pingos in antarctica abstract pingos or ice cored mounds are described for the first time from antarctica and for the first time on ice cored moraine seven pingos up to 4 m high and 12 m in diameter occur on former dering of lakes on the moraine exposes water saturated sediments to freezing and consequent lake sediments on flanders moraine vestfold hills antarctica 68 40 s 78 00 e lateral wandering formation of closed system pingos the pingos are probably only a few hundred years old the apparent absence of pingo scars in the southern hemisphere may be due to lack of suitable substrates rather than to unsuitable climatic conditions

pitted rock surfaces on mars a mechanism of formation by transient melting of snow and ice 1 pits in rocks on the surface of mars have been observed at several locations similar pits are observed in rocks in the mars like hyperarid hypothermal stable upland zone of the antarctic dry valleys these form by very localized chemical weathering due to transient melting of small amounts of snow on dark dolerite boulders preferentially heated above the melting point of water by sunlight we examine the conditions under which a similar process might explain the pitted rocks seen on the surface of mars rock surface temperatures above the melting point atmospheric pressure exceeding the triple point pressure of h2o an available source of solid water to melt we find that on mars today each of these conditions is met locally and regionally but that they do not occur together in such a way as to meet the stringent requirements for this process to operate in the geological past however conditions favoring this process are highly likely to have been met for example increases in atmospheric water vapor content due for example to the loss of the south perennial polar co2 cap could favor the deposition of snow which if collected on rocks heated to above the melting temperature during favorable conditions e g perihelion could cause melting and the type of locally enhanced chemical weathering that can cause pits even when these conditions are met however the variation in heating of different rock facets under martian conditions means that different parts of the rock may weather at different times consistent with the very low weathering rates observed on mars furthermore as is the case in the stable upland zone of the antarctic dry valleys pit formation by transient melting of small amounts of snow readily occurs in the absence of subsurface active layer cryoturbation

weathering of granite in antarctica ii thermal stress at the grain scale granular disintegration has long been recognized and referred to in weathering texts from all environments including the antarctic despite this universal identification and referral few to no data exist regarding thermal conditions at this scale and causative mechanisms remain little more than conjecture here as part of a larger weathering study thermal data of individual grains using infrared thermometry and ultra fine thermocouples composing a coarse granite as well as the thermal gradients in the outer 10 cm using thermistors were collected from a north facing exposure measurements were also made regarding the surface roughness of the rock based on recorded temperatures the nature of the rock surface and the properties of the minerals an argument is made for complex stress fields that lead to granular disintegration mineral to mineral temperature differences found to occur were in part due to the changing exposure to solar radiation through the day and through seasons because the thermal conductivity and the coefficient of thermal expansion of quartz are not equal in all directions coupled with the vagaries of heating this leads to inter granular stresses although fracture toughness increases with a decrease in temperature it is suggested that the tensile forces resulting from falling temperatures are able to exceed this and produce granular disassociation the lack of equality with respect to crystal axis of both thermal conductivity and expansion in quartz further exacerbates the propensity to failure grain size and porosity also influence the thermal stresses and may help explain why some grains are held in place despite disassociation near the surface while the data presented here appear to beg more questions than providing answers they do provide a basis for better more detailed studies of this important weathering scale copyright 2007 john wiley sons ltd

preservation of miocene glacier ice in east antarctica antarctic climate during the pliocene has been the subject of considerable debate one view holds that during part of the pliocene east antarctica was largely free of glacier ice and that vegetation survived on the coastal mountains1a 4 an alternative viewpoint argues for the development of a stable polar ice sheet by the middle miocene which has persisted since then5a 10 here we report the discovery of buried glacier ice in beacon valley east antarctica which appears to have survived for at least 8 1 million years we have dated the ice by 40ar 39ar analysis of volcanic ash in the thin overlying glacial till which we argue has undergone little if any reworking isotope and crystal fabric analyses of the ice show that it was derived from an ice sheet we suggest that stable polar conditions must have persisted in this region for at least 8 1 million years for this ice to have avoided sublimation

honeycomb development on alexander island glacial history of george vi sound and palaeoclimatic implications two step cliffs mars oasis w antarctica abstract analysis of three generations of glacial deposits and of a range of geomorphic features including widespread honeycombs and tafonis at two step cliffs mars oasis 71 52 s 68 15 w provides new insights into the geomorphological evolution of west antarctica with special respect to alveolar weathering at two step terrace indicators of the inherited character of cavernous weathering were found such as 97 non flaking and varnished backwalls and 80 tafoni floors that are till covered and or sealed by lithobiontic coatings based on the ne predominant aspect of the alveolized boulder faces tafoni initiation is attributed to coastal salt spray weathering by halite coming from the george vi sound during the 6 5 ka bp open water period the present day activity of these inherited cavities is restricted to roof flaking attributed to a combination of processes involving thermal stresses this 6 5 ka bp phase of coastal alveolization is the first step of a six stage holocene geomorphological scenario that includes alternatively phases of glacial advance or stationing and phases of vegetal colonization and or rock weathering and aeolian abrasion on the deglaciated outcrops this geomorphic scenario is tentatively correlated with the available palaeoenvironmental record in the antarctic peninsula region with two potential geomorphic indicators of the holocene optimum being identified 1 clusters of centimetric honeycombs facing the sound marine optimum at 6 5 ka bp 2 salmon pink lithobiontic coatings preserved inside cavities and at the boulder surface terrestrial optimum at 4 3 ka bp

thermal conductivity and thermal diffusivity of cores from a 26 meter deep borehole drilled in livingston island maritime antarctic abstract during the month of january of 2008 a borehole permamodel gulbenkian 1 pg1 26 m deep was drilled on the top of mount reina sofia 275 m a s l near the spanish antarctic station of livingston island south shetland islands cores from 1 5 m to about 26 m deep were collected for measuring several physical properties the objective of the present work is to report the values of the thermal conductivity and the thermal diffusivity that were measured in the cores from the borehole and the heat production that was estimated for the geological formations intercepted by it seven cores were selected to measure the thermal conductivity and the thermal diffusivity the measured values for the thermal conductivity vary from 2 6 w mk to 3 3 w mk while the measured values for the thermal diffusivity vary from 1 1 10 6 m 2 s to 1 6 10 6 m 2 s both thermal conductivity and thermal diffusivity on average show a slight increase with depth average heat production was also estimated for two portions of the borehole one from 2 to 12 m and the other from 12 to 25 m a gamma ray spectrometer was used to estimate the concentrations of uranium thorium and potassium of the cores from which the heat production per unit volume was calculated the estimated heat production for the first half of the borehole is 2 218 w m 3 while for the second half it is 2 173 w m 3 these heat production values are compatible with acidic rock types porosity and density were also estimated for the same cores

spatial and temporal variability of ground surface temperature and active layer thickness at the margin of maritime antarctica signy island a calm grid with a data logger system to monitor the active layer thermal regime was established on signy island 60 43 s 45 38 wat 80 m a s l in december 2005 the active layer at each of the 36 nodes of the grid was monitored measuring the ground temperature at least at 4 different depths between 0 02 and 0 4 m at the end of the summer season in addition within the grid we selected four sites closely spaced in a ray of 25 m three of which with the same topographical characteristics north facing aspect but different vegetation coverage one bare ground bg1 and two sites with different vegetation andreaea sp and sanionia uncinata and the fourth bg2 it is as bg1 a bare ground but with south facing aspect in particular 4 thermistors were located at depths of 0 02 0 3 0 6 and 0 9 m at bg2 and at the andreaea sp site 9 thermistors at 0 02 0 3 0 6 1 1 2 1 4 1 6 2 and 2 5 mat bg1 and at 0 02 and 0 6 mof depth at sanionia site generally with the same aspect a thick vegetation cover as in sanionia site provides a greater insulative effect than a thinner vegetation cover as in andreaea site or bare ground bg1 because vegetation both shades and insulates the ground resulting in a reduction in summer heat flux ground surface temperature gst was colder and more buffered in spring and summer under the vegetated ground than in bg1 although the coldest gst and lowest thawing degree days tdd were recorded at bg2 and related to its southern aspect our data confirm that air temperature is the main driver of gst as already reported both in the arctic and antarctic we also found that the effect of air temperature changes seasonally being drastically reduced in winter and to a lesser extent in fall and spring when there is generally thin snow cover b30 cm during the summer when snow cover is usually absent the air temperature is the dominant driver although incoming radiation also had an effect on the northern exposed bare ground and to a lesser extent on the vegetated and southerly exposed bare ground the active layer ranges between 81 and 185 cm on the 4 continuously monitored sites and considering the sites with the same aspect it is thicker under bare ground between 10 up to more than 100 than under vegetated ground confirming previous observations in the arctic and antarctic however at our sites climate forcing has no effect on the active layer thickness enhancing the role of soil properties including the periods of high moisture content and lateral flow of water the lack of a statistically significant regressions between gst and active layer thickness could be due to the limited study period four years and or to the variationwith timeof changes in soil characteristics such as soilmoisture and the possible occurrence of non conductive heat transfer processes including the lateral flow of water further data are required to understand the role of moisture and possible ground water circulation within the active layer to explain the unexpected strong dichotomy between the gst regime and active layer thickness

the historical legacy of spatial scales in freeze thaw weathering misrepresentation and resulting misdirection discussion of weathering in cold regions has historically been dominated by widespread acceptance of the significance of the freeze thaw concept among periglacial geomorphologists and an essentially universal acceptance by those geomorphologists not directly involved in researching the topic debris produced by freeze thaw is frequently deemed to be angular in form and the observation of such debris has been used to identify the former or present operation of this weathering mechanism large debris blocks and small debris grains or flakes have been recognised as the outcome of the two scales of freeze thaw weathering macrogelivation and microgelivation respectively however the fusion of climatic geomorphology and process geomorphology in the ongoing development of the freeze thaw concept has resulted in the confusion of product with process whereby microgelivation producing small products and macrogelivation producing large products are seen due to the product dichotomy as distinctly different processes despite the recent highly sophisticated laboratory experimentation on freeze thaw weathering this historical process scale dichotomy still pervades thinking and experimental evaluation here we consider the historical development of microgelivation macrogelivation and outline what are thought to be fundamental flaws with the concepts and their underpinnings built within the two notions are elements of rock properties hard and soft and scale issues regarding rock attributes solid rock and existing weaknesses in rock that serve only to confuse the process and scale issues even more the whole notion of frost weathered debris having a specific form is also highly spurious there being no shape attribute that is uniquely diagnostic of frost action and this in turn leads to the further problem of process synergy or other processes entirely being the cause of rock failure in cold regions ultimately we argue that while there may be a range of product sizes and shapes resulting from frost weathering per se the widely invoked scale concepts are fraught with problems and are best dropped as too are any process shape connotations

active layer temperature in two cryosols from king george island maritime antarctica abstract this study presents soil temperature and moisture regimes from march 2008 to january 2009 for two active layer monitoring calm s sites at king george island maritime antarctica the monitoring sites were installed during the summer of 2008 and consist of thermistors accuracy of 0 2 c arranged vertically with probes at different depths and one soil moisture probe placed at the bottommost layer at each site accuracy of 2 5 recording data at hourly intervals in a high capacity datalogger the active layer thermal regime in the studied period for both soils was typical of periglacial environments with extreme variation in surface temperature during summer resulting in frequent freeze and thaw cycles the great majority of the soil temperature readings during the eleven month period was close to 0 c resulting in low values of freezing and thawing degree days both soils have poor thermal apparent diffusivity but values were higher for the soil from fildes peninsula the different moisture regimes for the studied soils were attributed to soil texture with the coarser soil presenting much lower water content during all seasons differences in water and ice contents may explain the contrasting patterns of freezing of the studied soils being two sided for the coarser soil and one sided for the loamy soil the temperature profile of the studied soils during the eleven month period indicates that the active layer reached a maximum depth of approximately 92 cm at potter and 89 cm at fildes longer data sets are needed for more conclusive analysis on active layer behaviour in this part of antarctica

distribution and characterization of soils and landform relationships in byers peninsula livingston island maritime antarctica abstract this paper presents the spatial distribution of soils from the northern part of byers peninsula livingston island which is the largest ice free area of the south shetlands archipelago maritime antarctica physical and chemical characteristics are presented for 23 soil profiles soil parent materials vary from marine sedimentary to volcanic and volcanoclastic rocks intruded by igneous bodies to assess soil landscape relationships twenty three soil profiles were described and sampled soil samples of selected horizons were submitted to chemical physical and mineralogical analyses soil mapping was based on the soil profiles integrated with the existent topographic map 1 25 000 scale a digital elevation model the geological map and a satellite image twenty different soil units were identified and mapped according to the world reference base for soil resources wrb system soils were classified as fluvisols regosols leptosols or cryosols which correspond mostly to fluvents orthents psamments inceptsols and gelisols respectively according to the soil taxonomy soils from northern byers peninsula are generally shallow and coarse textured with low organic matter content three soils from the rocky platforms of the northern coastal region possess ornithogenic character with lower ph higher p al 3 and organic c values when compared to soils not influenced by sea birds in non ornithogenic soils the presence of easily weatherable minerals in the clay fraction indicates that physical weathering occurs with limited chemical alteration of primary minerals the influence of penguin and other birds on coastal soils alters clay mineralogy with formation of poorly crystalline p rich phases a better understanding of the depth of the permafrost table and the spatial distribution of permafrost is necessary for a more conclusive classification of cryosols or gelisols

biofilms and case hardening on sandstones from al quwayra jordan on cambrian and ordovician sandstone inselbergs at al quwayra in southern jordan many near vertical rock walls exhibit marked case hardening detailed examination of the case hardened layer from four sites on both red and white sandstones has been carried out using schmidt hammer simple chemical analyses scanning electron microscopy energy dispersive spectroscopy and inductively coupled plasma mass spectrometry these analyses reveal a range of types of case hardening often in association with cryptoendolithic bio lms containing cyanobacteria and fungi iron manganese and calcium are all found to be common constituents of cements within the case hardened layer micro organic bio lms may assist in the formation of case hardening through aiding cementation but are by no means a necessary component of all the hardened layers in the wadi rum area copyright 2004 john wiley sons ltd

imaging of asteroid 433 eros during near s flyby reconnaissance during the 23 december 1998 flyby of asteroid 433 eros the near earth asteroid rendezvous near spacecraft obtained 222 images of eros as well as supporting spectral observations the images cover slightly more than two thirds of eros best resolution is approximately 400 meters per pixel and reveal an elongated cratered body with a linear feature extending for at least 20 kilometers our observations show that eros has dimensions of 33 x 13 x 13 kilometers the volume combined with the mass determined by the near radio science experiment leads to a density of 2 5 0 8 grams per cubic centimeter this relatively high density and the presence of an extensive linear feature suggest that eros may be a structurally coherent body

soil characteristics on varying lithological substrates in the south shetland islands maritime antarctica abstract soils in ice free areas of livingston island have been forming since the last deglaciation in a maritime warmer climate that is more humid than in interior antarctica a soil survey was carried out on byers and hurd peninsulas to characterize the soils and investigate the processes soils were sampled on two different substrates mudstones and volcanic rocks in byers peninsula and greywackes in hurd peninsula sampling sites were located on raised beaches platforms and on volcanic outcrops across an altitudinal range from few m to 150 m a s l the ph electrical conductivity carbonates and organic matter showed similar patterns in each geomorphic unit but their values differed between bedrocks the sand silt and clay contents differed greatly in the soils on mudstones and volcanic rocks the elemental composition was closely related to mineralogy of parent materials mg k zn mn and fe were similar in the soils on all bedrocks the al content was highest on the volcanic rocks the largest difference in the ca content was between the soils on greywackes and mudstones the na pb and ba contents in soils on the mudstones differed greatly from the rest of bedrocks geochemical and mineralogical characteristics suggest that the main process involved in soil development was the mechanical disintegration of bedrock although there was also some leaching cryogenic processes play a key role in soil development but chemical weathering processes were also involved in soil evolution although limited in extent due to the restriction of water circulation to summer

evolution of desert pavements and the vesicular layer in soils of the transantarctic mountains abstract compared to mid latitude deserts the properties formation and evolution of desert pavements and the underlying vesicular layer in antarctica are poorly understood this study examines the desert pavements and the vesicular layer from seven soil chronosequences in the transantarctic mountains that have developed on two contrasting parent materials sandstone dolerite and granite gneiss the pavement density commonly ranges from 63 to 92 with a median value of 80 and does not vary significantly with time of exposure or parent material composition the dominant size range of clasts decreases with time of exposure ranging from 16 64 mm on holocene and late quaternary surfaces to 8 16 mm on surfaces of middle quaternary and older age the proportion of clasts with ventifaction increases progressively through time from 20 on drifts of holocene and late quaternary age to 35 on miocene aged drifts desert varnish forms rapidly especially on dolerite clasts with nearly 100 cover on surfaces of early quaternary and older age macropitting occurs only on clasts that have been exposed since the miocene a pavement development index based on predominant clast size class pavement density and the proportion of clasts with ventifaction varnish and pits readily differentiated pavements according to relative age from these findings we judge that desert pavements initially form from a surficial concentration of boulders during till deposition followed by a short period of deflation and a longer period of progressive chemical and physical weathering of surface clasts the vesicular layer that underlies the desert pavement averages 4 cm in thickness and is enriched in silt which is contributed primarily by weathering rather than eolian deposition a comparison is made between desert pavement properties in mid latitude deserts and antarctic deserts

vegetation colonization of permafrost related landslides ellesmere island canadian high arctic 1 relationships between vegetation colonization and landslide disturbance are analyzed for 12 active layer detachments of differing ages located in three areas of the fosheim peninsula ellesmere island 80 n we discuss vegetation as an age index for landslides and a way to assess the time needed for complete recolonization of the surfaces since landslide detachment vegetation on undisturbed terrain is similar in the three areas but is more highly developed and complex inland due to a warmer summer climate on a regional scale the location of the area is as important as the effect of landslide age on vegetation colonization because of the influence of mesoclimatic conditions on vegetation development on a landscape scale there is a positive relationship between landslide age and vegetation development as represented by total vegetation cover floristic composition and successional stage consequently vegetation can be used at this scale as an indicator of landslide age fifty years are required to restore vegetation patches to a floristic composition similar to communities occurring in undisturbed conditions but with lower floristic richness and a discontinuous cover and without well developed layering the shorter time needed for landslide recovery in the area with the warmest summer climate confirms the sensitivity of arctic vegetation to small differences in air temperature this could trigger a set of interlinked feedbacks that would amplify future rates of climate warming

warming induced destabilization of peat plateau thermokarst lake complexes peat plateaus are widespread at high northern latitudes and are important soil organic carbon reservoirs a warming climate can cause either increased ground subsidence thermokarst resulting in l

metamorphism and tectonics of the himalaya metamorphism connected with the main growth and deformation stages of the himalaya ranges from mid cretaceous to the quaternary northward subduction gave rise in the early to mid cretaceous to an island are complex with greenschists amphibolites granulites and blueschists in the w kohistan ladakh and an andean type margin with greenschist amphibolite grade metamorphism in the e india and tibet ophiolitic nappes were thrust southwards over the indian continental margin in the palaeogene during the final stages of closure of the southern arm of tethys the indus zangbo suture bifurcates westwards and between the two sutures lies the kohistan ladakh island arc which was converted to an andean type arc in the palaeocene eocene the karakorum range underwent northward subduction at least during the late cretaceous to give rise to a complex and prominent calc alkaline batholith post collisional southward thrusting of crustal slabs over the indian continental margin took place in the early miocene with production of high grade metamorphism inverted isograds and crustal melt granites later southward thrusting in the pliocene to quaternary gave rise to localized low grade recrystallization against the thrusts

genesis properties and classification of cryosols from admiralty bay maritime antarctica abstract soils from maritime antarctica are different than those from other antarctic climatic zones and are among the least studied soils in antarctica we here present analytical and morphological data for the main soils found in admiralty bay king george island in the south shetland group fifty six 56 pedons were described sampled and analyzed according to standard international methods and classified according to both u s soil taxonomy and the wrb the soils are generally weakly developed and have chemical physical and morphological characteristics strongly influenced by the parent material we identify four main soil groups i basaltic andesitic ii acid sulfate iii weakly ornithogenic and iv ornithogenic soils small adjustments are proposed for both classification systems for allowing a more adequate classification for maritime antarctica greyish colored eutric lithic and typic haploturbels turbi leptic cryosols with neutral to alkaline reaction are the most common soils in admiralty bay and are usually developed from basaltic andesitic tills yellowish acid dystric sulphuric haploturbels turbi thionic cryosols are restricted to areas affected by pyritized andesites umbriturbels turbi umbric cryosols only occur at sites under bird influence ornithogenic soils are the most developed soils in admiralty bay and show pronounced chemical physical and morphological alteration of parent materials with formation of umbric epipedons and phosphatic b horizons fibristels organo turbic cryosols are restricted to hydromorphic areas under thick moss carpets

schmidt hammer studies in the maritime antarctic application to dating holocene deglaciation and estimating the effects of macrolichens on rock weathering in order to contribute to the reconstruction of the deglaciation history of the marguerite bay area 68 s maritime antarctic and to estimate the rock weathering rate in this antarctic sector 28 sites 7 on rothera point and 21 on anchorage island were characterised using schmidt hammer values the weathering effect of two of the most widespread species of macrolichens in this area usnea sphacelata and umbilicaria decussata was tested at 5 different sites on rothera point schmidt hammer data in conjunction with recent 14c age suggest a deglaciation age for the marguerite bay area of around 12 ka and an average uplift rate of 5 4 mm year 1 on anchorage island for the period between 3 3 and 5 2 ka the weathering rates are extremely slow e g three times slower than reported in norway our data confirm that lichens exert a strong impact on weathering decreasing the schmidt hammer r values on lichenised surfaces by a factor of 3 4 compared to bare rock surfaces the effect of lichens on weathering is mainly due to edaphic conditions and the type of the lichen involved rather the period of exposure

advances in permafrost and periglacial research in antarctica a review recently the research on permafrost periglacial morphology and processes had a great stimulus especially from the international polar year permafrost areas of continental antarctica with its extreme dry and cold environment can be considered an analog of extraterrestrial landscapes like those on mars but also preserve much paleoclimatic information of this crucial part of the global climatic system on the other hand maritime antarctica is one of the areas of the world currently affected by the greatest air warming and provides a unique opportunity to understand the impacts of climate change on permafrost and its related ecosystems despite the significant recent progress some gaps on permafrost distribution still remain as the network for permafrost and active layer monitoring needs further enlargement and better standardization ground ice its age and stability over time need further investigation as well as the role of living organisms on the weathering processes within the cryotic rocks the landscape evolution of continental antartica could be improved providing potential implications also for a better understanding and modeling of life and landscape evolution of other planets

reinterpretation of pingos in antarctica abstract in 1983 pingos were reported in the vestfold hills antarctica the features form dome shaped hills up to 4 m high and 12 m in diameter and occur on an ice cored moraine their form structure and sedimentary processes observed on the surface of the moraine together with a consideration of the environmental requirements for pingo growth preclude their origin as pingos they appear to be residual landforms that have formed on the surface of the moraine as the ice core has been destroyed by ablation and thermal erosion the previous interpretation of the features has relied on the shape of the hills and their occurrence in a similar geologic setting to pingos in the northern hemisphere the interpretation appears to have misinterpreted tension cracks and coherent slumping of sediment as dilation cracks and as evidence for the extrusion of a central sediment plug pingos on supraglacial debris have not been described from any other locations and it seems that their formation is inconsistent with the ablation of the ice core of moraines

periglacial processes and landforms in the south shetland islands northern antarctic peninsula region abstract periglacial processes and landforms together with the presence of permafrost are among the most relevant geomorphological elements in the northern antarctic peninsula region their distribution affects the hydrology and has consequences for the ecosystems of the ice free areas in this paper a compilation of the different types of periglacial landforms and processes occurring in the south shetland islands is carried out and their spatial distribution is analysed furthermore the relationships of the periglacial landforms with local conditions and permafrost distribution have been taken into account a total of thirty three types of periglacial landforms were identified and considered in this work patterned ground and stone fields are the most common periglacial landforms which are located within a wide altitudinal range and mainly on platforms field studies aerial photograph and satellite imagery interpretation were implemented to produce detailed maps from ten areas with different geological geomorphological and relief characteristics including the largest and most relevant ice free areas within the archipelago showing the presence and spatial distribution of periglacial landforms this work shows that the periglacial environment primarily conditioned by the regional climatic conditions has a great diversity in the studied region and that the distribution of the periglacial landforms is also related to local relief and geomorphological characteristics lithology hydrogeology and presence of permafrost where altitude plays an important role periglacial phenomena are widespread above 10 m a s l and are especially active on slopes and platforms between 30 and 100 m a s l the spatial distribution of periglacial landforms helps to identify the presence of permafrost that is dominant above 25 30 m a s l and more than 70 of the surface is occupied by active layer related landforms