permafrost and climate in europe monitoring and modelling thermal geomorphological and geotechnical responses we present a review of the changing state of european permafrost within a spatial zone that includes the continuous high latitude arctic permafrost of svalbard and the discontinuous high altitude mountain permafrost of iceland fennoscandia and the alps the paper focuses on methodological developments and data collection over the last decade or so including research associated with the continent scale network of instrumented permafrost boreholes established between 1998 and 2001 under the european union pace project data indicate recent warming trends with greatest warming at higher latitudes equally important are the impacts of shorter term extreme climatic events most immediately reflected in changes in active layer thickness a large number of complex variables including altitude topography insolation and snow distribution determine permafrost temperatures the development of regionally calibrated empirical statistical models and physically based process oriented models is described and it is shown that though more complex and data dependent process oriented approaches are better suited to estimating transient effects of climate change in complex mountain topography mapping and characterisation of permafrost depth and distribution requires integrated multiple geophysical approaches and recent advances are discussed we report on recent research into ground ice formation including ice segregation within bedrock and vein ice formation within ice wedge systems the potential impacts of climate change on rock weathering permafrost creep landslides rock falls debris flows and slow mass movements are also discussed recent engineering responses to the potentially damaging effects of climate warming are outlined and risk assessment strategies to minimise geological hazards are described we conclude that forecasting changes in hazard occurrence magnitude and frequency is likely to depend on process based modelling demanding improved understanding of geomorphological process response systems and their impacts on human activity

a multi method monitoring of timing magnitude and origin of rockfall activity in the japanese alps abstract a multi method monitoring was conducted to detect the timing and trigger of rockfall activity on an alpine rockslide cliff composed of cretaceous sandstone and shale in the southern japanese alps aresawa rockslide 2900 m above sea level the monitoring programme includes manual measurements of flaking from painted rock surface and collection of fallen debris daily time lapse imaging of the rockwall automated recordings of rock temperature rock moisture and influencing meteorological factors air temperature and precipitation a stereographic pair of sequential photographs is used to visually identify the location of new erosion and semi quantitative evaluation of detached materials at daily resolution six years 2010 2016 of debris trapping show major rockfall activity in winter between november and may and occasional activity associated with heavy rains in summer and yield an average rate of rockwall retreat on the order of 1 mm a 1 the rockwall shows heterogeneous debris production mainly reflecting joint spacing time lapse imaging displays at least 10 15 rockfall events per year within the shot area 500 m2 the integration of multiple data suggests at least five types of triggering processes towards rockfalls which recur annually 1 in summer and early autumn heavy rainfalls raise the moisture content of the shallow bedrock often triggering significant rockfalls probably due to raised water pressure in rock joints or lubrication of joints 2 in late autumn and late spring light or intermediate rainfalls are sometimes followed by high moisture shallow freezing rapid thawing and eventually by different scales of rockfalls 3 in winter and early spring the same process as in the second case but rainfall is replaced by snowfall triggers submeter scale rockfalls 4 deep seasonal freezing to about 5 m enables release of meter scale rockfalls during seasonal thawing periods from late spring to early summer 5 short term large thermal fluctuations that produce cyclic thermal stress may also contribute to submeter scale rockfalls mainly in winter locally enhanced by freeze thaw action

interpreting rockfall activity on an outcrop talus slope system in the southern japanese alps using an integrated survey approach abstract understanding relationships between meteorological conditions and rockfall activity is important for the management of rockfall risks as well as for the estimation of future rockfall activity under climate change seasonal activity of rockfall on talus slopes depends on the actual triggers of rockfall which in turn may vary as well between outcrops because of different rockfall sources and the influence of topography in this study we interpret spatial and temporal variations in rockfall activity and related sediment transfer processes in an outcrop talus slope system in central japan through monitoring using rock temperature and moisture sensors sediment traps and time lapse cameras in addition tree ring analysis has been added to understand possible changes of rockfall activity over longer time periods results suggest that the frequency of grouped gravel transport i e soil creep was higher than that of individual transport i e rockfall and dry ravel on the talus slope whereas rockfall likely is the predominant process from the outcrops observations from sediment traps showed that coarse gravel is characterized by higher bounce heights and that it travelled longer distances than fine gravel rockfall from the outcrops was most active during dormancy of trees which locally lasts from autumn to early spring and can be related to freeze thaw cycles in contrast rockfall and other sediment transfer processes were monitored on the talus slope all year round secondary movement of gravels on the talus slope such as soil creep during rainfall events likely triggers rockfall during times when the outcrops are not producing rockfall i e from late spring to summer consequently our results suggest that the spatio temporal rockfall activity varies substantially between outcrops and talus slopes and that differences in process behavior should be taken into account in future disaster mitigation measures

geoelectric investigations into sandstone moisture regimes implications for rock weathering and the deterioration of san rock art in the golden gate reserve south africa the clarens sandstone in the golden gate reserve south africa is the canvas for a collection of san bushmen rock art dating from neolithic times until as recently as 150 years ago this rock art is under threat from human interference but also to a greater degree from weathering processes on the rock surface the dominant weathering processes occurring in the rock shelters which host the rock art are flaking and honeycombing two rock shelter sites in the reserve have been investigated using electric resistivity tomography ert and supportive methods for measuring surface moisture protimeter and surface hardness equotip these non destructive techniques can be used in situ to assess the extent of weathering within a rock outcrop and are especially suited for investigations in sensitive areas such as rock art sites moisture movement has been mapped and related to the weathering processes observed on the surface the aim of the study is to aid rock art conservation in the golden gate reserve through a better understanding of the driving processes of surface weathering the evidence shows that the extensive flaking and honeycombing found in the rock shelters is most likely caused by water pockets in the near surface zone which are replenished through internal moisture transport driving the superficial weathering processes these weathering processes pose a significant problem rock art in the golden gate reserve shows severe deterioration due to flaking conservation strategies should therefore take internal processes into account as much as their superficial expression

weathering by wetting and drying some experimental results a series of experiments on sandstone and dolerite was undertaken in an attempt to better understand the wetting and drying weathering process as rock samples are frequently subjected to wet dry cycles within the simulation of other weathering mechanisms e g freeze thaw three common methods of moisture application were used and the influences of these evaluated it was found that the method of moisture application could affect the nature of the weathering products resulting from wetting and drying it was also observed that there were changes in the internal properties of the rock e g porosity microporosity and that these could influence the synergistic operation of other weathering processes although not all of the observations could be explained it is apparent that wetting and drying has both a direct and an indirect effect on the weathering of rock that has not been taken into account in simulations greater cognizance needs to be given to the role of this process both in the field and in laboratory simulations

structural and thermal controls of rockfall frequency and magnitude within rockwall talus systems swiss alps both from a systemic and natural hazard perspective it is essential to understand the causes and frequency of rockfalls in mountain terrain and to predict the block sizes deposited at specific locations commonly rockfalls are studied either retrospectively using talus slopes or directly by rockwall surveys nevertheless our understanding of rockfall activity particularly at the lower magnitude spectrum is still incomplete moreover the explanatory framework is rarely addressed explicitly in this study we investigate two rockwall talus systems in the swiss alps to estimate the rockfall frequency magnitude pattern and their key controls we present a holistic approach that integrates deductive geotechnical and thermal investigations of the source rockwalls with abductive talus based explanations of rockfall volume and frequency the rockwalls three dimensional 3d joint pattern indicates that 75 of the blocks may be released as debris fall 14 m3 and boulder falls 14 61 m3 which is mirrored in the corresponding talus material using two year records of near surface rockwall temperatures as input for a 1d heat conduction model underlines the destabilizing role of seasonal ice segregation deepest frost cracking of 300 cm may occur on the north northeast nne exposed snow rich rockwall with peaks at the outermost surface the synthesis of all data suggests that infrequent large planar slides approximately every 250 years overlain by smaller more frequent wedge and toppling failures approximately every 17 50 years as well as high frequency flake like clasts 3 6 events year characterize the rockfall frequency magnitude pattern at hungerli peak here we argue that small size rockfalls need more scientific attention particularly in discontinuous permafrost zones our study emphasizes that future frequency magnitude research should ideally incorporate site specific structural and thermal properties rather than just focusing on climatic or meteorological triggers we discuss how holistic rockwall talus approaches as proposed here could help to increase our process understanding of rockfalls in mountain environments copyright 2017 john wiley sons ltd

the freeze thaw weathering regime at a section of the niagara escarpment on the bruce peninsula southern ontario canada the bedrock freeze thaw and moisture regimes at an actively eroding site on the niagara escarpment bruce peninsula southern ontario were monitored between december 1983 and april 1984 and the results compared with amounts of debris collected in an adjacent rock trap frost wedging in pre existing rock fissures is the primary mechanism responsible for the observed rockfall events hydration effects are negligible debris production was more closely related to the duration of the freezing leg of the freeze thaw cycle than to intensity or to cycle frequency release also coincided with periods of high pore saturation 60 per cent and the seepage of water from cracks and fissures fewer freeze thaw cycles were recorded in the air than at 1 and 3 5 cm in the bedrock the number of cycles that could be declared geomorphologically effective according to established temperature criteria was normally less than half the total number of freeze thaw cycles recorded in both air and bedrock under the current temperature regime at the field site few effective cycles are capable of penetrating more than 5 cm into the free face

ambient seismic vibrations in steep bedrock permafrost used to infer variations of ice fill in fractures abstract the behavior of ice in frozen rock masses is an important control on rock slope stability but the knowledge of the formation extent and evolution of ice filled fractures in steep bedrock permafrost is limited therefore this study aims at characterizing the site specific ambient seismic vibration recorded at the matterhorn hornligrat fieldsite over the course of more than three years the observed normal mode resonance frequencies vary seasonally with four distinct phases persistent decrease during summer phase i rapid increase during freezing phase ii trough shaped pattern in winter phase iii and a sharp peak with a rapid decay during the melting thawing season phase iv the relation between resonance frequency and rock temperature exhibits an annually repeated pattern with hysteretic behavior the link between resonance frequency fracture width and rock temperature indicates that irreversible fracture displacement is dominant in summer periods with low resonance frequency these findings suggest that the temporal variations in resonance frequencies are linked to the formation and melt of ice fill in bedrock fractures

potential weathering by freeze thaw action in alpine rocks in the european alps during a nine year monitoring period abstract a quantification of rock weathering by freeze thaw processes in alpine rocks requires at least rock temperature data in high temporal resolution in high quality and over a sufficient period of time in this study up to nine years of rock temperature data 2006 2015 from eleven rock monitoring sites in two of the highest mountain ranges of austria were analyzed data were recorded at a half hourly or hourly logging interval and at rock depths of 3 10 and 30 40 cm these data have been used to quantify mean conditions ranges and relationships of the potential near surface weathering by freeze thaw action considering volumetric expansion of ice and ice segregation for the former freeze thaw cycles and effective freeze thaw cycles for frost shattering have been considered for the latter the intensity and duration of freezing events as well as time within the frost cracking window have been analyzed results show that the eleven sites are in rather extreme topoclimatic positions and hence represent some of the highest and coolest parts of austria and therefore the eastern alps only four sites are presumably affected by permafrost most sites are influenced by a long lasting seasonal snow cover freeze thaw cycles and effective freeze thaw cycles for frost shattering are mainly affecting the near surface and are unimportant at few tens of centimeters below the rock surface the lowest temperatures during freezing events and the shortest freezing events have been quantified at all eleven monitoring sites very close to the surface the time within the frost cracking window decreases in most cases from the rock surface inwards apart from very cold years sites with very low temperatures close to the surface as shown by this study and predicted climate change scenarios assumed warmer rock temperature conditions in the future at alpine rock walls in austria will lead to less severe freezing events and to shorter time periods within the frost cracking window statistical correlation analyses showed furthermore that the longer the duration of the seasonal snow cover the fewer are freeze thaw cycles the fewer are effective freeze thaw cycles the longer is the mean and the maximum duration of freezing events and the lower is the mean annual ground temperature the interaction of the winter snow cover history and the winter thermal regime has a complex effect on the duration of the frost cracking window but also on the number of freeze thaw cycles as shown by a conceptual model predicted future warmer and snow depleted winters in the european alps will therefore have a complex impact on the potential weathering of alpine rocks by frost action which makes potential weathering predictions difficult neglecting rock moisture and rock properties in determining rock weathering limits the usefulness of solely rock temperature data however rock temperature data allow getting an estimate about potential weathering by freeze thaw action which is often substantially more than previously known

evolution of the hydrothermal system at los azufres mexico based on petrologic fluid inclusion and isotopic data abstract the los azufres geothermal reservoir formed in a fractured upper miocene to pliocene andesite and basalt base complex is sealed to the surface by a silicic mainly rhyolitic sequence of pleistocene age almost the entire sequence is affected by hydrothermal alteration to varying extent petrological and fluid inclusion studies confirmed vertical zonation of the reservoir by secondary processes hydrothermal alteration processes under low temperature conditions at a depth of 1200 1500 m the maximum ice melting temperatures tmi values of 0 7 to 4 c and salinities of 6 4 wt nacl eq indicate boiling conditions of the geothermal brine in a vapor rich zone chlorite calcite quartz zeolite anhydrite albite sphene pyrite hematite and illite form the hydrothermal mineral paragenesis with maximum temperatures of 250 c and pressure conditions of 150 bar below 1500 m tmi reach maximum values of 0 1 c and low salinities of 0 2 wt nacl eq the minerals epidote amphibole prehnite and garnet indicate temperatures above 250 c and pressure conditions between 150 and 200 bar the measured homogenization temperatures th of fluid inclusions fi are consistently higher than the in situ measured temperatures which indicates retrograde cooling of the los azufres geothermal reservoir since the time of the hydrothermal mineral formation updoming temperature isotherms at the center of the geothermal field below well az 9 az 23 and az 25 indicate the heating up of the fluids by a shallow magma chamber stable isotope data 18o d of the geothermal brine indicates mixing processes between meteoric water and a minor magmatic component secondary reactions forming sericite may have caused a further positive shift in 18o in the shallow part of the geothermal reservoir

wind as a cooling agent substrate temperatures are responsible for variable lithobiont induced weathering patterns on west and east facing limestone bedrock of the negev spatial variability in lithobiont induced weathering patterns on desert rocks is aspect dependent while differences between the northern and southern aspects have been extensively studied little is known concerning the differences between east facing ef and west facing wf aspects in deserts including the negev desert whereas cobbles on both slopes are inhabited by endolithic lichens epilithic lichens which render the bedrock a smooth appearance and free living cyanobacteria which give the bedrock a rugged microrelief predominate on wf and ef bedrock respectively following previous research that regarded dew as the principal factor that determines lithobiont distribution measurements of radiation temperature wind and dew were carried out during 2008 2009 in the negev desert the data indicated that albeit slightly higher midday surface temperatures that characterize wf surfaces cobbles and bedrock nocturnal temperatures on these surfaces were significantly lower therefore facilitating higher dew condensation high amounts of dew result from the relatively rapid drop in temperatures 14 00 20 00 due to the afternoon northwesterly sea breeze wind with a cooling rate of the wf bedrock being 52 9 higher than on ef bedrock 2 6 c h 1 in comparison to only 1 7 c h 1 and facilitate the growth of high chlorophyll dew fed and rain fed epilithic lichens which may act as bio protectors on wf bedrock lack of condensation on ef bedrock results in turn in the growth of rain fed free living cyanobacteria responsible for high rock dissolution and subsequently for a rugged microrelief by affecting the nocturnal bedrock temperatures wind acts as a cooling agent impacting in turn the amount of dew and subsequently lithobiont composition and weathering patterns in the negev desert copyright 2016 john wiley sons ltd copyright 2016 john wiley sons ltd

thermal weathering of granite spheroidal boulders in a dry temperate climate northern dobrogea romania weathering microforms associated with exfoliation were investigated on 40 granitic spheroidal boulders identified on pricopan ridge m cin mountains in order to establish a spatial distribution pattern continuous thermal monitoring allowed the frequency and intensity distribution assessment of short term temperature changes triggered by summer storms of intense day night amplitudes and frost cycles across a uniform rounded boulder rock strength estimated by schmidt hammer tests differentiates a significantly weaker resistance on the southern face of the boulders rebound values of 27 to 33 in comparison with the northern face 43 50 the lowest resistance of the north south cross boulder profile corresponds to the southern gentle slopes 0 45 thus defining the most susceptible area to exfoliation and other weathering processes it is argued that this low resistant sector fits well with the maximum frequency and intensity of thermal processes recorded on the low and mid slopes 0 45 of the boulders south side with small differences from one process to another whilst the sector of 20 to 30 south corresponds to the peak activity of all in accordance the overlay map of exfoliated surfaces places the high frequency area on a spherical cap developed similarly between 5 north and 45 south the smallest exfoliated surfaces normally appear around 30 south and are inferred to extend in time both to the boulder top and downslope the correlations between the frequency intensity maps of thermal processes and the frequency map of exfoliated surfaces point to a complementary action in the exfoliated surfaces development of the short term temperature changes and diurnal cooling and heating due to the directional insolation effect as similarly inferred in the development of meridional cracks copyright 2016 john wiley sons ltd

runout analysis of a large rockfall in the dolomites italian alps using lidar derived particle sizes and shapes lidar data were used to quantify and analyse a rockfall event which occurred in 2003 in the western dolomites italian alps in addition to previously existing airborne laserscanning als data high resolution terrestrial laserscanning tls data were collected by using the original point clouds the volume axial ratio and runout length of single boulders as well as the surface roughness in the runout zone of the rockfall were derived the total volume of the rockfall event of approximately 10 000 m was estimated by a reconstruction of the pre event surface at the detachment zone the analysis of the laser scanning data of the accumulation zone revealed a power law scaling for boulder volumes larger than 8 m the dependence of runout length on boulder volume is complex it is moderated by particle sphericity in addition we used als and tls data to derive the spatial distribution of surface roughness on the talus cone tls allow for more accurate roughness mapping than als data but for most applications the point density of als data seems to be sufficiently high to derive measures of roughness different sampling approaches for plane fitting on the scale of 5 m did not show significant effects besides the computational time the results of our analyses provide important perspectives for rockfall modelling and process understanding with potential applications in both applied natural hazards and pure geomorphological research copyright 2012 john wiley sons ltd

near surface wetting of a ponded basalt surface observations using time domain reflectometry abstract the changes in dielectric constant k a during an infiltration test on a fractured basalt surface in south eastern idaho were monitored using time domain reflectometry tdr because changes in k a were caused largely by changing amounts of water in the formation and to a small extent by diurnal and seasonal temperature fluctuations tdr served as a useful indicator of the moisture status in the formation our results indicate that wetting and drying were spatially variable within and immediately beyond a 7 8 m 2 pond various locations close to the surface responded to fast flow whereas others showed evidence of poor hydraulic communication with the surface data collected during a rainfall event which occurred a few days after ponding ceased indicated that this boundary condition evoked a similar hydrologic response to ponding this effort suggests that tdr is a useful tool for detecting moisture changes in fractured media

a quantitative determination of the effect of moisture on purple mudstone decay in southwestern china aims the moisture condition is well known to be a key factor that apparently influences rock decay but little is known about the quantitative correlations between a rock s decay rate and its moisture content which makes it difficult to quantitatively predict the rate of rock decay under varied moisture conditions thus in this paper our aim is to observe the decay rates of various purple mudstones with different moisture contents and to develop an equation to calculate the decay rate

thermo cryogenic controls of fracture kinematics in permafrost rockwalls thermo cryogenic processes prepare and trigger rockfalls and rockslides in alpine environments temporal occurrence controls and applied stresses of thermo cryogenic processes on rock masses are poorly understood this paper reports annual crackmeter measurements with 3 h resolution across perennially ice filled fractures in an unstable rock permafrost crestline thermo cryogenic processes are controlled by snow cover onset and duration thermal changes in snow free periods control expansion and contraction coincident temperature gradients on a daily to seasonal scale we can show how snow cover promotes sustained temperatures from 9 to 1 c and boosts ice segregation related fracture opening up to 1 cm in 8 months during snowmelt meltwater induces ice erosion and ice relaxation which occur in the freeze thaw window close to the thawing point we hypothesize that thermo cryogenic processes and their cyclic repetition can lead to thermo cryogenic fatigue preparing rock slope failure and can control type and location of rockfalls in a changing climate

cave development by frost weathering abstract this paper deals with the description and genesis of a special type of shelter cave in german they are termed auswitterungshohlen which goes back to the 19th century and the genesis is supposed to be related to frost weathering but to our knowledge detailed studies are missing so far this type of cave is very common in the area of investigation that comprises pre alpine and alpine regions in the north eastern part of the eastern alps they make up 32 of the 5138 registered caves but surprisingly they entirely developed in carbonate rocks although most of them are smaller than a dozen metres some have lengths of more than 50 m and entrances can be more than 100 m wide or similarly high besides general observations that lead to a list of characteristics for these caves two of them in a pre alpine setting were studied in depth a detailed map descriptions and measurements concerning cave morphology host rock geology and climate are given the thickness and composition of clastic sediments were investigated by small trenches and electric resistivity measurements sediment thicknesses reach up to 2 m inside the caves and below the entrances for one year nets were installed to measure rockfall in both caves in warm periods generally less than 5 g month of debris could be collected but a few 100 g month for frost periods this strong correlation and the significant amount of debris together with other observations suggest that frost weathering is an on going and very important process for the formation of these caves grain size distribution of the collected debris argues for the activity of both microgelivation and ice segregation therefore we suggest that the term frost weathering caves should be used for shelter caves whose genesis is related to frost weathering as dissolution seems to be of marginal importance for the genesis they are a paradox as they develop in karstic rock but have pseudokarst features

a laboratory simulation of rock breakdown due to freeze thaw in a maritime antarctic environment results of freeze thaw simulations on three large blocks of quartz micaschist are presented three types of water to ice phase change were identified from temperature and ultrasonic measurements it is suggested that the type of phase change results from a particular combination of rock moisture content solute concentration freeze amplitude and rate of fall of temperature the temperature at which ice thawed inside the rock 0 7 to 1 9 c was also found and this indicates the possibility of freeze thaw effects without positive temperatures approximately 80 per cent of the water that will freeze under natural conditions in the maritime antarctic environment under study appears to have done so by 6

field experiments on physical weathering and wind erosion in an antarctic cold desert field experiments were carried out over a five year period with the aim of understanding contemporary weathering and erosional environments in the sor rondane mountains an antarctic cold desert region these include observations of 1 scaling from rockwalls 2 disintegration of tuff blocks with or without saline solutions and 3 abrasion of artificial walls by wind monitoring was also made of rock surface temperature and wind speed despite frequent temperature oscillations across 0 c rock scaling due to frost action was generally very slow because of low moisture content in the rockwalls exposure to the cold dry climate led to the rapid disintegration of porous tuff blocks including soluble salts like halite and thenardite this indicates that rates of weathering are increased greatly with the accumulation of such salts in the bedrock although gypsum did not cause any visible damage over four years its widespread occurrence in heavily damaged rocks demonstrates that increasing gypsum contents may also intensify rock breakdown the snow laden katabatic wind resulted in rapid wearing of the windward face of an asbestos board with the peak erosion at 30 40 cm above the ground nonetheless the landforms expected from the unidirectional wind characteristics are by no means common features because of lack of abrasive materials such as snow and sand particles these experiments suggest that frost weathering and wind erosion are only locally effective where plenty of moisture or an abrasive material is available whilst salt weathering and removal of the waste by wind play a major role in constructing erosional landforms over the mountains

glacial and gully erosion on mars a terrestrial perspective the mid to high latitudes of mars host assemblages of landforms consistent with a receding glacial landscape on earth these landforms are postulated to have formed 5 ma under a different climate regime when mars orbital obliquity was on average 10 higher than today here we investigate the spatiotemporal relationship between gullies and glacial landforms both common in the mid latitudes gullies are kilometre scale landforms with a source alcove transportation channel and depositional apron the glacial landforms comprise 1 extant viscous flow features vff that extend from the base of crater walls into the interior of crater floors and are widely interpreted as debris covered glaciers containing extant ice and 2 landforms such as arcuate ridges at the base of crater walls that have been interpreted as relicts of more recent less extensive glacial advances focussed on crater walls we measure headwall retreat associated with glacial landforms and date their host craters to constrain minimum headwall retreat rates we record headwall retreat rates up to 102 m my 1 for the youngest suite of glacial landforms equivalent to erosion rates of wet based glaciers on earth and to headwall retreat rates associated with martian bedrock gully systems we find extensive evidence for a single erosional episode dating 5 10 ma which postdates emplacement of the majority of vff but seems to predate formation of the gullies we propose that the wet based glacial episode was associated with glaciation focussed on the crater walls rather than melting of the glacial ice deposits on the crater floors vff this is consistent with our observations of crater wall morphologies including the presence of arcuate ridges consistent with terrestrial glaciotectonic features that require liquid water to form textural alteration of the eroded bedrock surface consistent with ice segregation and frost shattering and the presence of downslope pasted on terrain tentatively interpreted here as glacial till deposits sourced from glacial erosion of the crater wall the pasted on terrain is usually interpreted as a thicker latitude dependant mantle located on sloping terrain formed from airfall of ice nucleated on dust but we suggest that it has been reworked by glaciation and is predominantly glacial in origin although our results cannot substantiate that gullies are produced by meltwater the discovery of this wet glacial event does provide evidence for widespread meltwater generation in mars recent history

application of refraction seismics in alpine permafrost studies a review abstract refraction seismics is a common geophysical application to investigate permafrost in alpine studies this study reviews the physical basis of the use of refractions seismics and introduces the history of its application in alpine environments seismic properties are influenced by rock or soil properties and fluid or ice effects in laboratory measurements these influences are determined and linked to mechanical properties or used for calibration of field studies in field conditions supplementary environmental factors influence the seismic properties of landforms in this paper laboratory studies of rocks from different lithologies and with different properties as well as case studies on rock glaciers moraines talus slopes and debris covered slopes are collected and influencing factors quantitatively analyzed the data demonstrate how lithology porosity and anisotropy influence p wave velocity environmental factors result in a high variation of p wave velocities in landforms however p wave velocities enable the differentiation of active layer and permafrost in rock glaciers and moraines in talus slopes and debris covered slopes p wave velocity contrasts between active layer and permafrost layer might be insufficient and require the application of additional methods for a final differentiation

enhanced bedrock weathering in association with late lying snowpatches evidence from livingston island antarctica an indication of the extent of weathering on different aspects of rock outcrops on livingston island antarctica was obtained by means of a schmidt hammer a cone indenter and measurement of weathering rind thickness results show that weathering particularly chemical weathering is enhanced on the lee side of outcrops where snow accumulates as a result of prolonged wetting by the melting snow rock moisture and temperature data indicate that the south facing snow accumulation side of obstacles have high rock moisture levels and maintain relatively high temperatures whilst chemical weathering is greater on the leeward side of outcrops mechanical processes are greater on the windward side the presence of late lying snow thus appears to exert a strong influence on weathering

south pacific circulation changes and their connection to the tropics and regional antarctic warming in austral spring 1979 2012 after 1979 statistically significant warming in antarctica is only observed in austral spring september november son across west antarctica and the antarctic peninsula while previous work has linked this warming to reductions in sea ice cover we note that a substantial 30 60 portion of the warming is related to changes in the son atmospheric circulation in particular western antarctic peninsula warming is consistent with increasing pressure in the south atlantic while western west antarctica warming is tied to a deepening of the amundsen sea low near the eastern ross sea while both of these circulation changes are associated with increased warm northerly flow toward the antarctic continent they are connected with different aspects of tropical variability the increase in pressure in the south atlantic is associated with a trend toward more la nina like conditions in the tropical pacific and an associated rossby wave train in contrast the deepening of the amundsen sea low is more strongly tied to a shift in the pacific decadal oscillation pdo toward its negative phase since the 1990s compared to typical la nina events the recent negative pdo events display a different tropical forcing which drives a rossby wave train that propagates more meridionally across the south pacific culminating in the eastern ross sea rather than in the south atlantic the results suggest multiple independent forcing mechanisms governing the son pressure trends and associated antarctic peninsula and west antarctica warming after 1979 which partially cancel each other out in the amundsen sea and portions of eastern west antarctica

the chemical weathering regime of karkevagge arctic alpine sweden abstract karkevagge is a valley located in swedish lapland at approximately 68 n and represents an arctic alpine landscape it is a presently periglacial glaciated trough incised into essentially horizontal metamorphic rocks some of which are presumably pyrite rich a set of coordinated studies was undertaken to investigate the nature of chemical weathering and pedogenesis in the valley and upon the abutting ridges august 1996 water quality measures reveal considerable spatial variation in solute totals with the highest total dissolved solute abundances being correlated with high sulfate abundances ridge crest soils exhibited poor horizonation but more extensive development of secondary clay minerals developed in situ than was found in valley flank and valley bottom soils valley soils exhibited multiple thin horizons many of which were buried and are taken to reflect great paraglacial and periglacial instability favorable microenvironments in the valley permit significant development of spodosols coarse debris along and across the valley bears both weathering rinds and rock coatings rock coatings in the valley include several types of iron films sulfate crusts carbonate skins and heavy metal skins karkevagge represents a mild arctic environment which does not preclude substantial chemical weathering in locations where abundant pyrite rich bedrock and water coincide this weathering follows pathways which are eminently expectable given that weathering of the pyrite rich rock permits generation of sulfuric acid which in turn weathers muscovite mica and calcite in local schists and marble respectively zones of intense chemical weathering also generate clearly visible deposits of gypsum and iron sulfate deposits such as jarosite not all arctic and or alpine environments are likely to be so active chemically but the results from karkevagge clearly show that dismissal of chemical weathering in cold regions on the basis of presumed first principles is erroneous consequently chemical weathering in such environments merits substantially more attention than it has hitherto received

climatic controls on frost cracking and implications for the evolution of bedrock landscapes 1 in mountainous landscapes the role of periglacial processes in producing sediment is poorly defined despite evidence of abundant talus slopes ice growth in rock has long been recognized as an efficient erosion mechanism but the effects have not been readily applied to landscape evolution in response to tectonic and climatic forcing here we quantify how and where ice driven mechanical erosion occurs in cold bedrock dominated landscapes using a simple one dimensional numerical heat flow model in our model ice grows by water migration to colder regions in shallow rock by the reduction in chemical potential associated with intermolecular forces between ice and mineral surfaces a process called segregation ice growth the depth and intensity of frost cracking is primarily dependent on mean annual temperature mat with positive mat sites characterized by intense cracking in the top meter of the rock mass and a maximum frost penetration of 4 m in contrast negative mat areas have less intense cracking that primarily occurs at depths between 50 and 800 cm we compare the depth and intensity of frost cracking predicted by our model with measures of the intensity of frost processes determined in three studies the first measured the timing of rockfall in the canadian rockies niagara escarpment and japanese alps the second analyzed scree deposits in the southern alps new zealand and the third documented rockfall frequency in utah these natural examples show that rockfalls tend to nucleate at elevations that coincide with zones of intense frost cracking predicted by our model as such climatic variations associated with interglacial glacial cycles may impart a significant influence on the denudation of mountainous landscapes

rock moisture content in the field and the laboratory and its relationship to mechanical weathering studies rock moisture content is a major control of mechanical weathering particularly freeze thaw and yet almost no data exist from field situations this study presents moisture content values for rocks taken from a variety of positions and conditions in the maritime antarctic additional information regarding the amount of water the rock could take up as observed from laboratory experiments is also presented the results show that the approaches used in simulation experiments particularly that of soaking a rock for 24 hours may produce exaggerated results it was found that the saturation coefficient s value was a good indicator of frost susceptibility based on water content but that the derivation of that value may underestimate the potential of some rocks the distribution of moisture within rocks is seen as an important but unkown factor the results of these field moisture contents suggest that for simulations of freeze thaw or hydration to be meaningful then they should have rock water contents based on field observations

rock moisture measurements techniques results and implications for weathering rock moisture is an important factor for the intensity and distribution of frost weathering processes however quantitative measurements are scarce which is partly due to the lack of reliable measurement techniques this paper presents five different techniques for obtaining rock moisture data while collecting rock pieces and two dimensional geoelectric measurements allow determination of the spatial moisture distribution the temporal variability can be derived from conductivity and time domain reflectometry records computer simulations using rock properties and climatic records as input data render it possible to clarify the important aspects that are responsible for the moisture distribution it proved to be advisable to use several methods to check and validate the results the results obtained in study areas in the bavarian alps make it clear that direct rainfall is the main source of rock moisture the influence of snow is limited to the immediate vicinity of the snow fields and is not equally pronounced at different times and positions rock moisture levels are higher in summer than they are in winter since in winter less water is supplied in liquid form northerly exposed rockwalls are generally more moist than those exposed in a southerly direction which is due to the different insolation as well as to the wind direction during rainfall in every position the rock is on average wetter on the inside than it is on the surface this means that shallow frost cycles as typical for south exposed sites are not affecting weathering since they take place at a depth level that is mostly dried out numerous spatial and temporal patterns of rockfall found in the same study areas can be explained through variations in rock moisture thus the moisture content of the rock is considered to be one of the major controlling factors of the frost shattering rate copyright 2005 john wiley sons ltd

the rate of bedrock weathering by frost action field measurements and a predictive model shattering rate surface temperature moisture content and the physical and strength properties of bedrock were measured in four rockwall sites of the japanese alps five year observations revealed that the bedrock shattering rate was usually much higher in the freeze thaw period from october to next may than in the frost free period from june to september this indicates that frost action is the most important shattering process although unusual heavy rainstorms in summer are also responsible for the shattering a combination of some empirical relationships derived from recent laboratory experiments leads to a predictive model of the frost shattering rate this model shows that the annual shattering rate is dependent on the annual freeze thaw frequency on the rock surface and the degree of saturation and tensile strength of the rock masses the coefficients involved in the model were determined using the field data

potential use of time domain reflectometry for measuring water content in rock abstract quantifying water movement through bedrock materials requires a technique which can accurately measure water content at precise locations within the medium time domain reflectometry tdr is widely used to measure the water content of soil and has a measurement sensitivity which is tightly confined to the area immediately surrounding the probes this study applies tdr to the measurement of water content in rocks the technique was evaluated using sandstone and welded tuff in a series of laboratory experiments a block of each rock type was instrumented with a series of evenly spaced tdr probes each block was first saturated with water and then allowed to air dry the water content was determined gravimetrically using the tdr over a period of several weeks the results indicate that the tdr technique can be used to determine the water content of rock with an accuracy comparable with that reported for the technique used in soils