crustal structure due to collisional and escape tectonics in the eastern alps region based on profiles alp01 and alp02 from the alp 2002 seismic experiment 1 alp01 and alp02 are the longest profiles recorded during alp 2002 a large international seismic refraction and wide angle reflection experiment undertaken in the eastern alps in 2002 alp01 crosses the alpine orogen from north to south thus providing a cross section mainly affected by the collision between europe and the adriatic microplate alp02 extends from the eastern alps to the pannonian basin supplying evidence on the relation between alpine crustal structure and tectonic escape to the pannonian basin during this experiment 363 single channel recorders were deployed along these profiles with an average spacing of 3 2 km recordings from 20 inline shots were used in this study two dimensional forward modeling using interactive ray tracing techniques produced detailed p wave velocity models that contain many features of tectonic significance along alp01 the european moho dips generally to the south and reaches a maximum depth of 47 km below the transition from the eastern to the southern alps the adriatic moho continues further south at a significantly shallower depth moho topography and a prominent south dipping mantle reflector in the alpine area support the idea of southward subduction of the european lithosphere below the adriatic microplate the most prominent tectonic feature on the alp02 profile is a vertical step of the moho at the transition between the alpine and pannonian domains suggesting the existence of a separate pannonian plate fragment the development of the pannonian fragment is interpreted to be a consequence of crustal thinning due to tectonic escape from the alpine collision area to the pannonian basin

palinspastic reconstruction and topographic evolution of the eastern alps during late tertiary tectonic extrusion this paper presents a new palinspastic restoration of the eastern alps for neogene time and an attempt to reconstruct the neogene palaeogeology palaeotopography and palaeohydrography in connection with the structural evolution the eastern alps underwent radical horizontal displacement during the neogene due to large strike slip systems and formation of structural windows our palinspastic reconstruction considers a the rearrangement of tectonic units dismembered during tectonic extrusion b the tectonic denudation driven by displacement of the crystalline blocks c geochronological arguments and d the sedimentary record of the syn extrusion basins the rearrangement of tectonic blocks results in a remarkably good fit of highly dismembered zones both in crystalline and sedimentary areas and shows the pre miocene unstretched pattern of the eastern alps reduced to 65 of its present day e w elongation using this structural frame and considering the sedimentary record a set of palaeogeologic and palaeotopographic sketch maps with the palaeo river systems is presented for three time slices pre syn and post extension situation in late oligocene and early miocene times the western eastern alps were already mountainous whereas the eastern part of the orogen formed lowlands or hilly areas enhanced block movement in the course of the extrusion process around the early middle miocene boundary led to the formation of intramontane sedimentary basins and a fault induced reorientation of the drainage pattern which forms the basis of the modern river system in the area east of the tauern window this region where pre miocene land surfaces are preserved probably became a mountainous area not before late miocene time and never reached the elevations of the areas further west

pace of landscape evolution in the sierra nevada california revealed by cosmogenic dating of cave sediments we report 26 al 10 be based ages of sierra nevada caves that constrain detailed late pliocene and quaternary river incision his tories for five river canyons rapid incision of 0 2 mm yr from 2 7 to ca 1 5 ma slowed markedly to 0 03 mm yr thereafter likely reflecting the combined effects of a transient erosional re sponse to pliocene rock uplift and periodic mantling of riverbeds with glacially derived sediment in the late quaternary while 400 m of incision has occurred in the past 2 7 m y outpacing interfluve erosion and thereby increasing the local relief canyons as deep as 1 6 km existed prior to that time these new erosion rates strength en the case for tectonically driven late cenozoic uplift

subsidence analysis and quantitative basin modelling in the styrian basin pannonian basin system austria abstract we present the results of subsidence analysis and of quantitative basin modelling using isostatical and flexural models for basin evolution along four cross sections in the styrian basin the westernmost subbasin of the pannonian basin system subsidence analysis reveals a first ottnangian karpatian synrift phase our local isostatic models predict crustal stretching values up to 1 3 and subcrustal stretching values of 1 6 for this event stretching factors of a minor sarmatian extension phase are below 1 04 the termination of subsidence during the pannonian and a rapid quaternary uplift phase can be explained by major changes in the regional stress field a w e cross section through the northern furstenfeld subbasin provides a key for the understanding of the dynamics of basin formation it crosses a narrow karpatian rift basin the metamorphic core complex of the penninic eisenberg window and shows an eastward tilting of the easternmost part of the basin during pannonian times uplift of the penninic window can only be modelled with an extremely weak lithosphere equivalent elastic thickness eet 2 km whereas a best fit between observed and modelled tilting is obtained with an eet value of 5 km these results suggest that the lithosphere was extremely weak during the onset of basin evolution in ottnangian karpatian times probably caused by high extension rates and high heat flows associated with karpatian to early badenian magmatic activity subsequent cooling led to a pronounced increase in flexural rigidity an eet of 5 km fits well with estimations in other parts of the pannonian realm depth dependent rheology models based on palaeo heat flow estimates indicate a similar increase in lithospheric strength with time the impact of plio pleistocene volcanism on rheology appears to be relatively modest which can be explained by a deep position of the magma chamber for this event

morphological analysis of the drainage system in the eastern alps abstract we study the morphology of the major rivers draining the eastern alps to test whether the active tectonics of this part of the orogen is reflected in the shape of channel profiles of the river network in our approach we compare channel profiles measured from digital elevation models with numerically modelled channel profiles using a stream power approach it is shown that regions of high stream power coincide largely with regions of highest topography and largest uplift rates while the forelands and the pannonian basin are characterised by a significantly lower stream power from stream power modelling we conclude that there is young uplift at the very east of the eastern alps in the bohemian massif and in the pohorje range the impact of the pleistocene glaciations is explored by comparing properties of rivers that drain in proximal and distal positions relative to the ice sheet during the last glacial maximum our analysis shows that most knick points wind gaps and other non equilibrium features of catchments covered by ice during the last glaciations salzach enns can be correlated with glacial processes in contrast the ice free catchments of the mur and drava are characterized by channels in morphological equilibrium at the first approximation and are showing only weak evidence of the strong tectonic activity within these catchments finally the channel profiles of the adige and the divide between the upper rhine and danube catchments differ significantly from the other catchments we relate this to the fact that the adige and the rhine respond to different base levels from the remainder of the eastern alps the adige may preserve a record from the messininan base level change and the rhine is subject to the base level lowering in the rhine graben

tectonics and sedimentation in the fohnsdorf seckau basin miocene austria from a pull apart basin to a half graben the miocene intramontane fohnsdorf seckau basin is situated at the junction of the sinistral mur murz fault system and the dextral pols lavanttal fault system the basin comprises a 2 400 m thick coal bearing fluviodeltaic lacustrine succession lower to middle miocene upper karpatian lower badenian which is overlain by a 1 000 m thick alluvio deltaic conglomeratic succession apfelberg formation middle upper badenian in the south a three stage model for the basin evolution has been reconstructed from structural analysis and basin fill geometries during a first pull apart phase subsidence occurred along ene trending sinistral strike slip faults of the mur murz fault system and ne sw to n s trending normal faults forming a composite pull apart basin between overstepping en echelon strike slip faults the seckau and fohnsdorf sub basins are considered as two adjacent pull aparts which merged into one basin during the second phase n s to nnw sse extension and normal faulting along the southern basin margin fault formed a half graben filled by wedge shaped alluvial strata apfelberg formation during the third phase after the end of basin sedimentation the dextral pols lavanttal fault system reshaped the western basin margin into a positive flower structure

the control mechanisms of erosion and weathering at basin scale from cosmogenic nuclides in river sediment the study of a sample of river sediment enables the determination of spatially averaged denudation rates that provide an exceptional perspective on erosion and weathering processes that have taken place within a landscape these measurements are done with in situ produced cosmogenic nuclides e g 10be 26al mostly in quartz from alluvial sediment cosmogenic nuclides are produced when secondary cosmic rays interact with the very uppermost layer of the earth s surface they are produced within a characteristic depth scale of about 1 m which means that the measured concentrations record an integrated denudation history while material passed through this depth interval depending on the denudation rate the resulting integration time scales are 103 to 105 years and one obtains a robust long term estimate of natural denudation that is relatively insensitive to short term changes the last 10 years have seen significant research activity using these methods and an array of fascinating tectono geomorphologic and geochemical insights are emerging amongst these is the ability to identify the physical and chemical processes with which a landscape responds to tectonic activity or climate change a compilation of world wide denudation rates in non glaciated areas that however does not yet include some of the world s most active mountain belts has resulted in the following findings some of which have been unexpected 1 no obvious relationship between precipitation or mean annual temperature and total denudation is apparent 2 topographic relief alone does not result in high rates of denudation 3 denudation rates are high in areas of landscape rejuvenation that is triggered and controlled by tectonic activity faulting escarpment formation and retreat rifting surface uplift 4 rates of weathering using a combination of cosmogenic nuclides and zirconium normalised cation loss balances co vary primarily with physical erosion rates and much less with temperature or precipitation 5 in some areas of high land use short term rates from river load gauging exceed those from cosmogenic nuclides by several orders of magnitude which serves to highlight the severity of geomorphic change caused by human action in the future the control mechanisms over denudation will be determined on all spatial scales ranging from the single soil section to entire river basins the same analysis can be done back through time on well dated terraces lake records and marine sediment cores which is possible with 10be for the past 1 2 my the rates obtained will be used to develop a quantitative understanding of tectonic geomorphologic and geochemical landscape processes which in turn is a prerequisite to design and calibrate models of the response of landscapes to tectonic climate and anthropogenic forcing

thermal history of tertiary basins in slovenia alpine dinaride pannonian junction abstract the transition zone between the alps the dinarides and the pannonian basin was affected by syn collisional magmatism in oligocene time and post collisional lateral escape followed by extreme extension in early and middle miocene times numeric heat flow models for sixteen sites and 650 vitrinite reflectance data from paleogene and neogene sediments were used to evaluate temporal and lateral heat flow variations related to these events oligocene oligocene smrekovec volcanism is the main heat source for paleogene sediments south of the periadriatic lineament vitrinite reflectance patterns suggest dextral displacement along the donat fault of the order of 50 km coalification of paleogene coal bearing sequences south of the pohorje is a result of the emplacement of the oligocene pohorje tonalite early middle miocene extremely elevated early middle miocene heat flow 200 mw m2 occurred in the styrian basin the pohorje area the maribor radgona area and along the boc anticline it is partly a consequence of magmatic activity however no igneous rocks are known from the maribor radgona area a large shallow early miocene pluton could explain the observed miocene heat flow rapid uplift of hot basement rocks in the pohorje kozjak region may have increased surface heat flow neither volcanic rocks nor metamorphic core complexes are known from the boc area the ormo selnica anticline was probably influenced by a middle miocene heating event 150 mw m2 coeval volcanism south of the anticline represents a potential heat source post middle miocene the wsw ene trending ljutomer and radgona depressions are characterized by moderate neogene heat flow 60 75 mw m2 whereas late miocene to present day heat flow in the ormo selnica anticline is 80 90 mw m2 a recent heat flow anomaly occurs in the somat benedikt area

erosion driven uplift of the modern central alps abstract we present a compilation of data of modern tectono geomorphic processes in the central european alps which suggest that observed rock uplift is a response to climate driven denudation this interpretation is predominantly based on the recent quantification of basin averaged late holocene denudation rates that are so similar to the pattern and rates of rock uplift rates as determined by geodetic leveling furthermore a gps data based synthesis of adriatic microplate kinematics suggests that the central alps are currently not in a state of active convergence finally we illustrate that the central alps have acted as a closed system for holocene redistribution of sediment in which the peri alpine lakes have operated as a sink for the erosional products of the inner central alps while various hypotheses have been put forward to explain central alpine rock uplift e g lithospheric forcing by convergence mantle processes or ice melting we show with an elastic model of lithospheric deformation that the correlation between erosion and rock uplift rates reflects a positive feedback between denudation and the associated isostatic response to unloading thus erosion does not passively respond to advection of crustal material as might be the case in actively converging orogens rather we suggest that the geomorphic response of the alpine topography to glacial and fluvial erosion and the resulting disequilibrium for modern channelized and associated hillslope processes explains much of the pattern of modern denudation and hence rock uplift therefore in a non convergent orogen such as the central european alps the observed vertical rock uplift is primarily a consequence of passive unloading due to erosion

an outline of neotectonic structures and morphotectonics of the western and central pannonian basin abstract neotectonic deformation in the western and central part of the pannonian basin was investigated by means of surface and subsurface structural analyses and geomorphologic observations the applied methodology includes the study of outcrops industrial seismic profiles digital elevation models topographic maps and borehole data observations suggest that most of the neotectonic structures in the pannonian basin are related to the inverse reactivation of earlier faults formed mainly during the miocene syn and post rift phases typical structures are folds blind reverse faults and transpressional strike slip faults although normal or oblique normal faults are also present these structures significantly controlled the evolution of landforms and the drainage pattern by inducing surface upwarping and river deflections our analyses do not support the postulated tectonic origin of some landforms particularly that of the radial valley system in the western pannonian basin the most important neotectonic strike slip faults are trending to east northeast and have dextral to sinistral kinematics in the south western and central eastern part of the studied area respectively the suggested along strike change of kinematics within the same shear zones is in agreement with the fan shaped recent stress trajectories and with the present day motion of crustal blocks derived from gps data

palaeogeography subsidence and thermal history of the neogene styrian basin pannonian basin system austria abstract the neogene styrian basin represents an extensional structure on top of a crustal wedge which was moving eastward during the final stages of the alpine orogeny eastward extrusion was a consequence of continental escape and extensional collapse within the eastern alps in a simple model the evolution of the styrian basin can be subdivided into an early miocene ottnangian to karpatian synrift and a subsequent postrift phase basement subsidence rates during the synrift phase reached 30 cm 100 yr and more than 2000 m of limnic to marine sediments were deposited the coincidence of the synrift phase and the formation of pull apart structures along strike slip zones bordering the eastward moving wedge is evidence for the close genetic relation between extrusion tectonics and basin formation a miocene magmatic phase is related to subduction along the carpathian front magmatic activity started during the synrift stage and continued into the postrift stage heat flow in the vicinity of the miocene volcanoes increased dramatically 300 mw m2 a second volcanic phase producing basalts in plio pleistocene times had only little influence on the heat flow pattern limnic to marine sediments of the synrift stage are separated by a major unconformity from middle to late miocene badenian to pontian marine to limnic fluvial postrift sediments sedimentation during the postrift phase was controlled by marine ingressions during middle miocene early badenian and sarmatian times from the south and a subsequent regression with a decline in salinity subsidence rates during the postrift stage were mostly below 2 5 cm 100 yr in pliocene times subsidence was replaced by uplift which resulted in erosion of a few hundred metres of sediment present day high heat flows are a consequence of thinned crust beneath the styrian basin

post collisional sediment budget history of the alps tectonic versus climatic control based on the sediment budget of the eastern swiss and western alps since the oligocene the regional tectonic evolution has been identified as the dominant factor it is superimposed on the influence of both regional and global climate change and global sea level change during late pliocene and pleistocene times climate became the dominant factor because of cyclic glaciations the early post collisional history of the alps is characterized by a doubling of sediment discharge rates around the rupelian chattian boundary this increase is attributed to isostatic re adjustment either after large scale thermal reorganization of the lithosphere related to slab break off or to crustal thickening as continental crust became subducted from middle oligocene to late miocene times the overall trend of sediment discharge rates in the entire alps was modified only during relatively short lived phases these are characterized by an increase in aquitanian ca 23 21 ma and late burdigalian times ca 18 16 4 ma and a decrease in early to middle burdigalian 21 19 ma and langhian to serravalian times 16 4 12 ma an important still ongoing period of uplift reflected by rapidly increasing sediment discharge rates started in latest miocene times in the swiss and western alps and affected the eastern alps some 2 million years later the reason for this uplift is not clear but deep seated lithospheric processes appear to be likely

active crustal deformation in two seismogenic zones of the pannonian region gps versus seismological observations abstract the seismicity and the associated seismic hazard in the central part of the pannonian region is moderate however the vulnerability is high as three capital cities are located near the most active seismic zones in our analysis two seismically active areas the central pannonian and mur murz zones have been considered in order to assess the style and rate of crustal deformation using global positioning system gps and earthquake data we processed data of continuous and campaign gps measurements obtained during the years 1991 2007 velocities relative to the stable eurasia have been computed at hgrn cegrn and epn gps sites in and around the pannonian basin uniform strain rates and relative displacements were calculated for the investigated regions gps data confirm the mostly left lateral strike slip character of the mur murz vienna basin fault system and suggest a contraction between the eastward moving alpine north pannonian unit and the carpathians the computation of the seismic strain rate was based on the kostrov summation the averaged unit norm seismic moment tensor which describes the characteristic style of deformation has been obtained from the available focal mechanism solutions whereas the annual seismic moment release showing the rate of the deformation was estimated using the catalogues of historical and recent earthquakes our analysis reveals that in the central pannonian zone the geodetic strain rate is significantly larger than the seismic strain rate based on the weakness of the lithosphere the stress magnitudes and the regional features of seismicity we suggest that the low value of the seismic geodetic strain rate ratio can be attributed to the aseismic release of the prevailing compressive stress and not to an overdue major earthquake in the mur murz zone although the uncertainty of the seismic geodetic strain rate ratio is high the seismic part of the deformation seems to be notably larger than in the case of the central pannonian zone these results reflect the different deformation mechanism rheology and tectonic style of the investigated zones

internal structural geometry of the paleozoic of graz the paleozoic of graz is an isolated nappe complex of about 1 500 km2 size and belongs to the austroalpine units of the eastern european alps despite more than 500 publications on stratigraphy paleontology and local structure many aspects of the internal geometry of this complex as a whole remained unclear in this contribution we present integrated geological profiles through the entire nappe complex based on these profiles we present 1 a simplified lithological subdivision into 13 rock associations 2 a modified tectonostratigraphy where we consider only two major tectonic units an upper and a lower nappe system and in which we abandon the traditionally used facies nappe concept and 3 a modified paleogeography for the whole complex finally we discuss whether the internal deformation of the paleozoic of graz is of variscan or eo alpine age and which of the published models best explain the tectonic evolution of the paleozoic of graz

cold spots during the cenozoic evolution of the eastern alps thermochronological interpretation of apatite fission track data abstract the tectonical and morphological evolution of the eastern alps during the cenozoic is discussed in the light of sedimentary record and thermochronological data of crystalline basement rocks the regional distribution of apatite fission track data in the central eastern alps reveals the differential cenozoic exhumation in contrast to the penninic of the tauern window which has been strongly uplifted and eroded since the early miocene the amount of neogene denudation was much smaller in most areas east of the hohe tauern a sudden change in the regional cooling behaviour is observed at the katschberg fault system which must have been active in post oligocene times within the austroalpine only the schladming tauern have experienced a rather strong denudation the seckau core complex east of the pols line and the area of the northern koralpe cooled to below 100 c at the end of the cretaceous and in the early eocene respectively and have never been heated again during the cenozoic these parts of the austroalpine nappe pile were always near to the surface and therefore may be summarized under the term cold spots a major post cretaceous thickening of the austroalpine can be excluded because it would have produced more uplift and erosion any remnants of miocene or older landforms are certainly not preserved in the area of the tauern window the uppermost planation surfaces in the crystalline basement at the western border of the styrian basin koralpe probably developed in the late miocene

rapid exhumation in the western alps driven by slab detachment and glacial erosion identifying topographic and erosion rate response to tectonic and climatic forcing remains challenging this is in part because of the difficulty in isolating the respective roles of climate and tectonics here we exploit 2500 thermochronometric data points collected over several decades of research using a new inverse technique to image the space time evolution of erosion rate across the european alps over the past 35 m y the most striking feature of our results is a two to three fold increase in erosion rate over the past 2 m y exclusively within the western and central alps this increase appears to be controlled by the inferred high rock uplift rate due to the progressive detachment of the european slab under the western alps the similarity in mean elevation between the western and eastern alps indicates a surprisingly low topographic response to this differential tectonic forcing and points to the role of enhanced glacial erosion in response to surface uplift

rates of erosion and topographic evolution of the sierra nevada california inferred from cosmogenic26al and10be concentrations concentrations of cosmogenic 26 al and 10 be in cave sediments and bedrock surfaces combined with studies of landscape morphology elucidate the topographic history of the southern sierra nevada over the past 5 ma caves dated by 26 al 10 be in buried sediments reveal that river incision rates were moderate to slow between c 5 and 3 ma 0 07 mm a 1 accelerated between 3 and 1 5 ma c 0 3 mm a 1 and then have subsequently become much slower c 0 02 mm a 1 although the onset of accelerated incision coincides in time with both postulated pliocene tectonism and pronounced global climate change we argue that it primarily represents the response to a discrete tectonic event between 3 and 5 ma dated cave positions reveal that prior to 3 ma river canyons displayed up to 1 6 km of local relief suggesting that pliocene rock uplift elevated pre existing topography renewed incision beginning c 3 ma deepened canyons by up to 400 m creating narrow inner gorges tributary streams exhibit strong convexities indicating that the transient erosional response to pliocene uplift has not yet propagated into upland surfaces concentrations of 26 al and 10 be in bare bedrock show that upland surfaces are eroding at slow rates of c 0 01 mm a 1 over the past c 3 ma upland surfaces eroded slowly while adjacent rivers incised rapidly increasing local relief although relief production probably drove at least modest crestal uplift considerable prepliocene relief and low spatially averaged erosion rates suggest that climatically driven rock uplift is not sufficient to explain all uplift implied by tilted markers at the western edge of the range despite the recent pulse of erosion spatially averaged erosion rates are low and have probably acted to preserve the broad topographic form of the sierra nevada throughout much of the late cenozoic copyright 2005 john wiley sons ltd

abrupt glacial valley incision at 0 8 ma dated from cave deposits in switzerland glacial erosion dramatically alters mountain landscapes but the pace at which glaciers carve a previously fluvial landscape remains poorly defined because long term valley incision rates are difficult to measure here we reconstruct the lowering history of the aare valley switzerland over the past 4 m y by dating cave sediments with cosmogenic 26al and 10be incision accelerated from 120 m m y to 1200 m m y at 0 8 1 0 ma at least 1 m y after the onset of local glaciation rapid incision may have been triggered by lowering of the equilibrium line altitude at the mid pleistocene climate transition

relation between rock uplift and denudation from cosmogenic nuclides in river sediment in the central alps of switzerland 1 a north south traverse through the swiss central alps reveals that denudation rates correlate with recent rock uplift rates in both magnitude and spatial distribution this result emerges from a study of in situ produced cosmogenic 10be in riverborne quartz in central alpine catchments as a prerequisite we took care to investigate the potential influence of shielding from cosmic rays due to snow glaciers and topographic obstructions to calculate a possible memory from last glacial maximum lgm glaciation and to identify a watershed size that is appropriate for systematic sampling mean denudation rates are 0 27 0 14 mm a for the alpine foreland and 0 9 0 3 mm a for the crystalline central alps the measured cosmogenic nuclide derived denudation rates are in good agreement with post lgm lake infill rates and are about twice as high as denudation rates from apatite fission track ages that record denudation from 9 to 5 ma in general denudation rates are high in areas of high topography and high crustal thickness the similarity in the spatial distribution and magnitude of denudation rates and those of rock uplift rates can be interpreted in several ways 1 postglacial rebound or climate change has introduced a transient change in which both uplift and denudation follow each other with a short lag time 2 the amplitude of glacial to interglacial changes in both is small and is contained in the scatter of the data 3 both are driven by ongoing convergence where their similarity might hint at some form of long term quasi steady state or 4 enhanced continuous quaternary erosion and isostatic compensation of the mass removed accounts for the distribution of present day rock uplift

stress induced late stage subsidence anomalies in the pannonian basin abstract subsidence sedimentation and tectonic quiescence of the pannonian basin was interrupted a few million years ago by tectonic reactivation this recent activity has manifested itself in uplift of the western and eastern flanks and continuing subsidence of the central part of the pannonian basin low to medium magnitude earthquakes of the carpathian pannonian region are generated mostly in the upper crust by reverse and wrench fault mechanisms there is no evidence for earthquakes of extensional origin 2 d model calculation of the subsidence history shows that a recent increase in magnitude of horizontal compressional intraplate stress can explain fairly well the observed quaternary uplift and subsidence pattern we propose that this stress increase is caused by the overall europe africa convergence in late pliocene consumption of subductible lithosphere at the eastern margin of the pannonian basin was completed and the lithosphere underlying the pannonian basin became locked in a stable continental frame consequently extensional basin formation has come to an end and compressional inversion of the pannonian basin is in progress

crustal uplift in the alps why the drainage pattern matters introductionmountain belts grow by accretion ofupper crustal material into the orogen icwedge fig 1 materialenteringthewedge gets deformed uplifted andexhumed basedontheoreticalmodels willett et al 1993 concluded thatorogensadoptadistinctgeometrywitha low tapered pro wedge facing thesubduction plate and a high taperedretro side this geometry establishesbecauseorogenstendtobeonthevergeof gravitational failure davis et al 1983 according to these models thevelocity eld of the crust and hence the exhumation path of rock particles depends on erosion at the surface e g horton 1999 consequently anychanges in erosion rates potentiallyresult in a modi cation of the patternof strain rates of surface erosion however depend on climate exposedlithologies the size of the catchmentarea thegeometriccon gurationofthedrainage basin and rates of crustaluplift tucker and slingerland 1996 although the impact of these para meters on surface erosion has beenstudied extensively using numericalmodels tucker and slingerland 1997 ku hni and p ffner 2001 schlu neggeret al 2001 verylittleattentionhas been paid to the in uence of thedrainage geometry on the spatial pat tern of erosion and on strain the central swiss alps provide anexample where the present daydrainage geometry reveals a distinctpattern that is characterized by largeorogen parallel dispersal systems therhone and rhine rivers fig 2a that drain the core of the alps and smaller orogen normal rivers according to the conceptual modelsoutlined above it is reasonable tospeculate that the asymmetry of thealpine drainage pattern is likely toin uence the pattern of crustal up lift speci cally the highest rates ofstrain release are expected in therhone and rhine valleys becausethe large drainage basins of theserivers are likely to result in enhancederosional potentials this hypothesiswill be tested in the following chap ters this present paper evaluates thepotential controls of the asymmetriccon guration of the alpine drainagepattern on possible variations oferosional potential as well as onpresent day and glacial sedimentyield this information is then rela ted to the published pattern ofcrustal uplift allowing possible pos itive feedback between surface ero sion and lithospheric forcing to beidenti ed the intention is not todiscard other processes as possiblecontrols on the pattern of crustaluplift e g exural rebound afterremoval of the pleistocene ice sheet kahle et al 1997 but rather topropose an alternative model thatmight enrich the range of possibleinterpretations pattern of crustal upliftand seismic activityfigure 2 a displays the recent verti cal movements of the swiss alpscomputed for rst order levellingbenchmarks relative to the benchmarkat aarburg gubler et al 1981 kahleet al 1997 the geodetic data wascollected repeatedly between c 1905and 1990 measured uplift is inter preted in terms of crustal upliftbecause benchmarks have not experi enced erosion i e they record theshort term velocity eld of upper most crustal levels the data indicatea considerable increase of crustaluplift rates from the foreland tothe rear of the alps where currentrates of 1 mm yr

cosmogenic nuclide derived rates of diffusive and episodic erosion in the glacially sculpted upper rhone valley swiss alps denudation rates of small tributary valleys in the upper rhone valley of the swiss central alps vary by more than an order of magnitude within a very small distance tens of kilometers morphometric data indicate two distinct erosion processes operate in these steep mountain valleys we determined the rates of these processes using cosmogenic beryllium 10 10be in pooled soil and stream sediment samples denudation in deep glacially scoured valleys is characterized by rapid non uniform processes such as debris flows and rock falls in these steep valleys denudation rates are 760 2100 mm kyr 1 in those basins which show minimal previous glacial modification denudation rates are low with 60 560 mm kyr 1 the denudation rate in each basin represents a binary mixture between the rapid non uniform processes and soil creep the soil production rate measured with cosmogenic 10be in soil samples averages at 60 mm kyr 1 mixing calculations suggest that the debris flows and rock falls are occurring at rates up to 3000 7000 mm kyr 1 these very high rates occur in the absence of baselevel lowering since the tributaries drain into the rhone trunk stream up stream of a knickzone the flux weighted spatial average of denudation rates for the upper rhone valley is 1400 mm kyr 1 which is similar to rock uplift rates determined in this area from leveling the pace and location of erosion processes are determined by the oscillation between a glacial and a non glacial state preventing the landscape from reaching equilibrium copyright 2010 john wiley sons ltd

tectonic implications of the gps velocity field in the northern adriatic region 1 continuous and episodic gps observations between 1991 and 2004 show that adria moves independently of both stable eurasia and nubia adria moves nne at 3 4 5 mm yr increasing from n to s relative to eurasia and may be fragmenting along the gargano dubrovnik seismic zone the observed 2 3 mm yr of n s adria eurasia convergence is taken up by contraction across a narrow 70 km zone in the eastern alps and concomitant extrusion of the alpine north pannonian unit the adria central dinarides boundary is a broader collisional zone with intense 1 1 5 mm yr shortening near shore and 2 mm yr spread across the dinarides the remaining 1 2 mm yr motion e of the alps and ne of the dinarides is absorbed by the inverted contracting pannonian basin leaving no significant deformation above 0 5 mm yr in the western and northern carpathians and european platform

young uplift in the non glaciated parts of the eastern alps abstract we report the first incision rates derived from burial ages of cave sediments from the mur river catchment at the eastern margin of the eastern alps at the transition zone between the alpine orogen and the pannonian basin this river passes through the paleozoic of graz a region of karstifiable rocks called the central styrian karst this river dissects the study area in a north south direction and has left behind an abundance of caves these caves can be grouped into several distinct levels according to their elevation above the present fluvial base level age estimates of abandoned cave levels are constrained by dating fluvial sediments washed into caves during the waning stages of speleogenesis with the terrestrial cosmogenic nuclide method these ages and the elevations of the cave levels relative to the current valley floor are used to infer a very complex history of 4 million years of water table position influenced by the entrenchment and aggradation of the mur river we observe rather low rates of bedrock incision over the last 4 ma in the order of 0 1 mm y with an e folding decrease in this trend to lower rates at younger times we relate this incision history to a tectonic setting where an increase of drainage area of the mur river due to stream piracy in late miocene to pliocene times is linked to surface uplift the later decrease in valley lowering rates is attributed to the rise of the base level related to aggradation of sediments within the valley sediment transport through the valley from the upstream section of the mur river limited the erosional potential of the river to a transport limited state at the later stages of the incision history

pleistocene holocene climate change re establishment of fluvial drainage network and increase in relief in the swiss alps abstract data are presented about modern sediment discharge of the swiss rivers and related to the size of catchments the information reveals that the central alps have experienced denudation rates of 0 15 mm yr 1 in the foreland and 0 5 mm yr 1 in the alpine core mapping however indicates that modern erosion only affects 30 50 of the alpine surface and that fluvial and associated hillslope processes have focused erosion in 50 200 m deep valleys these valleys are incised into the glacial surface if this limited spatial extent of erosion is considered then effective erosion rates are significantly higher than average denudation rates these effective rates equal or locally exceed modern rates of rock uplift this implies that the modification of erosional processes related to the pleistocene holocene climate change has resulted in an increase in the relief at a local scale at a drainage basin scale however the relief appears not to change at present

late cenozoic increase in accumulation rates of terrestrial sediment how might climate change have affected erosion rates abstract accumulation rates of terrestrial sediment have increased in the past few million years both on and adjacent to continents although not everywhere apparently erosion has increased in elevated terrain regardless of when last tectonically active or what the present day climate in many regions sediment coarsened abruptly in late pliocene time sparser data suggest increased sedimentation rates at 15 ma approximately when oxygen isotopes in benthic foraminifera imply high latitude cooling if climate change effected accelerated erosion understanding how it did so remains the challenge some obvious candidates such as lowered sea level leading to erosion of continental shelves or increased glaciation account for increased sedimentation in some but not all areas perhaps stable climates that varied slowly allowed geomorphic processes to maintain a state of equilibrium with little erosion until 3 4 ma when large oscillations in climate with periods of 20 000 40 000 years developed and de

application of stacking and inversion techniques to three dimensional wide angle reflection and refraction seismic data of the eastern alps summary we present new methods for the interpretation of 3 d seismic wide angle reflection and refraction data with application to data acquired during the experiments celebration 2000 and alp 2002 in the area of the eastern alps and their transition to the surrounding tectonic provinces bohemian massif carpathians pannonian domain dinarides data was acquired on a net of arbitrarily oriented seismic lines by simultaneous recording on all lines of seismic waves from the shots which allows 2 d and 3 d interpretations much 80 of the data set consists of crossline traces low signal to noise s n ratio in the area of the young orogens decreases the quality of travel time picks in these seismically heterogeneous areas it is difficult to assign clearly defined arrivals to the seismic phases in particular on crossline record sections in order to enhance the s n ratio signal detection and stacking techniques have been applied to enhance the pg pn and pmp phases further inversion methods have been developed for the interpretation of war r data based on automated 1 d inversion pg and the application of the delay time concept pn the results include a 3 d velocity model of the crust based on pg waves time and depth maps of the moho and a pn velocity map the models based on stacked data are robust and provide a larger coverage than models based on travel time picks from single fold unstacked traces but have relatively low resolution especially near the surface they were used as the basis for constructing models with improved resolution by the inversion of picks from single fold data the results correlate well with geological structures and show new prominent features in the eastern alps area and their surrounds the velocity distribution in the crust has strong lateral variations and the moho in the investigation area appears to be fragmented into three parts

latest pannonian and quaternary evolution at the transition between eastern alps and pannonian basin new insights from geophysical sedimentological and geochronological data the transition zone between eastern alps and pannonian basin is a key area for the investigation of the interplay between regional uplift local tectonic subsidence and depositional environment our study area the western margin of the little hungarian plain is characterized by gentle hills plateaus and depressions of which several are filled by lakes including one of austria s largest and shallowest lakes lake neusiedl geological investigation is hampered by the scarcity of outcrops and thus direct observation of sedimentological or structural features is difficult despite a long research history in the area a consistent landscape evolution model considering all relevant constraints is lacking so far in this study we apply multidisciplinary methods to decipher the complex tectonic and fluvial depositional evolution of the region local data from shallow lake drilling and seismic investigation are combined with regional data from industrial seismics and core data to gain new insights into the latest pannonian late miocene and quaternary evolution shallow lake seismic data show the erosionally truncated pannonian sediments dipping and thickening toward southeast toward the modern depocenter of the little hungarian plain overlying quaternary fluvial sediments show a very similar thickening trend except for the area on the plateau north of the lake indicating ongoing subsidence in major parts of the basin drill cores from locations along the lake seismic lines were analyzed concerning their age mineralogy and heavy minerals and compared with outcrop samples from the surrounding plains and the plateau to derive indications on sediment provenance a key observation is the apparent lack of a significant gravel layer on top of the tilted pannonian sediments beneath lake neusiedl small scale faults can be observed in the lake seismic sections along with key sedimentary features significant differences of the current elevation of the top pannonian between the surrounding plains and the plateau indicate post pannonian normal faulting which is a key process in shaping the present day morphology of the region luminescence ages of samples from the quaternary fluvial gravels on top of the pannonian sediments are a significantly higher 300 ka compared to the gravels in the plain 102 11 and 76 8 ka suggesting ongoing tectonic subsidence

climate induced rebound and exhumation of the european alps foreland basins record the regional isostatic compensation of mountain belts during periods of crustal thickening they subside and when erosion unloads the mass of the mountains the basins rebound and are eroded in order to evaluate this mechanism for rebound it is critical that the timing and magnitude of erosion are documented we present data estimating the timing and magnitude of late orogenic or postorogenic erosion in the north alpine foreland basin of switzerland mineral cooling ages demonstrate that the basin underwent 1 3 km of erosion soon after 5 ma this erosion coincided with a decline in structural deformation in the swiss alps and a doubling of sediment accu mulation rates in surrounding depocenters we propose that accelerated erosional un roofing of the swiss alps triggered isostatic rebound and erosion of the foreland basin after 5 ma a projection of the isostatic rebound of the basin into the mountains suggests that at least 6 5 km of erosion should have occurred in the high topography of the aar massif accelerated erosion in the swiss alps at that time is explained by an increase in atmospheric moisture driven by an intensification of the atlantic gulf stream at 4 6 ma consequently we propose that the changing erosional capacity of the climate triggered late orogenic to postorogenic mass reduction and isostatic rebound of the swiss alps and their neighboring foreland basin

present crustal movement and strain distribution in central europe inferred from gps measurements in 1992 an international collaboration was initiated to study the present day geodynamics of central europe the primary tool of this research is the global positioning system gps therefore the central european gps geodynamic reference network was established in 1994 the network extends from the south in the eurasian african plate boundary zone to the east european pre cambrian platform in the northeast during the first phase of the project four gps campaigns were organized between 1994 and 1997 analysis of gps data provided rms repeatabilities around 2 mm in the horizontal and 5 6 mm in the vertical component for each campaign the velocities of gps sites situated on the eurasian plate were compared with those predicted by the nnr nuvel 1a plate velocity model the intraplate velocity field shows that the northern part of central europe seems generally stable with velocities under 2 mm yr however the southern sites close to the plate boundary zone show higher values and abrupt changes of velocities indicating the existence of narrow deformation zones the primary feature revealed by the strain calculation in the alpine pannonian dinaric system is the dominant north south contraction resulting from the collision of the african and eurasian plates transmitted by the adriatic microplate however the direction of contraction in the alpine pannonian dinaric junction zone changes from nw se at the northeastern boundary of the adriatic microplate to ne sw toward the bohemian massif the magnitudes of these strain rates are similar 8 0 5 3 ppb yr and 8 6 2 5 ppb yr respectively over 200 350 km subnetworks we observe e w oriented 93 13 right lateral shear 12 5 ppb yr between the alpine north pannonian unit and the southernmost sites in the dinarides and southern alps along with left lateral shear 97 7 10 2 ppb yr relative to the stable bohemian massif in the north both the strain field and the intraplate velocities presented show that the alpine north pannonian unit is presently crushed out to the east with 2 mm yr velocity on average along two main fault zones as a consequence of the compression caused by the adria alpine collision

dating sediment burial with in situ produced cosmogenic nuclides theory techniques and limitations abstract dating sediment burial over million year time scales is crucial in many areas of the earth sciences and archeology but is often difficult using traditional techniques sediment burial can be dated by the radioactive decay of cosmogenic nuclides provided that the sediment was exposed to cosmic rays prior to burial dating calculations are straightforward if sediment is buried deeply and rapidly enough to prevent cosmogenic nuclide production after burial however the analysis can be complicated by postburial production if sediment is insufficiently shielded from secondary cosmic ray nucleons and muons this paper discusses how buried sediments can be dated over timescales up to 5 myr using 26 al and 10 be in quartz

cosmic ray production rates of 10be and 26al in quartz from glacially polished rocks we have studied the concentrations of 10be and 26al in quartz crystals extracted from glacially polished granitic surfaces from the sierra nevada range these surfaces were identified with the glacial advance during the tioga period 11 000 years ago our measurements yield the most accurate estimates to date for the absolute production rates of these nuclides in sio2 due to cosmic ray nucleons and muons for geomagnetic latitudes 43 8 44 6 n and altitudes 2 1 3 6 km the estimates are relatively free from uncertainties in snow cover since we studied a suite of rock surfaces inclined 0 75 with respect to the horizontal the principal uncertainty arises due to the lack of a precise date for the glacial retreat event about 10 the 26al 10be ratio at production 6 0 is determined more accurately since the exposure age of the samples is 2 orders of magnitude smaller than the mean lives of the two nuclides production rates of 10be and 26al in quartz at other latitudes and altitudes in the troposphere can be determined from the present measurements by scaling using the known altitude and latitude dependence of cosmic ray fluxes of nucleons and negative muons knowledge of the production rates of these nuclides is a prerequisite for their application in erosion and geomorphological studies

the dachstein paleosurface and the augenstein formation in the northern calcareous alps a mosaic stone in the geomorphological evolution of the eastern alps the central and eastern areas of the northern calcareous alps nca are characterized by remnants of the dachstein paleosurface which formed in late eocene to early oligocene time and is preserved with limited modification on elevated karst plateaus in oligocene time the dachstein paleosurface subsided and was sealed by the augenstein formation a terrestrial succession of conglomerates and sandstones which are only preserved in small remnants on the plateaus some in an autochthonous position thermochronological data suggest a maximum thickness of the augenstein formation of 1 3 km possibly 2 km the age of the augenstein formation is constrained by the overall geological situation as early oligocene to earliest miocene fission track age data support an early oligocene age of the basal parts of the formation the source area of the augenstein formation consisted predominantly of weakly metamorphic paleozoic terrains greywacke zone and equivalents as well as the late carboniferous to scythian siliciclastic base of the nca to the south of the depositional area to the west the augenstein formation interfingered with the tertiary deposits of the inntal sedimentation of the augenstein formation was terminated in early miocene time in the course of the orogenic collapse of the eastern alps the augenstein sediments were eroded and redeposited in the foreland molasse zone from pannonian times 10 ma on the nca and the denuded dachstein surface experienced uplift in several pulses the dachstein paleosurface has been preserved in areas in which thick limestone sequences allowed subsurface erosion by cave formation and thus prevented major surface erosion

identification of the mechanism of interdecadal variability in the north atlantic ocean the aim of this paper is to identify the physical mechanism of interdecadal variability in simulations of the north atlantic ocean circulation with the modular ocean model of the geophysical fluid dynamics laboratory to that end a hierarchy of increasingly complex model configurations is used the variability in the simplest case that of viscous purely thermally driven flows in a flat bottom ocean basin with a box shaped geometry is shown to be caused by an internal interdecadal mode the westward propagation of temperature anomalies and the phase difference between the anomalous zonal and meridional overturning that characterize the interdecadal mode are used as fingerprints of the physical mechanism of the variability in this way the variability can be followed toward a less viscous regime in which the effects of continental geometry and bottom topography are also included it is shown that although quantitative aspects of the variability like period and spatial pattern are changing the physical mechanism of the interdecadal variability in the more complex simulations can be attributed to the same processes as in the simplest model configuration

increase in late neogene denudation of the european alps confirmed by analysis of a fission track thermochronology database abstract a sharp increase in deposited sediment volume since pliocene times has been observed worldwide and in particular around the european alps this phenomenon has been linked to a rise in denudation rates controlled by an increase of either climatic or tectonic forcing observation of in situ cooling histories for orogens is critical to assess the reality of the inferred increase in denudation rates and to determine whether this phenomenon is widespread or localized at active tectonic structures we exploit the unique density of fission track ages in the western european alps to reconstruct cooling isoage surfaces and to estimate exhumation rates on the orogen scale between 13 5 and 2 5 ma our novel technique is based on the association of isoage contours with age elevation relationships it uses map view interpolation enabling a spatio temporal analysis of exhumation rates over the entire western alps the resulting exhumation histories reconstructed for eight areas of the western alps display strong similarities in timing and rates with orogen wide average denudation rates inferred from sediment volumes this consistency validates the use of both techniques for the study of an orogen characterized by strong relief and high recent exhumation rates we conclude that exhumation rates in the western alps have increased more than twofold since late miocene times this increase may have been locally modulated by the distinct response of different tectonic units

pliocene pleistocene incision of the green river kentucky determined from radioactive decay of cosmogenic 26al and 10be in mammoth cave sediments cosmogenic 26al and 10be in sediments washed into mammoth cave kentucky record the history of 3 5 m y of water table position governed by incision and aggradation of the green river a tributary of the ohio river upper levels of the cave formed during a period of slow river incision and were later filled with sediment due to river aggradation at 2 3 2 4 ma a brief surge of river incision ca 2 ma was followed by river stability and cave passage formation at a lower level rapid incision through 15 m of bedrock ca 1 5 ma was prompted by repositioning of the ohio river to its present course along an ice sheet margin renewed incision ca 1 2 ma and aggradation at 0 7 0 8 ma correlate with major ice advances in the ohio river basin measurements of 26al and 10be also indicate that sandstone capped uplands have maintained slow erosion rates of 2 7 m m y for the past 3 5 m y despite accelerated pleistocene river incision rates of 30 m m y

intensive hydration of the mantle transition zone beneath china caused by ancient slab stagnation the mantle transition zone beneath china is anomalously hydrated geochemical analyses of basalts erupted above the mantle transition zone in northeast china indicate that water may have been added to this zone during the dehydration of subducted slabs on two separate occasions over the past one billion years

comparison of u th paleomagnetism and cosmogenic burial methods for dating caves implications for landscape evolution studies caves are useful in landscape evolution studies because they often mark the level of previous water tables and when dated yield incision rates dating caves is problematic however because their ages are only constrained by the oldest deposits contained within which may be far younger than the cave itself we dated cave deposits in the sierra nevada using u th dating of speleothems paleomagnetic dating of fine sediment and cosmogenic 26 al 10 be burial dating of coarse sediment the sampled caves formed sequentially as the water table lowered providing an important stratigraphic test for the dating methods large discrepancies between deposit ages from similar cave levels demonstrate that even when accurately determined deposit ages can seriously underestimate the timing of cave development drip type speleothems are most prone to this minimum age bias because they can accumulate long after caves form and because the u th method is limited to 400 ka paleomagnetic dating requires correlation with the global reversal chronology and is hindered by a lack of continuous stratigraphy the fine sediment analyzed for paleomagnetism is also highly susceptible to remobilization and deposition in cave passages well above base level cosmogenic 26 al 10 be dates bedload material deposited when caves were at or very near river level and can date material as old as 5 ma in the sierra nevada speleothem u th ages and sediment burial ages from the same cave levels differ by as much as an order of magnitude these results suggest speleothem ages alone may significantly underestimate cave ages