the bulk density and water content of soils. With global temperatures changing, it becomes important to understand how soil properties influence heat transfer and active layer depths in climatically sensitive regions, such as the Antarctic Peninsula. In this study we analyzed conductive energy transfer through several soil types on Amsler Island and Cierva Point in the central region of the western Antarctic Peninsula. Active layer temperatures on Amsler Island were monitored every three hours using iButton thermistors installed at regular depth intervals down to 2 m. Soil textures were loamy to sandy with water contents between 5 and 27%. Freezing and thawing transmission rates for all soils ranged from 1.4 to 6.9 cm/day. Thermal transmission rates were fastest in sandy soils with low water contents, indicating that the large, interconnected pores of the sandy soils facilitated the quick movement of heat with water flow through the soil profile. Snow accumulation differences also played a significant role on winter thermal propagation by providing a thermal barrier between the ground surface and atmosphere. Although there was a wide range in thermal transmission among the soils, active layer depths had little variation (7.8-9.7 m). This consistency derives from the greater dependence of very thick active layers on long-term climatic conditions rather than on soil properties. The presence of thick moss significantly slowed thermal transmission and decreased active layer thicknesses. These effects primarily are due to the high heat capacity of water and air retained within the moss, slowing thermal transmission rates, acting as a thermal buffer between atmospheric conditions and the underlying soils. Copyright Copyright 2016 John Wiley & Sons, Ltd.

DOI: 10.1002/esp.3926

2016086801 Wang Xiaqing (Chinese Academy of Sciences, Institute of Earth Environment, Xi'an, China); Jin Zhangdong; Chen Liumei; Xiao Jun and Zhang Fei. High-resolution X-ray fluorescence core scanning of landslide-dammed reservoir sediment sequences on the Chinese Loess Plateau; new insights into the formation and geochemical processes of annual freeze-thaw layers: Geoderma, 279, p. 122-131, illus. incl. 2 tables, sketch map, 40 ref., October 2016.

Landslide-dammed reservoirs are widespread on the Chinese Loess Plateau (CLP). Due to the contrasting seasonality of the monsoonal hydroclimate, sediment sequences in landslide-dammed reservoirs are characterized by deposition couplets of eroded loess with annual freeze-thaw layers that are ideal objects to reconstruct catchment erosion processes, hydrologic events, land use and human activity history. Identifying annual freeze-thaw layer from the deposition couplets in a given year is crucial for dating sediment sequences and for reconstructing erosion history using sediments because they are considered to be the boundary of the last hydrological event in an individual year. Using high-resolution XRF core scanning, grain size and mineralogy, fine-grained layers were identified in two representative core sections from the Jingbian and Heshui landslide-dammed reservoirs on the northern and southern CLP. The results show that both annual and intra-annual fine-grained layers have high Ca, Fe, and Mn contents but low Si contents and are dominated by clays, calcite and fine silt as a result of sorting and stratification during deposition. However, Ca exhibits two distinct trends with Fe (and Mn) in these fine-grained layers from both core sections. The steeper slopes of the relationship between them reflect further concentrations of both Ca and Fe (and Mn) that potentially result from freeze-thaw processes. The fine-grained layers with high concentrations of Ca and Fe and high slopes of their correlations are therefore identified as the annual freeze-thaw layers. The identification of annual freeze-thaw layers in landslide-dammed reservoir sediment sequences by high-resolution XRF core scanning provides new insights into their formation and mobile elemental enrichment processes as well as dating of the sediment sequences.

DOI: 10.1016/j.geoderma.2016.06.008

2016084697 Mironov, Valery (Kirensky Institute of Physics, Krasnoyarsk, Russian Federation) and Savin, Igor. A temperature-dependent multi-relaxation spectroscopic dielectric model for thawed and frozen organic soil at 0.05-15 GHz: in Emerging science and applications with microwave remote sensing data (Islam, Tanvir, editor; et al.), Physics and Chemistry of the Earth (2002), 83-84, p. 57-64, illus. incl. 2 tables, 13 ref., 2015.

A dielectric model for thawed and frozen Arctic organic-rich soil (50% organic matter) has been developed. The model is based on soil dielectric measurements that were collected over ranges of gravimetric moisture from 0.03 to 0.55 g/g, dry soil density from 0.72 to 0.87 g/cm³, and temperature from 25 to -30 °C (cooling run) in the frequency range of 0.05-15 GHz. The refractive mixing dielectric model was applied with the Debye multi-relaxation equations to fit the measurements of the soil's complex dielectric constant as a function of soil moisture and wave frequency. The spectroscopic parameters of the dielectric relaxations for the bound, transient bound, and unbound soil water components were derived and were complimented by the thermodynamic parameters to obtain a complete set of parameters for the proposed temperature-dependent multi-relaxation spectroscopic dielectric model for moist soils. To calculate the complex dielectric constant of the soil, the following input variables must be assigned: (1) density of dry soil, (2) gravimetric moisture, (3) wave frequency, and (4) temperature. The error of the dielectric model was evaluated and yielded RMSE_e' values of 0.348 and 0.188 for the soil dielectric constant and the loss factor, respectively. These values are on the order of the dielectric measurement error itself. The proposed dielectric model can be applied in active and passive microwave remote sensing techniques to develop algorithms for retrieving the soil moisture and the freeze/thaw state of organic-rich topsoil in the Arctic regions. Abstract Copyright (2015) Elsevier, B.V.

DOI: 10.1016/j.pce.2015.02.011

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2016083183 Biller, Nicole (Boston College, Department of Earth and Environmental Sciences, Chestnut Hill, MA); Shakun, Jeremy D.; McGee, David; Hardt, Benjamin F.; Ford, Derek C. and Lauriol, Bernard. Pleistocene permafrost thawing history of the North American Arctic and Cordillera from U-Th dating of cave speleothems [abstr.]: in Geological Society of America, Northeastern Section, 51st annual meeting, Abstracts with Programs - Geological Society of America, 48(2), Abstract no. 39-9, 2016. Meeting: Geological Society of America, Northeastern Section, 51st annual meeting, March 21-23, 2016, Albany, NY.

Permafrost, or permanently frozen ground, is widespread in the Arctic, sub-Arctic and northern cordillera of North America. It is estimated to contain twice as much carbon as the atmosphere in the form of frozen organic matter, which can be released to the atmosphere as greenhouse gases under a warming climate. However, because permafrost can be slow to respond to warming, the short instrumental record does not adequately capture long-term temperature trends. The modest temperature changes of the past few millennia provide poor analogues for understanding the substantial warming projected for the next century or beyond unless the response of permafrost can be accurately predicted. One way to address this problem is to assess the stability of permafrost during previous interglacial periods, some warmer than today. Speleothems in caves in the Arctic and other regions that are currently permafrost are relicts of past periods of thaw that enabled meteoric waters to seep into caves and deposit calcite (e.g., Lauriol et al., 1997). We employed uranium-thorium (U-Th) dating to constrain the chronology and extent of permafrost thaw in these North American regions during the past 600,000 years. We sampled caves from a range of permafrost zones (continuous, discontinuous, and isolated permafrost) and latitudes (66.5N to 49N), in the Yukon, Alaska, Northwest Territories, and Rocky Mountains of Alberta/British Columbia. Thirty-nine samples from 30 speleothems have been analyzed at this point in time; 23 samples lie beyond the U-Th dating range, and finite ages tend to cluster near the Marine Isotope Stage (MIS) 11 interglacial 400,000 years ago, as well as perhaps MIS 9, 13, and 15. This preliminary data set, coupled with a similar study in Siberia (Vaks et al., 2013), thus suggests an episode of widespread thawing during MIS 11 when global temperature was perhaps only ~1C warmer than known pre-industrial temperatures. We anticipate dating more speleothems in the months prior to NEGSA, and exploring the use of U-Pb for samples extending beyond the analytical limit of U-Th dating.

DOI: 10.1130/abs/2016NE-272115

2016083206 Karig, Daniel E. (Cornell University, Department of Earth and Atmospheric Sciences, Ithaca, NY) and Peteet, Dorothy. Evidence for permafrost conditions in New York between the LGM and the B-A warmup [abstr.]: in Geological Society of America, Northeastern Section, 51st annual meeting, Abstracts with Programs - Geological Society of America, 48(2), Abstract no. 42-6, 2016. Meeting: Geological Society of America, Northeastern Section, 51st annual meeting, March 21-23, 2016, Albany, NY.

Ideas for deglacial conditions in New York between the LGM and the B/A warmup range from a continuous ice cover to a complete ice retreat into the Ontario basin. Two new data streams from central and southern New York suggest other possible responses. The first is a thick pro-glacial lacustrine sequence south of Cayuga Lake that underlies Port Bruce deposits and overlies till of probable Nissouri age. Plant macros recovered from near the middle of this inorganic exposure indicate a tundra environment, with an age of 18.2 cal yr BP, confirming an Erie Interstade age. The very cold environment at this time corroborates the local evidence for a lack of Erie ice retreat north of Ithaca and indicates local permafrost conditions during this interval. The second data set is the compilation of the AMS macrofossil dates from inorganic basal clays in lakes and bogs over a large latitudinal transect from the NY-NJ terminal moraine to near the north end of Cayuga Lake. The ages over this 350 km transect show no discernable gradient, but vary mostly between 14.2 and 15.1 cal yr BP. Three of the ages at the terminal moraine are older than 16 cal kyr, and include a basal tundra assemblage (Dryas, Betula, Salix). Younger southern sites sometimes indicate tundra but include conifer needles as well, suggesting park-tundra conditions. Understanding this inorganic deposition is important, linking it to a modern analog. Kettle bog bases near Ithaca tend to be slightly younger, have no Dryas and are Picea dominated, suggesting boreal conditions. One way to explain this age distribution and vegetational response is that most of the region continued to have very cold and permafrost conditions until about 14.7 ka when the Bolling-Allerod warming began. During this interval buried ice masses could not melt, but during the subsequent warming the ice blocks melted at rates dependent on their size and burial conditions, which could account for the scatter in ages. Alternatively, isolated ice regions were still present surrounding southern sites until the Bolling. These models fit our age distribution better than postulating a large-scale ice retreat to the Ontario basin and very rapid re-advance to the Valley Heads moraine location.

DOI: 10.1130/abs/2016NE-272435

2016083178 Clements, Siobhan M. (State University of New York at Buffalo, Department of Geology, Buffalo, NY) and Jason, Briner. A compilation of basal radiocarbon ages from post-glacial lakes and bogs in western New York [abstr.]: in Geological Society of America, Northeastern Section, 51st annual meeting, Abstracts with Programs - Geological Society of America, 48(2), Abstract no. 39-4, 2016. Meeting: Geological Society of America, Northeastern Section, 51st annual meeting, March 21-23, 2016, Albany, NY.

In eastern New York, recent work has revealed a gap in time between initial ice sheet deglaciation and when the first organic matter is deposited in lakes and bogs (Peteet et al., GRL, v. 39, 2012); such an age gap is not apparent in Ohio (K.C Glover et al., Quaternary Research, v. 76, 2011). We hypothesize that the northeastern US seaboard was chilled, with active permafrost, during the first millennia following deglaciation. We aim to investigate this time period in western New York (WNY), which lies between Ohio and eastern New York. Multiple lakes and bogs have been cored in western New York. We compile sediment core basal radiocarbon ages from a large pool of published literature. The radiocarbon ages are calibrated using the Calib 7.1 program and reported with two sigma uncertainty. We are awaiting new basal ages from a site that lies immediately inboard of the Laurentide Ice Sheet terminal moraine, which will be key for testing the eastern New York vs. Ohio models of post-glacial sediment history. At our new field location in southern WNY, sediment cores were extracted from Allenberg Bog just inside the margin of southernmost extent of the Laurentide ice sheet. Allenberg Bog is just south of New Albion, New York, in Cattaraugus County. A 14.6 meter long sediment core was recovered using a Livingstone piston corer and consists of tightly packed gray glacial sediment overlain by organic-rich lacustrine sediments that we targeted for radiocarbon dating. Once the ages are returned we will compare it with the dates compiled from literature. Results will be presented at the conference.

DOI: 10.1130/abs/2016NE-272322

2016083160 Snyder, Rebecca (Lamont-Doherty Earth Observatory, Palisades, NY); Peteet, Dorothy; Nichols, Jonathan; Finkelstein, Sarah and Packalen, Maara. Macrofossil and biomarker record from Hudson Bay Lowland South Ridge Hollow Bog, northeast Ontario [abstr.]: in Geological Society of America, Northeastern Section, 51st annual meeting, Abstracts with Programs - Geological Society of America, 48(2), Abstract no. 36-8, 2016. Meeting: Geological Society of America, Northeastern Section, 51st annual meeting, March 21-23, 2016, Albany, NY.

A sediment core was taken from VM Bog Tower + 375 m South Ridge Hollow in the Hudson Bay Lowlands of Northeast Ontario at 52°69' N, 83°94' W. Ontario's Hudson Bay Lowlands are predominantly comprised of bogs and fens (approximately 60%) and characterized by a cool, moist subarctic climate with sporadic permafrost in the area from which the core was taken (Riley, 2011). Bogs in the region can be treed or open, and are typically dominated by Sphagnum fuscum as well as various shrubs including Chamaedaphne calyculata and Vaccinium spp., with ridges comprised primarily of conifers such as Picea mariana. The core depth extends to 258cm and has been dated using radiocarbon. By analyzing the presence of macrofossils and leaf wax biomarkers in the sampled peat, this paper seeks to reconstruct past vegetational and climatic conditions. While pollen analysis provides important information about regional distribution of plant species, macrofossils are more indicative of the presence of local species as they generally do not travel as far as pollen and spores. Further, hydrogen isotope ratios of leaf wax biomarkers can provide paleohydrological information. Completed samples, extending to a depth of 20 cm, indicate the presence of Picea spp., Larix laricina, Chamaedaphne calyculata and possibly Vaccinium spp., in addition to the dominant (~90%) Sphagnum spp. typical of bogs in the region. Cyperaceae spp. remains appear to be present at a depth of 18 to 20 cm from the surface, along with fungal remains. These findings are generally consistent with surface vegetational observations. Further analysis of greater depths, however, may reveal vegetational shifts.

DOI: 10.1130/abs/2016NE-272882

2016082573 Anderson, M. T. (U. S. Geological Survey, Rapid City, SD); Valder, J. F. and Carter, J. M. Development of groundwater modeling capacity in Mongolia; keys to success [abstr.]: in AGU 2015 fall meeting, American Geophysical Union Fall Meeting, 2015, Abstract H51A-1346, December 2015. Meeting: American Geophysical Union 2015 fall meeting, Dec. 14-18, 2015, San Francisco, CA.

Ulaanbaatar, the capital city of Mongolia, is totally dependent on groundwater for its municipal and industrial water supply. Water is drawn from a network of shallow wells in an alluvial aquifer along the Tuul River. Evidence, however, suggests that current water use and especially the projected water demand from a rapidly growing urban population, is not sustainable from existing water sources. In response, the Mongolia Ministry of Environment and the Mongolian Fresh Water Institute requested technical assistance on groundwater modeling through the U.S. Army Corps of Engineers to the U.S. Geological Survey (USGS). Scientists from the USGS-SD Water Science Center provided a workshop to Mongolian water experts on basic principles of groundwater modeling using MODFLOW. The purpose of the workshop was to bring together representatives from the Government of Mongolia, local universities, technical experts, and other key stakeholders to build in-country capacity in hydrogeology and groundwater modeling. A preliminary steady-state groundwater flow model was developed to simulate groundwater conditions in the Tuul River Basin and for use in water use decision-making. The model consisted of 2 layers, 226 rows, and 260 columns with uniform 500 meter grid spacing. The upper model layer represented the alluvial aquifer and the lower layer represented the underlying bedrock, which includes areas characterized by permafrost. Estimated groundwater withdrawal was 180 m³/day, and estimated recharge was 114 mm/yr. The model will be modified and updated by Mongolian scientists as more data are available. Ultimately the model will be used to assist managers in developing a sustainable water supply, for current use and changing climate scenarios. A key to success was developing in-country technical capacity and partnerships with the Mongolian University of Science and Technology, Mongolian Freshwater Institute, a non-profit organization, UNESCO, and the government of Mongolia.

2016086196 Bendixen, Mette (University of Copenhagen, Department for Geosciences and Natural Resource Management, Copenhagen, Denmark) and Kroon, Aart. Arctic coastal zone mapping; evolution of sedimentary coasts in Greenland [abstr.]: in AGU 2015 fall meeting, American Geophysical Union Fall Meeting, 2015, Abstract EP23A-0942, December 2015. Meeting: American Geophysical Union 2015 fall meeting, Dec. 14-18, 2015, San Francisco, CA.

Climate change threatens many of the coastal areas all over the world. In the Arctic, the warming happens at a rate which is three times faster than the global average increasing the pressure on the coast. Arctic coasts differ from coasts in lower latitude in terms of the natural conditions prevailing, i.e. sea-ice, permafrost, and thermal erosion. These factors are likely to change with an increasing temperature, and thereby the erodibility of the shores and the erosivity of the coastal processes are changing. The majority of studies on arctic coasts focus on tundra coasts. Here, there is a general increase of coastal erosion rates over the last decades. However, the arctic coastal areas of Greenland differ; they are often close to hard rock protrusions and are characterized by large differences in geomorphology, erodibility of sediments, and erosivity by coastal processes. Sedimentary coasts in Greenland are only sporadically investigated, and it is thus difficult to predict the impact of climate changes in these areas. With this work we focus on sedimentary coasts in Greenland and present shoreline analysis of two sedimentary coastal sites. We show how the position of the shoreline has changed since the 1930's and we address the responsible factors controlling this evolution. The hotspots of coastal change are all located near delta mouths and the detected changes are coupled to dominating process occurring here.

2016082588 Normani, S. D. (University of Waterloo, Waterloo, ON, Canada). Incorporating discrete irregular fracture zone networks into 3D paleohydrogeologic simulations [abstr.]: in AGU 2015 fall meeting, American Geophysical Union Fall Meeting, 2015, Abstract H51C-1376, December 2015. Meeting: American Geophysical Union 2015 fall meeting, Dec. 14-18, 2015, San Francisco, CA.

Dual continuum computational models which include both porous media and discrete fracture zones are valuable tools in assessing groundwater migration and pathways in fractured rock systems. Fracture generation models can produce stochastic realizations of fracture networks which honor geological structures and fracture propagation behaviors. Surface lineament traces can be propagated to depth based on fracture zone statistics to produce representations of geological structures in rock. The generated discrete, complex and irregular fracture zone networks, represented as a triangulated mesh, are embedded using orthogonal quadrilateral elements within a three-dimensional hexahedral finite element mesh. A detailed coupled density-dependent paleohydrogeologic groundwater analysis of a hypothetical 104 km² portion of the Canadian Shield has been conducted using the discrete-fracture dual continuum finite element model FRAC3DVS to investigate the characterization of large-scale fracture zone networks on groundwater and tracer movement during a 120,000 year paleoclimate cycle. Permeability reduction due to permafrost was also applied. Time series data for the depth of permafrost, along with ice thickness and lake depth, were provided by the University of Toronto (UofT) Glacial Systems Model. The crystalline rock between fracture zones was assigned properties characteristic of those reported for the Canadian Shield. Total dissolved solids concentrations of 300 g/L are encountered at depth. Surface water features and a Digital Elevation Model (DEM) were used in a GIS framework to define the watershed boundaries at surface water divides and to populate the finite element mesh. This work will illustrate the long-term evolution and stability of the geosphere and groundwater systems to external perturbations caused by glaciation through the use of performance measures such as Mean Life Expectancy and the migration of a unit tracer to depth over a paleoclimate cycle.

2016082415 Rathburn, Sara L. (Colorado State University, Fort Collins, CO); Comiti, Francesco; Brardinoni, Francesco; Sparacino, Matthew and Schook, Derek M. Drainage basin sensitivity to climate change in the eastern Italian Alps [abstr.]: in AGU 2015 fall meeting, American Geophysical Union Fall Meeting, 2015, Abstract EP33A-1047, December 2015. Meeting: American Geophysical Union 2015 fall meeting, Dec. 14-18, 2015, San Francisco, CA.

In the past decades, increases in summer air temperatures generate glacial-melt floods with higher than normal magnitudes, increase the frequency of high intensity rainfall events, and lead to permafrost degradation of steep rocky slopes prone to mass wasting. Continued climatic warming has the potential to drastically increase the sediment supply to the channel network. A US-Italy collaboration is characterizing response domains for drainage basins undergoing deglaciation in the Italian Alps to develop sensitivity indices of changes in flow and sediment dynamics. Six glaciated basins 85-160 km2 in size within the upper Adige River Valley are analyzed. Three study basins have multi-year data on either the spatial distribution of mass wasting and sediment production or hydrology and sediment transport over snow and glacial melt, or both. The other three basins are tested for applicability of the sensitivity indices where field data are lacking. Preliminary results indicate basin lithology and degree of sediment connectivity are the dominant controls on drainage basin response. Four broadly applicable response domains incorporate metamorphic, sedimentary, or mixed bedrock lithology with high to low connectivity. The sensitivity indices for fluvial response are controlled by valley confinement and channel morphologic changes. A historic topographic map from 1858 provides qualitative channel geometry information at the end of the Little Ice Age and glacial extent for all basins. Aerial photographs from 1945, 1954, 1971, and lidar and imagery from 2005 or 2011, along with field verification quantify valley confinement, braiding index and sediment connectivity. Key controls on sediment delivery to channels include glacially-inherited topography and the distribution of glacigenic surficial materials. Sediment cascade modeling will identify sediment sources, pathways and sinks and provide a first order understanding of basin-scale response to climate change.

2016086193 Richmond, Bruce M. (U. S. Geological Survey, California Water Science Center Sacramento, Sacramento, CA); Gibbs, Ann; Erikson, Li H. and Beitch, Marci J. Seasonal to decadal change of Arctic coastal bluffs, Barter Island, Alaska [abstr.]: in AGU 2015 fall meeting, American Geophysical Union Fall Meeting, 2015, Abstract EP23A-0938, December 2015. Meeting: American Geophysical Union 2015 fall meeting, Dec. 14-18, 2015, San Francisco, CA.

Warming air and sea temperatures in the Arctic are leading to elevated levels of permafrost thaw and longer periods of ice-free conditions during the summer months which can lead to increased coastal exposure to storm surge and wave impacts. Using recently collected time-lapse photography, historical maps and imagery, and DEM's derived from airborne lidar and aerial photography using structure from motion (SfM) algorithms, we document coastal bluff change along a 5 km stretch of coast on Barter Island in NE Alaska during a single summer and over several decades. Time-lapse cameras installed during the summers of 2014 and 2015 on the coastal bluffs are used to create an archive of hourly air temperature and pressure, bluff morphology, and sea conditions allowing us to document individual bluff failure events and conditions at the time of failure. The historical rates of bluff retreat are derived from 1947 T-sheet maps, various periods of satellite imagery, aerial orthophoto mosaics, and more recently acquired lidar and SfM DEM data. Coastal change rates at 50 m transect spacing have been calculated over a seven decade time span. We combine these results with elevation models and bluff geology to estimate overall volume change and sediment contribution to the nearshore. These combined datasets are used to better understand the timing and processes of Arctic coastal retreat.

2016088096 Larson, Phil (Vesterheim Geoscience, Duluth, MN); Mooers, Howard and Meyer, Margretta. Glacial geology of the Laurentian uplands: in Institute on Lake Superior Geology; 62nd annual meeting; Part 2, Field trip guidebook (Miller, James D., Jr., chairperson; et al.), Proceedings and Abstracts - Institute on Lake Superior Geology. Meeting, 62, Part 2, p. 1-13, illus. incl. sect., sketch maps, 32 ref., May 2016. Meeting: Institute on Lake Superior Geology 62nd annual meeting, May 4-8, 2016, Duluth, MN.

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2016082127 Oldenborger, G. A.; LeBlanc, A. M. and Sladen, W. E. Electrical and electromagnetic data for permafrost characterization at Iqaluit International Airport, Nunavut: Open-File Report - Geological Survey of Canada, Rep. No. 7750, 41 p., illus. incl. tables, 55 ref., 2015.

Iqaluit International Airport presently suffers from instabilities and subsidence along its runway, taxiways and apron. In particular, asphalt surfaces are significantly impacted by settlement and cracking. These instabilities may be related to permafrost, permafrost degradation and associated drainage conditions. This Open File reports on electrical and electromagnetic geophysical data collected and processed by the Geological Survey of Canada at the Iqaluit International Airport as part of the Land-Based Infrastructure Project within the Climate Change Geoscience Program. Galvanic and capacitive electrical resistivity surveys, along with low induction number electromagnetic measurements, were performed over selected areas within the airport boundary and in the near vicinity to assist with permafrost characterization and to investigate active permafrost processes. The recovered electrical resistivities suggest distinct electrical signatures for different terrain units and sediment types, and for ice-rich material including ice wedges. Even with continuous permafrost and cold permafrost temperatures, the resistivity models reveal anomalously conductive material at depth that is not obviously correlated to mapped surficial sediments. The anomalous regions are correlated with localized settlement problems and downward multi-season displacement derived from D-InSAR. The geophysical surveys also exhibit features indicative of seasonal freezing of localized groundwater beneath airport infrastructure and variable active layer thickness under infrastructure that is thicker than for undeveloped ground.

DOI: 10.4095/295978

2016082111 Riedel, M. and Jin, Y. K. Regional geological setting and permafrost regime in the Canadian Beaufort Sea: in Overview of field operations during a 2013 research expedition to the southern Beaufort Sea on the RV Araon (Jin, Y. K.; et al.), Open-File Report - Geological Survey of Canada, Rep. No. 7754, p. 25-37, illus., 21 ref., 2015.

DOI: 10.4095/295856

2016082090 Crow, H. L.; Good, R. L.; Hunter, J. A.; Burns, R. A.; Reman, A. and Russell, H. A. J. Borehole geophysical logs in unconsolidated sediments across Canada: Open-File Report - Geological Survey of Canada, Rep. No. 7591, 39 p., illus. incl. tables, 70 ref., 2015.

Over the past four decades, the Near-Surface Geophysics group at the Geological Survey of Canada (GSC) has collected borehole geophysical logs in Quaternary sediments across Canada. Project work has primarily been driven by long term research programs related to permafrost, groundwater, and natural hazards. This work has resulted in a dataset of geophysical logs in 226 boreholes across the country. Primary logging methods include natural and active gamma, inductive conductivity and magnetic susceptibility, fluid temperature, and compressional and shear wave velocities. Over the years, tool calibration runs have been conducted at the Bell's Corners Borehole Calibration Facility in Ottawa, ON, to ensure that all the tools provide repeatable results which are in agreement with the standards published by the GSC. The compilation presented in this report provides logs as digital Log ASCII Standard (LAS) files, WellCAD files, and also in an interactive Google Earth format with links to PDF images of the log suites. The purpose of this Open File is to release the complete suite of geophysical logs so that the all members of the public may have access to this valuable national dataset

DOI: 10.4095/295753

2016082129 Hu, K.; Brent, T. A.; Issler, D. R. and Chen, Z. Synthetic seismograms from borehole seismic data and well logs, Beaufort-Mackenzie Basin: Open-File Report - Geological Survey of Canada, Rep. No. 6056, 228 p., illus. incl. tables, strat. cols., 2015.

Borehole seismic survey data are compiled for 202 wells in the Beaufort-Mackenzie Basin, including vertical seismic profile, check shot and crystal cable surveys. On the basis of the well seismic data, well logs and deviation survey data (for deviated wells), synthetic seismograms are generated for the 202 wells using Well Editor (GeoGraphix, R2007.2). The resulting synthetics are illustrated with a time/depth window, well logs, well seismic data, calculated velocity, as well as stratigraphic information and casing shoe depths. The presentation of results provides key time-depth relationships important to seismic interpretation, but it also shows log responses in the time domain to rationalize reflection events by effectively tying well tops and other levels to surface-seismic reflection profiles. The information is also useful for the identification of permafrost (Hu et al., 2013) and gas hydrate zones as well as for other types of sedimentary basin studies.

DOI: 10.4095/296213

2016084608 Hungr, O. (University of British Columbia, Vancouver, BC, Canada) and Locat, J. Examples of common landslide types in Canada; Canadian technical guidelines and best practices related to landslides; a national initiative for loss reduction: Open-File Report - Geological Survey of Canada, Rep. No. 7897, 88 p., illus., 225 ref., 2015.

The second largest country in the world, Canada has an area of nearly 10 million km2. A wide variety of landslides occur in the mountains, along river valleys, on hills and escarpments, in the extensive areas of permafrost, along the shores of oceans and lakes, and under water. Landslides are associated with both natural slopes and engineered excavations and fill slopes. The purpose of this report is to update the record with recent examples, present the landslides in the context of both geographic distribution and physical characteristics, and describe loss reduction approaches.

DOI: 10.4095/296666

2016082108 Jin, Y. K. (Korea Polar Research Institute, Incheon, South Korea); Riedel, M.; Hong, J. K.; Nam, S. I.; Jung, J. Y.; Ha, S. Y.; Lee, J. Y.; Kim, G. Y.; Yoo, J.; Kim, H. S.; Kim, G.; Conway, Kim W.; Standen, G.; Ulmi, M. and Schreker, M. Overview of field operations during a 2013 research expedition to the southern Beaufort Sea on the RV Araon: Open-File Report - Geological Survey of Canada, Rep. No. 7754, 181 p., illus. incl. tables, 2015. Individual papers within scope are cited separately.

The Expedition ARA04C is a highly multidisciplinary undertaking in the Beaufort Sea, carried out in collaboration between the Korea Polar Research Institute (KOPRI), Geological Survey of Canada (GSC), Department of Fisheries and Ocean (DFO), Monterey Bay Aquarium Research Institute (MBARI), and the Alfred Wegener Institute (AWI). During Expedition ARA04C on the IBRV Araon from September 6 to September 24, 2013, in the Beaufort Sea, multiple research experiments were undertaken to study geological processes related to degrading permafrost, fluid flow and degassing, and associated geohazards, paleo-oceanography of the Beaufort shelf and slope region, as well as physical and chemical oceanography measurement of the Arctic Ocean linked with continuous atmospheric studies. The expedition focused on two main research areas: offshore Barrow, Alaska, from September 7 to September 9, 2013, and in the Canadian Beaufort Sea from September 10 to September 24, 2013.

DOI: 10.4095/295856

2016084611 Smith, S. L.; Chartrand, J.; Duchesne, C. and Ednie, M. Report on 2014 field activities and collection of ground thermal and active layer data in the Mackenzie Corridor, Northwest Territories: Open-File Report - Geological Survey of Canada, Rep. No. 7935, 104 p., illus. incl. tables, 18 ref., 2015.

This report presents a summary of field activities conducted in 2014 in the Mackenzie Corridor, N.W.T. Air temperature, ground thermal and active layer data acquired from permafrost monitoring sites visited in 2014 throughout the corridor are presented in graphical and tabular format. The ground temperature records for selected sites for 2007-14 are also provided and indicate that some permafrost warming has occurred. The data presented provide essential baseline information that can be utilized by stakeholders and others for various purposes such as land management activities, regulatory processes and design of northern infrastructure. This report will be distributed to community organizations and stakeholders in the study region to provide an update on field activities.

DOI: 10.4095/296958

2016082123 Smith, S. L. and Ednie, M. Ground thermal data collection along the Alaska Highway easement (KP 1559-1895) Yukon, summer 2014: Open-File Report - Geological Survey of Canada, Rep. No. 7762, 27 p., illus. incl. 2 tables, 22 ref., 2015.

Ground temperature data were acquired in summer 2014 from eight boreholes instrumented in summer 2013 along the Alaska Highway easement between KP1559 and the Alaska border. Permafrost was found to be present at six boreholes and was generally at temperatures above -0.7°C except near the Alaska border where permafrost temperature was -3°C. Summer thaw depths at permafrost sites range from 0.8 to 2.4 m. A warm period in January 2014, during which air temperatures rose above 0°C, appears to have had an impact on shallow winter ground temperatures at most sites. The information provided contributes to the characterization of regional permafrost conditions and supports decisions regarding development projects in the region, climate change assessments and adaptation planning.

DOI: 10.4095/295974

2016082124 Couture, N. J.; Forbes, D. L.; Fraser, P. R.; Frobel, D.; Jenner, K. A.; Manson, G. K.; Solomon, S. M.; Szlavko, B. and Taylor, R. B. A coastal information system for the southeastern Beaufort Sea, Yukon and Northwest Territories: Open-File Report - Geological Survey of Canada, Rep. No. 7778, 21 p., illus. incl. tables, 13 ref., 2015.

This report provides coastal data and a classification of the Canadian Beaufort Sea coast and is part of the Coastal Information System (CIS) maintained by the Geological Survey of Canada. Coastal attributes such as the physical form of the coast and the materials which comprise it have been interpreted and mapped from aerial photography and video for over 1900 kilometres of coastline. These attributes are mapped as line segments for three different shore-parallel zones: the backshore, the foreshore, and the nearshore. Additional points of interest such as water bodies, anthropogenic sites, or ground ice features are also mapped. Qualitative coastal change was mapped along select portions of the coast based on the availability of repetitive, multi-year coastal video and imagery. A glossary has been developed to control the language used in the descriptions. The data are contained in a geographic information system. A published map file is also included, which provides examples for displaying and symbolizing the CIS data.

DOI: 10.4095/295975

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