a seismic discontinuity in the upper mantle between the eastern alps and the western carpathians constraints from wide angle reflections and geological implications abstract seismic investigation of the lithosphere by means of active source experiments is mostly confined to the crust and the moho structures in the upper mantle are more likely to be discovered by analyses of teleseismic data although these methods are restricted in their resolution capabilities the relatively rare evidence for upper mantle refractors or reflectors in active source data enables challenging and interesting studies of the lower and not so well known part of the lithosphere we present such an example from the tectonically complex region between the eastern alps and the western carpathians this area was covered by several extensive 3d wide angle reflection refraction experiments within the last decade and their layout was designed to illuminate the crustal structure and in particular the moho discontinuity in some areas reflections from below the moho are also recorded these reflections occur at recording offsets between 200 and 500 km and they are particularly strong in cross line recordings we derive a set of travel times from the data and perform a tomographic inversion for the depth and shape of the reflecting interface the inversion makes use of an existing 3d crustal model which also includes the moho topography since the upper mantle velocities are poorly constrained and the azimuthal distribution of the rays is biassed several tests are applied to investigate the reliability of possible solutions the results from the tomographic inversion indicate an overall horizontal and radially dipping reflector the average depth of the reflector is 55 km which is about 25 km below the crust mantle transition and amplitude modelling suggests that the reflecting interface represents a velocity increase the investigated area is further characterised by deep sedimentary basins high heat flow high velocities in the lower crust diffuse moho signature and a strong positive bouguer anomaly nearby xenolith outcrops exhibit a pronounced change in anisotropy and indicate the presence of two distinct layers in the lithospheric mantle whereas the deeper layer is thought to present more juvenile lithosphere derived from thermal relaxation in the post extension phase most likely the upper mantle reflector also represents this change in anisotropy though other scenarios are also possible we conclude that the entire lithosphere is significantly shaped by extensional processes which affect the area since the late oligocene early miocene

seismic velocity model of the crust and upper mantle along profile pancake across the carpathians between the pannonian basin and the east european craton abstract results are presented of a seismic wide angle reflection refraction survey along a profile between the pannonian basin pb and the east european craton eec called pancake the p and s wave velocity model derived can be divided into three sectors the pb the carpathians including the transcarpathian depression and the carpathian foredeep and the south western part of the eec including the trans european suture zone tesz seismic data support a robust model of the vp velocity structure of the crust in the pb the 22 23 km thick crust consists of a 2 5 km thick sedimentary layer vp 2 4 3 7 km s 17 20 km thick upper crystalline crust 5 9 6 3 km s and an up to 3 km thick lower crustal layer vp 6 4 km s in the central part of the carpathians a 10 24 km thick uppermost part of the crust with vp 6 0 km s may correspond to sedimentary rocks of different ages several high velocity bodies vp 5 35 5 95 and 6 05 km s within the sedimentary flysch sequences may represent volcanic sequences the moho depth changes from 25 km to 45 km over ca 100 km distance beneath the carpathians west of tesz the cratonic crust has a typical three layer structure with a pronounced thickening of the lower crust towards the ukrainian shield where a high velocity lower crust vp 7 2 km s is observed two low velocity lenses in the upper crust of the eec are interpreted beneath major sedimentary troughs lviv and volyn podolsk mantle reflectors are observed at depths of 45 km and 75 km below the pb and 10 20 km below the moho in the eec sub moho pn velocities increase from 8 0 km s beneath the pb to 8 1 km s beneath the carpathians and to 8 3 km s beneath the eec s waves of acceptable quality are recorded in the eec their signal to noise ratios increase towards the ukrainian shield

geomorphic evidence for active and inactive phases of late devensian ice in north central ireland abstract in the clogher valley north central ireland subglacial and proglacial landforms provide evidence for phases of active and inactive subglacial and ice marginal processes during the late devensian weichselian glaciation 22 13 kyr bp patterns of subglacial rogen moraines and drumlins record east to west ice flow along the valley axis during maximal ice stages eskers superimposed upon the rogen moraines and drumlins record later west to east ice flow and mark the first stages of ice retreat areas of large ice marginal non aligned ridges and mounds are separated by more extensive areas in which no deglacial landforms or sediments are present the non aligned ridges and mounds do not show a dominant directional signature have intricate basal outlines steep slopes and high relief

the sirente crater field italy we propose the sirente crater field to be the first discovered impact craters in italy they are located in the sirente plain within the mountains of the abruzzo region central italy the craters are distributed in a field 450 m long and 400 m wide this field consists of about 17 smaller craters close to a larger main crater the main crater is located in the southern end of the crater field and is 140 m long and 115 m wide measured rim to rim it has a well developed saddle shaped rim that rises at a maximum 2 2 m above the surrounding plain radiocarbon dating of the target surface preserved below the rim gave a calibrated age of formation at about 412 a d 1650 40 radiocarbon years b p this young age is consistent with the apparent little modification of the rim the morphology of the main crater and its relation to a crater field strongly points to its origin by impact from a projectile that broke up during its passage through the atmosphere quartz is very rare in the target and no planar deformation features pdfs have been found so far the rim material and the upper 4 m of the main crater infill are impregnated with ferric oxides which gives a more reddish colour compared to the other sediments of the plain rusty crusts with high fe and mn content occur in the rim material but have not been found in the plain s sediments some of these crusts can be separated by magnet and have sporadic micron sized ni rich granules the main crater is in the size range of craters with explosive dispersion of the projectile and has many features comparable to both large experimental and meteoritic impact craters formed in loose sediments we suggest that this crater represents a rare example of well preserved small impact craters formed in unconsolidated target materials

the messinian problem in the pannonian basin eastern hungary insights from stratigraphic simulations abstract earlier studies revealed a prominent unconformity in the messinian stratigraphic record of the lacustrine pannonian basin but it was unclear what factors were responsible for the formation of this unconformity and thus its origin remained controversial the problem was further complicated by the fact that stratal patterns in the messinian varied significantly along the paleo margins of the lake our study introduces quantitative stratigraphic simulations to analyze the role of subsidence sediment supply and lake level changes in the formation of the unconformity and the various architectural patterns that evolved in response to the messinian events the results suggest that a relative lake level fall occurred in the messinian accompanied and followed by tectonic inversion in several parts of the basin since the rate of tectonic subsidence and or uplift varied in space and time the size of the relative lake level fall varied significantly across the basin while various stratal architectural patterns formed in the same time interval the age of the unconformity was estimated based on seismic correlations with paleomagnetic chronozones to be between 5 6 ma which was refined by stratigraphic simulations galeacysta etrusca cysts were found in the unconformity which confirmed its late messinian age the surface is called the intra messinian unconformity imu in this paper seismic interpretations and simulations of stratal architecture led to the formulation of a basin fill model and identification of four stratigraphic architectural patterns related to messinian events including a major lake level fall and coeval and subsequent uplift events in certain parts of the basin

neotectonics of the somogy hills part ii evidence from seismic sections abstract the somogy hills are located in the pannonian basin south of lake balaton hungary above several important tectonic zones analysis of industrial seismic lines shows that the pre late miocene substratum is deformed by several thrust faults and a transpressive flower structure basement is composed of slices of various palaeo mesozoic rocks overlain by sometimes preserved paleogene thick early miocene deposits middle miocene partly overlying a post thrusting unconformity partly affected by the thrusts is also present late miocene thick basin fill forms onlapping strata above a gentle paleo topography and it is also folded into broad anticlines and synclines these folds are thought to be born of blind fault reactivation of older thrusts topography follows the reactivated fold pattern especially in the central western part of the study area the map pattern of basement structures shows an eastern area where ne sw striking thrusts folds and steep normal faults dominate and a western one where e w striking thrusts and folds dominate folds in late neogene are also parallel to these directions a ne sw striking linear normal fault and associated n s faults cut the highest reflectors the ne sw fault is probably a left lateral master fault acting during after late miocene gravity anomaly and pleistocene surface uplift maps show a very good correlation to the mapped structures all these observations suggest that the main early miocene shortening was renewed during the middle and late miocene and may still persist two types of deformational pattern may explain the structural and topographic features a nw se shortening creates right lateral slip along e w faults and overthrusts on ne sw striking ones another nne ssw shortening creates thrusting and uplift along e w striking faults and transtensive left lateral slip along ne sw striking ones traces of both deformation patterns can be found in quaternary exposures and they seem to be consistent with the present day stress orientations of the pannonian basin too the alternation of stress fields and multiple reactivation of the older fault sets is thought to be caused by the northwards translation and counter clockwise rotation of adria and the continental extrusion generated by this convergence

the formation and failure of natural dams of the numerous kinds of dams that form by natural processes dams formed from landslides glacial ice and late neoglacial moraines present the greatest threat to people and property landslide dams form in a wide range of physiographic settings the most common types of mass movements that form landslide dams are rock and debris avalanches rock and soil slumps and slides and mud debris and earth flows the most common initiation mechanisms for dam forming landslides are excessive rainfall and snowmelt and earthquakes landslide dams can be classified into six categories based on their relation with the valley floor type i dams 11 of 184 landslide dams from around the world that we were able to classify do not reach from one valley side to the other type ii dams 44 span the entire valley floor in some cases depositing material high on opposite valley sides type iii dams 41 move considerable distances both upstream and downstream from the landslide failure type iv dams 1 are rare and involve the contemporaneous failure of material from both sides of a valley type v dams 1 also are rare and are created when a single landslide sends multiple tongues of debris into a valley and forms two or more landslide dams in the same reach of river type vi dams 3 involve one or more failure surfaces that extend under the stream or valley and emerge on the opposite valley side many landslide dams fail shortly after formation in our sample of 73 documented landslide dam failures 27 of the landslide dams failed less than 1 day after formation and about 50 failed within 10 days over topping is by far the most common cause of failure the timing of failure and the magnitude of the resulting floods are controlled by dam size and geometry material characteristics of the blockage rate of inflow to the impoundment size and depth of the impoundment bedrock control of flow and engineering controls such as artificial spill ways diversions tunnels and planned breaching by blasting or conventional excavation glacial ice dams can produce at least nine kinds of ice dammed lakes the most dangerous are lakes formed in main valleys dammed by tributary glaciers failure can occur by erosion of a drainage tunnel under or through the ice dam or by a channel over the ice dam cold polar ice dams generally drain supraglacially or marginally by downmelting of an outlet channel warmer temperate ice dams tend to fail by sudden englacial or subglacial breaching and drainage late neoglacial moraine dammed lakes are located in steep mountain areas affected by the advances and retreats of valley glaciers in the last several centuries these late neoglacial dams pose hazards because 1 they are sufficiently young that vegetation has not stabilized their slopes 2 many dam faces are steeper than the angle of repose 3 these dams and lakes are immediately downslope from steep crevassed glaciers and near vertical rock slopes and 4 downstream from these dams are steep canyons with easily erodible materials that can be incorporated in the flow and increase flood peaks the most common reported failure mechanism is overtopping and breaching by a wave or series of waves in the lake generated by icefalls rockfalls or snow or rock avalanches melting of ice cores or frozen ground and piping and seepage are other possible failure mechanisms natural dams may cause upstream flooding as the lake rises and downstream flooding as a result of failure of the dam although data are few for the same potential energy at the dam site ownstream flood peaks from the failure of glacier ice dams are smaller than those from landslide moraine and structed earth fill and rock fill dam failures moraine dam failures appear to produce some of the largest downstream flood peaks for potential energy at the dam site greater than 1011 1012 joules differences in flood peaks natural dam failures appear to be controlled by dam characteristics and failure mechanisms

ophiolitic detritus in cretaceous clastic formations of the dinarides nw croatia evidence from cr spinel chemistry cr spinel is a common heavy mineral in the sandstones of cretaceous synorogenic sedimentary formations of the nw dinarides croatia the rocks occur in isolated exposures in the uplifted basement units of medvednica ivanscica umberak and samobor mountains near zagreb in this area evidence of the early alpine evolution of the dinarides is obscured due to strong dismemberment of pre tertiary tectonostratigraphic units resulting from an intense tectonic history as well as due to the widespread sedimentary cover of the pannonian basin electron microprobe analyses of detrital cr spinels from the ostrc formation reveal that in the early cretaceous the ophiolitic source area was predominantly composed of harzburgite peridotites and associated cumulate rocks which developed in a supra subduction zone setting the supply of cr spinels with the same chemical signature remained dominant until the end of the cretaceous suggesting that exposed remnants of the same ophiolite belt persisted through the cretaceous and or that recycling was significant similarities with data reported from the northern calcareous alps and the transdanubian central range imply that a rather extensive harzburgitic ophiolite belt probably extended along the adriatic margin during the early cretaceous a slight trend of increasing variation in the cr is observed from the early to the latest cretaceous suggesting that the source areas became more heterogeneous with the ongoing cretaceous tectonic evolution differences in cr spinel compositions in two contemporaneous latest cretaceous formations are well in line with existing data on heavy mineral proportions which together identify contrasting hinterland geology for these formations and strongly suggest the coeval existence of two separate basins

the eureka river landslide and dam peace river lowlands alberta the eureka river landslide of june 1990 at 50 mm3 is one of the largest historical landslides on the interior plains of canada it is one of seven large translational landslides to have occurred in the peace river lowlands within the last 65 years each landslide occurred in quaternary sediments deposited within a preglacial valley each landslide formed a dam the rupture surface of the eureka river landslide in preglacial lacustrine sediment 125 m below the peace river lowlands plains extended beneath the river channel causing the channel to be elevated the resulting landslide dam was over 20 m high forming a lake exceeding 8 km in length the river cut a new channel around the toe of the landslide abandoning the prelandslide channel as the new channel is free of armour incision has been rapid after 10 years the dam now stands approximately 5 m high key words landslide landslide dam peace river alberta preglacial valley geomorphology

magnetic fabric of late miocene clay rich sediments from the southern pannonian basin the magnetic fabric of late miocene sediments from the southern pannonian basin was studied on oriented samples collected from 19 geographically distributed localities all of them are characterized by near horizontal magnetic foliation plane after tilt correction indicating weak deformation well developed lineations were observed for 16 localities which are interpreted as due to compressional transpressional deformation except from three localities where the fabric must have been formed in an extensional setting comparison between the orientation of the map scale folds and faults and magnetic lineation directions shows that magnetic lineation is either related to nne ssw directed compression leading to the formation of folds or it can be connected to nw se or nne ssw trending dextral faults

late wisconsin ice flow history in the buffalo head hills kimberlite field north central alberta ice flow of the last glaciation in the buffalo head hills kimberlite field of northern alberta is reconstructed from landform interpretations and clast orientations for the purpose of aiding kimberlite exploration in the region the paucity of bedrock outcrop and the absence of preserved striae and other erosional ice flow indicators on the soft cretaceous marine sediments inhibit detailed interpretations on glacial flow chronology poorly developed bedrock drumlins on the buffalo head hills and erosional ice flow indicators preserved on the kimberlite outcrops indicate southwestward ice flow during the maximum extent of ice during the last glaciation during the deglaciation of northern alberta later phases of ice flow were controlled by lobes of surging ice which surged into proglacial lakes west of the buffalo head hills the maximum phase of southwest flow was followed by southeastward ice movement of the peace river ice lobe similarly east of the buffalo head hills the maximum phase of ice flow was superceded by a south southwest ice advance of the wasbasca ice lobe

glacial lake saskatchewan and lake agassiz deltas in east central saskatchewan with special emphasis on the nipawin delta the nipawin delta extends eastward from the town of nipawin in east central saskatchewan the prince albert and fort a la corne deltas formed in lake saskatchewan at the mouths of the south and north saskatchewan rivers whereas the nipawin and mossy vale deltas formed in lake agassiz at the mouth of the saskatchewan river these deltas became lower in elevation and younger eastward clays beneath the nipawin and mossyvale deltas can be traced beneath the prince albert and fort a la corne deltas with little change in thickness suggesting that most of the clays beneath the nipawin and mossyvale deltas were deposited during the formation of the prince albert and fort a la corne deltas the nipawin delta formed between 10 200 and 9500 bp the campbell strandline emerson phase was the shoreline of the nipawin delta the mossyvale delta formed about 9500 bp the surface of the mossyvale delta mccauleyville level is about 40 m below the surface of the nipawin delta campbell level

fluvial clastic sediment yield in canada scaled analysis this report presents a set of maps of regional fluvial sediment yield in canada based mainly on the water survey of canada archive of riverine suspended sediment observations regional scaling rel

thermal evolution of an extensional detachment as constrained by organic metamorphic data and thermal modeling graz paleozoic nappe complex eastern alps abstract following early cretaceous nappe stacking the eastern alps were affected by late orogenic extension during the late cretaceous in the eastern segment of this range a late cretaceous detachment separates a very low to low grade metamorphic cover graz paleozoic nappe complex gpnc above a low to high grade metamorphic basement synchronously the kainach gosau basin kgb collapsed and subsided on top of the section metamorphism of organic material within this section has been investigated using vitrinite reflectance data and raman spectra of extracted carbonaceous material in the southern part of the gpnc vitrinite reflectance indicates a decrease in organic maturity towards the stratigraphic youngest unit the remaining part of the gpnc is characterized by an aureole of elevated vitrinite reflectance values and raman r2 ratios that parallels the margins of the gpnc vitrinite reflectance in the kgb shows a steep coalification gradient and increases significantly towards the western basin margin the observed stratigraphic trend in the southern gpnc is a result of deep paleozoic to early cretaceous burial this maturity pattern was overprinted along the margins by advective heat and convective fluids during late cretaceous to paleogene exhumation of basement rocks during shearing the fault zone was heated up to ca 500 c this overprint is explained by a two dimensional thermal model with a ramp flat fault geometry and a slip rate of 1 to 1 5 cm year during 5 ma fault movement the collapse basin above the detachment subsided in a thermal regime which was characterized by relaxing isotherms

machine learning based mapping of micro topographic earthquake induced paleo pulju moraines and liquefaction spreads from a digital elevation model acquired through laser scanning abstract the advent of public open source airborne laser scanning produced digital elevation models als dem has provided new perspectives on glacial geomorphology in the nordic countries seismically induced micro topographic paleo landforms can now be identified and mapped throughout the former fennoscandian ice sheet allowing spatial safety assessment for nuclear waste disposal automated machine learning techniques enable recognition of these fine scale geomorphological features efficiently and in a consistent way nationwide the current study focuses on automated recognition of paleo liquefaction spreads and pulju moraines in northern finland geomorphometric variables in different cell sizes were first derived from the 2 m als dem by gabor and principal curvature filtering to emphasize the elevational multi scale texture of these paleo seismic landforms the gabor textural variables were considered as a baseline method and the principal curvature features including maximum and minimum curvature were used because they have previously been proven critical in recognition of concave and convex elongated features both sets of raster variables were then turned into histogram based features and input into a non linear supervised multilayer perceptron early stop committee which is a neural network classifier the leave one out cross validation performance results indicated principal curvature features to be highly successful with 94 accuracy principal curvatures provided a clear improvement to gabor based features which provided significantly lower accuracies between 83 and 85 the study demonstrates the high success of supervised neural network based classification of als dem data and derived textural features capturing the multi scale nature of the micro topographic liquefaction spreads and pulju moraines the approach could be utilized for time efficient mapping of these paleo seismic geomorphologies to complete paleo seismic databases in formerly glaciated regions

landform assemblage in isidis planitia mars evidence for a 3 ga old polythermal ice sheet abstract the floor of isidis planitia a giant impact basin located close to the martian equator exhibits a landform assemblage nicknamed thumbprint terrain made of arcuate ridges aligned cones isolated cones cone fields associated with a peripheral network of sinuous ridges linear depressions and mounds from a new comprehensive mapping initiative of these landforms and from comparisons with terrestrial analogues ribbed moraines dirt cones kettle holes eskers tunnel valleys and moraine plateaux we demonstrate that this distinctive assemblage is a glacial landsystem inherited from the presence of a massive polythermal ice sheet over the basin during the hesperian the flow of the ice sheet was controlled by its basal thermal regime wet based conditions led to the formation of arcuate ridges and aligned cones in most parts of the basin while a negative geothermal anomaly due to impact related crustal thinning was responsible for cold based conditions in its central part where only isolated cones and cones fields are present sinuous ridges linear depressions and mounds at the basin margins are interpreted as relicts of a radial network of subglacial channels which drained the glacial meltwater produced within the interior of the ice sheet across its cold based periphery

continuity and episodicity in the early alpine tectonic evolution of the western carpathians how large scale processes are expressed by the orogenic architecture and rock record data

complex structural pattern of the alpine dinaridic pannonian triple junction due to the political boundaries between the central european countries on one hand and the thick tertiary cover in the pannonian basin on the other the eastward continuation of the alpine and dinaridic units has been ambiguous and poorly documented based on comparative analyses the aim of the present paper is to define the pre tertiary structural units in the junction area of the alpine dinaridic and pannonian regions in the sw part of the pannonian basin and to draw conclusions on the continuation of the alpine and dinaridic units according to diagnostic characteristics of the periadriatic lineament system the balaton lineament system may be considered as its direct eastern continuation north of the periadriatic balaton lineament system the transdanubian range unit due to its pre tertiary paleogeographic setting shows mainly south alpine facies relations however its present structural position is identical to that of the upper austroalpine nappes between the periadriatic balaton and zagreb zemplin lineament systems heterogeneous structural units are juxtaposed forming the sava composite unit in the northern part of this composite unit non metamorphosed nappes occur which can be considered the eastern continuation of the south alpine units these nappes are overthrust onto internal dinaridic units in the tertiary the zagreb zemplin mid hungarian lineament separates the sava unit from the tisza unit showing close affinity to the tethyan margin of the eurasian plate during the early stage of the alpine evolution

paleogene early miocene igneous rocks and geodynamics of the alpine carpathian pannonian dinaric region an integrated approach a review of paleogene early miocene igneous rocks of the alpine carpathianpannonian dinaric region is presented in this paper we attempt to reveal the geodynamic link between paleogene early miocene igneous rocks of the mid hungarian zone and those of the alps and dinarides our summary suggests that paleogene early miocene igneous rocks of all these areas were formed along a single subduction related magmatic arc the study also highlights orthopyroxene rich websterite mantle xenoliths from west hungary and east serbia that were formed in the vicinity of a subducted slab we discuss the location and polarity of all potential subduction zones of the area that may account for the igneous rocks and orthopyroxene rich mantle rocks however results of seismic tomography on subducted slabs beneath the studied area combined with geological data demonstrate that igneous rocks and mantle rocks cannot be explained by the same subduction process we propose that the paleogene early miocene arc was mainly generated by the budva pindos subduction zone subordinately by penninic subduction whereas mantle rocks were possibly formed in the vicinity of the older vardar subduction zone continental blocks possibly moved together with their mantle lithosphere the present diverging shape of the proposed arc has been achieved by considerable shear and rotations of those lithospheric blocks

deglacial and postglacial evolution of the pingualuit crater lake basin northern quebec canada abstract the pingualuit crater located in the ungava peninsula northern quebec canada is a 1 4 ma old impact crater hosting a 245 m deep lake the lake has a great potential to preserve unique paleoclimatic and paleoecological sedimentary records of the last glacial interglacial cycles in the terrestrial canadian arctic in order to investigate the stratigraphy in the lake and the late quaternary glacial history of the pingualuit crater this study compiles data from three expeditions carried out in may 2007 9 m long sediment core in august 2010 50 km of seismic lines and in september 2012 high resolution terrestrial lidar topography of the inner slopes despite the weak penetration 10 m of the 3 5 khz subbottom profiling caused by the presence of boulders in the sedimentary column seismic data coupled with the stratigraphy established from the sediment core enabled the identification of two glaciolacustrine units deposited during the final stages of the laurentide ice sheet lis retreat in the crater two episodes of postglacial mass wasting events were also identified on the slopes and in the deep basin of the crater the high resolution topography of the internal slopes of the crater generated from the lidar data permitted the confirmation of a paleolake level at 545 m and determination of the elevation of drainage outlets together with the mapping of glacial and deglacial landforms from air photographs the lidar data allowed the development of a new deglaciation and drainage scenario for the pingualuit crater lake and surrounding area the model proposes three main phases of lake drainage based on the activation of seven outlets following the retreat of the lis front toward the southwest finally as opposed to other high latitude crater lake basins such as lake el gygytgyn or laguna potrok aike where high resolution paleoclimatic records were obtained owing to high sediment accumulation rates the seismic data from the pingualuit crater lake suggest extremely low sedimentation rates after the retreat of the lis owing to the absence of tributaries

miocene tectonics of the maramures area northern romania implications for the mid hungarian fault zone the interplay between the emplacement of crustal blocks e g alcapa tisza dacia and subduction retreat is a key issue for understanding the miocene tectonic history of the carpathians coeval thrusting and basin formation is linked by transfer zones such as the mid hungarian fault zone which seperates alcapa from tisza dacia the presented study provides new kinematic data from this transfer zone early burdigalian 20 5 to 18 5 ma se directed thrusting of the easternmost tip of alcapa pienides over tisza dacia is linked to movements along the mid hungarian fault zone and the periadriatic line accommodating the lateral extrusion of alcapa minor late burdigalian 18 5 to 16 ma ne sw extension is interpreted as related to back arc extension post burdigalian post 16 ma ne sw shortening and nw se extension correlate with soft collision of tisza dacia with the european foreland coupled with southward migration of active subduction during this stage the bogdan voda and dragos voda faults were kinematically linked to the mid hungarian fault zone sinistral transpression 16 to 12 ma at the bogdan voda fault was followed by sinistral transtension 12 10 ma along the coupled bogdan dragos voda fault system during the transtensional stage left lateral offset was reduced eastwards by sw trending normal faults the fault system finally terminating in an extensional horse tail splay

deformation in the asthenospheric mantle beneath the carpathian pannonian region to better understand the evolution and present day tectonics of the carpathian pannonian region cpr we characterize the upper mantle anisotropic structure we present a shear wave splitting analysis from teleseismic events recorded at the carpathian basin project and permanent stations located in the cpr the results show a large scale uniform nw se fast orientation under the entire cpr compared with the complexity of geologic structures the anisotropy expresses a relatively simple pattern of deformation we attribute this anisotropy to an asthenospheric origin and interpret it as flow induced alignments within the upper mantle we also observe a few measurements depicting ne sw fast orientation in line with the mid hungarian shear zone this suggests the likely contribution of either lithosphere or northeastward flow into a slab gap under the northern dinarides we observe splitting delay times on average of 1 s showing noticeable change 60 in the middle pannonian basin this change correlates well with the variation in the thickness of low velocity zones that were previously imaged between a depth of 75 and 400 km by velocity tomography in order to evaluate the relation between anisotropy and tectonics we compare our data with the tectonic models that have so far been suggested to explain the evolution and current stage tectonics of the region we present here a plausible tectonic model responsible for the nw se anisotropy within the asthenospheric mantle in this model nw se deformation is mainly generated in a northeastward compressional tectonic regime acting in a wide region between the adriatic microplate and the east european platform

laboratory experiments on the failure of coarse homogeneous sediment natural dams on a sloping bed we present the results of a systematic series of 168 laboratory experiments that examine the critical conditions for the failure of landslide dams which obstruct the course of mountain rivers the experiments were carried out by using three different sediment materials with a quasiuniform grain size distribution and with a flume bed slope angles that ranged between 0 and 5 71 0 10 three main typologies of dam failure were observed for increasing values of the dam s downstream face angle 1 overtopping 2 headcutting which led to the formation of an erosion channel on the dam s downstream face that progressively migrated up to the dam crest and 3 initial slide of large part of superficial layer of the dam s downstream face which was followed by headcutting the experiments focused on the second type of failure to provide a safety criterion based on the upstream reservoir level the quantities that govern this phenomenon have been identified and a functional relationship is proposed based on

the tectonic evolution of a critical segment of the dinarides alps connection kinematic and geochronological inferences from the medvednica mountains ne croatia the transition zone between the alps and dinarides is a key area to investigate kinematic interactions of neighboring orogens with different subduction polarities a study combining field kinematic and sedimentary data microstructural observations thermochronological data rb sr and fission track and regional structures in the area of medvednica mountains has revealed a complex polyphase tectonic evolution we document two novel stages of extensional exhumation the first stage of extension took place along a late cretaceous detachment following the late early cretaceous nappe stacking burial and greenschist facies metamorphism two other shortening events that occurred during the latest cretaceous oligocene were followed by a second event of extensional exhumation characterized by asymmetric top ne extension during the miocene top nw thrusting took place subsequently during the pliocene inversion of the pannonian basin the cretaceous nappe burial late cretaceous extension and the oligocene earliest miocene contraction are events driven by the alps evolution in contrast the latest cretaceous eocene deformation reflects phases of dinaridic contraction furthermore the miocene extension and subsequent inversion display kinematics similar with observations elsewhere in the dinarides and eastern alps all these processes demonstrate that the medvednica mountains were affected by alpine phases of deformations to a much higher degree than previously thought similarly with what has been observed in other areas of contractional polarity changes such as the mediterranean black sea or new guinea systems the respective tectonic events are triggered by rheological weak zones which are critical for localizing the deformation created by both orogens

hummocky moraine sedimentary record of stagnant laurentide ice sheet lobes resting on soft beds abstract over large areas of the western interior plains of north america hummocky moraine hm formed at the margins of laurentide ice sheet lis lobes that flowed upslope against topographic highs current depositional models argue that hm was deposited supraglacially from stagnant debris rich ice disintegration moraine across southern alberta canada map and outcrop data show that hm is composed of fine grained till as much as 25 m thick containing rafts of soft glaciotectonized bedrock and sediment chaotic non oriented hm commonly passes downslope into weakly oriented hummocks washboard moraine that are transitional to drumlins in topographic lows the same subsurface stratigraphy and till facies is present throughout these landforms and others such as doughnut like rim ridges flat topped moraine plateaux and linear disintegration ridges are identified as belonging to subglacially deposited soft bed terrain this terrain is the record of ice lobes moving over deformation till derived from weakly lithified bentonite rich shale drumlins record continued active ice flow in topographic lows during deglaciation whereas hm was produced below the outer stagnant margins of ice lobes by gravitational loading pressing of remnant dead ice blocks into wet plastic till intervening zones of washboard moraine mark the former boundary of active and stagnant ice and show hybrid drumlins whose streamlined form has been altered by subglacial pressing humdrums below dead ice the presence of hummocky moraine over a very large area of interior north america provides additional support for glaciological models of a soft bedded laurentide ice sheet

the formation and impact of landslide dams state of the art abstract the blocking of river courses by mass movements is very common in mountainous areas with deep and narrow valleys landslide dams may pose serious threats to people and their livelihoods downstream in the case of abrupt dam failure since the publication of benchmark reviews of costa and schuster 1988 and korup 2002 there is a growing number of studies focusing on the formation stability and short term impacts of landslide dams this review combines the insights of all these studies builds on current concepts of landslide dams and suggests ways to unify terminologies and classifications we furthermore present a new worldwide database compiled from literature data it contains 410 landslide dams 1 million m3 in volume that were formed since 1900 since these have the most complete data entries these data show that dam longevity is among other factors correlated with the type of landslide forming the dam those formed by rock debris avalanches and rockslides have longest lifespans however the influence of landslide type or material on dam longevity decreases with time after dam formation to ensure consistency in the next database generation we suggest guidelines for data collection to provide a solid basis for evaluating dam stability and governing factors a preliminary classification matrix for landslide dam stability that combines topographic setting and the internal structure of the dam body is another outcome of our review furthermore an evaluation of the various geomorphic stability indices proposed in the literature regarding their suitability and limitations in assessing dam formation and stability shows that they predict the probability of dam formation reasonably well but that their application to longevity estimates requires further assessment the geomorphic impacts of landslide dams in the short medium and long term are summarized and illustrated with key examples finally for a better understanding of the factors controlling dam stability we recommend to 1 include dam composition and sedimentary structures in future case studies 2 maintain and update the worldwide database for sound statistical analyses 3 refine landslide dam stability indices and test them for different landslide types and 4 study hazard cascades related to multiple dams in one watershed for long term landscape evolution studies we suggest to 5 quantify terrestrial sediment flux related to landslide dams 6 detect ancient landslide dams in river profiles and 7 further exploit the sediment archives in former impoundment areas

the 1939 montagneuse river landslide alberta the 1939 landslide on the west wall of the montagneuse river valley 1300 m long 1400 m wide and 80 m thick with av olume of 76 10 6 m 3 is the largest historic rapid landslide on the interior plains of canada it lasted about a minute dammed the river and formed a reservoir 1 5 km long the reservoir was filled before 1952 by lake deposits which were eroded by the river by 1988 the landslide contained two major blocks the downslope block 950 m long kept intact without obvious tilting indicating that the block moved almost horizontally on a comparatively deep rupture surface the displaced material included part of the preslide river channel so the montagneuse river was pushed eastward the toe of the block moved up and dammed the river the upslope block with a length of 300 350 m slid with little rotation but broke up into at least five smaller blocks most trees on the upslope block postdate the slide two sag ponds on the landslide visible in 1952 had enlarged by 1988 probably a result of water running off from the recently cleared farmland behind the scarp the main scarp has been substantially modified by earth flows and slides landslides in the montagneuse river valley coincide with the shaftesbury buried preglacial channel of the peace river the surfaces of rupture of five historic landslides in the peace river lowland follow clays deposited in preglacial channels confirming that these deposits may be hazardous when eroded

eolian contribution to geochemical and mineralogical characteristics of some soil types in medvednica mountain croatia abstract six pedological profiles were analyzed above five typical lithological units in medvednica mountain to determine the effect of eolian additions to the soil composition as well as the possible influence of relief vegetation cover and anthropogenic input on the dynamics of pedogenesis bedrock composition was defined using petrographic thin sections and chemical analyses major and trace element contents whereas pedological sedimentological and geochemical characteristics of six cross sections were determined by chemical major and trace element contents mineralogical modal analysis and grain size analysis soils developed on sedimentary bedrock mollic rendzic leptosols calcaric and albic luvisol sceletic mostly originate from weathering of siliciclastic detritus that was exposed to oxidization before diagenesis furthermore soils on metasiltstone marble and lithothamnium limestone exhibit similar modal and geochemical composition and element distribution across the soil profile in contrast soils developed on igneous bedrock originate mostly from weathering of minerals of the first weathering cycle and thus abound with chemically less resistant minerals and less mobile elements however all profiles contain higher concentrations of lead with respect to bedrock indicating airborne contamination

a crustal model for the eastern alps region and a new moho map in southeastern europe in the last two decades south central europe and the eastern alps have been widely explored by many seismic refraction experiments e g celebration 2000 alp 2002 sudetes 2003 although quite detailed images are available along linear profiles a comprehensive three dimensional crustal model of the region is still missing this limitation makes this region a weak spot in continental wide comprehensive representations of crustal structure to improve on this situation we select and collect 37 published active source seismic lines in this region after geo referencing each line we sample them along vertical profiles every 50 km or less along the line and derive p wave velocities in a stack of homogeneous layers separated by discontinuities depth of crystalline basement top of lower crust and moho we finally merge the information using geostatistical methods and infer s wave velocity and density using empirical scaling relations we present here the resulting crustal model for a region encompassing the eastern alps dinarides pannonian basin western carpathians and bohemian massif covering the region within 45 circ text 51 circ hbox n and 11 circ text 22 circ hbox e with a resolution of 0 2 circ times 0 2 circ we are also able to extend and update the map of moho depth in a wider region within 35 circ text 51 circ hbox n and 12 circ text 45 circ hbox e gathering moho values from the collected seismic lines other published dataset and using the european plate reference epcrust as a background all the digitized profiles and the resulting model are available online

subduction evolution of the dinarides and the cretaceous orogeny in the eastern alps hints from a new paleotectonic interpretation

mesozoic plate tectonic reconstruction of the carpathian region abstract palaeomagnetic palaeobiogeographic and structural comparisons of different parts of the alpine carpathian region suggest that four terranes comprise this area the alcapa tisza dacia and adria terranes these terranes are composed of different mesozoic continental and oceanic fragments that were each assembled during a complex late jurassic cretaceous palaeogene history palaeomagnetic and tectonic data suggest that the carpathians are built up by two major oroclinal bends the alcapa bend has the meliata oceanic unit correlated with the dinaric vardar ophiolite in its core it is composed of the western carpathians eastern alps and southern alcapa units transdanubian range bukk this terrane finds its continuation in the high karst margin of the dinarides further elements of the alcapa terrane are thought to be derived from collided microcontinents czorsztyn in the n and a carbonate unit tisza in the se the tisza dacia bend has the vardar oceanic unit in its core it is composed of the bihor and getic microcontinents this terrane finds its continuation in the serbo macedonian massif of the balkans the bihor getic microcontinent originally laid east of the western carpathians and filled the present carpathian embayment in the late palaeozoic early mesozoic the vardar ocean occupied an intermediate position between the western carpathian austroalpine transdanubian high karst margin and the bihor getic serbo macedonian microcontinent the vardar and pindos oceans were opened in the heart of the mediterranean adriatic microcontinent in the late permian middle triassic vardar subducted by the end of jurassic causing the bihor getic serbo macedonian microcontinent to collide with the internal dinaric western carpathian margin an external penninic vahic ocean tract began opening in the early jurassic separating the austroalpine western carpathian microcontinent and its fauna from the european shelf further east the severin ceahlau magura also began opening in the early jurassic but final separation of the bihor getic ribbon and its fauna from the european shelf did not take place until the late middle jurassic the alcapa and the tisza dacia were bending during the albian maastrichtian the two oroclinal bends were finally opposed and pushed into the gates of the carpathian embayment during the palaeogene and neogene at that time the main n s shortening in distant alpine and hellenic sectors was linked by a broader right lateral shear zone along the former vardar suture

a suggested method for estimating setbacks from the crests of slopes on the interior plains in alberta a method of estimating safe setbacks from the crests of river valley slopes in alberta was evaluated for 39 slopes of which eight are presented to illustrate the method and assess its reliability

ground penetrating radar antenna orientation effects on temperate mountain glaciers abstractground penetrating radar gpr surveys on glaciers are generally restricted to a single pair of bistatic dipole antennas orientated either parallel or perpendicular to the surveying direction extensive helicopter borne and ground based gpr investigations on the glacier d otemma switzerland demonstrated that the detectability of the ice bedrock interface varies substantially with dipole orientation we recorded several across and along profiles using two different commercial gpr systems operated with 15 25 50 and 70 mhz antennas dipole alignments parallel to the glacier flow generated considerably stronger and more coherent bedrock reflections compared with a perpendicular dipole setup we observed the behavior for all the systems and antenna frequencies that we used to help explain these findings we performed 3d numerical modeling using the open source software gprmax simulations with 20 mhz transmitting and receiving dipoles indicated that the changes of the bedrock reflection amplitude

thermal modeling of carboniferous to triassic sediments of the karawanken range southern alps as a tool for paleogeographic reconstructions in the alpine dinaridic pannonian realm vitrinite reflectance was measured in late carboniferous to triassic shales siltstones and marls of the karawanken range thermal models of the central south karawanken range were calibrated on the basis of these data they suggest an eroded overburden of more than 3 200 m of jurassic to cretaceous sediments and a heat flow in the range of 42 to 60 mw m 2 during the time of maximum subsidence because the reconstructed thermal history of the south karawanken range is very similar to the thermal history of the generoso basin western southern alps these data provide strong evidence for a deep basinal position of the southern karawanken range during jurassic to cretaceous times a vitrinite reflectance anomaly at the northern margin of the south karawanken range is explained by advective heat transport during the oligocene the heat source for the anomalies at the western margin of the seeberg rise and in the area between the periadriatic lineament and the donat fault zone is unknown vitrinite reflectance in late triassic sediments indicates the south karawanken range and the south zala unit of the pannonian basement as exotic blocks in the sava composite unit this is explained by miocene displacement of structural units which were derived from different paleogeographical segments of the permo mesozoic western tethyan margin

hummocky moraine landscape on jaeren sw norway implications for glacier dynamics during the last deglaciation abstract the jaeren area sw norway can topographically be divided in two regions lagjaeren and hogjaeren hogjaeren is a plateau 120 m a s l covered by quaternary sediments the stratigraphically youngest deposit is a sandy diamicton which accumulated in ridges and hummocks during the last deglaciation this hummocky moraine landscape has previously been interpreted as the record of a stagnant glacier detailed morphological mapping and sedimentological investigations have revealed that various glacigenic elements exist and dominate different areas of the hogjaeren plateau glacigenic elements formed by an active wet based glacier characterize the southern central hummocky area and include marginal moraine ridges and drumlins while circular moraine ridges and glaciofluvial features formed in a stagnant glacial regime dominate the northern central hummocky area the distribution of glacigenic elements within the hummocky moraine landscape shows that active and stagnant ice coexisted on hogjaeren during the last deglaciation and that actively flowing ice was focused through eastward extending valleys it is not possible to determine whether ice flow was kept active in the southern area throughout the deglaciation or if the glacier was reactivated a possible readvance is suggested to have happened simultaneous to a readvance previously suggested based on the morphology on lagjaeren

the influence of drainage boundaries on specific mass balance results a case study of engabreen norway mass balance measurements were initiated on engabreen an outlet glacier from the svartisen ice cap norway in 1970 the glacier boundary was defined based on where meltwater drained as the interest in engabreen was mainly hydrological however the apparent discrepancy between the calculated cumulative glacier mass balance since 1970 and changes in glacier geometry prompted a re examination of the glacier boundary the glaciological drainage boundary is defined by studying whether ice flow physically contributes to engabreen tongue and corresponds to a glacier with an area of 27 2 km 2 significantly smaller than that defined by the hydrological drainage boundary at 39 6 km 2 this glaciological drainage boundary is here named the ice flow perimeter the area difference between this and the hydrological drainage boundary is largest for the altitudinal range 1300 1400 m a s l generally the glaciological glacier is lower in mean altitude than the hydrological glacier and this affects the calculated specific mass balance using the glaciological boundary leads to reductions in mean annual winter and summer balance when spatial differences are ignored of 0 12 m w e from 2 92 to 2 80 m w e and 0 15 m w e from 2 32 to 2 47 m w e respectively the reduction in mean net balance for the period 1970 2006 is 0 27 m w e from 0 59 to 0 32 m w e which is about 50 of the calculated mass surplus in this period this illustrates that the choice of glacier outline can significantly influence the long term cumulative mass balance and that results from outlet glaciers must be interpreted with care when used for regional estimates of glacier change

glacial geomorphology of terrestrial terminating fast flow lobes ice stream margins in the southwest laurentide ice sheet glacial geomorphological mapping of southern alberta canada reveals landform assemblages that are diagnostic of terrestrial terminating ice streams fast flowing outlet glaciers with lobate snouts spatial variability in features that comprise the landform assemblages reflects changes in a palaeo ice stream activity switch on off and b snout basal thermal regimes associated with climate sensitive steady state flow palaeo ice stream tracks reveal distinct inset sequences of fan shaped flowsets indicative of receding lobate ice stream margins former ice lobe margins are demarcated by a major often glacially overridden transverse moraine ridges commonly comprising glacitectonically thrust bedrock and b minor closely spaced recessional push moraines and hummocky moraine arcs details of these landform types are well exhibited around the former southern margins of the central alberta ice stream where larger scale more intensive mapping identifies a complex glacial geomorphology comprising minor transverse ridges mtr types 1 3 hummocky terrain ht types 1 3 flutings and meltwater channels spillways the mtr type 1 constitute the summit corrugation patterns of glacitectonic thrust moraines or major transverse ridges and have been glacially overrun and moderately streamlined the mtr type 2 sequences are recessional push moraines similar to those developing at modern active temperate glacier snouts the mtr type 3 document moraine construction by incremental stagnation because they occur in association with hummocky terrain the close association of hummocky terrain with push moraine assemblages indicates that they are the products of supraglacial controlled deposition on a polythermal ice sheet margin where the ht type 3 hummocks represent former ice walled lake plains the ice sheet marginal thermal regime switches indicated by the spatially variable landform assemblages in southern alberta are consistent with palaeoglaciological reconstructions proposed for other ice stream fast flow lobes of the southern laurentide ice sheet where alternate cold polythermal and temperate marginal conditions associated with climate sensitive steady state flow sequentially gave way to more dynamic streaming and surging activity

in the wake of a counterclockwise rotating adriatic microplate neogene paleomagnetic results from northern croatia in northern croatia the neogene sediments cover complicated basement rocks which consist of alpine and dinaridic elements in the zagorje area and variscan alpine formations of the tisia tisza megatectonic unit in the slavonian mountains mts the neogene sediments were deposited in two separate basins before the karpatian but sedimentation became uniform from the karpatian onwards 17 5 ma of the 24 localities that we have studied so far paleomagnetically from northern croatia 16 localities are of karpatian or younger age while the rest are pre karpatian

ice thickness measurements and volume estimates for glaciers in norway glacier volume and ice thickness distribution are important variables for water resource management in norway and the assessment of future glacier changes we present a detailed assessment of thickness distribution and total glacier volume for mainland norway based on data and modelling glacier outlines from a landsat derived inventory from 1999 to 2006 covering an area of 2692 81 km 2 were used as input we compiled a rich set of ice thickness observations collected over the past 30 years altogether interpolated ice thickness measurements were available for 870 km 2 32 of the current glacier area of norway with a total ice volume of 134 23 km 3 results indicate that mean ice thickness is similar for all larger ice caps and weakly correlates with their total area ice thickness data were used to calibrate a physically based distributed model for estimating the ice thickness of unmeasured glaciers the results were also used to calibrate volume area scaling relations the calibrated total volume estimates for all norwegian glaciers ranged from 257 to 300 km 3

controlled moraines origins characteristics and palaeoglaciological implications abstract controlled moraines are supraglacial debris concentrations that become hummocky moraine upon de icing and possess clear linearity due to the inheritance of the former pattern of debris rich folia in the parent ice linearity is most striking wherever glacier ice cores still exist but it increasingly deteriorates with progressive melt out as a result moraine linearity has a low preservation potential in deglaciated terrains but hummocky moraine tracts previously interpreted as evidence of areal stagnation may instead record receding polythermal glacier margins in which debris rich ice was concentrated in frozen toe zones recent applications of modern glaciological analogues to palaeoglaciological reconstructions have implied that a controlled moraine development can be ascribed to a specific process e g englacial thrusting or supercooling and b controlled moraine preservation potential is good enough to imply the occurrence of the specific process in former glacier snouts e g ancient polythermal or supercooled snouts these assumptions are tested using case studies of controlled moraine construction in which a wide range of debris entrainment and debris rich ice thickening mechanisms are seen to produce the same geomorphic features polythermal conditions are crucial to the concentration of supraglacial debris and controlled moraines in glacier snouts via processes that are most effective at the glacier permafrost interface end moraines lie on a process form continuum constrained by basal thermal regime the morphological expression of englacial structures in controlled moraine ridges is most striking while the moraines retain ice cores but the final deposits landforms tend to consist of discontinuous transverse ridges with intervening hummocks preserving only a weak impression of the former englacial structure these are arranged in arcuate zones of hummocky moraine up to 2 km wide containing ice walled lake plains and lying down flow of streamlined landforms produced by warm based ice a variety of debris entrainment mechanisms can produce the same geomorphic signature spatial and temporal variability in process form relationships will lead to the sequential development of different types of end moraines during the recession of a glacier or ice sheet margin

theory of glacial erosion transport and deposition as a consequence of subglacial sediment deformation a theory of erosion transport and deposition of unlithified sediments by glaciers is presented it predicts the large scale areal distribution of zones and rates of erosion and deposition in time and space through a complete glacial cycle together with the resultant intensity of large scale lincations drumlins which will be incised in the landscape the theory also predicts the dispersal patterns of subglacial lithologies together with the form of dispersal trains derived from distinctive sources and the vertical and horizontal distribution of lithologies within a till it predicts major erosional discontinuities within tills and the formation of boulder pavements it suggests that the dominant proportion of the lowland tills produced by pleistocene mid latitude ice sheets was generated by subglacial deformation and explains why they are predominantly fine grained the theory is based on an analysis of glacier dynamic processes and therefore can be used to infer the dynamic behaviour of former ice sheets from the distribution of tills and their lithologic composition

towards bedmap himalayas development of an airborne ice sounding radar for glacier thickness surveys in high mountain asia the thickness of glaciers in high mountain asia hma is critical in determining when the ice reserve will be lost as these glaciers thin but is remarkably poorly known because very few measurements have been made through a series of ground based and airborne field tests we have adapted a low frequency ice penetrating radar developed originally for antarctic over snow surveys for deployment as a helicopter borne system to increase the number of measurements the manoeuvrability provided by helicopters and the ability of our system to detect glacier beds through thick dirty temperate ice makes it well suited to increase greatly the sample of measurements available for calibrating ice thickness models on the regional and global scale the bedmap himalayas radar survey system can reduce the uncertainty in present day ice volumes and therefore in projections of when hma s river catchments will lose this hydrological buffer against drought

laurentide glaciation in west central alberta a single late wisconsinan event the grande prairie region in west central alberta shows evidence of late wisconsinan laurentide glaciation in the form of a widespread till containing abundant erratic clasts derived from the canadian shield two sections located on the smoky river at watino and on the simonette river 80 km to the southwest expose sediment lying stratigraphically below the till a similar sequence is exposed in both localities 5 10 m of coarse quartzite gravel overlain by a thick sequence of sand and silt the gravel contains no laurentide erratics and is thus preglacial the contact between the basal gravel and the overlying sand and silt is sharp and conformable 14c dates from the base of the simonette section and throughout the watino section suggest a middle wisconsinan age thus the sediment exposed is interpreted as a conformable middle wisconsinan sequence the sedimentary sequences were deposited in a moderate to low energy braided stream system flowing towards the north the general fining up trend in the

geotechnical model for great plains hummocky moraine formed by till deformation below stagnant ice abstract hummocky or disintegration moraine is a widespread late wisconsin glacial terrain type across the glaciated great plains of mid continent north america this terrain consists of chaotic hummocks and enclosed kettle hollows that are widely underlain by clay rich till the prevailing interpretation of this terrain is one of supraglacial deposition from debris covered stagnant ice and is based largely on geomorphologic comparisons with modern valley glacier margins recently in contrast it has been argued that hummocky moraine can form subglacially by the pressing of fine grained deformable till under the overburden pressure of stagnant ice in this paper we test the postulated subglacial origin of hummocky moraine using a geotechnical model of a deforming soil till the model confirms that hummocky topography can be the result of failure and deformation of fine grained till by differential loading below stagnant ice differential pressures at the ice bed contact arise from the complete or partial perforation of thin stagnant ice sheet lobes by numerous water filled doline like depressions the growth and decay of ponds as ice down wastes result in repeated cycles of subglacial till failure and landform development resulting in the observed random linear circular elongate and other patterns of hummocks ridges and hollows formerly streamlined preferentially oriented subglacial landforms such as drumlins and rogen moraines can also be overprinted forming washboard moraine

glacial geomorphology of the neutral hills uplands southeast alberta canada the process form imprints of dynamic ice streams and surging ice lobes abstract the neutral hills uplands of southern alberta canada is an area of complex and varied glacial landforms dominated by glacitectonic compressional structures but also containing expansive areas of hummocky terrain and kame and kettle topography it lies between the strongly streamlined trunks of the former central alberta cais and maskwa palaeo ice streams of the sw laurentide ice sheet lis and hence comprises an inter ice stream regional moraine zone constructed at around 15 5 cal ka bp this study aimed to compile a regional map of the glacial geomorphology of central southeast alberta in order to decipher the landform sediment signatures of overprinted ice stream margins in terrestrial continental environments and to refine the palaeoglaciological reconstructions for the southwest lis detailed mapping from lidar and aerial imagery identifies distinctive glacial landsystems diagnostic of the partial overprinting of cross cutting ice stream trunks and fast flow lobes widespread evidence of surge diagnostic features indicates that the ice streams experienced repeated flow instabilities consistent with the broader scenario of a highly dynamic and unstable sw lis characterised by markedly transitory and cross cutting palaeo ice streams the inter ice stream moraine zone is characterised by spectacular glacitectonic compression of bedrock cupola hill construction and mega raft displacement but also displays evidence of multi phase stagnant ice melt out where partially overprinted surge lobes advanced into large areas of buried glacier ice contemporaneous ice melting led to the widespread development of glacier karst and the production of eskers at a range of scales the largest of which record deranged drainage patterns indicative of ice walled channel sedimentation controlled by the regional bedrock slope towards the northeast these process form regimes have created a significant local relief that is a product of not only glacitectonic compression of bedrock but also the creation and melting of a melange of ice and bedrock sediment blocks of variable ice volume which are representative of former buried snout ice with a glacier karst system that was repeatedly proglacially thrust due to surging widespread evidence for subglacial channel cutting is likely strongly linked to the transitory surging and cross cutting nature of the palaeo ice streams in the region whereby ice streams switched on and surged in response to the build up migration and marginal outbursts of subglacial water reservoirs in addition to the reduced basal friction caused by the low permeability of the cretaceous bedrock pressurized groundwater and potentially also shallow biogenic gas deposits were likely important to the process form regimes of surging lobes of soft bedded ice streams in a region where ice flow was against an adverse bed slope a scenario that gave rise to a variety of enigmatic landforms such as doughnuts doughnut chains apparent blow out features and possible till eskers as well as glacitectonic mega rafts

provenance and variscan low grade regional metamorphism recorded in slates from the basement of the sw hungary a metapelitic sequence with silurian protolith from the horvathertelend unit tisza mega unit hungary has a k white mica chlorite quartz albite anatase tourmaline mineral assemblage moderately developed disjunctive and well developed continuous foliations are present geochemical results reflect a dominantly felsic source of the protoliths suggesting an intermediate to acidic volcanic arc in the provenance area metasandstone pebbles in the metaconglomerate indicate a recycled sedimentary source raman spectroscopy of carbonaceous material indicates a 350 370 c peak metamorphic temperature the kubler index kibasel values of the phengitic k white mica indicate epizonal metamorphism 0 22 0 04 2 the chlorite crystallinity index chccis suggests metamorphic alteration near to the anchizone epizone boundary 0 31 0 06 2 k ar ages of k white mica are interpreted as a result of variscan metamorphism c 310 ma and post variscan uplift c 290 ma the predominance of lydite and slate of llandoverian age and the overlying coarse grained metagreywacke and metaconglomerate beds of the szalatnak slate formation show strong lithological similarities with the proximal silurian sequences in the malopolska massif kielce region holy cross mountains poland the original position of the horvathertelend unit is presumably to the northeast from the bohemian massif next to the upper silesian block moravo silesian zone and the malopolska terrane

the glacial origins of relict pingos wales uk ramparted depressions doughnut shaped debris cored ridges with peat and or sediment filled central basins are commonly perceived to represent the relict collapsed forms of permafrost ground ice mounds i e pingos or lithalsas in wales uk ramparted depressions of late pleistocene age have been widely attributed to permafrost related processes however a variety of alternative glacial origins for these enigmatic landforms are also consistent with the available geological and geomorphological evidence although previous studies have barely considered such alternative processes of formation from detailed geophysical sedimentological and remote sensing studies at two field sites we demonstrate that i the wastage of stagnating glacier ice is a viable alternative explanation for the formation of ramparted depressions in wales ii the glacial geomorphology and geology of these landforms is analogous to supraglacial and subglacial landforms from the last laurentide and fennoscandian ice sheets iii these landforms have significant potential for characterising the nature of deglaciation around the margins of the irish sea during the last glacial cycle and may record evidence for the overextension and stagnation of the south eastern margin of the irish sea ice stream and iv investigations of ramparted depressions within formerly glaciated terrains must consider both glacial and periglacial mechanisms of formation

tectonic units of the alpine collision zone between eastern alps and western turkey abstract we present a map that correlates tectonic units between alps and western turkey accompanied by a text providing access to literature data explaining the concepts used for defining the mapped tectonic units and first order paleogeographic inferences along strike similarities and differences of the alpine eastern mediterranean orogenic system are discussed the map allows 1 for superimposing additional information such as e g post tectonic sedimentary basins manifestations of magmatic activity onto a coherent tectonic framework and 2 for outlining the major features of the alpine eastern mediterranean orogen dinarides hellenides anatolides and taurides are orogens of opposite subduction polarity and direction of major transport with respect to alps and carpathians and polarity switches across the mid hungarian fault zone the dinarides hellenides taurides and apennines consist of nappes detached from the greater adriatic continental margin during cretaceous and cenozoic orogeny internal units form composite nappes that passively carry ophiolites obducted in the latest jurassic earliest cretaceous or during the late cretaceous on top of the greater adriatic margin successions the ophiolites on top of composite nappes do not represent oceanic sutures zones but root in the suture zones of neotethys that formed after obduction suturing between greater adria and the northern and eastern neotethys margin occupied by the tisza and dacia mega units and the pontides occurred in the latest cretaceous along the sava izmir ankara erzincan suture zones the rhodopian orogen is interpreted as a deep crustal nappe stack formed in tandem with the carpatho balkanides fold thrust belt now exposed in a giant core complex exhumed in late eocene to miocene times from below the carpatho balkan orogen and the circum rhodope unit its tectonic position is similar to that of the sakarya unit of the pontides we infer that the rhodope nappe stack formed due to north directed thrusting both rhodopes and pontides are suspected to preserve the westernmost relics of the suture zone of paleotethys

one million cubic kilometers of fossil ice in valles marineris relicts of a 3 5 gy old glacial landsystem along the martian equator abstract self consistent landform assemblages suggest that valles marineris the giant valley system that stretches along the martian equator was entirely glaciated during late noachian to early hesperian times and still contains huge volumes of fossil ice some of these glacial landform assemblages are illustrated here with representative examples selected in three regions ius chasma central candor chasma and the junction between coprates chasma and capri chasma a morphological boundary separating an upper spur and gully morphology from a smooth basal escarpment has been spectacularly preserved along valley walls throughout valles marineris the boundary winds around topographic obstacles and displays long wavelength variations in elevation it is associated with lateral benches hanging valleys and truncated spurs comparisons with terrestrial analogs indicate that it is most reasonably interpreted as a glacial trimline chasma floors are covered by various kinds of terrains including hummocky terrains platy terrains lateral banks layered benches and a draping mantle landforms in these terrains and their spatial relationship with the interpreted trimline suggest that they correspond to various disintegration stages of an ancient glacial fill currently protected by a superficial cover of ablation till altogether these landforms and terrains compose a full glacial landsystem with wet based glaciers that were able to flow and slide over their beds it was most probably fed by ice accumulating at low elevations directly from the atmosphere onto valley floors and walls with only minor contributions from tributary glaciers flowing down from higher elevations similar fossil glacial landsystems dating back from the early martian history are to be expected in many other low latitude troughs such as chasmata chaos valleys impact craters and other basins

airborne radar sounder for temperate ice initial results from patagonia we describe the development of a low frequency airborne radar specifically designed for the sounding of temperate ice the system operates at a central frequency of 1 mhz and consists of an impulse transmitter with an output voltage up to 5000 v and a digital receiver with a maximum gain of 80 db the radar was deployed on board a casa 212 aircraft which also carries a laser altimeter an inertial navigation system a digital camera and a gps receiver a description of the radar system is provided as well as preliminary results obtained at glaciar tyndall campo de hielo sur southern patagonia icefield where an ice depth of 670 m was reached

basal conditions at engabreen norway inferred from surface measurements and inverse modelling engabreen is an outlet glacier of the svartisen ice cap located in northern norway it is a unique glacier due to the svartisen subglacial laboratory which allows direct access to the glacier bed in this study we combine both sub and supraglacial observations with ice flow modelling in order to investigate conditions at the bed of engabreen both spatially and temporally we use the full stokes model elmer ice and satellite based surface velocity maps from 2010 and 2014 to infer patterns of basal friction direct measurements of basal sliding and deformation of lower layers of the ice are used to adjust the ice viscosity and provide essential input to the setup of our model and influence the interpretation of the results we find a clear seasonal cycle in the subglacial conditions at the higher elevation region of the study area and discuss this in relation to the subglacial hydrological system our results also reveal an area with an overdeepening where basal friction is significantly lower than elsewhere on the glacier all year round we attribute this to either water pooling at the base or saturated sediments and increased strain heating at this location which softens the ice further

tectonic evolution of the northwestern internal dinarides as constrained by structures and rotation of medvednica mountains north croatia this paper attempts to explain the tectonic history and the possible reasons for the change of trend of the northwestern part of internal dinarides in a transitional area between the southern eastern alps central dinarides and tisia north of zagreb structural and palaeomagnetic data collected in pre neogene rocks at medvednica mts combined with palaeomagnetic data available form neogene rocks in the surrounding area point to the following conclusions 1 the reason for dramatic deflection in structural trend of the internal dinarides in the area north of zagreb is a 130o clockwise rotation and eastward escape of a tectonic block comprising medvednica mts and the surrounding inselbergs bounded to the north by the easternmost tip of the periadratic lineament in medvednica mts the main period of tectonic escape and associated clockwise rotation occurred in late palaeogene possibly in oligocene earliest miocene 2 when rotated into the original position the trend of observed pre neogene structures of medvednica mt becomes parallel to the major structural trend of the central dinarides in view of their original orientation these structures are interpreted in the following way a the first d1 deformational event is attributed to the aptian albian nappe stacking in the central northern dinarides that was accommodated by a top to the north directed shearing and northward propagation of already obducted ophiolites of the central dinaridic ophiolite zone this nappe stacking which resulted in a weak regional metamorphism in tectonic units underlying the ophiolites was orogen parallel or at a very acute angle to known structural and possibly palaeogeographic trends this implies a major left lateral shear component along the former adriatic margin and obducted dinaridic ophiolite zone b this was followed by early albian orogen perpendicular shortening d2 that was accommodated by folding and top to the west thrusting this deformation resulted in gradual cooling of the metamorphic stack and also in uplift and erosion of the higher structural units c d3 deformational event was driven by renewed e w shortening that took place after the paleocene most probably during the middle eocene oligocene i e synchronous with the main dinaridic tectonic phase of the external dinarides this shortening was probably triggered by collision and thrusting of tisia over the northern segment of the internal dinarides d this was finally followed by d4 pervasive right lateral n s shearing that is tentatively interpreted as being related to the right lateral shearing of the sava zone during the eocene oligocene e following the main period of tectonic escape and induced clockwise rotation in late palaeogene possibly in oligocene earliest miocene the medvednica mts and the surrounding area were affected by repeated extensions and inversions since the early miocene to recent times palaeomagnetic data suggest that in the early miocene but probably before the karpatian this area was part of a regional block that shifted northwards and rotated in counter clockwise sense a second episode of counter clockwise rotation occurred at the present latitude in post pontian times since ca 5 ma driven by the counter clockwise rotating adriatic plate

stratigraphy facies and geodynamic settings of jurassic formations in the bukk mountains north hungary its relations with the other areas of the neotethyan realm jurassic melange complexes related to the subduction of the neotethys ocean occur in the bukk mountains north hungary this paper characterizes the sedimentary sequence of basin and slope facies that occur in the southwestern part of the bukk mountains placing special emphasis on the redeposited sedimentary rocks olistostromes olistoliths monosbel group in order to obtain information on the provenance of the clasts and the mode and time of their redeposition the series of formations studied shows a general coarsening upwards trend based on radiolarians and foraminifera the monosbel group formed in early to late bathonian time the lower part of the complex is typified by a predominance of pelagic carbonates shale and radiolarite with andesitic volcaniclastic intercalations the higher part of the succession is characterized by polymictic olistostromes large olistoliths that are predominantly blocks of bathonian shallow marine limestone bukkzserc limestone appear in the upper part of the sequence based on the biostratigraphic and sedimentological data results of analyses of the redeposited clasts and taking into consideration the concepts of the development of the western neotethys domain the evolutionary stages of the sedimentary basins were defined the onset of the compressional stage led to initiation of nappe stacking that led to the formation of polymict olistostromes and then to the redeposition of large blocks derived from out of sequence nappes of the former platform foreland

influence of landslides on biophysical diversity a perspective from british columbia landslides have long been overlooked or underestimated as important natural disturbance agents in particular the ecological role of landslides in maintaining biological diversity has been largely ignored here we provide a western canadian british columbian perspective on the influences of landslides on biophysical diversity which is related in several ways to biological diversity we recognize several types of biophysical ecological diversity site diversity soil diversity and the derivative habitat or ecosystem including aquatic ecosystems diversity there are also a variety of landslide types depending on materials and on the rate and style of movement we discuss the roles of different landslide types on various aspects of terrestrial diversity landslides are simultaneously depositional and erosional processes that influence sites by redistributing materials and changing surface expression usually creating a complex microtopography that can include very dry ridges and hummocks and sometimes depressions with standing water landslide impacts to site also influence soil and soil development portions of landslides with exposed parent material are set back to the initial stages of soil development and ecological succession landslides can also change soil density structure porosity surface texture chemistry and microclimate by changing site and soil landslides also influence habitat landslides influence habitat diversity by engendering a mosaic of seral stages often both primary and secondary and in overwhelmingly forested landscapes often create nodes or hotspots of non forested habitat and biota in some areas like the boreal forest there is an important interplay between landslides and fire while on the coast of british columbia debris and snow avalanches can be the dominant disturbance agent low gradient and deep seated landslides are often opportunistically colonized by beaver and other water and shrub loving fauna sag ponds and impounded streams provide aquatic habitat often with standing dead trees landslide rubble and scarps provide denning nesting habitat escape terrain and cliff habitat for vertebrates

ice shaped ring forms in western canada their airphoto expressions and manifold polygenetic origins abstract a variety of ice shaped ring forms and patterns in western canada are strikingly expressed in black and white aerial photographs the most common forms are round and oval mounds and plateaus with rim ridges around summit craters it is speculated that small clusters and large fields of them originated from dead ice supraglacial and subglacial wasting processes and often from a combination of both where shallow glacial lake waters were present other ice shaped ring features and patterns illustrated in this paper result from former and present permafrost and periglacial activity groundwater discharge and winter ice mounding and expansion that transfer fine sediment from circular orifices to their margins slush formation that creates fractal like patterns on thin ice floating on shallow snow covered lakes and wind driven icebergs and lake ice that produce circular scours on the beds of glacial lakes portions of contact airphotos have been included to show better examples of ring forms and patterns in western canada speculations on their manifold polygenetic origins are presented

the landslide dam on the saddle river near rycroft alberta alberta s largest historic landslide dammed the saddle river near rycroft alberta and thrust the bed of the river upward against the opposite valley wall forming a type 6 landslide dam the rycroft landslide occurred within a day or two of 17 june 1990 on the north wall of the saddle river 12 km northeast of rycroft alberta the triggers for the landslide are considered to be the lateral and vertical erosion of the river as a result of a severe rainstorm and the ensuing flood the slide scarp arcs for 1 km through a cultivated field the loss of farmed land was 13 h 32 acres a further 10 h 25 acres may be lost by retrogression of the scarp the toe heaved the riverbed upward as much as 20 m and thrust it laterally 60 m to be compressed against the opposite valley wall about 40 mm3 of ground moved the rupture surface dipped steeply through postglacial lake clay and till curved abruptly to pass on a subhorizontal surface through preglacial clay then curved upward under the riverbed this pregla