the influence of crustal strength fields on the patterns and rates of fluvial incision gradients in the bedrock strength field are increasingly recognized as integral to the rates and patterns of landscape evolution to explore this influence we incorporate data from fault strength profiles into a landscape evolution model under the assumption that erodibility of rock is proportional to the inverse square root of cohesion for bedrock rivers incised by bedload abrasion our model calculations illustrate how patterns in the crustal strength field can play a dominant role in local fluvial erosion rates and consequently the development of fluvial network patterns fluvial incision within weak zones can be orders of magnitude faster than that for resistant bedrock the large difference in erosion rate leads to the formation of a straight high order channel with short orthogonal tributaries of low order in comparison channels incising into homogeneous strength fields produce dendritic drainage patterns with no directional dependence associated with erodibility gradients channels that cross the strength gradient experience local variations in knickpoint migration rate and the development of stationary knickpoints structurally confined channels can shift laterally if they incise into weak zones with a shallow dip angle and this effect is strongly dependent on the magnitude of the strength difference the dip angle and the symmetry and thickness of the weak zone the influence of the strength field on drainage network patterns becomes less apparent for erodibility gradients that approach homogeneity there are multiple natural examples with drainage network patterns similar to those seen in our numerical experiments

impact of the german harz mountain weichselian ice shield and valley glacier development onto palaeolithic and megafauna disappearances abstract three pleistocene stages are recorded by 3d google earth geomorphology cave sediments river terraces megafauna archaeological sites of the harz mountain range and its forelands of northern germany central europe peak 1141 a s l late pleistocene glaciation stages are modeled preliminary in valley elevations between 407 and 760 a s l starting all southeast below the brocken ice field above 750 a s l the 14 11 km long oder and bode valley glaciers left typical moraines kames or dead ice depressions such as fluvial cave relic sediments the bode river glacier passed during the lgm the rubeland caves where it deposited reworked kames lateral moraines in the baumann s cave which floods mixed a neanderthal camp leopard lair and cave bear den area 60 km downstream fluvial to aeolian deposits were trapped in the gypsum karst doline westeregeln neanderthal camp hyena den late aurignacians replaced in the region neanderthals but a gap of late palaeolithic gravettian magdalenian 26 000 16 000 bp settlement and latest starting speleothem genesis around 24 260 568 bp correlate to the lgm when an arctic reindeer fauna with alpine elements ibex chamois accumulated in bone assemblages of a wolverine polar fox mustelid such as european eagle owl dens which allow landscape reconstructions

two million years of river and cave aggradation in ne brazil implications for speleogenesis and landscape evolution abstract this study characterizes and provides ages for an extensive sedimentary record occurring in lapa doce and torrinha caves ne brazil with 40 km of surveyed passages these caves integrate a distributary cave system fed by allogenic recharge from the surrounding sandstone plateaus sediment petrography together with descriptions of depositional facies and architectural elements shows four depositional units related to fluvial and standing water environments these include from bottom to top 1 a channel unit including lateral bars deposited during an ordinary flood regime 2 a sandy flood unit including minor channel and scour fills derived from bank full equivalent flood events 3 mud caps deposited in standing water that often reach the ceiling and 4 intraclast breccias associated with collapse of the mud caps under saturated conditions the deposits were dated using a combination of cosmogenic nuclide burial dating and u series dating of flowstone cosmogenic nuclide data point to fluvial aggradation being active since 1 91 0 12 my and extending until 0 36 0 08 my with intensive cave and valley aggradation events between 0 78 0 10 my and 0 44 0 12 my long term alluviation of the cave system seems to be important in forming passages determining their configuration and setting up a general distributary pattern evident in passage morphology and sedimentary sequences mud caps overlapping the fluvial deposits are interpreted as the products of successive rising and lowering of the water table static level radiometric ages of interstratified flowstones and speleothems show that these oscillations were active at least since 115 ky ago and finally ceased around 12 ky ago indicated by the recurrent age obtained from uneroded capping flowstones these long term water table oscillations may drive paragenetic expansion of the whole cave system valleys caves and other landforms in our study area are part of an ancient landscape with multiple episodes of burial and exhumation despite the possibility of much older sediment being preserved somewhere in the cave system our data indicate a younger quaternary age for the bulk of the sediment filling the study caves

analysis of dolines using multiple methods applied to airborne laser scanning data abstract delineating dolines is not a straightforward process especially in densely vegetated areas this paper deals quantitatively with the surface karst morphology of a miocene limestone occurrence in the styrian basin austria the study area is an isolated karst mountain with a smooth morphology former planation surface of pliocene age densely vegetated mixed forest and with a surface area of 1 3 km 2 the study area is located near the city of wildon and is named wildoner buchkogel the aim of this study was to test three different approaches in order to automatically delineate dolines the data basis for this was a high resolution digital terrain model dtm derived from airborne laser scanning als and with a raster resolution of 1 1 m the three different methods for doline boundary delineation are a the traditional method based on the outermost closed contour line b boundary extraction based on a drainage correction algorithm filling up pits and c boundary extraction based on hydrologic modelling watershed extracted features are integrated in a gis environment and analysed statistically regarding spatial distribution shape geometry elongation direction and volume the three methods lead to different doline boundaries and therefore investigated parameters show significant variations the applied methods have been compared with respect to their application purpose depending on delineation process between 118 and 189 dolines could be defined the high density of surface karst features demonstrates that solutional processes are major factors in the landscape development of the wildoner buchkogel furthermore the correlation to the landscape evolution of the grazer bergland is discussed

threshold behavior of karst aquifers the example of the lurbach karst system austria threshold behavior in hydrological systems generally involves a qualitative change of a single process the system response or the functioning of the system different types of thresholds and their underlying controls are examined using the example of the lurbach karst system austria this karst system receives allogenic recharge from the sinking stream lurbach which under low flow conditions only resurges at the hammerbach spring yet under medium to high flow conditions an overflow toward another spring the schmelzbach outlet occurs thresholds in physicochemical spring responses and their underlying controls are identified from the analysis of heat and solute transport processes in karst conduits applying this concept to the hammerbach spring suggests that the threshold controlling the response of the spring water temperature was changed in the time period from 2006 to 2009 relative to the years before at the same time changes are observed in the behavior of the spring hydrograph and the discharge threshold at which the overflow to the schmelzbach system is activated all of these observations can be consistently explained by a decreased diameter of the conduit pathways within the indicated time period presumably caused by the redistribution of sediments due to a flood event in 2005 thus thresholds in the physicochemical spring response were successfully employed to support the identification of a change in the functioning of the lurbach karst system which occurred possibly because a threshold related to the sediment transport within the karst conduits was crossed

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

single event time series analysis in a binary karst catchment evaluated using a groundwater model lurbach system austria the lurbach karst system styria austria is drained by two major springs and replenished by both autogenic recharge from the karst massif itself and a sinking stream that originates in low permeable schists allogenic recharge detailed data from two events recorded during a tracer experiment in 2008 demonstrate that an overflow from one of the sub catchments to the other is activated if the discharge of the main spring exceeds a certain threshold time series analysis autocorrelation and cross correlation was applied to examine to what extent the various available methods support the identification of the transient inter catchment flow observed in this binary karst system as inter catchment flow is found to be intermittent the evaluation was focused on single events in order to support the interpretation of the results from the time series analysis a simplified groundwater flow model was built using modflow the groundwater model is based on the current conceptual understanding of the karst system and represents a synthetic karst aquifer for which the same methods were applied using the wetting capability package of modflow the model simulated an overflow similar to what has been observed during the tracer experiment various intensities of allogenic recharge were employed to generate synthetic discharge data for the time series analysis in addition geometric and hydraulic properties of the karst system were varied in several model scenarios this approach helps to identify effects of allogenic recharge and aquifer properties in the results from the time series analysis comparing the results from the time series analysis of the observed data with those of the synthetic data a good agreement was found for instance the cross correlograms show similar patterns with respect to time lags and maximum cross correlation coefficients if appropriate hydraulic parameters are assigned to the groundwater model the comparable behaviors of the real and the synthetic system allow to deduce that similar aquifer properties are relevant in both systems in particular the heterogeneity of aquifer parameters appears to be a controlling factor moreover the location of the overflow connecting the sub catchments of the two springs is found to be of primary importance regarding the occurrence of inter catchment flow this further supports our current understanding of an overflow zone located in the upper part of the lurbach karst aquifer thus time series analysis of single events can potentially be used to characterize transient inter catchment flow behavior of karst systems

extension during continental convergence in the eastern alps the influence of orogen scale strike slip faults in the miocene the european eastern alps extruded laterally along orogen scale strike slip faults due to both extensional gravitational collapse and compressional tectonic forcing horizontal extension is most prominently evidenced by detachments east and west of the tauern window it is commonly explained by a retreating slab beneath the carpathian arc hundreds of kilometers east of the orogen horizontal compression is shown by north south shortening in the tauern window and the entire eastern alps in response to the convergence of the adriatic plate with europe it is interesting that analogue and numerical models for the eastern alps designed to describe the east directed lateral extrusion have failed to explain the extensional regime in the region of the tauern window using a numerical model for plan view deformation that considers internal faults we show here that orogen scale strike slip faults are mechanically required to cause extension during plate convergence in the miocene eastern alps we test the idea by coupling this model with a landscape evolution model and by comparing modeled and observed drainage system geometries

extension in compressional orogenic belts the eastern alps extension in the eastern alps encompasses the following 1 extension accompanying simple shear crustal stacking subhorizontal stretching occurs along flat lying foliations and regionally consistent stretching lineations with associated high strains on a local scale stretching results from extrusion of ductile sediments squeezed between rigid basement blocks basement blocks during thrust sheet imbrication the overall geometric effect is crustal thickening 2 classical extensional tectonics extension first occurs as a consequence of accretion and underthrusting of continental and oceanic material and represents gravitational adjustment of an unstable orogenic wedge extension then occurs as a consequence of terminal continental collision and is accommodated by lateral extrusion of crustal of crustal blocks the overall geometric effect is crustal thinning extension is generally oriented subparallel to the strike of the orogen

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

determination of the conduit structure in a karst aquifer based on tracer data lurbach system austria a structure model was used to analyse solute transport parameter estimates based on tracer breakthrough curves in the model system groundwater flow is envisioned to be organised in a complex conduit network providing a variety of short circuits with relative small carrying capacities along different erosion levels the discharge through the fully filled conduits is limited owing to void geometries and turbulent flow thus a hierarchic overflow system evolves where conduits are re activated or dried up depending on the flow condition exemplified on the lurbach tanneben karst aquifer the applicability of the model approach was tested information derived from multi tracer experiments performed at different volumetric flow rates enabled to develop a structural model of the karst network under constraint of the geomorphological and hydrological evolution of the site depending on the flow rate groundwater is divided into up to eight flow paths the spatial hierarchy of flow paths controls the sequence of flow path activation conduits of the topmost level are strongly influenced by reversible alteration processes sedimentation or blocking causes an overflow of water to the next higher conduit flow path specific dissolutional denudation rates were estimated using the temporal development of the partial discharge copyright 2012 john wiley sons ltd

age and prematurity of the alps derived from topography abstract the european alps are one of the best studied mountain ranges on earth but yet the age of their topography is almost unknown even their relative stage of evolution is unclear are the alps still growing in a steady state or already decaying and is there a significant difference between western and eastern alps using a new geomorphic parameter we analyze the topography of the alps and provide one of the first quantitative constraints demonstrating that the range is still in its infancy in contrast to several other mountain ranges the alps have still more than half of their evolution to a geomorphic steady state to go combining our results with sediment budget data from the surrounding basins we infer that the formation of the present topography began only 5 6 million years ago our results question the apparent consensus that the topographic evolution is distributed over much of the miocene and might give new impulses to the reconstruction of paleoclimate in central europe

an active margin across the adriatic sea central mediterranean sea abstract new seismological and structural data from the central adriatic gargano promontory area demonstrate that the current models of an aseismic and slightly deformed adriatic block have to be revised a seismically active deformational belt is mapped along two main fault systems the tremiti islands and mattinata faults moreover geologic and geophysical evidence suggests that a more extensive lithospheric boundary may cut across the central italian peninsula to the tyrrhenian basin

dramatic increase in late cenozoic alpine erosion rates recorded by cave sediment in the southern rocky mountains abstract apparent increases in sedimentation rates during the past 5 ma have been inferred at sites around the globe to document increased terrestrial erosion rates but direct erosion rate records spanning this period are sparse modern and paleo erosion rates for a small alpine catchment 3108 m above sea level in the southern rocky mountains are measured using the cosmogenic radionuclides crns 10be and 26al in cave sediment bedrock on the overlying landscape surface and coarse bedload in a modern fluvial drainage the unique setting of the marble mountain cave system allows the inherited erosion rates to be interpreted as basin averaged erosion rates resulting in the first crn based erosion rate record from the rocky mountains spanning 5 myr pliocene erosion rates derived from the oldest cave sample 4 9 0 4 ma for the landscape above the cave are 4 9 1 1 m myr 1 mid pleistocene erosion rates are nearly an order of magnitude higher 33 1 2 7 to 41 3 3 9 m myr 1 and modern erosion rates are similar due to the effects of snow shielding these erosion rate estimates are likely higher than actual rates by 10 15 the most likely explanation for this dramatic increase in erosion rates which likely occurred shortly before 1 2 ma is an increase in the effectiveness of periglacial weathering processes at high elevations related to a cooler and wetter climate during the pleistocene providing support for the hypothesis that changes in late cenozoic climate are responsible for increased continental erosion

incised relict landscapes in the eastern alps abstract we investigate landscape evolution in a region of the alps that has escaped glacial erosion during periodic glaciations of the last million years the research is thus suited to investigate landscaping processes on a longer time scale at the eastern end of the alps morphometric analysis reveals the presence of incised relict landscapes in several regions in the koralpe range topographic analysis is interpreted in terms of the relict landscape being present on both sides of the eastward tilted koralpe block this suggests that the relict landscape is younger than the tilting of the range which is inferred to have taken place between 18 and 16 ma in the pohorje region a relict landscape is developed across the contacts of a 19 ma pluton we use apatite u th he thermochronology to constrain the possible age of the koralpe and pohorje relict landscapes the results indicate that the pohorje massif had cooled below 70 c by about 15 ma suggesting that the relict landscape must be younger consistent with the interpretation of the koralpe range these results suggest that many relict landscapes of the eastern alps may have formed after 15 ma in a period of tectonic quiescence and erosion however in both ranges channel profile projections show that about 387 105 m uplift and incision occurred subsequently this incision is likely to have occurred during the last 6 5 ma in response to the uplift of the whole region it testifies to a renewed and ongoing uplift event that is earlier than the glaciation periods but might easily be confused with impact of glacial erosion elsewhere in the eastern alps

new empirical relationships among magnitude rupture length rupture width rupture area and surface displacement source parameters for historical earthquakes worldwide are compiled to develop a series of empirical relationships among moment magnitude m surface rupture length subsurface rupture length downdip rupture width rupture area and maximum and average displacement per event the resulting data base is a significant update of previous compilations and includes the additional source parameters of seismic moment moment magnitude subsurface rupture length downdip rupture width and average surface displacement each source parameter is classified as reliable or unreliable based on our evaluation of the accuracy of individual values only the reliable source parameters are used in the final analyses in comparing source parameters we note the following trends 1 generally the length of rupture at the surface is equal to 75 of the subsurface rupture length however the ratio of surface rupture length to subsurface rupture length increases with magnitude 2 the average surface displacement per event is about one half the maximum surface displacement per event and 3 the average subsurface displacement on the fault plane is less than the maximum surface displacement but more than the average surface displacement thus for most earthquakes in this data base slip on the fault plane at seismogenic depths is manifested by similar displacements at the surface log linear regressions between earthquake magnitude and surface rupture length subsurface rupture length and rupture area are especially well correlated showing standard deviations of 0 25 to 0 35 magnitude units most relationships are not statistically different at a 95 significance level as a function of the style of faulting thus we consider the regressions for all slip types to be appropriate for most applications regressions between magnitude and displacement magnitude and rupture width and between displacement and rupture length are less well correlated and have larger standard deviation than regressions between magnitude and length or area the large number of data points in most of these regressions and their statistical stability suggest that they are unlikely to change significantly in response to additional data separating the data according to extensional and compressional tectonic environments neither provides statistically different results nor improves the statistical significance of the regressions regressions for cases in which earthquake magnitude is either the independent or the dependent parameter can be used to estimate maximum earthquake magnitudes both for surface faults and for subsurface seismic sources such as blind faults and to estimate the expected surface displacement along a fault for a given size earthquake

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

timing of late pleistocene climate change in lowland switzerland abstract a chronology of climate change in lowland switzerland for the time between the last interglacial and the last glaciation maximum lgm is provided by complementary radiocarbon 230 th u and luminescence dating of the gossau key section the gossau interstadial complex is consistently dated to 50 000 30 000 yr bp and hence correlated with marine oxygen isotope stage mis 3 palaeotemperature readings reconstructed from coleoptera analyses and pollen assemblages evidence oscillating environmental conditions from tundra to open woodland and reflect changing climate during the middle wurmian delta deposits from the lower part of the gossau section indicate a cold period prior to the interstadial complex this severe climatic deterioration is correlated with mis 5d based on luminescence dating sedimentological evidence implies the presence of glaciers at the northern margin of the swiss alps during this time

late cretaceous exhumation of the metamorphic gleinalm dome eastern alps kinematics cooling history and sedimentary response in a sinistral wrench corridor abstract the metamorphic gleinalm dome eastern alps was uplifted and exhumed within a releasing structure in a sinistral wrench corridor during the late cretaceous the dome is confined by a system of ductile shear zones including low angle normal faults and steep sinistral tear faults which define a large releasing structure with the metamorphic dome in its center the fabrics developed within all ductile shear zones record processes which were operating during decreasing temperatures from initial epidote amphibolite upper greenschist facies conditions with crystal plastic fabrics in quartz to temperatures below ca 300 c with predominantly cataclastic fabrics a cooling path based on 40ar 39ar amphibole 95 4 1 2 ma and muscovite ages 87 6 0 6 84 3 0 7 ma together with sphene zircon and apatite fission track data indicate cooling through ca 500 c at ca 94 ma to below ca 250 200 c at 65 ma subsidence of the adjacent late cretaceous kainach gosau basin occurred synchronously with cooling and uplift of the gleinalm dome internal depositional patterns record rapid subsidence at the time of cooling with internal synsedimentary block rotation above an intra crustal ductile normal fault the sinistral wrench corridor of the eastern alps developed by sinistral displacement of the austroalpine units against a relatively stable europe during the late cretaceous

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

genesis types and evolution of crevice type caves in the flysch belt of the western carpathians czech republic abstract crevice type caves are among the least investigated natural phenomena connected with the development of slope failures these caves present complex and peculiar underground systems with their own development and resulting landforms we investigated eight caves in the czech part of the outer western carpathians to determine their genesis types and evolution crevice formation is predisposed according to the lithological tectonic and morphological characteristics of the landslide body including the position and location of bedding planes joints and faults we performed several analyses including speleological mapping evaluation of high resolution topography above the caves geophysical ert measurements and structural investigations within cave passages in accordance with these analyses various mechanisms responsible for cave development were revealed an intra bed translation is responsible for the creation of regularly shaped passages with flat ceilings toppling as well as back and horizontal rotation of rock blocks determine the specific morphology and shapes of passages a relatively novel aspect of the current study is the identification of the subsidence of massive rock wedges due to the widening of cracks all of these mechanisms control the specific morphological characteristics within crevices e g typical shapes of passages cave level ordering and ceiling types some of these processes also influence topography above the caves finally the different phases of evolution of these caves were determined

short term climate changes during the last glacial holocene transition comparison between mediterranean records and the grip event stratigraphy this paper presents biostratigraphical and stable isotope data obtained from core cm92 43 which was recovered from the central adriatic as part of a comprehensive investigation of the palaeoenvironmental history of the basin the data span the period of the last glacial holocene lg h transition ca 18000 to 8000 grip ice core yr bp regional biozones are defined on the basis of characteristic assemblages of planktic foraminifera and these are compared with other foraminiferal biostratigraphical schemes from the southern adriatic and the tyrrhenian sea variations in relative abundance of selected planktic foraminifera and in selected pollen types are shown alongside variations in 18o and 13c obtained from globigerina bulloides and relative abundance of globigerinoides ex gr ruber the data are compared with the grip ice core record and the event stratigraphy scheme based on this record and it is concluded that the climate forcing mechanisms that controlled climate variations in the north atlantic region during the lg h transition also extended their influence into the mediterranean region over the same period copyright 1999 john wiley sons ltd

constraints on the miocene landscape evolution of the eastern alps from the kalkspitze region niedere tauern austria abstract in order to unravel aspects of the miocene landscape evolution of the eastern european alps we present geomorphic and isotopic data from the western niedere tauern region austria the region is critical for such interpretations because it is one of the few regions along the topographic axis of the eastern alps where the highest peaks up to 2500 m a s l are dominated by limestone as such the region contains a record of miocene landscape forming events that survived the pleistocene glaciations not preserved elsewhere in the central eastern alps this record includes karst caves karstified planation surfaces and crystalline fluvial pebbles augenstein formation preserved on planation surfaces and in karst caves caves in the region occur in three distinct levels that correlate with well known cave levels in the northern calcareous alps although they are somewhat higher in the niedere tauern in part these cave elevations also correlate with three planation surfaces and knickpoints of major streams draining the region testifying their pre glacial origin we report details of a karst cave durchgangshohle from the highest cave level located at 2340 m a s l in this cave allochthonous fluvial gravels are present overgrown by speleothems one speleothem yielded an early middle pleistocene u pb age 682 17 ka we regard this as a minimum age for the erosion of the fluvial cave deposits during marine isotope stages 17 or 16 carbon and oxygen isotope data of these speleothems imply a climate that is consistent with this interpretation cosmogenic 21 ne data of fluvial quartz clasts collected from the surface on plateaus of the northern calcareous alps suggest minimum exposure durations of 115 and 262 ka they probably reflect successive exposure since removal of the sediment cover of the oligocene augenstein formation during the pleistocene while our geochronological data fail to record aspects of the earlier miocene uplift history they are consistent with the overall geomorphic history inferred from the geomorphic markers this suggests that the niedere tauern share a common uplift history with the northern calcareous aps and implies a moderate south north topographic gradient that has been maintained since the miocene

correlations of cave levels stream terraces and planation surfaces along the river mur timing of landscape evolution along the eastern margin of the alps the transition zone of the eastern alps to the pannonian basin provides one of the best sources of information on landscape evolution of the eastern alpine mountain range the region was non glaciated during the entire pleistocene thus direct influence of glacial carving as a landscape forming process can be excluded and relics of landforms are preserved that date back to at least the late neogene in this study we provide a correlation between various planation surfaces across the orogen basin transition in particular we use stream terraces planation surfaces and cave levels that cover a vertical spread of some 700 m our correlation is used to show that both sides of the transition zone uplifted together starting at least about 5 ma ago for our correlation we use recently published terrestrial cosmogenic nuclide tcn burial ages from cave sediments new optically stimulated luminescence osl ages of a stream terrace and u th ages from speleothems minimum age constraints of cave levels from burial ages of cave sediments covering the last 4 ma are used to place age constraints on surface features by parallelizing cave levels with planation surfaces the osl results for the top section of the type locality of the helfbrunn terrace suggest an early wurm development 80 5 3 7 to 68 7 4 0 ka the terrace origin as a penultimate gravel deposit in classical alpine terminology riss is therefore questioned u series speleothem ages from caves nearby indicate formation during marine isotope stages mis 5c and 5a which are both interstadial warm periods as osl ages from the terrace also show a time of deposition during mis 5a ending at the mis 5 4 transition this supports the idea of temperate climatic conditions at the time of deposition in general tectonic activity is interpreted to be the main driving force for the formation and evolution of these landforms whilst climate change is suggested to be of minor importance obvious hiatuses in miocene to pleistocene sediments are related to ongoing erosion and re excavation of an uplifting and rejuvenating landscape

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

quaternary downcutting rate of the new river virginia measured from differential decay of cosmogenic 26al and 10be in cave deposited alluvium the concentrations of the cosmogenic radionuclides sup 26 al and sup 10 be in quartz can be used to date sediment burial here we use sup 26 al and sup 10 be in cave deposited river sediment to infer the time of sediment emplacement sediment burial dates from a vertical sequence of caves along the new river constrain its quaternary downcutting rate to 27 3 4 5 m m y and may provide evidence of regional tectonic tilt 32 refs 3 figs 1 tab

seismotectonics of the southern apennines and adriatic foreland insights on active regional e w shear zones from analogue modeling 1 the active tectonics at the front of the southern apennines and in the adriatic foreland is characterized by e w striking right lateral seismogenic faults interpreted as reactivated inherited discontinuities the best studied among these is the molise gondola shear zone the interaction of these shear zones with the apennines chain is not yet clear to address this open question we developed a set of scaled analogue experiments aimed at analyzing 1 how dextral strike slip motion along a preexisting zone of weakness within the foreland propagates toward the surface and affects the orogenic wedge 2 the propagation of deformation as a function of displacement and 3 any insights on the active tectonics of southern italy our results stress the primary role played by these inherited structures when reactivated and confirm that regional e w dextral shear zones are a plausible way of explaining the seismotectonic setting of the external areas of the southern apennines

subsurface magnetostratigraphy of pleistocene sediments from the po plain italy constraints on rates of sedimentation and rock uplift we used facies analysis to reconstruct the pleistocene sedimentary evolution of seven cores from the central northern po plain italy the cores record an overall regressive sequence consisting of shallow water marine and fl uvial deltaic deposits overlain by fully continental sediments we used magnetostratigraphy to date marine and fl uvial deltaic sediments to the early pleistocene and continental sediments to the middle late pleistocene sediment accumulation rates were 30 40 cm k y in the early pleistocene whereas relevant unconformities and or an overall reduction in sediment accumulation rates characterized the middle late pleistocene a simple airy compensation model was applied to restore actual sediments elevations to elevations at times of deposition expressed in meters above current sea level the correlation of isostatically corrected sedimentary facies to a sea level curve obtained from classic oxygen isotope studies shows that an event of rock uplift on the order of 70 120 m occurred in the middle late pleistocene literature studies of vegetational cyclicity used in conjunction with the sea level curve allowed us to link sedimentary facies to climate variability we propose that the onset of fully and persistently continental sedimentation occurred in response to the waxing of the fi rst major pleistocene glaciation in the alps currently correlated to marine isotope stage 22 at ca 0 87 ma and that the episode of uplift occurred at least in part as a consequence of erosion and crustal rebound of the alpine chain triggered by pleistocene glacialinterglacial cycles

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

the myth of the brackish sarmatian sea the biota of the 1 5 ma period of the middle miocene sarmatian of the central paratethys lack stenohaline components this was the reason to interpret the sarmatian stage as transitional between the marine badenian and the lacustrine pannonian stages however our new data indicate that brackish water conditions could not have prevailed sarmatian foraminifera molluscs serpulids bryozoans dasycladacean and corallinacean algae as well as diatoms clearly indicate normal marine conditions for the entire sarmatian during the lower sarmatian however a sea level lowstand forced the development of many marginal marine environments during the late sarmatian a highly productive carbonate factory of oolite shoals mass occurrences of thick shelled molluscs and larger foraminifera as well as marine cements clearly point to normal marine to hypersaline conditions this trend is not restricted to the western margin of the pannonian basin system but can be observed in the entire central and even eastern paratethys

neotectonic extrusion of the eastern alps constraints from u th dating of tectonically damaged speleothems we suggest that the salzachtal ennstal mariazell puchberg semp fault a major strike slip system in the european alps is active it has accommodated lateral extrusion of the central part of the eastern alps toward the pannonian basin the main tectonic activity of this fault dates back to oligocene and miocene time but until now it was largely unknown whether the fault was still active we present here the first field evidence of neotectonic activity from a cave in the hochschwab karst massif styria austria that intersects a segment of the semp fault zone damaged speleothems in this cave include scratched flowstone a hitherto undescribed feature massive flowstone disrupted by a fault and ruptured flowstone the superposition of younger flowstone layers allows constraining the time frame of the tectonic events using u th dating the youngest flowstone of the pre damage generation is ca 118 ka end of the last interglacial and the oldest post event layer is ca 9 ka early holocene the tectonic event bracketed by these layers coincided with a growth hiatus during the last glacial period consistent with the high alpine setting of the cave geologic evidence precludes deformation mechanisms other than tectonic these new data are consistent with vectors of continuous global positioning system measurements as well as instrumental seismicity data and collectively suggest that the semp is an active fault and that lateral extrusion of the eastern alps is ongoing

chronology of the last glacial cycle in the european alps chronological data for glacier advances in the european alps between the last interglacial eemian and the holocene are summarised 115 to 11 ka during this time glaciers were most extensive extending tens of kilometres out onto the forelands between 30 and 18 ka that is synchronous with the global ice volume maximum of marine isotope stage mis 2 evidence for ice expanding to just past the mountain front for an earlier major glacier advance comes from swiss sites where advances have been luminescence dated to mis 5d 100 ka and mis 4 70 ka up to now no such evidence has been found in the eastern alps by 18 ka more than 80 of the late wurmian ice volume had gone subsequently glaciers readvanced reaching into the upper reaches of the main valleys during the lateglacial gschnitz stadial which likely occurred around 17 ka with final moraine stabilisation no later than 15 4 ka the link of the egesen stadial with the younger dryas climate deterioration is supported by exposure ages from four sites as well as minimum limiting radiocarbon dates from bogs within former glacier tongue areas key questions on the spatial and temporal variability of ice extents throughout the last glacial cycle have yet to be answered copyright 2008 john wiley sons ltd

crustal structure and active tectonics in the eastern alps 1 during the last decade a series of controlled source seismic experiments brought new insight into the crustal and lithospheric structure of the eastern alps and their adjacent tectonic provinces a fragmentation of the lithosphere into three blocks europe eu adria ad and the new pannonian fragment pa was interpreted and a triple junction was inferred the goal of this study has been to relate these deep crustal structures to active tectonics we used elastic plate modeling to reconsider the moho fragmentation we interpret subduction of eu below ad and pa from north to south and underthusting of ad mantle below pa from southwest to northeast the moho fragmentation correlates well with major upper crustal structures and is supported by gravity seismic and geodetic data an analysis of crustal thickening suggests that active convergence is associated with continued thrusting and lateral extrusion in the central eastern alps and thickening of the adriatic indenter under the southern alps according to the velocity relations at the triple junction pa moves relative to eu and ad along ene and se striking faults mainly by strike slip an eastward directed extensional component is compensated by the lateral extrusion of the central eastern alps the periadriatic insubric line east of the triple junction and the mid hungarian fault zone have relatively recently lost their role as first order active structures we favor the idea that the pannonian fragment and the tisza block merged to a soft microplate surrounded by the eastern and southern alpine carpathian and dinaric orogens

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

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

sub millennial scale climatic oscillations in the central adriatic during the lateglacial palaeoceanographic implications abstract a multi proxy study of a sedimentary core obtained from the central adriatic basin provides evidence of short term events of palaeoceanographic variability during the last glacial lateglacial period grip event stages gi 1 and gs 1 comparison of the adriatic results with other mediterranean records reveals a common sequence of changes in palaeoceanographic conditions variations in foraminiferal assemblage data and in stable isotopic compositions indicate two short term cold oscillations which interrupted an overall cooling trend that commenced at the beginning of the greenland gi 1 episode bolling allerod episode these cold events considered to be contemporaneous with gi 1b and gi d of the grip ice core record are indicated by distinctive foraminiferal assemblages which reflect episodes of high productivity under relatively restricted water circulation with in particular reduced vertical mixing during winter differences in the foraminiferal assemblages indicate that the younger of the two cold spells is characterized by reduced ventilation of bottom waters our results combined with published data from neighbouring marine basins suggest a widespread reduction in deep water formation in the central mediterranean which commenced during the gi 1b episode and reached its maximum effect during the onset of the gs 1 younger dryas episode moreover three intervals with reduced vertical mixing correspond to the two cold spells during gi 1 and the lower phase of the gs 1 episode and show close similarities with the palaeoceanographic changes reported for the north atlantic this similarity indicates that the mediterranean and north atlantic may have been responding more or less synchronously to common forcing mechanisms

quantifying tectonic versus erosive denudation by the sediment budget the miocene core complexes of the alps abstract the denudation budget of the alps is quantified for the main period of lateral extrusion between 22 and 12 ma the relative importance of tectonic denudation increases from w to e from 70 in the lepontine window in the swiss alps to 80 in the tauern window and to more than 95 in the rechnitz window the driving mechanism of tectonic denudation was eastward extrusion due to an unconstrained orogenic margin in the pannonian basin tectonic denudation in the alps was responsible for about 30 of the total exhumation between 22 and 12 ma

u th age constraints on the absence of ice in the central inn valley eastern alps austria during marine isotope stages 5c to 5a abstract calcitic flowstones are present in fractures of a pleistocene breccia near innsbruck austria and record periods of carbonate precipitation in the unsaturated zone between 101 500 1500 and 70 300 1800 yr constrained by u series disequilibrium dates the occurrence of these speleothems their low carbon isotopic composition and the lack of infiltrated siliciclastic material demonstrate that the central inn valley which harbored one of the most extensive valley glaciers during the last glacial maximum was ice free during marine isotope stages 5c to 5a climatically warm periods are separated by distinct drops in the oxygen isotopic composition of the speleothem calcite attributed to strong and possibly seasonally biased atmospheric cooling during these intervening stadials which mirror those identified in the greenland ice cores and marine sea surface temperature records calcite deposition apparently came to a halt but the inn valley remained ice free the youngest calcite layer formed between 74 000 and 70 000 yr and places a maximum age limit on the likely expansion of alpine glaciers during the marine isotope stage 5 4 transition consistent with other speleothem records

the initiation of northern hemisphere glaciation for well over a century scientists have speculated that variations in the atmospheric concentration of radiatively important trace gases such as carbon dioxide could control the earth s climate e g arrhenius 1 896 recent observations of significant glacial interglacial variation in atmo spheric co2 in ice cores put this idea on a firm observational as well as theoretical footing e g barnola et ai1 987 in this century as atmospheric co2 levels creep steadily upwards in response to the burning of fossil fuels and forests the specter of manmade global climate change looms before us ipcc 1990 a possibility that has heightened interest in the natural variability of climate in the past in particular the 3 c warming pre dicted for the next century has stimulated interest in past warm climates such as the middle pliocene around 3 0 million years ma ago an interval that has often been invoked as a greenhouse world budyko et al 1985 in this paper the climate transition from the warm mid pliocene around 3 2 ma to the onset of northern hemisphere ice ages around 2 4 ma is examined evidence for the initiation of significant northern hemisphere glaciation is examined as well as how this event affected climate around the globe while the cause of individual glacial interglacial oscillations is tied to milankovitch variations in the earth s orbit around the sun e g imbrie et ai 1 992 these insolation changes cannot account for the long term cooling trend which culminated in northern hemisphere glaciation in the final section of this paper mechanisms of long term climate change

quaternary erosion induced isostatic rebound in the western alps the high elevation and deep incision of the alps have traditionally been used as an argument for recent tectonic activity that has elevated the belt and increased erosion rates normal faulting and horizontal extension however dominate current tectonic activity and isostatic compensation of thinning crust should lead not to increased but to decreased mean elevations here we test the idea that enhanced quaternary erosion of the alps and isostatic compensation of the mass removed can account for the distribution of present day geodetically measured rates of vertical movement in the western alps using geophysical relief and kuhlemann s estimated average erosion rate for the alps we quantify the spatial distribution of erosion and the volume of eroded rock respectively from these we obtain a map of rock eroded within a given time span the calculated isostatic response of the alpine lithosphere to erosional unloading for a variety of values of the flexural rigidity of the alpine lithosphere reaches a maximum of 500 m since 1 ma in the inner swiss alps and vertical movement extends across the entire belt including peri alpine basins assuming a steady erosion rate since 1 ma this rebound accounts for half of the measured vertical motion of 1 1 mm yr in the southern valais thus a significant fraction 50 of the present day vertical movement results from the isostatic response to enhanced erosion during plio quaternary time

decoupling along plate boundaries key variable controlling the mode of deformation and the geometry of collisional mountain belts the consequences of decoupling between weak orogenic wedges and strong adjacent foreland plates are investigated by means of lithospheric scale analogue modeling decoupling is implemented in the three layer models by lubrication of the inclined boundary between a strong foreland and a weak orogenic wedge plate boundaries are orthogonal to the convergence direction experimental results show that strong decoupling between the foreland and the orogenic wedge leads to underthrusting of the former underneath the orogenic wedge and deformation of the orogenic wedge by folding shearing and minor backthrusting shortening is mainly taken up along the main overthrust the decoupled boundary and within the orogenic wedge leaving the indenter devoid of deformation in contrast strong coupling between the foreland and the orogenic wedge favors buckling involving both the weak zone and the strong plates the results of these end member models have implications for collision zones for example the eastern alps in europe such that the switch from localized deformation within the orogenic wedge during the oligocene middle miocene to orogen scale uplift and deformation during the late miocene pliocene involving the foreland and indenter plates respectively is interpreted as reflecting a change from a decoupled to a coupled system

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

a first attempt to date the original deckenschotter of penck and bruckner with cosmogenic nuclides abstract in the classical area of alpine quaternary stratigraphy bavaria germany a succession of four gravel spreads that are separated from each other by valley incision was recognized by penck and bruckner 1909 die alpen im eiszeitalter tauchnitz leipzig 1199p the two older gravel terraces attributed to glaciations named gunzian and mindelian have so far not been dated recent advances in the use of cosmogenic nuclides allow the burial age determination of sediments the method uses the different decay of the two nuclides 26al and 10be to date the time since a deposit was shielded from further radiation a depth profile makes it possible to model ages for surface sediments that are not shielded completely this paper discusses the various constraints that must be addressed in order to date surface sediments and it presents the ages obtained 2 35 ma for gunzian 0 68 ma for mindelian these dates are in good agreement with measurements of tectonic displacement and development of catchments the results confirm that the burial age determination method is basically feasible for such terraces

the linking of the upper middle and lower reaches of the yellow river as a result of fluvial entrenchment abstract the upper middle yellow river flows through the fenwei graben a structure resulting from extensional tectonism that was formed and repeatedly extended during the cenozoic the drainage system within this graben was formerly isolated from the lower reaches of the yellow river system by the xiaoshan mountains an actively growing nw se trending range the modern course of the yellow river takes it through this range along the sanmen gorge the formation of which was of great significance in that it initiated through going drainage between the upper middle and lower reaches of the system the timing of this event which was clearly a critical point in the evolution of the yellow river can be established by dating the terraces in the gorge intermittent deepening of this gorge by the yellow river from a high level planation surface capping the mountain range has resulted in the formation of five terraces magnetostratigraphic records from aeolian deposits accumulated on these surfaces provide a geochronological sequence for this geomorphic archive in which the ages of the planation surface and of terraces t5 t4 t3 t2 and t1 have been determined as 3 63 ma 1 24 ma 0 86 ma 0 62 ma 129 ka and 12 ka respectively under the constraint of this chronological framework a model for landscape evolution is proposed here uplift of the inner fenwei graben and of the surrounding mountain ranges led to dissection of the 3 63 ma old planation surface in conjunction with the formation of the sanmen gorge drainage of the lake previously occupying the basin would have promoted incision into the fluvio lacustrine graben sediments indeed gorge formation through the xiaoshan may have been initiated or intensified by lake overflow the ages obtained for the planation surface and uppermost terrace suggest that the formation of the sanmen gorge and the initiation of the through going eastward drainage of the yellow river occurred between 3 63 and 1 24 ma before the start of gorge entrenchment the products of erosion in the modern upper catchment of the yellow river were unable to reach the sea the dramatic increase in deposition rates in the bohai gulf at the mouth of the modern yellow river in the east china sea 1 0 ma ago thus resulted from the initiation of an integral enlarged yellow river catchment drainage through the sanmen gorge it does not imply an increase in erosion rates at that time

shelf edge erosion sediment failure and inception of bari canyon on the southwestern adriatic margin central mediterranean abstract we investigate the impact of regional tectonic setting and sedimentary dynamics on the onset of bari canyon the main sediment conduit on the southwestern adriatic margin sam since the middle pleistocene deposition on the sam a foreland basin relative to the southern apennines was primarily controlled by glacio eustatic cycles however a number of tectonic structures active since the early cenozoic impacted on the stacking of progradational deposits and on the overall slope setting and stability along the sam four depositional sequences accomplished the progradation of the shelf margin between ca 450 kyr bp and the last glacial maximum lowstand ca 20 ka bp these sequences are variably dissected by two large scale erosional features on the upper slope 1 bari canyon and 2 gondola slide headscarp further north the shelf facing these two major erosional structures shows several smaller scale incisions that merge with the sequence boundaries between each of the four stacked depositional sequences the distribution of these erosional features reflects the location of tectonic structures that are still active suggesting that both the intense erosion and the sediment failure in these areas were enhanced by tectonic deformation we define the age of these older episodes of shelf edge erosion and mass wasting that were conducive to the inception of bari canyon as we know it today moreover we envisage the following predisposing factors as responsible for the inception and subsequent evolution of bari canyon a long term regional uplift and margin tilt likely controlling the lateral variability in shelf width and shelf slope profile b rapid margin progradation during the deposition of middle late pleistocene sequences c recent tectonic deformation resulting in gentle folds growing during the canyon evolution

late neogene erosion of the alps a climate driver as with many mountain belts globally the alps have seen a large increase in sediment yield in the late neogene the hypothesis that this increase results from climate change impacts on erosion rate over the past 5 ma is testable given the extensive work completed in the alps sediment budgets thermochronology based cooling rates and estimates of modern rock uplift and erosion in the western alps are reviewed to search for correlation in space and time that might fingerprint climatic events major increases in sediment yield are apparent starting in the late messinian 5 5 mya and accelerating toward the present day this suggests the occurrence of a series of climatic changes that increased erosion rates even as tectonic processes appear to have slowed or stopped at present tight correlations in time are difficult to establish and there remain open questions about the role of tectonics in the coupled system

lava fountains from the 1999 tvashtar catena fissure eruption on io implications for dike emplacement mechanisms eruption rates and crustal structure the first direct evidence that patterns of basaltic eruptive activity may be very similar on io and earth was seen on november 26 1999 when the solid state imaging system on board the galileo spacecraft obtained high resolution images of a fissure eruption taking place in one of the calderas of the tvashtar catena complex we analyzed the dynamics of the fissure eruption from the morphology of the lava fountains and pyroclastic deposits and derived an estimate of the eruption rate our best estimate of the volume eruption rate per unit length of fissure lies in the range 0 7 to 7 m3 s 1 m 1 and multiplying this rate by the fissure length of 25 km yields a total volume eruption rate of magma of 2 104 to 2 105 m3 s 1 the upper end of the inferred eruption rate is very close to the upper end of the range of eruption rates observed or inferred for fissure eruptions on earth theoretical models of the possible dike systems feeding the fissure show that for eruptions of positively buoyant magma the elastic properties of rocks are such that a magma flux of 6 to 7 m3 s 1 m 1 is the largest value that can ever be realized in such eruptions this limiting value being independent of planetary gravity and thus the same on all silicate bodies the eruption rate inferred for tvashtar can also be achieved by a negatively buoyant magma but in that case the source depth cannot be much greater than a few tens of kilometers we find that some eruptive events are consistent with the effusion of magmas which are buoyant relative to the crust whereas others appear to involve magmas which are not this implies that the distribution of crustal volatiles is laterally very inhomogeneous our analyses suggest that the depths from which magmas make their final ascent to the surface of io are generally of order tens rather than hundreds of kilometers

the topographic state of fluvially conditioned mountain ranges abstract the topography of mountain ranges reflects the competition of constructive and destructive processes driven by tectonics and climate respectively there is a vital debate whether the topography of individual orogens reflects stages of growth steady state or decay that is fueled by the million year time scales hampering direct observations on landscape evolution the superposition of various process patterns and the complex interactions among different processes hence there is a demand for sophisticated analysis tools to extract constraints on the long term evolution of orogens from their topography we review the field of orogen scale landscape evolution from a numerical perspective summarize the most prominent modelling concepts and their implications for the fluvially driven development of mountain topography and finally evaluate their applicability for understanding real world orogens following the concept of equilibrium a state where uplift rates are balanced by erosion rates and topography remains steady over time the erosional long term response of rivers and hillslopes can be mathematically formalised by the stream power and mass diffusion equations respectively based on a simple 1 dimensional model consisting of two rivers separated by a watershed we explain the influence of uplift rate and rock erodibility on steady state channel profiles and show the time dependent development of the channel drainage divide system dynamic drainage network reorganisation adds additional complexity and its effect on topography is explored on a two dimensional model river capture events and drainage divide migrations as expression of the ongoing drainage network reorganisation cause changes in topography until a stable network topology and hence full topographic steady state is achieved the long time spans needed for this drainage network optimization suggest that orogens on earth may never reach full topographic steady state in real world orogens we find evidence for premature mature and decaying topography as well as relief rejuvenation by analysing slope elevation distributions and trace the expression of crustal strain distorting drainage networks by applying the transform we conclude that modern concepts of landscape evolution allow sophisticated analyses of real world orogens but emphasize that unambiguous results are mostly derived from regions dominated by a limited number of interacting processes such as mountain ranges with limited or no glacial imprint this results in a high demand for techniques to disentangle the complex topography of real world orogens into the signals resulting from the individual land shaping processes

cooling and vertical motions of crustal wedges prior to during and after lateral extrusion in the eastern alps new field kinematic and fission track data from the mur murz fault system new structural and thermochronological zircon and apatite fission track data from the eastern most alps highlight distinct deformation phases affecting the austroalpine unit along a major sinistral strike slip fault system the mur murz fault mmf the data link deformation to vertical motions prior to during and after the main phase of lateral extrusion of the orogen zircon fission track ages document rapid ca 15 c myr and diachronous eastward younging cooling and rock exhumation during the latest cretaceous to paleocene subsequent regional eocene to early miocene cooling below the closure temperature of the apatite fission track system occurred at slow rates ca 2 c myr suggesting that the region was not subject to major surface uplift and erosion during that period fault kinematic analysis along the mmf document pre extrusion nnw sse contraction middle miocene syn extrusion ne sw to nne ssw directed shortening and late miocene e w contraction all phases are characterized by strike slip fault regimes formation of the complex mmf zone triggered the exhumation of small fault bound crustal blocks within the fault zone as documented by middle miocene apatite fission track ages overall ages are similar on both sides of the fault suggesting that lateral extrusion along the mmf was not associated with significant differential vertical motions local pliocene rock cooling and exhumation was probably related to the buttressing effect of the underthrust bohemian basement spur whereas large scale post extrusion surface uplift of the extruding crustal wedges such as the styrian block must have been related to long wavelength deformation processes affecting the easternmost alps

lithospheric memory and stress field controls on polyphase deformation of the pannonian basin carpathian system abstract the pannonian basin carpathian system displays pronounced lateral variation in lithopsheric structure and sedimentary basin configuration the tectonic history of the system is characterised by a polyphase history with late miocene extension in the pannonian basin and simultaneously occurring compression in the carpathian arc pre existing structures play a key role in subsequent basin reactivation explaining anomalous features in subsidence characteristics and inferred thinning factors the area exhibits a relatively high level of neotectonic activity imaged by high resolution seismic data intraplate seismicity and stress indicator data major parts of the system have experienced a rapid late neogene uplift and erosion amounting up to several kilometres in the romanian carpathians a major part of the present basin configuration previously primarily attributed to basin formation mechanisms such as stretching in the pannonian basin and lithospheric flexure in the carpathians appears to be strongly affected by recent deformation postdating basin formation of the pannonian basin and the carpathian foredeep these findings affect modelling predictions of basin subsidence sediment sourcing thermal evolution and hydrodynamic regime with implications for hydrocarbon play concepts in the area

luminescence dating of fluvial sediments and overbank deposits from gossau switzerland fine grain dating abstract last glacial fluvial sediments and overbank deposits from gossau switzerland have been investigated applying infrared stimulated luminescence irsl and thermoluminescence tl to polymineral fine grains age estimates have been determined using irsl and tl broad band blue yellow and uv emissions the irsl dates are mainly consistent with independent dating results while most of the tl measurements result in age overestimations caused by insufficient bleaching before deposition

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

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

lgm and late glacial fluctuations in the eastern alps abstract studies of glacier development in the eastern alps around the last glacial maximum lgm for more than a hundred years have created a reasonably well based knowledge of glacier extent sedimentation and palaeoclimate as well as chronology this was obtained from broad and detailed mapping palynological investigations and radiocarbon dating despite a very cold climate between 31 and 21 ka bp topographical constraints meant that glacier extent was limited to tributary valleys of the main trenches until about 24 ka bp then rapid ice build up in the main longitudinal valleys led to extended ice streams and to piedmont glaciers in the foreland this build up virtually ended at ca 21 ka bp according to radiocarbon dates obtained from organic matter embedded in the outwash and periglacial gravels niederterrasse the lgm possibly lasted 3000 4000 years and shows a short maximalstand and a more prolonged hochstand both connected with outwash deposits the ice decay was apparently very fast and the glaciers vanished from the longitudinal valleys probably within some hundreds of years this retreat was interrupted by two short oscillations of active glaciers in contact with huge masses of inactive ice occupying the main valley floors before these became totally ice free these events at the beginning of the oldest dryas ca 16 ka bp were followed by a distinct glacier readvance gschnitz marked by end moraines and outwash fans according to some radiocarbon dates this occurred around 14 ka bp during the bolling interstade the valleys became almost ice free the next two glacier readvances daun and egesen were limited to cirques and the higher parts of the valleys and are dated to the older and younger dryas stades respectively

a new chronology for the age of appalachian erosional surfaces determined by cosmogenic nuclides in cave sediments the relative chronology of landscape evolution across the unglaciated appalachian plateaus of kentucky and tennessee is well documented for more than a century geomorphologists have carefully mapped and correlated upland erosional surfaces inset by wide valley straths and smaller terraces constraining the timing of river incision into the appalachian uplands was difficult in the past due to unsuitable dating methods and poorly preserved surface materials today burial dating using the differential decay of cosmogenic 26al and 10be in clastic cave sediments reveals more than five million years of landscape evolution preserved underground multilevel caves linked hydrologically to the incision history of the cumberland river contain in situ sediments equivalent to fluvial deposits found scattered across the eastern highland rim erosional surface cave sediments correlate with 1 thick lafayette type gravels on the eastern highland rim deposited between c 5 7 and c 3 5 ma 2 initial incision of the cumberland river into the eastern highland rim after c 3 5 ma 3 formation of the parker strath between c 3 5 ma and c 2 0 ma 4 incision into the parker strath at c 2 ma 5 formation of a major terrace between c 2 0 ma and c 1 5 ma 6 shorter cycles of accelerated incision and base level stability beginning at c 1 5 ma and 7 regional aggradation at c 0 85 ma initial incision into the appalachian uplands is interpreted as a response to eustasy at 3 2 3 1 ma incision of the parker strath is interpreted as a response to eustasy at 2 5 2 4 ma a third incision event at c 1 5 ma corresponds with glacial reorganization of the ohio river basin widespread aggradation of cave passages at c 0 85 ma is interpreted as the beginning of intense glacial interglacial cycling associated with global climate change copyright 2006 john wiley sons ltd

are the alps collapsing abstract orogenic collapse is a process that transfers gravitational potential energy from regions of high potential energy to regions of lower potential energy this transfer is classically considered to be accomplished by extension in the orogenic core and by synchronous shortening in foreland regions of the orogen not all extensional features in collisional mountain belts need however reflect orogenic collapse normal faulting thrust faulting and strike slip faulting are all active in different parts of the alps today and reflect complex local responses to ongoing europe adria convergence the western alps is the only area today where extension and shortening radial to orogen trend occur synchronously and where orogenic collapse may be an important process elsewhere in the alps normal faults are oriented at a high angle to orogen trend and were primarily active in oligocene and miocene time most present day activity in the central and eastern alps is on strike slip faults that are accommodati

revealing the late pliocene to middle pleistocene alluvial archive in the confluence of the western carpathian and eastern alpine rivers 26al 10be burial dating from the danube basin slovakia abstract the danube basin located in the junction of the eastern alps and western carpathians comprises up to 600 m thick alluvial succession which was previously assigned to the quaternary without geochronological constraints the internal stratigraphy and timing of the succession remained unknown although it has potential to provide an important record of geological evolution of the region the present study involves 26al 10be burial dating of 17 samples from wells along with facies correlation from the nw margin towards the basin centre with the purpose of recovering the pliocene quaternary depositional archive obtained ages ranging from 0 58 0 06 to 3 39 2 11 ma allow for four separate members to be distinguished the lowermost kolarovo fm with inferred depositional age of 5 2 6 ma shows lateral variability with gradual shift of channel fills composed of sands and gravelly sands across the floodplain pond facies from nw to se an abrupt increase of sediment supply accommodation ratio was observed at 2 6 ma and led to the dominance of amalgamated gravelly channel fills in the centre of the basin another sharp increase of sediment supply was observed at 1 2 ma reflected in a brief period of dominance of gravelly channel fill facies across the basin this highly supplied environment then gradually occupied the whole basin after 0 9 ma petrographic study implies a distant provenance for the period 5 0 2 6 ma the subsequent interval is characterised by sediment sourcing from uplifting mountains of the western carpathians on the margins of the danube basin drained by the vah river a notable change appeared after 0 9 ma when the eastern alpine provenance of clasts brought by the danube river prevailed based on a review of existing data about regional tectonics and climate the changes in this depositional record are interpreted as an interplay of climate changes 2 6 ma and 1 2 ma and local vertical movements affecting both sediment input and drainage network patterns the accommodation space was formed without contribution of fault activity according to the observed settings a noteworthy observation is time transgressive shift of facies boundaries in the pliocene quaternary succession

middle pleistocene to holocene activity of the gondola fault zone southern adriatic foreland deformation of a regional shear zone and seismotectonic implications abstract recent seismicity in and around the gargano promontory an uplifted portion of the southern adriatic foreland domain indicates active e w strike slip faulting in a region that has also been struck by large historical earthquakes particularly along the mattinata fault seismic profiles published in the past two decades show that the pattern of tectonic deformation along the e w trending segment of the gondola fault zone the offshore counterpart of the mattinata fault is strikingly similar to that observed onshore during the eocene pliocene interval based on the lack of instrumental seismicity in the south adriatic offshore however and on standard seismic reflection data showing an undisturbed quaternary succession above the gondola fault zone this fault zone has been interpreted as essentially inactive since the pliocene nevertheless many investigators emphasised the genetic relationships and physical continuity between the mattinata fault a positively active tectonic feature and the gondola fault zone the seismotectonic potential of the system formed by these two faults has never been investigated in detail recent investigations of quaternary sedimentary successions on the adriatic shelf by means of very high resolution seismic stratigraphic data have led to the identification of fold growth and fault propagation in middle upper pleistocene and holocene units the inferred pattern of gentle folding and shallow faulting indicates that sediments deposited during the past ca 450 ka were recurrently deformed along the e w branch of the gondola fault zone we performed a detailed reconstruction and kinematic interpretation of the most recent deformation observed along the gondola fault zone and interpret it in the broader context of the seismotectonic setting of the southern apennines foreland region we hypothesise that the entire 180 km long molise gondola shear zone is presently active and speculate that also its offshore portion the gondola fault zone has a seismogenic behaviour

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