paraglacial rock slope stability glaciation and deglaciation along with their associated climatic and non climatic processes modify slope stresses and influence slope stability paraglacial slope failures are those that are a part of or influenced by the transition from glacial conditions to non glacial conditions gravitational failure of rock slopes is a primary and dominant process of slope evolution in mountainous terrain and is the subject of this paper which 1 reviews the approaches taken for researching paraglacial rock slope failure patterns and processes 2 summarises the spatial and temporal patterns of post glacial failures 3 assesses the factors influencing slope stability during glaciation and deglaciation 4 explores some of the applications of paraglacial research and 5 highlights some of the outstanding issues to be resolved and provides recommendations for terminology relating to paraglacial slope processes

defining the centre of glacio isostatic uplift of the last scottish ice sheet the parallel roads of glen roy scottish highlands the parallel roads of glen roy scottish highlands represent a series of ice dammed lake shorelines produced during the cold climate of the younger dryas it is shown here that each lake shoreline exhibits evidence of glacio isostatic tilting associated with the decay of the last late devensian ice sheet the directions of tilting of the three shorelines in the quadrant between north and east are at variance with published glacio isostatic uplift isobases based on marine shoreline data that suggest a pattern of decreased uplift towards the northwest the gradient of shoreline tilting between 0 11 and 0 14 m km 1 is similar to measured regional tilts of a well developed marine shoreline the main rock platform considered to have been produced in scotland during the same period of extreme cold climate consideration of the ice dammed lake shoreline data also points to the former occurrence of two separate episodes of tectonic activity during the younger dryas copyright 2002 john wiley sons ltd

pore water pressure effects on the detachment of cohesive streambeds seepage forces and matric suction erosion of cohesive channel materials is not fully understood but is assumed to occur largely as a result of hydraulic shear stress however field and laboratory observations of pore water pressures in cohesive streambed materials reveal the presence of positive and negative pore water pressure effects that may significantly affect the erosion process as contributing and resisting forces respectively measurements of pore water pressures below cohesive streambeds in the loess area of the midwestern usa were conducted in situ and in undisturbed cores with a digital miniature tensiometer results disclosed matric suction values in the range of 15 50 kpa in eastern nebraska and northern mississippi repetitive tests in soft materials verified a change from positive pore water pressures in the upper 10 15 cm to negative pore water pressures to depths of at least 50 cm in firm materials the entire sampled profile was unsaturated laboratory experiments were carried out in which synthetic hydrographs were imposed on undisturbed streambed cores from the same sites miniature tensiometers in the cores monitored the resulting pattern of pore water pressures and revealed upward directed seepage forces on the recessional limb of the hydrograph maximum calculated values of the force ranged from 10 to 275 kn for the materials and heads tested the maximum value obtained after application and release of a 2 5 m head was 119 kn with 275 kn after a 5 0 m head these results were supported independently by subsequent simulations using a finite element hydrology model coupled with a stress deformation model a numerical scheme was developed to calculate the forces acting on cohesive aggregates in an idealized streambed and to evaluate the potential for their detachment the scheme added upward directed seepage as an additional driving force and matric suction as an additional resisting force to the commonly applied factors of particle weight fluid drag and lift force results demonstrate that upward directed seepage forces of the magnitude measured in the laboratory with 5 0 m stages have the potential to detach particles larger than 10 cm in diameter without requiring fluid drag and lift forces when added to these hydraulic forces erosion thresholds are lowered enabling erosion at lower hydraulic stresses a hypothesis for detachment of chips or blocks of cohesive bed material is proposed 1 large 5 m rises in stage increase pore water pressures or decrease matric suction dramatically in the region just below the bed surface 2 a relatively rapid decrease in stage causing a loss of water pressure above the bed combined with low rates of excess pore water pressure dissipation just below the bed surface result in steepened hydraulic gradients and 3 a resulting net upward seepage force is great enough to contribute to detachment of cohesive bed material or rupture the bed by exceeding the available strength and confining stress published in 2001 by john wiley sons ltd

rock slope failure in the british mountains abstract in this first full review of extant quaternary rock slope failure rsf in the british mountains we provide a near complete inventory of 1082 sites 40 being rock slope deformations 40 arrested rockslides and 20 rock avalanches current rsf activity is negligible and this relict population is predominantly paraglacial with a parafluvial minority its spatial distribution is perplexing with rsf density varying greatly both regionally and locally in the scottish highlands eight main clusters account for 76 of rsf area in 15 of the montane area local concentrations occur in all the british ranges across high and low relief in core and peripheral locations and on varied geological and glaciological domains as conversely do extensive areas of sparsity even in similar lithologies generic interpretations are thus precluded geology is only a secondary control an association with concentrated erosion of bedrock ceb is proposed as a driver of intensified slope stresses ceb is most evident at those glacial breaches of main divides where the most vigorous recent incision is inferred and also in some trough heads a clear association between rsfs and these late developing breaches is demonstrated in the highlands in 42 localities with sparsity away from them it is also seen in seven lake district localities glaciological models identify ice sheet volatility capable of driving breach ramification high magnitude paleoseismic events are generally unlikely to have provoked rsf clusters a few candidates are considered rsf has been underrated as an agent of mountain landscape evolution in britain its spatio temporal incidence may assist in calibrating regional ice sheet models and in assessing climate change impacts we argue that the ceb rsf association has global relevance in identifying primary drivers of mass movement in bedrock

river channel adjustment to meander cutoffs on the river bollin and river dane northwest england morphological adjustment of a channel after cutoff should be expected but rarely has the mode and timescale of adjustment in natural channels been measured four natural cutoffs which have occurred since 1980 on two rivers in northwest england have been monitored from pre cutoff stage two of the cutoffs were neck cutoffs of large loops two were chute cutoffs in which significant bend curvature remained all the cutoffs were the terminal result of progressive bank erosion and or scour of the floodplain rather than overflow and all the cutoffs took place in peak flow events though two of these were of relatively low magnitude high frequency rapid widening and sedimentation took place within the straight channels produced by neck cutoffs immediately after breaching adjustment was mainly by formation of multiple riffles and bars producing a variable morphology in the first 2 4 years subsequently the morphology became more regular and in one case had stabilised within about eight years progressive steepening and acceleration of bank erosion appears to have been propagated upstream in one case but in the other cases erosion was very localised rates of vertical accretion at the entrances to the old channel were much higher than most quoted in the literature rates of change in all morphological sedimentary and biotic components exhibit an exponential decline with time but with slightly differing timescales on these active gravel bed streams major adjustment within the new channels may be completed within 6 12 years though lakes persist in the abandoned channels for much longer

a comparison of burial maturity and temperature histories of selected wells from sedimentary basins in the netherlands sedimentary basins in the netherlands contain significant amounts of hydrocarbon resources which developed in response to temperature and pressure history during mesozoic and cenozoic times quantification and modelling of burial maturity and temperature histories are the major goals of this study allowing for a better understanding of the general geological evolution of the different basins as well as petroleum generation all major basins in the netherlands encountered at least one time of inversion and therefore moderate to high amounts of erosion in order to determine the amount of inversion the basins have experienced a 1d study was performed on 20 wells within three basins west netherlands central netherlands and lower saxony basins new vitrinite reflectance values were obtained and existing data re evaluated to gain a good data base the burial histories of six wells two for each studied basin are presented here to demonstrate the differences in basin evolution that led to their present shape and petroleum potential the permo triassic subsidence phase can be recognized in all three basins but with varying intensity in the jurassic the basins experienced different relative movements that culminated in the cretaceous when the influence of the inversion caused erosion of up to 2 500 m most wells show deepest burial at present day whereas the timing of maximum temperature differs significantly springer verlag 2007

grain rimming kaolinite in permian rotliegend reservoir rocks upper rotliegend sediments of permian age from the northeast netherlands show moderate to good reservoir

flow and solute transport through the soil matrix and macropores of a hillslope segment subsurface flow from various portions of a soil profile on a steep forested hillslope was evaluated by two sets of step change miscible displacement tests at different application rates and antecedent hydrologic conditions solutions of nacl 1000 mg l 1 cl were applied at steady state rates equivalent to 20 and 30 mm h 1 of standing water over the entire plot area using a line irrigation source located 1 5 m upslope lateral distance from an excavated soil pit subsurface flow and tracer breakthrough from five portions the organic rich soil layer including macropores the mineral soil matrix and three groups of macropores in the mineral soil layer of the soil profile were individually measured and analyzed using a convective dispersive model matrix flow dominated discharge from the soil pit during tracer tests 70 93 of total discharge however during wet periods with upslope drainage macropores including organic rich soil contributed proportionally more flow than during periods when upslope drainage was minimal outflow from macropores during the test with wet antecedent conditions had lower cl concentrations than drainage from the soil matrix suggesting dilution in macropores from upslope drainage effective pore volumes calculated for the flow averaged breakthrough data from the entire profile were much less 40 than the estimates measured by tensiometers of total volume of pore water suggesting that preferential flow significantly contributed to subsurface transport of tracer the pore volume for the entire profile increased only slightly with increasing application rate however the relative proportions of pore volumes calculated for individual portions varied proportionally to antecedent hydrologic conditions these changes are attributed to the expansion of individual macropores with surrounding soil and the lateral extension of macropore networks during wetter conditions

surface subsurface water interactions in an alluviated mountain stream channel data from an instream tracer experiment performed in north fork dry run shenandoah national park virginia illustrate that the transport of water and conservative solute in the stream is greatly influenced by interaction with water present in both the relatively shallow gravel bed and in the relatively deeper alluvial infill material the shape of concentration time curves from the field tracer experiment exhibit storage of tracer in the subsurface short term storage imposed by exchange with the gravel bed and long term storage by exchange with the deeper alluvial infill time series models fit the observed concentration data very well estimates of mixing volumes generated by the time series analysis indicate that a large volume of the gravel bed participates in rapid mixing with the surface stream at one point along the study reach a second order time series model is supported by the data suggesting two independent parallel flow paths observations of tracer in wells more than 10 m from the stream and the very extended recession of the tracer in the stream where it flows over a bedrock ledge support the contention that the deeper alluvium plays an important role in transient storage of solute in north fork dry run the work implies that physically based models to predict transport and storage in alluviated mountain catchments may have to account for interactions between the stream and large portions of its floodplain

data mining in the dutch oil and gas portal a case study on the reservoir properties of the volpriehausen sandstone interval this paper presents the results of a data mining exercise on core measurements and reports of the triassic lower volpriehausen sandstone member rbmvl in the netherlands the availability of a large accurate online dataset via the dutch oil and gas portal nlog enables the definition of general reservoir property trends on a regional subregional scale accurately defined trends are capable of restricting the uncertainty range of key parameters in exploration studies e g porosity and permeability and thus of reducing risk plotting core porosity v core permeability resulted in a curved data cloud on a log normal plot although porosity permeability relationships are often defined by straight lines the dataset in this study shows that a curved relationship results in a better fit with permeability measurements over the entire porosity range two methods were applied to define a porosity depth relationship for sandstones of the rbmvl the results of both methods confirm and enable quantification of the well known trend of decreasing porosity with depth by assigning grain density attributes to the core measurements the dependency of the porosity depth relationship on sedimentary facies and diagenesis type grade could be determined this case study demonstrates the power of this free online dataset in understanding reservoir quality 2018 the author s

mesozoic resource potential in the southern permian basin area the geological key to exploiting remaining hydrocarbons whilst unlocking geothermal potential it is generally accepted that hydrocarbon exploration in northern europe has reached a mature stage a basin s maturity is defined by the underlying number of new discoveries and the declining production rate of mature fields spe 2015 for geoscientists a mature basin has well defined characteristics in terms of for example reservoir presence or trap formation e g byrne 2012 it is interesting therefore to note how much is still unknown about certain stratigraphic intervals in northern europe the mesozoic overburden of the southern permian basin sensu maystrenko et al 2008 doornenbal stevenson 2010 continues to provide fresh insights into the geological history of an area where as the name suggests historical hydrocarbon exploration has focused on the paleozoic the aim of this special publication is to increase knowledge of the mesozoic overburden as a driver for further hydrocarbon exploration production and the development of new geothermal energy sources the succeeding chapters are introduced by tectonic framework overviews that give a context for the papers that follow the remaining articles are organized in approximate stratigraphic order from old to young and include a variety of examples from semi regional to localized field or sub basin studies an overview of the study area for all the following chapters is given in figure 1 it is recognized that the overprinting mesozoic systems have different naming conventions across the study area e g the central european basin system sensu littke et al 2008 maystrenko et al 2008 here we use the title southern permian basin area to emphasize the resource opportunities associated with a region that has at least in large part been associated with hydrocarbon exploration and very large gas fields in the permian rotliegend for our purposes this includes part of the polish trough the highs surrounding the basin e g the ringkobing fyn high and analogous elements of the danish and norwegian offshore in this introduction an overview of the geological history and resource base of the area is presented as a framework for the chapters that follow a description of further prospective resources is then offered oil and gas plus geothermal potential

crustal movements and geodynamics in fennoscandia abstract morner n a 1981 crustal movements and geodynamics in fennoscandia in p vyskocil r green and h malzer editors recent crustal movements 1979 tectonophysics 71 241 251 the fennoscandian shield the classical area of glacial isostasy has been subjected to a complex sequence of motions throughout the late cenozoic still the geometry of the areas deformed has been roughly the same an asthenosphere of low viscosity 1020 1021 poises and a lithosphere of high flexural rigidity are established the present uplift represents an other mechanism than the rapid glacial isostatic readjustment of the low viscosity asthenosphere and seems to originate from mesospheric motions at around 1900 1910 there was a distinct geodynamic change which seems to be controlled by changes in the earth s rate of rotation the postglacial uplift of fennoscandia is found to be associated with intensive neotectonism faulting fracturing and seismicity

macropores as preferential flow paths in meander bends macropores are subsurface connected void spaces caused by processes such as fracture of soils micro erosion and fauna burrows they are common near streams e g hyporheic and riparian zones and may act as preferential flow paths between surface and groundwaters affecting hydrologic and biogeochemical processes we tested the hydrologic function of macropores by constructing an artificial macropore within the saturated zone of a meander bend open macropore om and later filling its upstream end partially filled macropore pfm for each treatment we injected saline tracer at an upgradient monitoring well within the meander and monitored downgradient hydraulics and tracer transport pressure transducers in monitoring wells indicated hydraulic gradients within the meander were 32 higher perpendicular to and 6 higher parallel to the macropore for the om than for the pfm additionally hydraulic conductivities measured via falling head tests were 29 to 550 times higher along the macropore than in nearby sediment we used electrical conductivity probes in wells and electrical resistivity imaging to track solute transport transport velocities through the meander were on average 9 and 21 higher per temporal moment analysis and observed tracer peak respectively for the om than for the pfm furthermore temporal moments of tracer breakthrough analysis indicated downgradient longitudinal dispersion and breakthrough tracer curve tailing were on average 234 and 182 higher for the om respectively this suggests the om enabled solute transport at overall shorter timescales than the matrix but also increased tailing our results demonstrate the importance of macropores to meander bend hydrology and solute transport copyright 2012 john wiley sons ltd

the effect of glaciation on the intensity of seismic ground motion seismicity is known to contribute to landscape denudation through its role in earthquake triggered slope failure but little is known about how the intensity of seismic ground motions and therefore triggering of slope failures may change through time topography influences the intensity of seismic shaking generally steep slopes amplify shaking more than flatter slopes and because glacial erosion typically steepens and enlarges slopes glaciation may increase the intensity of seismic shaking of some landforms however the effect of this may be limited until after glaciers retreat because valley ice or ice caps may damp seismic ground motions two dimensional numerical models flac 6 0 were used to explore how edifice shape rock stiffness and various levels of ice inundation affect edifice shaking intensity the modelling confirmed that earthquake shaking is enhanced with steeper topography and at ridge crests but it showed for the first time that total inundation by ice may reduce shaking intensity at hill crests to about 20 50 of that experienced when no ice is present the effect is diminished to about 80 95 if glacier ice level reduces to half of the mountain slope height in general ice cover reduced shaking most for the steepest sided edifices for wave frequencies higher than 3 hz and when ice was thickest and the rock had shear stiffness well in excess of the stiffness of ice if rock stiffness is low and shear wave velocity is similar to that of ice the presence of ice may amplify the shaking of rock protruding above the ice surface the modelling supports the idea that topographic amplification of earthquake shaking increases as a result of glacial erosion and deglaciation it is possible that the effect of this is sufficient to have influenced the distribution of post glacial slope failures in glaciated seismically active areas copyright 2012 john wiley sons ltd

hydrocarbon habitat of the west netherlands basin the traditional hydrocarbon charge model for the west netherlands basin was that the carboniferous coal measures have generated only gas and the jurassic posidonia shale only oil however it is now concluded that both have generated oil and gas and that an additional possible source rock for oil occurs in the lower part of the lower jurassic aalburg formation geochemical fingerprints have been established to distinguish the different groups of gas and oil the occurrence of which is consistent with their geological setting and possible migration routes the main phase of hydrocarbon generation and expulsion occurred prior to the mid cretaceous and the occurrence of biodegraded oils indicates that significant amounts of hydrocarbons were already in place at the onset of the tertiary previously it had been considered that charge ended during the late cretaceous inversion however recent modelling studies indicate that along the south west margin of the basin and in the lows between inversion highs charge continued during the tertiary at rates that should have been sufficient to at least compensate for any loss of hydrocarbons through imperfect seals the distribution of biodegraded oils in jurassic and cretaceous reservoirs suggests that biodegradation must have occurred during the earliest tertiary when meteoric fresh waters had access to the reservoirs significantly reservoirs that were at that time so deeply buried that temperatures exceeded 70 to 80 c and that were thus at levels where bacteria cannot survive do not contain biodegraded oils for the fault bounded traps in triassic reservoirs juxtaposition with triassic and jurassic sandstones and shales is the principal control of trap integrity and determines the spill point traps bounded by faults that have been reactivated during the tertiary have clearly been breached traps at upper jurassic and cretaceous levels are usually faulted dip closures and have always been found to be full to their spill points within the limits of seismic resolution

the effect of streambed topography on surface subsurface water exchange in mountain catchments a numerical hydrological simulation suggested that water exchange between stream channels and adjacent aquifers is enhanced by convexities and concavities in streambed topography at st kevin gulch an effluent stream in the rocky mountains of colorado subsurface hydraulic gradients and movement of ionic tracers indicated that stream water was locally recharged into well defined flow paths through the alluvium stream water filled flow paths in the alluvium referred to as substream flow paths returned to the stream a short distance downstream 1 to 10 m recharge to the substream flow paths occurred where stream water slope increased at the transition from pools 1 to steeper channel units 5 20 return of substream flow paths to the stream occurred where stream water slope decreased at the transition from steeper channel units to pools a net water flux calculation is typically used to characterize water and solute fluxes between surface and subsurface zones of catchments along our study reach at st kevin gulch the net inflow of water from subsurface to stream 1 6 ml s 1 m 1 underestimated the gross inflow 2 7 ml s 1 m 1 by 40 the influence of streambed topography is to enhance hydrological fluxes between stream water and subsurface zones and to prolong water sediment contact times these effects could have important consequences for solute transport retention and transformation in catchments

differential glacio isostatic uplift of crustal blocks at glen roy scotland abstract detailed measurements of the altitudes of the shorelines of former ice dammed lakes in glen roy and vicinity in the scottish highlands prove erroneous the conventional view that former shorelines in areas affected by glacio isostatic uplift are uniformly tilted and or gently warped the measurements demonstrate differential uplift of blocks of the earth s crust the surfaces of some blocks have no detectable tilt whereas others have gradients up to at least 4 6 m km and are tilted in different directions in three areas 0 7 2 0 km long shorelines are distorted by crustal movements all these areas have landslides attributed to earthquakes that accompanied the release of stress in the area of greatest local distortion three shorelines rose about 3 m above their average altitudes for the immediately surrounding area and a fault scarp was produced possibly these local distortions accompanied catastrophic lake drainage by jokulhlaup analogous to crustal movements associated with man made lakes a relationship between crustal movement and the limit of a glacial advance is demonstrated these findings have implications for other parts of the world affected by glacioisostatic uplift

probabilistic tectonic heat flow modeling for basin maturation assessment method and applications tectonic modeling is often neglected in the basin modeling workflow and heat flow is most times considered a user input such heat flows can therefore result in erroneous basin modeling outcomes resulting in false overoptimistic identification of prospective areas or failure to identify prospects this is particularly true for areas with limited data control such as frontier basin areas or deep unexplored plays in mature basins three major factors obstruct routinely use firstly because of the focus of most tectonic models on lithosphere scale processes a large range of models including the mckenzie rift model fail to take into account effects which are of paramount importance for basement heat flow such as transient effects of sediment infill and erosion and changes in crustal heat production over time secondly lithosphere tectonic models often fail to allow inversion of basin data making forward tectonic modeling a cumbersome exercise non vertical sediment movements and 2d and 3d loading effects can play an important role hampering a unique inversion thirdly lithosphere tectonic models generally fail to aid the user to understand the sensitivity of the model results in terms of basin maturation for permissible ranges of tectonic model parameters and for uncertainties in tectonic scenarios such as absence or presence of underplating or two layered stretching vs a mckenzie model for this reason we have developed a multi 1d probabilistic tectonic heat flow model which is capable of calculating tectonic heat flows incorporating a variety of tectonic scenarios the model is capable of inversion of burial histories calibrated to temperature and maturity data calibration and sensitivity analysis is done through monte carlo sampling analysis using an experimental design technique for computational efficiency the tectonic heat flows can easily be used as input for basin modeling in commercially available 3rd party software 2009 elsevier ltd all rights reserved

hyporheic flow as a potential geomorphic agent in the evolution of channel morphology in a gravel bed river abstract morphologic and hydrologic properties of head cut gullies formed in meandering bends of a gravel bed river in northern japan were examined to investigate their topographic development head cut gullies had incised to 2 m below the floodplain surface and had perennial seepage outflows because no surface runoff was observed across the meandering necks we hypothesized that hyporheic flow erosion cutting into the down river edge of the meandering necks is one factor for the development of head cut gullies several topographic features caused by sapping and piping erosion were observed within the head cut gullies a tracer experiment and examination of the water table water chemistry and water table responses in wells on the floodplain and within the head cut gully revealed that significant preferential hyporheic flow occurred between coarse cobble and fine sediment layers of the floodplain materials during a storm event water tables around the head cut gully quickly responded to changes in the water table of the stream channel this result also suggests that hyporheic flow occurred across the meandering bends hyporheic flow around the head cut gullies had higher hydraulic conductivities and preferential flow paths that may relate to buried beds of paleochannels an erosion model suggests that it is unlikely that hyporheic flow alone had enough energy to account for all the soil erosion thus a combination of hyporheic flow sapping erosion and channel erosion bank erosion appeared to contribute to the formation of the head cut gullies hyporheic flow is an important component in the geomorphic evolution of channels and the floodplain in a gravel bed river

cosmogenic nuclide exposure ages from the parallel roads of glen roy scotland the parallel roads of glen roy scotland are the shorelines of former ice dammed lakes created by the last glaciers to occupy the area we use surface exposure dating with cosmic ray produced 10be in quartz to provide the first numerical age control on the timing of formation of one of one of these shorelines and depositional features in glen roy four bedrock samples from the surface of the 325 m parallel road yielded a mean formation age of ca 11 5 11 9 ka this age range confirms the long held view that the parallel roads are loch lomond stadial ca 12 9 11 5 ka features the age range reflects variation in currently available cosmogenic nuclide scaling schemes and the related 10be production rates two samples from the surface of the turret fan indicate that the 260 m lake drained before ca 10 7 11 0 ka while two samples from the brunachan fan suggest that subaerial sedimentation occurred after ca 9 7 9 9 ka copyright 2009 john wiley sons ltd

the hofðaholar rock avalanche sturzstrom chronological constraint of paraglacial landsliding on an icelandic hillslope the hof aholar rock avalanche in the skagafjor ur area of northern iceland was investigated on the basis of a geomorphological analysis of its landforms and close surrounding environment thanks

enhanced rock slope failure following ice sheet deglaciation timing and causes this research was supported by nerc cosmogenic isotope analysis facility grant number 9046 0308

quaternary sea level changes in western scotland abstract in recent years major advances have been made in our understanding of late quaternary sea level changes in western scotland in particular new hypotheses have been advanced to explain the ages and origins of high level rock platform fragments and high level marine shell beds certain raised shorelines in islay and jura sw argyll and wester ross have been related to former margins of the last ice sheet and are associated with drops in the lateglacial marine limit in some areas the decline in lateglacial sea level took place in association with a stationary ice margin while in others the fall in sea level occurred in conjunction with considerable ice retreat during the lateglacial interstadial relative sea level fell rapidly between ca 13 and ca 12 ka bp and thereafter more slowly until ca 11 ka bp renewed marine erosion during the cold climate of the loch lomond younger dryas stadial ca 11 10 ka bp resulted in the production of the main lateglacial shoreline which declines in altitude to the w sw and s away from the centre of glacio isostatic uplift in the w highlands the shoreline has a maximum altitude of 10 11 m o d in the oban area and passes below sea level in ne islay ardnamurchan colonsay w mull kintyre and arran during the early holocene a pronounced marine transgression took place probably culminating between 6 6 and 7 0 ka bp the culmination of the transgression is represented by the main postglacial shoreline that reaches a maximum altitude of ca 14 m in the oban area and declines gently in altitude away from the centre of glacio isostatic uplift reconstruction of the uplift isobases for this shoreline appears to indicate a slight eastward migration of the uplift centre since the younger dryas in peripheral areas of western scotland the main postglacial shoreline is not present owing to the effect of holocene submergence

lateglacial rock slope failures in north west ireland age causes and implications nine postglacial quartzite rock slope failures rsfs in north west ireland were dated using cosmogenic 10be weighted mean rsf ages range from 17 7 0 9 to 12 5 0 7 ka or 16 6 0 7 to 11 7 0 5 ka depending on assumed 10be production rate all dated rsfs occurred within 5000 years following ice sheet deglaciation at 17 4ka 16 3 ka and all but two occurred within 2000 years after deglaciation the timing of rsfs rules out glacial debuttressing permafrost degradation and enhanced deglacial cleft water pressures as triggers of failure in most cases we infer that paraglacial stress release and associated fracture propagation were critical in reducing rock masses to critical stability although earthquakes caused by lateglacial glacio isostatic rebound and or release of stored tectonic stresses may have triggered failure in some or all cases in conjunction with data from related studies our results imply that most undated rsfs outside the limit of younger dryas glaciation in the british isles are of lateglacial age and that numerous lateglacial rsfs occurred inside these limits with subsequent removal of debris by glaciers they support the view that paraglacial rsf activity in tectonically stable intraplate terrains was concentrated within a few millennia following deglaciation

geomorphological and sedimentological evolution of a lake basin under strong volcano tectonic influence the seismic record of lago calafquen south central chile the chilean lake district is a geodynamically active area located at the foot of the andean cordillera and permanently influenced by the chilean active continental margin the study area is prone to steady mass movements that are triggered by active volcanism strong earthquakes and climatic forces on the glacial born lake lago calafquen high resolution seismic investigation was performed to select suitable coring sites for sedimentary analyses to revise the existing bathymetry and to integrate the lake bottom topography into the geomorphological context of the surroundings the sub bottom profiling reveals a complex structure of the lake floor which results in a division into an eastern and a central sub basin the eastern basin encompasses the deep basin plain which is a depositional area for dense suspension loaded underflows the morphology of the basement of the central sub basin is affected by large landslides large rock slope failures of debuttressed sidewalls fill the primary lake floor of the southern side covered by more than 40 m of sediment a high resolution seismic analysis of the sedimentary infill reveals deposits and structures of large mass movements and turbidites obviously triggered by strong earthquakes incidents related to rebound effects by isostatic uplift are also considered to provoke remarkable magnitudes that trigger mass movement processes in the central sub basin furthermore volcanic impact frequently interrupts normal lacustrine sedimentation of the sediment succession by deposition of tephra layers the serialized geodynamic impacts on lago calafquen cause severe damage to the sedimentary archive thus suitable coring sites for palaeoenvironmental reconstruction should be selected carefully

rock slope failure following late pleistocene deglaciation on tectonically stable mountainous terrain the ages of 31 postglacial rock slope failures rsfs in scotland and nw ireland derived from 89 cosmogenic isotope exposure ages are employed to analyse the temporal pattern of failure and its relationship to the timing of deglaciation rates of glacio isostatic crustal uplift and periods of rapid climate change rsf ages span almost the whole period since ice sheet retreat from 18 2 1 2 ka to 1 7 0 2 ka or from 17 1 1 0 ka to 1 5 0 1 ka depending on the production rate used in 10 be age calculation but catastrophic failure of rock slopes was w4 6 times more frequent prior to w11 7 ka than during the holocene 95 of dated rsfs at sites deglaciated during retreat of the last ice sheet occurred within w5400 years after deglaciation with peak rsf activity 1600e1700 years after deglaciation this time lag is inferred to represent 1 stress release initiated by deglacial unloading leading to 2 time dependent rock mass strength degradation through progressive failure plane development and ultimately 3 to either spontaneous kinematic release or failure triggered by some extrinsic mechanism by contrast 11 dated rsfs at sites reoccupied by glacier ice during the younger dryas stade yds of w12 9e11 7 ka exhibit no clear temporal pattern suggesting that glacial reoccupance during the yds was ineffective in preconditioning a renewed cycle of enhanced rsf activity comparison of timing of individual rsfs with that of deglaciation and rapid warming events at w14 7 ka and w11 7 ka suggests that glacial debuttressing enhanced joint waterpressuresduringdeglaciationandthawofpermafrosticeinrockjointscouldhavetriggeredfailurein only a small number of cases conversely the timing of maximum rsf activity following ice sheet deglaciation corresponds broadly with maximum rates of glacio isostatic crustal uplift suggesting that the two are linked by enhanced seismic activity a seismic failure trigger is consistent with full slope failure at all sites where failure planes are clearly defined our results indicate that numerous rsfs must have occurred in areas that were reoccupied by glacier ice during the yds but have not been identified because runout debris was removed by yds glaciers more generally they provide the first reliably dated body of evidence to support the view that retreat of the last ice sheets in tectonically stable mountainous terrain initiated a period of enhanced rock slope failure due to deglacial unloading and probably lateglacial seismic activity implying that most undated rsfs in such areas are probably of lateglacial or veryearly holocene age they also demonstrate however that a low frequency of rsf activity extended throughout the holocene

the influence of stream thermal regimes and preferential flow paths on hyporheic exchange in a glacial meltwater stream 1 given projected increases in stream temperatures attributable to global change improved understanding of relationships between stream temperatures and hyporheic exchange would be useful we conducted two conservative tracer injection experiments in a glacial meltwater stream to evaluate the effects of hyporheic thermal gradients on exchange processes including preferential flow paths pfps the experiments were conducted on the same day the first a stream injection during a cool morning period and the second dual stream and hyporheic injections during a warm afternoon period in the morning the hyporheic zone was thermally uniform at 4 c whereas by the afternoon the upper 10 cm had warmed to 6 12 c and exhibited greater temperature heterogeneity solute transport modeling showed that hyporheic cross sectional areas as at two downstream sites were two and seven times lower during the warm experiment exchange metrics indicated that the hyporheic zone had less influence on downstream solute transport during the warm afternoon experiment calculated hyporheic depths were less than 5 cm contrasting with tracer detection at 10 and 25 cm depths the hyporheic tracer arrival at one downstream site was rapid comparable to the in stream tracer arrival providing evidence for pfps we thus propose a conceptual view of the hyporheic zone in this reach as being dominated by discrete pfps weaving through hydraulically isolated areas one explanation for the simultaneous increase in temperature heterogeneity and as decrease in a warmer hyporheic zone may be a flow path preferentiality feedback mechanism resulting from a combination of temperature related viscosity decreases and streambed heterogeneity

late devensian and holocene relative sea level changes on the isle of skye scotland uk detailed litho and biostratigraphical analyses from three coastal sites in contrasting coastal settings on the isle of skye scotland uk reveal evidence for several changes in relative sea level during the late devensian and holocene at the start of the record relative sea level in the area was high at ca 12 500 14c ca 14 800 cal yr bp but then fell reaching a low point during the younger dryas at ca 11 000 10 000 14c ca 13 000 11 600 cal yr bp when a rock platform correlated with the main rock platform was formed in the early middle holocene relative sea level was rising by ca 8000 14c ca 8800 cal yr bp and in northeast skye a lagoonal surface correlated with the main postglacial shoreline was formed at ca 6600 14c ca 7500 cal yr bp by the late holocene relative sea level was again falling but a rise registered at at least two sites began probably before ca 4000 14c ca 4500 cal yr bp and a second lagoonal surface in northeast skye correlated with the blairdrummond shoreline was formed although by ca 3000 14c ca 3200 cal yr bp relative sea level in the area had resumed its downward trend the pattern of relative sea level changes disclosed is compared with evidence elsewhere in scotland

cosmogenic cl 36 dating of postglacial landsliding at the storr isle of skye scotland major postglacial rock slope failures are a common feature of the scottish highlands and other mountainous areas that were deglaciated at the end of the pleistocene but evaluation of the causes and triggers of failure has been hindered by a lack of reliable dating evidence we report the result of a pilot study designed to establish the absolute age of a large postglacial rotational rockslide at the storr on the isle of skye scotland using 36cl surface exposure dating exposure ages of 6 3 0 7 cal ka bp and 6 6 0 8 cal ka bp were obtained for rock samples from two separate landslide blocks giving an overall age estimate of 6 5 0 5 cal ka bp for rock slope failure at this site this date is consistent with ams radiocarbon dating of windblown sand derived from the failure scarp and with previous inferences based on relative dating evidence concerning an early holocene age for most rock slope failures in the scottish highlands the long time lag 7 ka between deglaciation and failure sugge

application of fluid flow systems analysis to reconstruct the post carboniferous hydrogeohistory of the onshore and offshore netherlands abstract the reconstruction of the post carboniferous hydrogeohistory of the onshore and offshore netherlands is part of an ongoing tno project on fluid flow systems analysis on geological timescales the scope of the project is to assess the present day hydrogeological and fluid flow conditions of the sedimentary basins in the onshore and offshore netherlands and to analyse and model the evolution of fluid flow systems in these basins in order to increase the process based knowledge of the causes of present day physico chemical characteristics of rocks and fluids in the sedimentary fill of the dutch part of the north sea basin this article concerns the first phase of the project and provides an overview of the characteristic features of the post carboniferous evolution of external and internal processes acting on the sedimentary fill and their role in shaping the hydrogeological and hydrodynamical setting of the netherlands the post carboniferous evolution of the fluid flow conditions is described for five geological time periods during each time period different forces have acted simultaneously on the fluids and different fluid flow systems have coexisted and interacted the present day active driving forces and processes influencing fluid flow conditions include sedimentary loading gas generation tectonic forces topographic relief of the water table fluid density differences and human activities the article presents a brief outline of the resulting fluid flow systems observed direct and indirect indicators of fluid flow pressure temperature salinity sediment diagenetic minerals are consistent with the reconstructed hydrogeological and hydrodynamic setting of the netherlands

postglacial tectonics of the scottish glacio isostatic uplift centre new evidence combined with a detailed re evaluation of postglacial fault movements seismic activity and shoreline sequences suggests that the period of deglaciation and the early holocene was more seismically active than the mid to late holocene it is proposed that the large scale lateral displacements formerly proposed can not be justified rather all postglacial fault movements appear to be limited to metre scale vertical movements along pre existing fault lines in addition it is argued that the younger dryas ice advance may have produced localised crustal redepression but not the more widespread impact formerly proposed both tectonic and postglacial rebound stresses however may be needed to explain the contemporary seismotectonics of the scottish highlands

evidence for phase locked changes in climate between scotland and greenland during gs 1 younger dryas using micromorphology of glaciolacustrine varves from glen roy there is a current need to develop annual decadal chronologies from periods of rapid climate change in order to understand the rate and timing of climate events and identify how other proxies either lead or lag this climate forcing annually laminated or varved sediments are key proxies for understanding environmental change at such a scale this paper presents the results of microscale analysis of glaciolacustrine varve sediments from scotland and develops a new index called varve group which ranks the number of pulses of sediment observed in the summer component of the varve the varve group index is compared with data from the greenland ice core record and correspondence can be observed between the oxygen isotope records from greenland during the latter part of gs 1 and the 515 year lochaber varve group index the processes that control the number of sediment pulses into the lake basin are discussed and we examine how these factors might control both the isotopic composition of the ice cores and varve group formation it is proposed that the position of the sea ice in the north atlantic may provide such a mechanism

the beinn alligin rock avalanche nw scotland cosmogenic 10be dating interpretation and significance a tongue of very coarse rockslide debris that extends 1 25km downvalley below beinn alligin in nw scotland has been variously interpreted as a glacier cored rock glacier landslide debris redistributed by glacier ice or an excess runout landslide exposure dating with cosmogenic 10be demonstrates that the the debris mass was emplaced at 3950 320 yr bp and therefore was not associated with glacier ice calculations based on frictional considerations imply that the feature is an excess runout rock avalanche sturzstrom deposit the morphological characteristics of the deposit appear consistent with movement by grainflow or fragmental flow failure is inferred to reflect time dependent paraglacial stress release and consequent propagation of an internal joint network but may have been triggered by seismic activity the late holocene age of failure implies persistence of the e ects of paraglacial stress release over a time scale of several millennia

microstructures of early jurassic toarcian shales of northern europe the toarcian early jurassic posidonia shale formation is a possible unconventional gas source in northern europe and occurs within the cleveland basin united kingdom the anglo paris basin france the lower saxony basin and the southwest germany basin germany and the roer valley graben the west netherlands basin broad fourteens basin the central netherlands basin and the dutch central graben in the netherlands outcrops can be found in the united kingdom and germany since the posidonia shale formation does not outcrop in the netherlands sample material suitable for experimental studies is not easily available here we have investigated lateral equivalent shale samples from six different locations across northern europe germany the netherlands the north sea and united kingdom to compare the microstructure and composition of toarcian shales the objective is to determine how homogeneous or heterogeneous the shale deposits are across the basins using a combination of ion beam polishing scanning electron microscopy and x ray diffraction the work presented here shows that the toarcian shales of northern europe display considerable homogeneity in mineralogy and microstructure in the different investigated samples and formations where the largest variability is the carbonate content ranging from almost zero up to 80 we conclude that the outcrop locations in germany and the united kingdom are suitable analogues with respect to their mineralogy and microstructure for experimental studies on the posidonia shale in the dutch subsurface 2016 the authors

an example of rapid gully initiation and extension by subsurface erosion coastal san mateo county california abstract gully networks developed on coastal hillslopes in san mateo county california extended nearly 300 from 1941 to 1978 primarily by subsurface erosion in one drainage subsurface erosion expanded the gully network by 80 m nearly doubling the gully length from 1982 to 1987 intense gullying is restricted to areas underlain by members of the pliocene purisima formation a unit rich in unstable volcanic lithic fragments which weather to produce expansive smectite clays gully development proceeds through a sequence of lateral eluviation of clays near the base of the a horizon piping development of an open conduit in which erosion proceeds by turbulent concentrated flow tunneling and finally collapse of the tunnel roof exposing an open gully measurements made in one gully system during a 25 yr storm showed that the subsurface drainage network carried four times as much flow as the surface drainage net and had average suspended sediment concentrations an order of magnitude higher

towards improved empirical isobase models of holocene land uplift for mainland scotland uk a new approach to modelling patterns of glacio isostatic land uplift during the holocene in mainland scotland uk is described the approach is based upon altitude measurements at the inner margin or locally highest point of raised estuarine surfaces dated by radiocarbon assay supported by microfossil analyses 2241 altitudes have been analysed by a technique new to studies of former sea levels gaussian trend surface analysis and isobase models for four holocene shorelines the holocene storegga slide tsunami shoreline abandoned rapidly circa 7900 sidereal years bp the main postglacial shoreline abandoned during circa 6400 7700 sidereal years bp the blairdrummond shoreline abandoned during circa 4500 5800 sidereal years bp and a speculative fourth shoreline the wigtown shoreline abandoned during circa 1520 3700 sidereal years bp are shown in a series of maps the implications of the shoreline patterns for glaicio isostasy in the area are discussed it is maintained that the statistical technique used enables broad estimates to be made of nearshore sea surface change

the quaternary deposits and landforms of scotland and the neighbouring shelves a review abstract a thick sequence of quaternary sediments up to 1000 m has been deposited in the north sea basin and perhaps five major glacial episodes the first occurring prior to ca 1 8 2 1 ma bp and the last during the late devensian can be recognised between the glacial events periods of low salinity arctic marine or glacio marine sedimentation have been dominant although episodes of ameliorated climate when north atlantic drift waters had access to the north sea have been identified a number of horizons in separate boreholes have been correlated with the last interglacial oxygen isotope stage 5e and a sequence of water mass movements around the scottish coasts can be reconstructed for the last ca 125 ka on land sequences of quaternary deposits relating to several glacial and non glacial terrestrial and marine events occur in different areas but due to poor dating correlation between these sequences cannot yet be achieved in particular north east scotland has a complex glacial history with evidence for ice sheet glaciation on at least four occasions evidence from the outer hebrides north east scotland and the north sea basin indicates that the late devensian scottish ice sheet had a rather restricted extent only reaching a short distance offshore along much of the east and west coasts at this time ice free areas existed in north east scotland on the isle of lewis and probably in caithness and orkney whilst part of the outer shelf around st kilda was dry land a marine embayment extended down the east coast of scotland between the scottish and scandinavian ice sheets and independent ice caps existed on the outer hebrides and probably on shetland deglaciation of the greater part of the country took place prior to ca 13 ka bp whilst the climate was still very cold the ice retreat appears to have been orderly with stagnant ice masses being trapped only in topographically suitable locations a number of retreat stages or minor readvances occurred during the general deglaciation the firth of clyde was one of the last areas outside the highlands to be deglaciated and this occurred in a rapid possibly catastrophic fashion shortly prior to ca 13 ka bp despite the mild climate at the start of the lateglacial interstadial it is not known if there was complete deglaciation prior to the loch lomond readvance the readvance glaciers however may have started to advance during the latter part of the interstadial when declining terrestrial temperatures coincided with a period of mild marine conditions the loch lomond readvance maximum can only be dated to some time after ca 10 9 ka bp and it is likely that final ice free conditions were not achieved until the earliest holocene

sedimentary basin inversion and intra plate shortening abstract sedimentary basin inversion the shortening of formerly extensional basins is accommodated mainly by compressional reactivation of extant faults and fractures across a wide range of scales as such inversion is a large scale manifestation of byerlee friction the dynamic criterion for fault reactivation governing the effective shear strength of the shallow crust basin inversion generates distinctive deformational architecture and it is implicated strongly in sedimentary basin exhumation as a principal source of horizontal stress inversion drives significant sedimentary porosity reduction and resultant fluid flow upper crustal deformation is critically dependent on fluid overpressure i e pore fluid pressures greater than would be calculated from a hydrostatic gradient and perhaps more than in any other tectonic setting overpressures are potentially large during sedimentary basin inversion this review therefore includes discussion of the role of fluid overpressure in inversion and the evidence for it collectively inversion has profound implications good and bad for the prospectivity of many petroliferous sedimentary basins thus recognizing the evidence for basin inversion quantifying its magnitude and understanding the mechanisms that accommodate inversion and other phenomena affected by it have become essential components of the basin analyst s remit

soil properties controlling seepage erosion contributions to streambank failure the majority of sediment leaving catchments may be from streambank failure seepage erosion of unconsolidated sand above a restrictive layer is an important erosion process in incised streams that leads to streambank failure by undercutting banks the objective of this study was to determine the impact of soil properties on seepage erosion and the resulting streambank failure seepage flow and sediment concentrations were measured in situ at eight locations along the banks of a deeply incised stream in northern mississippi using field observations as a guide the soil profile conditions of a shallow 45 cm streambank consisting of 30 cm of topsoil a 10 cm conductive layer and a 5 cm restrictive layer were mimicked in laboratory lysimeter experiments to quantify the hydrologic properties controlling seepage erosion and bank failure under a 40 cm head the time to flow initiation and the flow rate were linearly related to the slope of the restrictive layer seepage erosion began within minutes of flow initiation and resulted in substantial 3 to 34 cm undercutting of the bank sediment concentrations of seeps were as high as 660 g l 1in situ and 4500 g l 1 in the lysimeters sediment concentrations were related to the layer slope thereby indicating the importance of detailed site characterization the usda ars streambank stability model demonstrated the increase in instability of banks due to undercutting by seepage erosion but failed to account for the sediment loss due to sapping for stable banks and overestimated the sediment loads for failed banks published in 2006 by john wiley sons ltd

variations in the pattern and rate of isostatic uplift indicated by a comparison of holocene sea level curves from scotland differences in the timing of maxima and minima and shape between sea level curves from the western forth valley lower strathearn inner moray firth and eastern solway firth areas of scotland are interpreted as being due to differences in isostatic uplift and different methodologies used to interpret the basic data possible changes in the relative rates of uplift between areas suggest that the practice of applying the western forth model of relative sea level change to other parts of scotland must be questioned

piping sapping erosion ii identification diagnosis although erosion of streambanks and other shorelines by emergent seepage is widespread this erosion mechanism termed piping or sapping has not been recognized as important to the overall erosion process the mechanism is complex and interactions with other bank and shore processes tend to mask the effects of piping sapping direct evidence water emerging from a soil face and carrying away soil particles is rarely encountered several types of indirect evidence are presented and illustrated in this paper including cavities formed by piping deposits of dislocated particles below piping zones blind gullies staining produced by persistent seepage outflow and particular types of localized failures slab toppling block shearing and tensile falls caused by undercutting due to piping sapping the interactions of this erosion mechanism with other erosion deposition processes are described the purpose of this paper is to facilitate identification and evaluation of piping sapping erosion particularly

suspended sediment discharge in subsurface flow from the head hollow of a small forested watershed northern japan surface flow and suspended sediment discharge from the head hollow of the jozankei experimental watershed in hokkaido northern japan were measured to clarify the implications of subsurface hydrology for soil movement subsurface discharges during the extremely large storms of 1993 to 1994 were measured in a v notch weir installed at a natural spring near the bottom of the head hollow and shallow groundwater levels were observed in the wells excavated in the hollow sediment samples whose particle size range from 0 001 to 0 1 mm were manually and automatically collected at 15 to 60 min intervals by use of 1 or 21 polyethylene bottles maximum concentration and flux of suspended sediment during the storms preceded the peak discharge of subsurface flow by several hours neither the changes in concentration mg l 1 nor flux mg s 1 of suspended sediment coincided with those in subsurface discharge l s 1 furthermore sediment concentration was poorly correlated with the rate of change in subsurface discharge l s 2 during the rising limb of the hydrograph suspended sediment flux during the acceleratory limb however was closely correlated with the rate of change in subsurface discharge the relationship between suspended sediment flux and rate of change in subsurface discharge were in inverse proportion to initial subsurface discharge before the storm runoff and they represented rare seasonal variation subsurface hydraulic erosion and transport of suspended sediment resulting from changes in rate of change in subsurface discharge actively occur during the acceleratory rising limb of the hydrograph accordingly subsurface hydraulic erosion during the acceleratory rising limb of the hydrograph can be physically understood by analysing suspended sediment flux associated with rate of change in subsurface discharge and initial subsurface discharge 1997 john wiley sons ltd

annually resolved events of younger dryas glaciation in lochaber glen roy and glen spean western scottish highlands this paper presents the results of micromorphological analysis of laminated sediments that accumulated in ice dammed lakes in lochaber glen roy and vicinity during the younger dryas loch lomond stadial these lakes were responsible for the formation of the famous parallel roads of glen roy agassiz 1840 prominent shorelines cut into the valley sides of glen roy and adjacent valleys annually deposited varved layers which can be distinguished from other rhythmites by micromorphological examination have enabled the construction of a varve chronology which underpins the glacial history of the region the duration of the lake stands and rates of ice margin advance and retreat the lake system existed for a total of 515 a during a rise in lake levels the lowermost 260 m middle 325 m and highest 350 m lakes existed for minimal periods of 191 112 and 116 a respectively and the fall of lake levels from 350 m to 260 m took 95 years ice advance rates of between 13 4 and 41 9 m a 1 are inferred while ice retreat is estimated to have been 38 5 m a 1 a provisional correlation between the lochaber varve and grip ice core records suggests that the lakes started to form at ca 12 165 a bp in turn implying that the loch lomond readvance limits in this area were not achieved until late in the younger dryas interval a conclusion which does not accord with that based on numerical model simulations copyright 2010 john wiley sons ltd

large rock slope failures in the highlands of scotland characterisation causes and spatial distribution abstract a comprehensive database of larger rock slope failures rsfs has been compiled and characterised for a whole mountain range possibly for the first time apart from iceland most rsfs in the scottish highlands occurred soon after deglaciation a threshold size of 0 25 km 2 focuses on rsfs which contribute significantly to gross erosion in the glacial paraglacial cycle and on the spatial concentration of this poorly recognised process database verification indicates that at least 90 of the total extant population in the highlands is covered standard mass movement typologies are broadly applicable but require some refinement to characterise rsfs in a passive margin glaciated mountain range comprised mainly of ancient metasediments most larger rsfs here are complex and difficult to categorise a continuum from cataclasmic failures including rock avalanches through arrested translational slides to almost in situ slope deformations is identified the prevailing modes of large rsf are arrested short travel translational sliding and gravitational sagging cataclasmic failure is rare and sub cataclasmic outcomes are more evident a significant class of deformations exhibits compressional rather than extensional features and may be responding to localised glacio isostatic rebound stresses the large rsf population is widely but very unevenly distributed across the main mountain areas 65 are in seven main clusters with the rest non randomly scattered previous glaciological lithological and seismotectonic explanations are insufficient to explain this spatial pattern and overlook the basic engineering geology prerequisites for failure massifs of similar relief and lithology can display intense or sparse rsf incidence geomorphological appraisal suggests an association with recently active glacial breaches of main and secondary watersheds with rsf being scarce or absent in valleys inherited from tertiary uplift and in mountain groups away from the main watersheds valleys which adapted early to ice discharge are seen as stress hardened with their slopes unlikely to reach critical thresholds for failure after subsequent reoccupations by ice concentrated erosion in the last glaciations is most likely to be found close to where breaches are actively forming or enlarging such erosion in the slope foot and valley floor may have daylighted failure planes or generated rebound stresses augmenting those from other endemic sources sufficiently to provoke widespread paraglacial rsf slope stress models for deglaciated valleys and comparative studies in other glaciated mountain ranges are required to test this concept and may assist in geohazard assessments