Permafrost Monthly Alerts (PMAs)

12101355 Ayris, Paul Martin (University of York, Environment Department, York, United Kingdom) and Delmelle, Pierre. The immediate environmental effects of tephra emission: Bulletin of Volcanology, 74(9), p. 1905-1936, illus. incl. 5 tables, 303 ref., November 2012.

The Earth's history is punctuated by large explosive eruptions that eject large quantities of magma and silicate rock fragments into the atmosphere. These tephra particles can sometimes be dispersed across millions of square kilometres or even entire continents. The interaction of tephra with or in receiving environments may induce an array of physical, chemical and biological effects. The consequences for affected systems and any dependent communities may be chronic and localised in the event of frequent, small eruptions, while larger and rarer events may have acute, regional-scale impacts. It is, therefore, necessary to document the range of possible impacts that tephra may induce in receiving environments and any resulting effects in interconnected systems. We collate results from many studies to offer a detailed multidisciplinary and interdisciplinary review of the immediate post-eruptive effects of tephra emission into the atmosphere, onto vegetation, soil or ice/snow surfaces and in aquatic systems. We further consider the repercussions that may be induced in the weeks to years afterwards. In the atmosphere, tephra can influence cloud properties and air chemistry by acting as ice nuclei (IN) or by offering sites for heterogeneous reactions, respectively. Tephra on vegetation causes physical damage, and sustained coverage may elicit longer-term physiological responses. Tephra deposits on soils may alter their capacity to exchange gas, water and heat with the atmosphere or may have a specific chemical effect, such as nutrient input or acidification, on sensitive soils. Tephra deposition onto snow or ice may affect ablation rates. Rivers and lakes may experience turbidity increases and changes in their morphology as a result of fallout and prolonged (months or years) erosion from the tephra-covered catchment. In the first weeks after deposition, tephra leaching may affect river chemistry. The abundance and speciation of phytoplankton populations in lakes may be altered by tephra-induced changes in water chemistry or sediment-water nutrient cycling. In the oceans, tephra deposition may fertilise Fe-limited waters, with potential impacts on the global carbon cycle. Embracing the full complexity of environmental effects caused by tephra fall demands a renewed investigative effort drawing on interdisciplinary field and laboratory studies, combined with consideration of the interconnectivity of induced impacts within and between different receiving environments. Copyright 2012 Springer-Verlag Berlin Heidelberg and Springer-Verlag

DOI: 10.1007/s00445-012-0654-5

12095562 Hyvaluoma, Jari (MTT Agrifood Research Finland, Jokioinen, Finland); Thapaliya, Mahesh; Alaraudanjoki, Jarno; Siren, Taisto; Mattila, Keijo; Timonen, Jussi and Turtola, Eila. Using microtomography, image analysis and flow simulations to characterize soil surface seals: Computers & Geosciences, 48, p. 93-101, illus. incl. 2 tables, 35 ref., November 2012.

Raindrops that impact on soil surface affect the pore structure and form compact soil surface seals. Damaged pore structure reduces water infiltration which can lead to increased soil erosion. We introduce here methods to characterize the properties of surface seals in a detailed manner. These methods include rainfall simulations, x-ray microtomography, image analysis and pore-scale flow simulations. Methods were tested using clay soil samples, and the results indicate that the sealing process changes several properties of the pore structure.

DOI: 10.1016/j.cageo.2012.05.009

12095619 Amon, R. M. W. (Texas A&M University, Department of Marine Sciences, Galveston, TX); Rinehart, A. J.; Duan, S.; Louchouarn, P.; Prokushkin, A.; Guggenberger, Georg; Bauch, D.; Stedmon, C.; Raymond, P. A.; Holmes, R. M.; McClelland, J. W.; Peterson, B. J.; Walker, S. A. and Zhulidov, A. V. Dissolved organic matter sources in large Arctic rivers: Geochimica et Cosmochimica Acta, 94, p. 217-237, illus. incl. 4 tables, 78 ref., October 1, 2012.

The biomarker composition of dissolved organic carbon (DOC) of the six largest Arctic rivers was studied between 2003 and 2007 as part of the PARTNERS Project. Samples were collected over seasonal cycles relatively close to the river mouths. Here we report the lignin phenol and p-hydroxybenzene composition of Arctic river DOC in order to identify major sources of carbon. Arctic river DOC represents an important carbon conduit linking the large pools of organic carbon in the Arctic/Subarctic watersheds to the Arctic Ocean. Most of the annual lignin discharge (>75%) occurs during the two month of spring freshet with extremely high lignin concentrations and a lignin phenol composition indicative of fresh vegetation from boreal forests. The three large Siberian rivers, Lena, Yenisei, and Ob, which also have the highest proportion of forests within their watersheds, contribute about 90% of the total lignin discharge to the Arctic Ocean. The composition of river DOC is also characterized by elevated levels of p-hydroxybenzenes, particularly during the low flow season, which indicates a larger contribution from mosses and peat bogs. The lignin composition was strongly related to the average ¹⁴C-age of DOC supporting the abundance of young, boreal-vegetation-derived leachates during spring flood, and older, soil-, peat-, and wetland-derived DOC during groundwater dominated low flow conditions, particularly in the Ob and Yukon Rivers. We observed significant differences in DOC concentration and composition between the rivers over the seasonal cycles with the Mackenzie River being the most unique, the Lena River being similar to the Yenisei, and the Yukon being most similar to the Ob. The observed relationship between the lignin phenol composition and watershed characteristics suggests that DOC discharge from these rivers could increase in a warmer climate under otherwise undisturbed conditions. Abstract Copyright (2012) Elsevier, B.V.

DOI: 10.1016/j.gca.2012.07.015

12101403 Paces, James B. (U. S. Geological Survey, Denver, CO) and Whelan, Joseph F. The paleohydrology of unsaturated and saturated zones at Yucca Mountain, Nevada, and vicinity: in Hydrology and geochemistry of Yucca Mountain and vicinity, southern Nevada and California (Stuckless, John S., editor), Memoir - Geological Society of America, 209, p. 219-276, illus. incl. strat. cols., 4 tables, sketch maps, 235 ref., October 2012.

Surface, unsaturated-zone, and saturated-zone hydrologic conditions at Yucca Mountain responded to past climate variations and are at least partly preserved by sediment, fossil, and mineral records. Characterizing past hydrologic conditions in surface and subsurface environments helps to constrain hydrologic responses expected under future climate conditions and improve predictions of repository performance. Furthermore, these records provide a better understanding of hydrologic processes that operate at time scales not readily measured by other means. Pleistocene climates in southern Nevada were predominantly wetter and colder than the current interglacial period. Cyclic episodes of aggradation and incision in Fortymile Wash, which drains the eastern slope of Yucca Mountain, are closely linked to Pleistocene climate cycles. Formation of pedogenic cement is favored under wetter Pleistocene climates, consistent with increased soil moisture and vegetation, higher chemical solubility, and greater evapotranspiration relative to Holocene soil conditions. The distribution and geochemistry of secondary minerals in subsurface fractures and cavities reflect unsaturated-zone hydrologic conditions and the response of the hydrogeologic system to changes in temperature and percolation flux over the last 12.8 m.y. Physical and fluid-inclusion evidence indicates that secondary calcite and opal formed in air-filled cavities from fluids percolating downward through connected fracture pathways in the unsaturated zone. Oxygen, strontium, and carbon isotope data from calcite are consistent with a descending meteoric water source but also indicate that water compositions and temperatures evolved through time. Geochronological data indicate that secondary mineral growth rates are less than 1-5 mm/m.y., and have remained approximately uniform over the last 10 m.y. or longer. These data are interpreted as evidence for hydrological stability despite large differences in surface moisture caused by climate shifts between the Miocene and Pleistocene and between Pleistocene glacial-interglacial cycles. Secondary mineral distribution and d¹⁸O profiles indicate that evaporation in the shallower welded tuffs reduces infiltration fluxes. Several near-surface and subsurface processes likely are responsible for diverting or dampening infiltration and percolation, resulting in buffering of percolation fluxes to the deeper unsaturated zone. Cooler and wetter Pleistocene climates resulted in increased recharge in upland areas and higher water tables at Yucca Mountain and throughout the region. Discharge deposits in the Amargosa Desert were active during glacial periods, but only in areas where the modern water table is within 7-30 m of the surface. Published groundwater models simulate water-table rises beneath Yucca Mountain of as much as 150 m during glacial climates. However, most evidence from Fortymile Canyon up gradient from Yucca Mountain limits water-table rises to 30 m or less, which is consistent with evidence from discharge sites in the Amargosa Desert. The isotopic compositions of uranium in tuffs spanning the water table in two Yucca Mountain boreholes indicate that Pleistocene water-table rises likely were restricted to 25-50 m above modern positions and are in approximate agreement with water-table rises estimated from zeolitic-to-vitric transitions in the Yucca Mountain tuffs (less than 60 m in the last 11.6 m.y.).

DOI: 10.1130/2012.1209(05)

12101277 Vonk, J. E. (Stockholm University, Department of Applied Environmental Science, Stockholm, Sweden); Sanchez-Garcia, L.; van Dongen, B. E.; Alling, V.; Kosmach, D.; Charkin, A.; Semiletov, I. P.; Dudarev, O. V.; Shakhova, N.; Roos, P.; Eglinton, T. I.; Andersson, A. and Gustafsson, Orjan. Activation of old carbon by erosion of coastal and subsea permafrost in Arctic Siberia: Nature (London), 489(7414), p. 137-140, illus. incl. sketch maps, 30 ref., September 6, 2012. Supplemental information/data is available in the online version of this article.

DOI: 10.1038/nature11392

12094275 Burn, C. R. (Carleton University, Department of Geography and Environmental Studies, Ottawa, ON, Canada) and Allard, M., editors. Fundamental and applied research on permafrost in Canada--Recherche fondamentale et appliquée sur le pergélisol au Canada: Canadian Journal of Earth Sciences = Revue Canadienne des Sciences de la Terre, 49(8), p. 865-986 (French sum.), illus., August 2012. WWW. Accessed on August 23, 2012; individual papers are cited separately.

12094281 Calmels, Fabrice (University of Alberta, Department of Earth and Atmospheric Sciences, Edmonton, AB, Canada); Froese, Duane G. and Clavano, Wendy R. Cryostratigraphic record of permafrost degradation and recovery following historic (1898-1992) surface disturbances in the Klondike region, central Yukon Territory: in Fundamental and applied research on permafrost in Canada--Recherche fondamentale et appliquée sur le pergélisol au Canada (Burn, C. R., editor; et al.), Canadian Journal of Earth Sciences = Revue Canadienne des Sciences de la Terre, 49(8), p. 938-952 (French sum.), illus. incl. sect., 2 tables, sketch map, 42 ref., August 2012. WWW. Accessed on August 23, 2012.

We present a detailed cryostratigraphic reconstruction of the degradation and recovery of near-surface permafrost in the southern Klondike goldfields, central Yukon Territory. Two ice-rich layers are recognized in near-surface permafrost and attributed to thermal impacts following vegetation disturbance. At an undisturbed forest site, the base of the modern active layer is stable. At an adjacent site, where a late twentieth century disturbance of surface vegetation and permafrost degradation occurred, there is evidence of recovery in the form of aggradation (upward shift) of the permafrost table following limited vegetation succession. Underlying both the undisturbed forest and the late twentieth century disturbance is an older thaw unconformity corresponding to a thaw depth of ~2 m, likely associated with early twentieth century (gold rush era) impacts. Field and air photo surveys allow identification of the nature of the disturbances, while a chronology of the surface disturbance has been established using age estimates from tree rings, and the presence of tritium and post-bomb ¹⁴C from organic samples within aggradational ice. Collectively, these data underscore the importance of vegetation cover in maintaining ground temperatures in the discontinuous permafrost zone and suggest that, at least at the study site in recent decades, permafrost shows the potential to recover from disturbance in the modern climatic regime of the region.

DOI: 10.1139/E2012-023

12094282 de Grandpré, Isabelle (Université de Montréal, Département de Gèographie, Montreal, QC, Canada); Fortier, Daniel and Stephani, Eva. Degradation of permafrost beneath a road embankment enhanced by heat advected in groundwater: in Fundamental and applied research on permafrost in Canada--Recherche fondamentale et appliquée sur le pergélisol au Canada (Burn, C. R., editor; et al.), Canadian Journal of Earth Sciences = Revue Canadienne des Sciences de la Terre, 49(8), p. 953-962 (French sum.), illus. incl. 2 tables, sketch maps, 33 ref., August 2012. WWW. Accessed on August 23, 2012.

For the past few decades, northwestern North America has been affected by climate warming, leading to permafrost degradation and instability of the ground. This is problematic for all infrastructure built on permafrost, especially roads and runways. Thaw settlement and soil consolidation promote embankment subsidence and the development of cracks, potholes, and depressions in road pavement. In this study, we investigate highway stability in permafrost terrain at an experimentally built road embankment near Beaver Creek, Yukon. A network of 25 groundwater monitoring wells was installed along the sides of the road to estimate groundwater flow and its thermal impact on the permafrost beneath the road. Data on topography, water-table elevation, ground temperature, and stratigraphy of the soil were collected at the site. The geotechnical properties of each soil layer were determined by laboratory analysis and used to calibrate a two-dimensional groundwater flow model. Field observations showed that water was progressively losing heat as it flowed under the road embankment. Our results suggest that advective heat transfer related to groundwater flow accelerated permafrost degradation under the road embankment

DOI: 10.1139/E2012-018

12094283 Ensom, T. P. (Carleton University, Department of Geography and Environmental Studies, Ottawa, ON, Canada); Burn, C. R. and Kokelj, S. V. Lake- and channel-bottom temperatures in the Mackenzie Delta, Northwest Territories: in Fundamental and applied research on permafrost in Canada--Recherche fondamentale et appliquée sur le pergélisol au Canada (Burn, C. R., editor; et al.), Canadian Journal of Earth Sciences = Revue Canadienne des Sciences de la Terre, 49(8), p. 963-978 (French sum.), illus. incl. 2 tables, sketch maps, 36 ref., August 2012. WWW. Accessed on August 23, 2012; includes appendix.

Temperature loggers were placed in 17 lakes and 13 channels throughout the Mackenzie Delta to determine the annual mean bottom temperature (Tb) and its spatial and temporal variation for June 2009-June 2010. The lakes were classified as perched or connected, depending on the duration of their connection to the channel hydrologic system. Average Tb values for nine perched lakes, five channels, and eight connected lakes distributed throughout the Mackenzie Delta were 5.5, 4.6, and 3.4°C, respectively. The range of Tb among all instrumented water bodies in the Delta was 4.0°C. Over the year, bottom temperatures ranged from >20°C in midsummer to -5°C in midwinter, with relative stability between freezeup in mid-October and breakup at the beginning of June. Channel, perched, and connected lake Tb, and mean annual near-surface ground temperatures of -4°C in alluvial sedge wetlands and -2.25°C in forest, were used to estimate that about 60% of Delta lakes and nearly the entire channel network maintain through-taliks

DOI: 10.1139/E2012-001

12094284 Godin, Etienne (Université de Montréal, Geography Department, Montreal, QC, Canada) and Fortier, Daniel. Geomorphology of a thermo-erosion gully, Bylot Island, Nunavut, Canada: in Fundamental and applied research on permafrost in Canada--Recherche fondamentale et appliquée sur le pergélisol au Canada (Burn, C. R., editor; et al.), Canadian Journal of Earth Sciences = Revue Canadienne des Sciences de la Terre, 49(8), p. 979-986 (French sum.), illus. incl. sketch maps, 26 ref., August 2012. WWW. Accessed on August 23, 2012.

A thermo-erosion gully has been monitored in the valley of glacier C-79 on Bylot Island since 1999. The main channel of the gully reached 390 m in length a few months after its initiation and grew between 38 and 50 m/year over the following decade, for an overall approximated average of 75 m/year. In 2009, the total gully length and area, including the main and relict channels, were 2500 m and 25 000 m², respectively. Gullies affect snow accumulation, and therefore ground temperature, local water flow, and drainage. Sinkholes, gully heads, pools, baydzherakhi, tunnels, and collapses were grouped as a function of time since gully formation in that area. Sinkholes and tunnels were formed every year after gully inception, and aydzherakhi were found in 3-10 year old sections of the gully. Stabilization of the gully floor and sides took about a decade.

DOI: 10.1139/E2012-015

12094278 Morse, P. D. (Carleton University, Department of Geography and Environmental Studies, Ottawa, ON, Canada); Burn, C. R. and Kokelj, S. V. Influence of snow on near-surface ground temperatures in upland and alluvial environments of the outer Mackenzie Delta, Northwest Territories: in Fundamental and applied research on permafrost in Canada--Recherche fondamentale et appliquée sur le pergélisol au Canada (Burn, C. R., editor; et al.), Canadian Journal of Earth Sciences = Revue Canadienne des Sciences de la Terre, 49(8), p. 895-913 (French sum.), illus. incl. 5 tables, sketch maps, 44 ref., August 2012. WWW. Accessed on August 23, 2012.

Relations between snow cover, active-layer thickness, and near-surface ground temperatures were determined in 2005-2009 for a diverse range of alluvial and upland settings in the outer Mackenzie Delta. Here, the snow cover developed primarily by wind redistribution, with its spatial variation controlled by topography in uplands and vegetation height in alluvial lowlands. Snow cover was the primary influence on freeze-back duration and the mean annual temperature at the top of permafrost (TTOP), with the difference in median TTOP between alluvial (-3.7°C) and upland (-6.1°C) settings related to the greater snow depth and soil moisture in the alluvial plain. The active layer was generally deeper in the wet alluvial lowlands, where the average duration of active-layer freeze back (101 days) was nearly double the time taken in the well-drained uplands (55 days). The surface offset (DT_S; up to 11°C) dominated the difference between annual mean air temperature (AMAT) and TTOP (DT). In alluvial terrain, DT_S varied with snow depth, but in the uplands, DT_S was more consistent from site to site. The small thermal offset (<2°C) was slightly greater in alluvial terrain than in the uplands. The overall range in DT (2-10°C) led to a range during the study of 7.2°C in TTOP at the sites. The range in AMAT was 1.3°C but up to 1.7°C in TTOP at any one site. Permafrost was well established throughout the area except adjacent to channels where TTOP was close to 0°C.

DOI: 10.1139/E2012-012

12094277 Palmer, Michael J. (Aboriginal Affairs and Northern Development Canada, Cumulative Impact Monitoring Program, Yellowknife, NT, Canada); Burn, C. R. and Kokelj, S. V. Factors influencing permafrost temperatures across tree line in the uplands east of the Mackenzie Delta, 2004-2010: in Fundamental and applied research on permafrost in Canada--Recherche fondamentale et appliquée sur le pergélisol au Canada (Burn, C. R., editor; et al.), Canadian Journal of Earth Sciences = Revue Canadienne des Sciences de la Terre, 49(8), p. 877-894 (French sum.), illus. incl. 6 tables, sketch map, 43 ref., August 2012. WWW. Accessed on August 23, 2012; includes appendix.

Air and near-surface ground temperatures, late-winter snow conditions, and characteristics of the vegetation cover and soil were measured across the forest-tundra transition in the uplands east of the Mackenzie Delta, Northwest Territories, in 2004-2010. Mean late-winter snow depth decreased northward from 73 cm in the subarctic boreal forest near Inuvik to 22 cm in low-shrub tundra. Annual near-surface ground temperatures decreased northward by 0.1-0.3°C/km near the northern limit of trees, in association with an abrupt change in snow depth. The rate decreased to 0.01-0.06°C/km in the tundra. The freezing season is twice as long as the thawing season in the region, so measured differences in the regional ground thermal regime were dominated by the contrast in winter surface conditions between forest and tundra.

DOI: 10.1139/E2012-002

12094279 Smith, Sharon L. (Natural Resources Canada, Geological Survey of Canada, Ottawa, ON, Canada); Throop, Jennifer and Lewkowicz, Antoni G. Recent changes in climate and permafrost temperatures at forested and polar desert sites in northern Canada: in Fundamental and applied research on permafrost in Canada--Recherche fondamentale et appliquée sur le pergélisol au Canada (Burn, C. R., editor; et al.), Canadian Journal of Earth Sciences = Revue Canadienne des Sciences de la Terre, 49(8), p. 914-924 (French sum.), illus. incl. 4 tables, sketch maps, 22 ref., August 2012. WWW. Accessed on August 23, 2012.

Climate and ground temperature records up to 30 years in length from permafrost monitoring sites in a polar desert at Alert, Nunavut, and a boreal forest at Table Mountain, Northwest Territories, were analyzed by season and year to assess the ground thermal response to recent climate warming. Methods were developed to standardize incomplete ground temperature data sets and to hindcast air temperatures for comparative analysis. The timing and magnitude of climate warming varied, beginning in the 1960s in the Mackenzie Valley and the 1970s in the High Arctic. Ground temperature increases occurred in both regions but varied in magnitude and timing in relation to the external forcing and permafrost conditions. Significant increases in winter air temperatures in both regions appear to be largely responsible for recent increases in ground temperature, particularly at the polar desert sites where snow cover is minimal

DOI: 10.1139/E2012-019

12094276 Throop, Jennifer (University of Ottawa, Department of Geography, Ottawa, ON, Canada); Lewkowicz, Antoni G. and Smith, Sharon L. Climate and ground temperature relations at sites across the continuous and discontinuous permafrost zones, northern Canada: in Fundamental and applied research on permafrost in Canada--Recherche fondamentale et appliquée sur le pergélisol au Canada (Burn, C. R., editor; et al.), Canadian Journal of Earth Sciences = Revue Canadienne des Sciences de la Terre, 49(8), p. 865-876 (French sum.), illus. incl. 3 tables, sketch map, 40 ref., August 2012. WWW. Accessed on August 23, 2012.

Climate--ground temperature relations are examined under a range of conditions for 10 sites across northern Canada. The sites are located between 60°N and 83°N and at elevations of 40 to 1840 m above sea level. They encompass various environmental and climatic conditions, with permafrost temperatures that range from just below 0 to -15°C. The substrates range from bedrock to fine-grained sediment with high ice content, and vegetation types include coniferous forests in the Mackenzie Valley, shrub tundra at high elevation in the southern Yukon Territory, and polar desert in the High Arctic. Permafrost conditions at all of these sites are determined primarily by air temperature, followed by snow and substrate conditions. The apparent thermal diffusivity is relatively high at colder sites and in bedrock and is lower at sites in sediment with high ice content. Snow has a greater influence on air-ground temperature relations at sites where mean annual air temperatures and active-layer moisture contents are relatively high, leading to physically significant latent heat effects and a slower freeze-back of the active layer.

DOI: 10.1139/E11-075

12094280 Zhang, Yu (Natural Resources Canada, Canada Centre for Remote Sensing, Ottawa, ON, Canada); Li, Junhua; Wang, Xiping; Chen, Wenjun; Sladen, Wendy; Dyke, Larry; Dredge, Lynda; Poitevin, Jean; McLennan, Donald; Stewart, Heather; Kowalchuk, Sheldon; Wu, Wanli; Kershaw, G. Peter and Brook, Ryan K. Modelling and mapping permafrost at high spatial resolution in Wapusk National Park, Hudson Bay Lowlands: in Fundamental and applied research on permafrost in Canada--Recherche fondamentale et appliquée sur le pergélisol au Canada (Burn, C. R., editor; et al.), Canadian Journal of Earth Sciences = Revue Canadienne des Sciences de la Terre, 49(8), p. 925-937 (French sum.), illus. incl. 3 tables, sketch maps, 45 ref., August 2012. WWW. Accessed on August 23, 2012; includes appendix.

Most spatial modelling of permafrost distribution and dynamics has been conducted at half-degree latitude/longitude or coarser resolution. Such coarse results are difficult to use for land managers and ecologists. Here we mapped permafrost distribution at 30 m´30 m resolution for a region in the northwest Hudson Bay Lowlands using a process-based model. Land-cover types and leaf area indices were derived from Landsat imagery; peat thickness was estimated from elevation based on field measurements; and climate data were interpolated from station observations. The modelled active-layer thickness and permafrost extent compared well with field observations, demonstrating that modelling and mapping permafrost at a high spatial resolution is practical for terrains such as these lowlands. The map portrayed large variations in active-layer thickness, with land-cover type and peat thickness being the most important controlling variables. The modelled active-layer thickness on average increased by 37% during the twentieth century due to increases in air temperature and precipitation, and permafrost disappeared in some southern areas. The spatial scale of the permafrost maps developed in this study is close to that of the ecosystem and landscape features; therefore, the results are useful for land management and ecosystem assessment.

DOI: 10.1139/E2012-031

12098050 Sandersen, Peter B. E. (Grontmij, Consulting Engineers, Aarhus, Denmark) and Jorgensen, Flemming. Substratum control on tunnel-valley formation in Denmark: Geological Society Special Publications, 368, illus. incl. sects., geol. sketch maps, 47 ref., May 2, 2012. (Online First).

Tunnel valleys formed by meltwater erosion underneath the margins of the Pleistocene ice sheets are present in high numbers in the Danish onshore area. The geographical distribution of the buried tunnel valleys is uneven, but when comparing with the substrata lithology we find a large number of valleys in areas dominated by low-permeable sediment and a smaller number in areas with highly permeable substrata. The observations point to the drainage capacity of the ice-sheet substratum as an important factor controlling tunnel-valley formation. Tunnel-valley formation appears to be favoured in areas with low-permeable substrata because meltwater drainage through the sediments is impeded, leading to the formation of a channelized subglacial drainage system. The high transmissivity in areas dominated by permeable substrata facilitates drainage of a part of the meltwater as groundwater. This causes a lowering of the subglacial meltwater pressures, and tunnel-valley formation is less likely. Once formed and filled, the tunnel valleys cause a change of the hydraulic properties of the substratum and if subglacial water pressures underneath a subsequent ice advance are sufficiently high, old tunnel valleys will be prone to reactivation.

DOI: 10.1144/SP368.12

12098034 Wang Genxu (Chinese Academy of Sciences, Institute of Mountain Hazards and Environment, Chengdu, China); Liu Guangsheng and Liu Lin'an. Spatial scale effect on seasonal streamflows in permafrost catchments on the Qinghai-Tibet Plateau: Hydrological Processes, 26(7), p. 973-984, illus. incl. 4 tables, sketch map, 35 ref., March 30, 2012.

The scale issue is of central concern in hydrological processes to understand the potential upscaling or downscaling methodologies, and to develop models for scaling the dominant processes at different scales and in different environments. In this study, a typical permafrost watershed in the Qinghai-Tibet Plateau was selected. Its hydrological processes were monitored for 4 years from 2004 to 2008, measuring the effects of freezing and thawing depth of active soil layers on runoff processes. To identify the nature and cause of variation in the runoff response in different size catchments, catchments ranging from 1·07 to 112 km² were identified in the watershed. The results indicated that the variation of runoff coefficients showed a 'V' shape with increasing catchment size during the spring and autumn seasons, when the active soil was subjected to thawing or freezing processes. A two-stage method was proposed to create runoff scaling models to indicate the effects of scale on runoff processes. In summer, the scaling transition model followed an exponential function for mean daily discharge, whereas the scaling model for flood flow exhibited a linear function. In autumn, the runoff process transition across multiple scales followed an exponential function with air temperature as the driving factor. These scaling models demonstrate relatively high simulation efficiency and precision, and provide a practical way for upscaling or downscaling runoff processes in a medium-size permafrost watershed. For permafrost catchments of this scale, the results show that the synergistic effect of scale and vegetation cover is an important driving factor in the runoff response. Abstract Copyright (2010), John Wiley & Sons, Ltd.

DOI: 10.1002/hyp.8187

12100219 Levy, Joseph S. (Oregon State University, Department of Earth, Ocean and Atmospheric Sciences, Corvallis, OR); Fountain, Andrew G.; Welch, Kathy A. and Lyons, W. Berry. Hypersaline "wet patches" in Taylor Valley, Antarctica: Geophysical Research Letters, 39(5), Citation L05402, illus. incl. 2 tables, 32 ref., 2012. Supplemental information/data is available in the online version of this article.

Spatially isolated patches of soil located in Taylor Valley, McMurdo Dry Valleys, Antarctica, are sites of elevated salt content and soil moisture. During Antarctic spring, in the absence of snow melt, visibly wet (reduced albedo) patches of soil are present at the surface. The soil pore fluids are hypersaline and have average water activity of 0.74 (the water activity of a solution determines the equilibrium vapor pressure of that solution), and are an order of magnitude more saline than average soils in the Dry Valleys. These salty soils are 3-5 times more water rich than average soils. Geochemical and meteorological analyses show that these wet patches are sites of direct vapor emplacement into soil pore fluids that may ultimately be sourced by the deliquescence of soil salts. These wet patches represent a non-precipitation, non-groundwater source for water into Antarctic permafrost.

DOI: 10.1029/2012GL050898

12094954 Panin, A. V. (Moskovskiy Gosudarstvennyy Universitet, Moscow, Russian Federation); Yeremenko, Ye. A. and Kovda, I. V. Tsikl erozionnogo raschleneniya i vypolneniya erozionnoy seti na severo-vostoke Stavropol'ya v kontse pleystotsena; St. 1, Lozhbinnaya set' [Cycle of erosion and deposition in drainage basins of northeastern Stavropol region; Paper 1, Gully network]: Geomorfologiya, 2011(1), p. 77-87 (English sum.), illus. incl. table, sketch maps, 20 ref., March 2011.

Systems of hollows were detected on satellite images in the northeastern Stavropol Upland. Their density is several times greater than that of the recent erosion network. Spatial pattern of the systems give evidence of their fluvial origin. A case study of one of the hollows in the Aigurka River catchment included field investigation of its morphology and geological composition and laboratory study of the hollow sedimentary infill. The authors concluded that the hollow systems represent upper reaches of an ancient erosion network, which were filled with deluvial and solifluction deposits during the Valdai (Vistulian) cold epoch in the late Pleistocene.

12097486 Noguchi, Shoji (Forestry and Forest Products Research Institute, Tohoku Research Center, Sendai, Japan); Sammori, Toshiaki; Tada, Yasuyuki and Yasuda, Yukio. Antecedent soil moisture around the epicenter during the periods preceding and following the Iwate-Miyagi Nairiku earthquake in 2008: Shin Sabo = Journal of the Japan Society of Erosion Control Engineering, 63(1), p. 39-43, (Japanese) (English sum.), illus. incl. 1 table, sketch map, 17 ref., May 2010.

Heavy rainfall and snowmelt cause sediment disasters. The wetter the soil moisture is, the higher the sediment disaster frequency becomes. In addition, antecedent precipitation and snowmelt influence sediment disaster generation. We investigated the moisture environment around the epicenter before and after the Iwate-Miyagi Nairiku earthquake of 2008 based on an antecedent soil moisture index (ASI₃₀) using AMeDAS data (precipitation, air temperature, snow depth). In order to calculate ASI₃₀, amount of snowmelt during snow cover period was estimated using advanced degree day method. The ASI₃₀ was highest during the snowmelt season and after heavy rainfall more than 100 mm. When the earthquake occurred, the ASI₃₀ values at the Matsurube and Komanoyu sites were 18.0 and 20.4 mm, respectively. These values did not appear to affect the damage caused by the earthquakes. Previously recorded ASI₃₀ values after heavy rainfall events or during the snowmelt seasons of heavy snowfall years were larger than were those recorded after the earthquakes. It was important to advance the remediation activity of the disaster, and to continue the monitor around the epicenter in the future.

12093076 Krasnoshchekov, Yu. N. (Russian Academy of Sciences, Sukachev Institute of Forestry, Krasnoyarsk, Russian Federation). Soils and the soil cover of mountainous tundra and forest landscapes in the central Khangai of Mongolia: Eurasian Soil Science, 43(2), p. 117-126, illus., 24 ref., February 2010.

Specific features of the soil formation and soil cover patterns in the mountainous alpine tundra and forest landscapes of the Central Khangai Range are analyzed. It is shown that the specific mucky grayhumus permafrost-affected soils are only formed under larch forests within the tundra-alpine and forest zones. Other soils have a wider geographic area. The morphological, physicochemical, and chemical characteristics of the widespread soils are given. A medium-scale map of the soil cover patterns-soil complexes, combinations, and mosaics-has been developed for the studied area. Copyright 2010 Pleiades Publishing, Ltd.

DOI: 10.1134/S1064229310020018

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12100177 Mostofi Javid, Sima. Spatial and temporal characteristics of water resources in south-central BC; implications for indigenous communities: 318 p., Doctoral, 2011, Trent University, Peterborough, ON, Canada. ISBN: 978-0-494-75358-3 Available from: Univ. Microfilms.

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12094302 Shand, C. A. (James Hutton Institute, Environmental and Biochemical Sciences, Aberdeen, United Kingdom); Eriksson, J.; Dahlin, A. S. and Lumsdon, D. G. Selenium concentrations in national inventory soils from Scotland and Sweden and their relationship with geochemical factors: in Micronutrient biofortification of crop plants and food quality in relation to the geographical origin (Adamo, Paola, editor; et al.), Journal of Geochemical Exploration, 121, p. 4-14, illus. incl. 6 tables, 38 ref., October 2012. Meeting: International conference on Biogeochemistry of trace elements; symposium 9, July 3-7, 2011, Florence, Italy.

Soil is an important reservoir of trace elements that are essential for animal and human health. We report on the concentration of selenium (Se) in Scottish soils sampled during 2007 to 2009 and in Sweden for arable topsoils collected during 1988 to 2007 as part of national soil inventories. Soils in Scotland were sampled on the basis of their genetic horizons and included a range of land cover. In contrast, soils from Sweden were sampled from the plough layer of arable soils with an auger to a fixed depth from the surface. We found that the Se concentrations of soils from Scotland and Sweden, which are richer in organic matter than other more southerly latitudes in Europe, are more related to organic matter content than other geochemical factors. In the Swedish soils the Se concentrations were elevated in areas close to the sea. In areas away from the sea, concentrations were also higher in soil associated with alum shales. The Se concentrations in arable topsoils were lower in Sweden than in Scotland. The distribution of Se in Scottish topsoils showed a propensity for higher concentrations in the west of the country. For soils from Scotland there was a significant decrease (p=0.05) in the mean Se concentration in soil from the A horizon (mean 0.64 mg kg^-1) compared to that of the C horizon (mean 0.26 mg kg^-1). The Se concentration of the plough layer soils from Sweden had a median value of 0.23 mg kg^-1 and a mean value of 0.30 mg kg^-1.

DOI: 10.1016/j.gexplo.2012.06.001

12101020 Williams, Kevin K. (Buffalo State College, Department of Earth Sciences, Buffalo, NY); Haltigin, Timothy W. and Pollard, Wayne H. Detecting ice wedge geometry using ground penetrating radar [abstr.]: in Geological Society of America, Northeastern Section, 47th annual meeting, Abstracts with Programs - Geological Society of America, 44(2), p. 88, March 2012. Meeting: Geological Society of America, Northeastern Section, 47th annual meeting, March 18-20, 2012, Hartford, CT.

Polygonal terrain is one of the most common landforms in continuous permafrost environments. This terrain has diverse appearances and occurs in a variety of surface materials. It has been estimated that over 30 percent of the top meter of ground can contain wedge ice in these environments, and characterization of ice wedge shapes can lead to better estimates of ice volume. As part of several studies using geophysical methods to detect ground ice in the Canadian Arctic, GPR data were collected over polygonal terrain at two locations on Devon Island. Polygon surface troughs varied in width from a thin depression to more than a meter. Although subsurface ice was not found beneath every trough, polygons with notable troughs contained fairly large ice wedges. At the Thomas Lee Inlet site east of the Haughton impact crater, polygons were formed in fine sediments, whereas they formed in gravel-to-cobble-sized deposits at the Lake Orbiter site north of the crater. GPR data were collected at 200 and 400 MHz and show the thickness of the active layer, the widths of the ice wedges, and other subsurface stratigraphic features very well. Locations and widths of wedge ice were confirmed by augering and trenching to the tops of a sample of the ice wedges. Ice wedge edges are clearly delineated in the GPR data, which enables a fairly accurate estimate of their widths. Additionally, surface tensional cracks above wedges at the Thomas Lee Inlet site correlate with the edges detected in GPR data. The tensional cracks are likely due to subsidence that may result from downward melting of the ice wedge in response to increasing temperatures over several years or more. This surface indicator of active layer thickening may be useful for studying past and current climate change in Arctic regions. Additionally, many polygonal features have been observed on Mars, so more detailed studies of terrestrial features may help to understand which could contain large amounts of subsurface ice.

URL: https://gsa.confex.com/gsa/2012NE/finalprogram/abstract_200453.htm

12097914 Alford, J. A. (Columbia University, Columbia Astrophysics Laboratory, New York, NY); Hodges, A. R.; Heggy, E. and Crotts, A. P. S. Exploring volatile deposition in lunar regolith: in Lunar and planetary science conference XLIII; papers presented to the Forty-third lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 43, Abstract 2938, illus., 10 ref., 2012. WWW. Meeting: Forty-third lunar and planetary science conference, March 19-23, 2012, Woodlands, TX. Accessed on May 29, 2012.

URL: http://www.lpi.usra.edu/meetings/lpsc2012/pdf/2938.pdf

12097954 Bapst, Jonathan (University of Washington, Department of Earth and Space Sciences, Seattle, WA) and Wood, Stephen E. The long-term effects of surface frosts, seasonal atmospheric water variation and ice fraction-dependent thermal conductivity on Martian ground ice: in Lunar and planetary science conference XLIII; papers presented to the Forty-third lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 43, Abstract 2808, illus., 16 ref., 2012. Meeting: Forty-third lunar and planetary science conference, March 19-23, 2012, Woodlands, TX. Accessed on Sept. 19, 2012.

URL: http://www.lpi.usra.edu/meetings/lpsc2012/pdf/2808.pdf

12100470 Costard, F. (Université Paris-Sud, Laboratoire Intéractions et Dynamique dans Environnements de Surface, Orsay, France); Sejourne, A.; Kargel, J. and Soare, R. Shallow melting and underground drainage in Utopia Planitia, Mars: in Lunar and planetary science conference XLIII; papers presented to the Forty-third lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 43, Abstract 1822, illus., 14 ref., 2012. Meeting: Forty-third lunar and planetary science conference, March 19-23, 2012, Woodlands, TX. Accessed on Aug. 3, 2012.

www.lpi.usra.edu/meetings/lpsc2012/pdf/1822.pdf

12097953 Cull, Selby (Bryn Mawr College, Department of Geology, Bryn Mawr, PA); Dundas, Colin; Mellon, Michael T. and Byrne, Shane. CRISM observations of fresh icy craters in mid- to high-latitudes on Mars: in Lunar and planetary science conference XLIII; papers presented to the Forty-third lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 43, Abstract 2145, illus. incl. 1 table, 8 ref., 2012. Meeting: Forty-third lunar and planetary science conference, March 19-23, 2012, Woodlands, TX. Accessed on Sept. 19, 2012.

URL: http://www.lpi.usra.edu/meetings/lpsc2012/pdf/2145.pdf

12100305 Dickson, J. (Brown University, Department of Geological Sciences, Providence, RI) and Head, J. W., III. Active-layer drainage without surface erosion; time-lapse photography of Antarctic slope lineae and implications for the flow of water on Mars: in Lunar and planetary science conference XLIII; papers presented to the Forty-third lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 43, Abstract 1085, illus., 9 ref., 2012. WWW. Meeting: Forty-third lunar and planetary science conference, March 19-23, 2012, Woodlands, TX. Accessed on May 14, 2012.

URL: http://www.lpi.usra.edu/meetings/lpsc2012/pdf/1085.pdf

12093994 Elliott, H. M. (University of Michigan, Department of Atmospheric, Oceanic and Space Sciences, Ann Arbor, MI); Martinez, G. M.; Halleaux, D. G.; Braswell, S. F. and Renno, N. O. The Michigan Mars Environmental Chamber (MMEC); determining the conditions at which liquid brines form on Mars: in Lunar and planetary science conference XLIII; papers presented to the Forty-third lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 43, Abstract 2117, illus., 5 ref., 2012. Meeting: Forty-third lunar and planetary science conference, March 19-23, 2012, Woodlands, TX. Accessed on Aug. 20, 2012.

www.lpi.usra.edu/meetings/lpsc2012/pdf/2117.pdf

12100248 Elphic, Richard C. (NASA, Ames Research Center, Planetary Systems Branch, Moffett Field, CA); Paige, David A.; Siegler, Matthew A.; Vasavada, Ashwin R.; Teodoro, Luis F. A. and Eke, Vincent R. Limits on the abundance and burial depth of lunar polar ice deposits: in Lunar and planetary science conference XLIII; papers presented to the Forty-third lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 43, Abstract 1895, sketch maps, 3 ref., 2012. Meeting: Forty-third lunar and planetary science conference, March 19-23, 2012, Woodlands, TX. Accessed on April 17, 2012.

URL: http://www.lpi.usra.edu/meetings/lpsc2012/pdf/1895.pdf

12094010 Englert, P. (University of Hawaii at Manoa, Honolulu, HI); Bishop, J. L.; Hunkins, L. D. and Koeberl, C. Martian soil analogs from Antarctica; chemical and mineralogical weathering scenarios: in Lunar and planetary science conference XLIII; papers presented to the Forty-third lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 43, Abstract 1743, illus., 21 ref., 2012. Meeting: Forty-third lunar and planetary science conference, March 19-23, 2012, Woodlands, TX. Accessed on Aug. 21, 2012.

www.lpi.usra.edu/meetings/lpsc2012/pdf/1743.pdf

12097863 Garcia, José H. (University of Texas at El Paso, Department of Geological Sciences, El Paso, TX) and Hurtado, José M., Jr. Phreatomagmatic activity on the Moon; possibility of pseudocraters on Mare Frigoris: in Lunar and planetary science conference XLIII; papers presented to the Forty-third lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 43, Abstract 1390, illus. incl. 1 table, 7 ref., 2012. WWW. Meeting: Forty-third lunar and planetary science conference, March 19-23, 2012, Woodlands, TX. Accessed on May 21, 2012.

URL: http://www.lpi.usra.edu/meetings/lpsc2012/pdf/1390.pdf

12100468 Haltigin, Timothy W. (Canadian Space Agency, Space Science and Technology, St. Hubert, QC, Canada); Pollard, W. H.; Dutilleul, P. and Osinski, G. R. Morphometric evidence of co-evolving polygonal and scalloped terrains in southwestern Utopia Planitia, Mars: in Lunar and planetary science conference XLIII; papers presented to the Forty-third lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 43, Abstract 2689, illus., 6 ref., 2012. Meeting: Forty-third lunar and planetary science conference, March 19-23, 2012, Woodlands, TX. Accessed on Aug. 3, 2012.

www.lpi.usra.edu/meetings/lpsc2012/pdf/2689.pdf

12097969 Johnsson, A. (Gothenburg University, Department of Earth Sciences, Goteborg, Sweden); Reiss, D.; Zanetti, M.; Hauber, E. and Hiesinger, H. Recent debris flow deposits in a pristine impact crater, Mars; insights from terrestrial analogues on Svalbard: in Lunar and planetary science conference XLIII; papers presented to the Forty-third lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 43, Abstract 2111, illus., 9 ref., 2012. Meeting: Forty-third lunar and planetary science conference, March 19-23, 2012, Woodlands, TX. Accessed on Sept. 19, 2012.

URL: http://www.lpi.usra.edu/meetings/lpsc2012/pdf/2111.pdf

12100299 Jouannic, G. (Université Paris-Sud, Laboratoire Interactions et Dynamique des Environnements de Surface, Orsay, France); Conway, S. J.; Gargani, J.; Costard, F.; Patel, M. R. and Ori, G. G. Experimental investigation of gully formation under low pressure and low temperature conditions: in Lunar and planetary science conference XLIII; papers presented to the Forty-third lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 43, Abstract 1509, illus., 6 ref., 2012. WWW. Meeting: Forty-third lunar and planetary science conference, March 19-23, 2012, Woodlands, TX. Accessed on May 11, 2012.

URL: http://www.lpi.usra.edu/meetings/lpsc2012/pdf/1509.pdf

12100464 Kite, Edwin S. (University of California at Berkeley, Department of Earth and Planetary Science, Berkeley, CA). Evidence for melt-fed meandering rivers in the Gale-Aeolis-Zephyria region, Mars: in Lunar and planetary science conference XLIII; papers presented to the Forty-third lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 43, Abstract 2778, illus., 17 ref., 2012. Meeting: Forty-third lunar and planetary science conference, March 19-23, 2012, Woodlands, TX. Accessed on Aug. 2, 2012.

www.lpi.usra.edu/meetings/lpsc2012/pdf/2778.pdf

12100304 Levy, J. S. (Oregon State University, College of Earth, Ocean, and Atmospheric Sciences, Corvallis, OR) and Fountain, A. G. Hydrological characteristics of recurrent slope lineae on Mars based on time-resolved HiRISE analyses and comparisons with fluid flow through an Antarctic terrestrial analog regolith: in Lunar and planetary science conference XLIII; papers presented to the Forty-third lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 43, Abstract 1029, illus., 9 ref., 2012. WWW. Meeting: Forty-third lunar and planetary science conference, March 19-23, 2012, Woodlands, TX. Accessed on May 14, 2012.

URL: http://www.lpi.usra.edu/meetings/lpsc2012/pdf/1029.pdf

12097907 Mitchell, Emily H. (University of Virginia, Laboratory for Atomic and Surface Physics, Charlottesville, VA); Schaible, Micah J.; Raut, Ujjwal; Fulvio, Daniele; Dukes, Catherine A. and Baragiola, Raul A. Photodesorption of absorbed water on the Moon: in Lunar and planetary science conference XLIII; papers presented to the Forty-third lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 43, Abstract 2362, illus., 3 ref., 2012. WWW. Meeting: Forty-third lunar and planetary science conference, March 19-23, 2012, Woodlands, TX. Accessed on May 29, 2012.

URL: http://www.lpi.usra.edu/meetings/lpsc2012/pdf/2362.pdf

12100688 Pedersen, G. B. M. (University of Iceland, Institute of Earth Sciences, Nordic Volcanological Center, Reykjavik, Iceland) and Head, J. W. Evidence of complex ice-volcano interactions in the transition zone between Elysium Rise and Utopia Basin: in Lunar and planetary science conference XLIII; papers presented to the Forty-third lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 43, Abstract 1169, illus. incl. geol. sketch map, 17 ref., 2012. WWW. Meeting: Forty-third lunar and planetary science conference, March 19-23, 2012, Woodlands, TX. Accessed on Apr. 24, 2012.

URL: http://www.lpi.usra.edu/meetings/lpsc2012/pdf/1169.pdf

12097902 Schorghofer, Norbert (University of Hawaii, Institute for Astronomy, Honolulu, HI). On the theory of migration of water on the Moon: in Lunar and planetary science conference XLIII; papers presented to the Forty-third lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 43, Abstract 1110, illus., 13 ref., 2012. WWW. Meeting: Forty-third lunar and planetary science conference, March 19-23, 2012, Woodlands, TX. Accessed on May 25, 2012.

URL: http://www.lpi.usra.edu/meetings/lpsc2012/pdf/1110.pdf

12097990 Schurmeier, L. R. (NASA, Ames Research Center, Moffett Field, CA); Heldmann, J.; Stoker, C.; Mckay, C.; Davila, A. F.; Marinova, M.; Karcz, J.; Smith, H. and Wilhelm, M. Characterization of a mid-latitude ice-rich landing site on Mars to enable in situ habitability studies: in Lunar and planetary science conference XLIII; papers presented to the Forty-third lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 43, Abstract 1271, illus. incl. sketch maps, 6 ref., 2012. Meeting: Forty-third lunar and planetary science conference, March 19-23, 2012, Woodlands, TX. Accessed on Sept. 20, 2012.

URL: http://www.lpi.usra.edu/meetings/lpsc2012/pdf/1271.pdf

12097912 Siegler, M. A. (University of California at Los Angeles, Department of Earth and Space Sciences, Los Angeles, CA); Bills, B. G. and Paige, D. A. Spatio-temporal evolution of lunar polar cold traps: in Lunar and planetary science conference XLIII; papers presented to the Forty-third lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 43, Abstract 2376, illus., 13 ref., 2012. WWW. Meeting: Forty-third lunar and planetary science conference, March 19-23, 2012, Woodlands, TX. Accessed on May 29, 2012.

URL: http://www.lpi.usra.edu/meetings/lpsc2012/pdf/2376.pdf

12100690 Soare, R. J. (Dawson College, Department of Geography, Montreal, QC, Canada); Conway, S. J.; Pearce, G. D. and Costard, F. Ice-enriched loess and the formation of periglacial terrain in mid-Utopia Planitia, Mars: in Lunar and planetary science conference XLIII; papers presented to the Forty-third lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 43, Abstract 1311, illus. incl. geol. sketch map, 22 ref., 2012. WWW. Meeting: Forty-third lunar and planetary science conference, March 19-23, 2012, Woodlands, TX. Accessed on Apr. 24, 2012.

URL: http://www.lpi.usra.edu/meetings/lpsc2012/pdf/1311.pdf

12100254 Tornabene, L. L. (University of Western Ontario, Centre of Planetary Science and Exploration, London, ON, Canada); Osinski, G. R.; McEwen, A. S.; Boyce, J. M.; Bray, V. J.; Caudill, C. M.; Grant, J. A.; Hamilton, C. W.; Mattson, S. and Mouginis-Mark, P. J. Wide-spread occurrence of crater-related pitted materials on Mars; implications for the role of target volatiles with respect to the impact process: in Lunar and planetary science conference XLIII; papers presented to the Forty-third lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 43, Abstract 2418, illus. incl. sketch map, 11 ref., 2012. Meeting: Forty-third lunar and planetary science conference, March 19-23, 2012, Woodlands, TX. Accessed on April 17, 2012.

URL: http://www.lpi.usra.edu/meetings/lpsc2012/pdf/2418.pdf

12100691 Valenciano, A. (Museo Nacional de Ciencias Naturales, Departamento de Paleobiología, Madrid, Spain) and de Pablo, M. A. Geological cartography of inner materials of an impact crater on Nephenthes Mensae, Mars: in Lunar and planetary science conference XLIII; papers presented to the Forty-third lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 43, Abstract 1038, illus. incl. geol. sketch maps, 19 ref., 2012. WWW. Meeting: Forty-third lunar and planetary science conference, March 19-23, 2012, Woodlands, TX. Accessed on Apr. 24, 2012.

URL: http://www.lpi.usra.edu/meetings/lpsc2012/pdf/1038.pdf

12093985 Webster, K. D. (Indiana University, Department of Geological Sciences, Bloomington, IN); Rebholz, J. A.; White, J. R.; Douglas, B. J. and Pratt, L. M. Using open-path laser measurement of atmospheric methane concentration along a major shear zone in western Greenland as an analogue for exploration on Mars: in Lunar and planetary science conference XLIII; papers presented to the Forty-third lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 43, Abstract 1514, illus., 6 ref., 2012. Meeting: Forty-third lunar and planetary science conference, March 19-23, 2012, Woodlands, TX. Accessed on Aug. 17, 2012.

www.lpi.usra.edu/meetings/lpsc2012/pdf/1514.pdf

12098005 Yakovlev, Valeriy (Laboratory of Water Quality "PLAYA", Kharkov, Ukraine). The ice nature of the Gale Crater central structure: in Lunar and planetary science conference XLIII; papers presented to the Forty-third lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 43, Abstract 1454, illus., 2 ref., 2012. Meeting: Forty-third lunar and planetary science conference, March 19-23, 2012, Woodlands, TX. Accessed on Sept. 21, 2012.

URL: http://www.lpi.usra.edu/meetings/lpsc2012/pdf/1454.pdf

12100119 Gislason, S. R. (University of Iceland, Institute of Earth Sciences, Reykjavik, Iceland); Eiriksdottir, E. S.; Alfredsson, H. A.; Sigfusson, B.; Jones, M. T. and Oelkers, E. H. The effect of time and climate on volcanic soil formation [abstr.]: in Goldschmidt 2011 abstract volume, Mineralogical Magazine, 75(3), p. 920, 3 ref., June 2011. WWW. Meeting: Goldschmidt2011, Aug. 8-14, 2011, Prague, Czech Republic.

Andosols, soils derived from volcanic material, cover about 1.9% of the terrestrial surface and store about 4.9% of the Earth's carbon [1]. Andosols cover most of the volcanic islands on Earth. These soils are fertile, most of the islands are heavily populated and much of the river suspended matter delivered to the ocean stems from these islands. To a great extent, the sol is formed from air borne volcanic ash, preventing nutrient depletions with time, but making it prone to mechanical erosion. In the days, weeks and months after deposition of air borne volcanic ash, nutrients and pollution will migrate into the soil at elevated rates. This is caused by soluble metal and proton salts coating the volcanic ash that dissolve orders of magnitude faster than the bulk volcanic ash that is mostly glass. Between these periodic fluxes of dissolved elements, weathering and erosion rates are primarily governed by climate, lithology, average rock age, topography and vegetation cover. A detailed study of catchments in NE Iceland shows that for each degree of temperature increase the runoff, mechanical weathering flux, and chemical weathering fluxes in these catchments have been found to increase from 6 to 16%, 8 to 30%, and 4 to 14% respectively, depending on the catchment [2]. These results demonstrate a significant feedback between climate and Earth surface weathering on the timescale of years to millions of years [3], and suggest that weathering rates are currently increasing with time due to global warming. [1] Eswaran et al. (1993) Soil Science Society of America Journal 57, 192-194. [2] Gislason et al. (2009) Earth Planet. Sci. Lett. 277, 213-222. [3] Gislason et al. (2006) Geology, 34, 49-52.

URL: http://minmag.geoscienceworld.org/content/75/3/878.full.pdf+html

12097618 Riedel, T. (Technische Universität Braunschweig, Institut für Umweltgeologie, Brunswick, Germany) and Biester, H. A HPSEC-ICP-MS study on the affinity of trace elements (Fe, Cu, I) to dissolved organic matter in natural water samples [abstr.]: in Goldschmidt 2011 abstract volume, Mineralogical Magazine, 75(3), p. 1723, June 2011. WWW. Meeting: Goldschmidt2011, Aug. 8-14, 2011, Prague, Czech Republic.

The speciation of trace elements in natural waters strongly influences their mobility and geochemical behavior in the environment. Especially, the presence of dissolved organic matter (DOM) in soil and peat runoff may favor complexation of certain metals, thereby increasing the solubility. Earlier studies were focused on the concept of metal binding to organic molecules which were thought to be of considerable size (some ten to hundred thousand Da in molecular weight). The existence of large organic substances, however, has recently been challenged. It was proposed, on the basis of several different studies, that DOM may consist of much smaller molecules, probably in the size fraction of only a few hundred to thousand Da. This raises the question if these smaller fractions can be separated by analytical techniques thereby enabling a study of the metal-binding capacity of "small" DOM. To resolve this question we used inductively coupled plasma mass spectrometry hyphenated with gel filtration liquid chromatography. The size exclusion column used was selected to efficiently separate substances with relatively low ionic radii thus resolving predominantly smaller fractions of DOM. Samples were river waters taken from remotes sites in Patagonia, Chile as well as from the Harz mountain region, Northern Germany. All samples were filtered with 0.45 mm. Samples were initially measured in their original composition. The influence of pH was studied via the addition of nitric acid. We found remarkable differences between the investigated metals with up to four different peaks in the chromatograms suggesting that a number of colloids/complexes of different size exist which can be separated. While some elements occurred exclusively in one or two fractions (Fe) others occur in all fractions (I, Cu) suggesting a rather non-specific binding. The addition of protons yielded the expected shift from larger to smaller fractions, possibly because metals desorb from the binding sites on the DOM or colloids/particles dissolve. Further investigations aim to exploit the characteristic size distributions observed to create fingerprints of natural waters that help to understand the environmental distribution and cycling of these trace metals.

URL: http://minmag.geoscienceworld.org/content/75/3/1685.full.pdf+html

12096615 Koehler, Rich D. (Alaska Division of Geological and Geophysical Surveys, Fairbanks, AK). Application of lidar to mapping geologic hazards along gas pipelines in Alaska [abstr.]: in Geological Society of America, Rocky Mountain Section, 63rd annual meeting; Geological Society of America, Cordilleran Section, 107th annual meeting, Abstracts with Programs - Geological Society of America, 43(4), p. 83-84, May 2011. Meeting: Geological Society of America, Rocky Mountain Section, 63rd annual meeting; Geological Society of America, Cordilleran Section, 107th annual meeting, May 18-20, 2011, Logan, UT.

Alaska is characterized by diverse geologic environments and a wide range of geologic processes and associated hazards. Recently proposed natural gas pipelines traverse rugged terrain across the state, requiring a better understanding of the location and types of geologic hazards that could potentially impact pipeline alignments and design. However, developing information on Quaternary active faults and other geologic hazards in Alaska has proved difficult due to rugged topography, limited road acess, dense vegetative cover, and inadequate aerial photography and remotely sensed imagery. Lidar digital topographic data provides a means to perform improved analysis of the landscape and facilitates efficient identification and characterization of geologic hazards in regions where other methods have been ineffective. The Alaska Division of Geological & Geophysical Surveys (DGGS) is acquiring high-resolution lidar data within a 1-mile-wide corridor along the entire length of proposed natural gas pipeline corridors from Prudhoe Bay to the Canada border and from Delta Junction to Valdez. Here I present preliminary observations and interpretations from a subset of the new lidar data relevant to the assessment of geologic hazards. Additionally, I show several techniques that DGGS is employing to map these hazards and reveal subtle topographic features that may indicate the locations of active faults, landslides, permafrost, erosion, and flooding hazards. These techniques include slope, aspect, and surface roughness maps, longitudinal profiles, and construction of high-precision topographic maps. Data products from these analyses will be combined with DGGS's previous Quaternary surficial-geologic and hazards mapping along the pipeline corridor in a project GIS. The analyses will be used to systematically evaluate geologic hazards over broad regions. These relatively new techniques have important implications to pipeline route selection and refinement, design, and construction in Alaska and around the world.

12093551 Pagani, Mark (Yale University, Department of Geology and Geophysics, New Haven, CT); Deconto, R.; Galeotti, S. and Beerling, D. Methane and the PETM; all good things must come to an end? [abstr.]: in Goldschmidt 2011 abstract volume, Mineralogical Magazine, 75(3), p. 1586, 2011. WWW. Meeting: Goldschmidt 2011, Aug. 8-14, 2011, Prague, Czech Republic.

Global warming during the Paleocene Eocene Thermal Maximum is often explained by a massive release of methane hydrates. However, modeled methane hydrate abundances during warm climates are lower than required to explain the carbon isotope shift that characterizes the PETM. Even if ancient hydrate abundances were greater than model predictions, a very high climate sensitivity to CO₂ would be required to explain the magnitude of warming during the event. While some portion of this high apparent climate sensitivity could be related to an assumed pre-warming that triggered hydrate instability, evidence for that warming is weak at best, and why this warming occurred repeatedly to trigger successive hyperthermals has never been adequately addressed. In contrast to the methane paradigm, an emerging supposition involving the storage and orbitally controlled release of terrestrial carbon from the arguably vast permafrost reservoirs of Antarctica and the high Arctic region readily explains the warming characteristics of the early Cenozoic hyperthermals. Modeled permafrost carbon estimates and simulations accounting for rising background greenhouse gas concentrations and orbital variability demonstrate terrestrial permafrost thawed during high eccentricity and obliquity orbital nodes once a long-term warming threshold was reached. This new supposition allows for the massive amount of carbon necessary to explain the magnitude of carbon isotope shifts, a reasonable climate sensitivity to CO₂, and the mechanistic basis for repeated warming events during an ever-warming planet.

URL: http://minmag.geoscienceworld.org/content/75/3/1584.full.pdf+html

12093620 Perdrial, Julia (University of Arizona, Soil, Water, and Environmental Science, Tucson, AZ); Brooks, Paul; Chorover, Jon; Harpold, Adrian; Heidbuechel, Ingo; McIntosh, Jennifer; Ray, James and Zapata-Rios, Xavier. Impact of water sources and flow paths on carbon in streams of seasonally snow-covered catchments [abstr.]: in Goldschmidt 2011 abstract volume, Mineralogical Magazine, 75(3), p. 1621, 2011. WWW. Meeting: Goldschmidt 2011, Aug. 8-14, 2011, Prague, Czech Republic.

Stream waters from seasonally snow-covered catchments of the Jemez River Basin Critical Zone Observatory in northern New Mexico are characterized by two distinct main water sources. While groundwater from deeper flow paths dominates the streams throughout the year, snowmelt and monsoon inputs additionally enter the streams through shallow soil flow paths. To investigate how changes in water sources influences dissolved carbon characteristics, 5 flumed streams at catchment outlets located around Redondo peak were sampled 10 times between March and October 2010 to analyze for total dissolved organic and inorganic carbon (DOC and DIC), DOC quality and stable isotopes of DIC. Stream water DOC showed a flushing pattern in all catchments, with highest concentrations during peak snowmelt and low concentrations during the dry season. SUVA₂₅₄ confirms presence of organic soil constituents of lignin based precursors during snow melt and monsoon season. Preliminary results of organic matter (OM) PARAFAC quantification identified a component with fluorescence in region II that dominates when shallow flow paths are activated. DIC concentrations show a dilution pattern with low concentrations during snowmelt. d¹³C values of DIC progressively increase with time since snowmelt, suggesting increasing inputs of groundwater enriched in ¹³C, possibly from microbial cycling of carbon in long transit time reservoirs. In waters from deeper flow paths, low SUVA₂₅₄ values and a PARAFAC component with fluorescence in region I dominate. Those results indicate that differences in source waters, flow paths and residence times have important impacts on stream water carbon characteristics.

URL: http://minmag.geoscienceworld.org/content/75/3/1584.full.pdf+html

12096715 Wierzchos, J. (Museo Nacional de Ciencias Naturales-Consejo Superior de Investigaciones Cientificas, Madrid, Spain); de los Rios, A.; Dávila, A. F.; Valea, S.; Cámara, B.; Artieda, O. and Ascaso, C. Life at the dry limit; microbial colonization of evaporites in the Atacama Desert [abstr.]: in Goldschmidt 2011 abstract volume, Mineralogical Magazine, 75(3), p. 2158, 5 ref., 2011. WWW. Meeting: Goldschmidt2011, Aug. 8-14, 2011, Prague, Czech Republic.

The hyper-arid core of the Atacama Desert is considered the driest region on Earth, one of the most challenging environments for life, and a Mars analog, due mainly to water scarcity. While Atacama soils are essentially lifeless, we have shown that hygroscopic halite crusts are colonized by endolithic communities composed of cyanobacteria, heterotrophic bacteria and archaea [1, 2]. The interior of the crusts provides shelter against extreme temperatures and UV radiation, and facilitates cell hydration through mineral deliquescence [3]. We also found that microporous and translucent gypsum crusts represent another evaporitic habitat for life in Atacama. This substrate is colonized by endolithic and hypoendolithic free living algae, fungi, cyanobacteria and heterotrophic bacteria, as well as by epilithic lichens [4]. The colonization of gypsum crusts appears to be controlled by atmospheric water potential. Based on our work in Atacama, we propose that putative Martian microorganisms withdrew to similar evaporitic micro environments as the planet dried out [5]. As such, evaporitic deposits would be primer targets for the search for life.

URL: http://minmag.geoscienceworld.org/content/75/3/2106.full.pdf+html

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