sequence of thrusting within a thick skinned tectonic wedge evidence from40ar 39ar and rb sr ages from the austroalpine nappe complex of the eastern alps the sequence of thrusting within a regional scale alpine thick skinned tectonic wedge has been constrained by rb sr and 40ar 39ar dating of whole rock constituent white mica and biotite from structural units of the austroalpine nappe complex eastern alps austria preservation of variscan and pre variscan isotopic signatures in pre alpine basement units indicates a non penetrative metamorphic alpine overprint alpine nappe assembly and accompanying ductile deformation occurred during maintenance of lower greenschist facies metamorphic conditions c 300 450 c analyses from greenschist facies metamorphic mylonites and penetratively ductile deformed cover sequences display decreasing 40ar 39ar plateau ages structurally downward thrusting and accompanied ductile deformation commenced at c 100 90 ma in the uppermost structural levels footwall fault propagation effected internal deformation and out of sequence thrusting within intermediate structural levels at c 95 80 ma this was contemporaneous wit

large wood recruitment processes and transported volumes in swiss mountain streams during the extreme flood of august 2005 abstract the extreme flood event that occurred in august 2005 was the most costly documented natural hazard event in the history of switzerland the flood was accompanied by the mobilization of 69 000 m3 of large wood lw throughout the affected area as recognized afterward wood played an important role in exacerbating the damages mainly because of log jams at bridges and weirs the present study aimed at assessing the risk posed by wood in various catchments by investigating the amount and spatial variability of recruited and transported lw data regarding lw quantities were obtained by field surveys remote sensing techniques lidar and gis analysis and was subsequently translated into a conceptual model of wood transport mass balance detailed wood budgets and transport diagrams were established for four study catchments of swiss mountain streams showing the spatial variability of lw recruitment and deposition despite some uncertainties with regard to parameter assumptions the sum of reconstructed wood input and observed deposition volumes agree reasonably well mass wasting such as landslides and debris flows were the dominant recruitment processes in headwater streams in contrast lw recruitment from lateral bank erosion became significant in the lower part of mountain streams where the catchment reached a size of about 100 km2 according to our analysis 88 of the reconstructed total wood input was fresh i e coming from living trees that were recruited from adjacent areas during the event this implies an average deadwood contribution of 12 most of which was estimated to have been in channel deadwood entrained during the flood event

geophysical geological transect and tectonic evolution of the swiss italian alps a complete alpine cross section integrates numerous seismic reflection and refraction profiles across and along strike with published and new field data the deepest parts of the profile are constrained by geophysical data only while structural features at intermediate levels are largely depicted according to the results of three dimensional models making use of seismic and field geological data the geometry of the highest structural levels is constrained by classical along strike projections of field data parallel to the pronounced easterly axial dip of all tectonic units because the transect is placed close to the western erosional margin of the austroalpine nappes of the eastern alps it contains all the major tectonic units of the alps a model for the tectonic evolution along the transect is proposed in the form of scaled and area balanced profile sketches shortening within the austroalpine nappes is testimony of a separate cretaceous age orogenic event west directed thrusting in these units is related to westward propagation of a thrust wedge resulting from continental collision along the meliata hallstatt ocean further to the east considerable amounts of oceanic and continental crustal material were subducted during tertiary orogeny which involved some 500 km of n s convergence between europe and apulia consequently only a very small percentage of this crustal material is preserved within the nappes depicted in the transect postcollisional shortening is characterized by the simultaneous activity of gently dipping north directed detachments and steeply inclined south directed detachments both detachments nucleating at the interface between lower and upper crust large scale wedging of the adriatic or apulian lower crust into a gap opening between the subduced european lower crust and the pile of thin upper crustal flakes alpine nappes indicates a relatively strong lower crust and detachment between upper and lower crust

if a tree falls in an urban stream does it stick around mobility characteristics and geomorphic influence of large wood in urban streams in northeastern ohio usa abstract large wood influences geomorphological ecological and biogeochemical functions of streams but in urban areas it is also considered an unaesthetic hazard quantifying the abundance and mobility of in stream wood along an urban intensity gradient and understanding the relationship between wood dynamics and stream reach network and watershed characteristics allows for a stronger understanding of the potential benefits and hazards of wood in urban streams repeat wood surveys were conducted at 11 stream reaches in the cleveland ohio area where wood removal is not practiced and forested riparian zones exist study reaches span a gradient of impervious surface cover and extent of the stream network with a forest buffer channel morphology and sediment size were also measured stream hydrology does not change when imperviousness is 12 40 in this region so quantification of impervious surfaces stands in for a broader suite of urban impacts wood abundance decreases and mobility increases as urban intensity in the watershed and along the stream network increases jams become smaller and less stable but the size and orientation of individual wood pieces do not change along an urban gradient over the 6 month study period wood mobility exceeded 100 in some of the most urbanized streams and transport distances are inferred to be on the order of 100s of meters there was a positive correlation between jam spacing and pool spacing and finer sediment sizes occurred in some wood associated deposits but overall geomorphic effects are limited where reaches are confined wood abundance is suppressed but impervious surfaces and the extent of forest along the stream network are stronger predictors of wood dynamics than reach scale characteristics these results emphasize the importance of situating understanding of reach scale wood dynamics in the context of larger scale phenomena

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

sedimentary tectonics and subsidence modelling of the type upper cretaceous gosau basin northern calcareous alps austria the upper cretaceous gosau group of the austrian northern calcareous alps records sedimentation and subsidence after early cretaceous thrusting the gosau basin in the gosau russbach area is approximately 8 km wide and 10 km long it is filled by more than 1000 m alluvial shallow marine deposits of the lower gosau subgroup upper turonian lower campanian facies and thickness changes within short horizontal distances suggest synsedimentary basin margin faulting extensional structures within the triassic basement of the basin include fibrous gashes which indicate w nw e se directed extension of 6 18 w nw directed normal faults at the southeastern basin margin a prominent se directed normal fault with a minimum fault throw of approximately 500 m at the nw basin margin and dextral strike slip at the southwestern margin suggest a pull apart origin of the basin between nw se trending right overstepping dextral strike slip faults backstripped tectonic subsidence curves yield values of total subsidence of 700 m in approximately 6 ma forward computer modelling based on extensional models results in stretching factors between 1 09 1 15 local extension along strike slip faults is suggested as the main mechanism for basin formation

causes of recent himalayan uplift deduced from deposited patterns in the ganges basin the hypothesis1 that late cenozoic uplift of many of the world s mountain ranges was a response to climate change rather than to tectonic processes is based on the premise that enhanced erosion in an altered climate led to a reduction in both the total mass of a mountain range and its mean elevation this reduction was coeval with increased regional relief and with passive isostatic uplift of the remaining summits the hypothesis is difficult to evaluate because both climate and tectonic forces affect uplift in many active ranges in the absence of sufficient denudational and uplift data from the mountains themselves depositional patterns in adjacent basins may sometimes be used to distinguish between uplift arising from erosional or from tectonic processes in foreland basins uplift of the proximal basin and a reduction or absence of asymmetric subsidence are predicted responses to erosionally driven uplift2 here i show that patterns of sediment accumulation and the position of major rivers in the neogene gangetic foreland basin seem to have changed markedly in plio pleistocene times these changes lend support to the hypothesis that the importance of erosional unloading has increased in the himalayas during the past 4 myr

wood recruitment and retention the fate of eroded trees on a braided river explored using a combination of field and remotely sensed data sources abstract this paper investigates wood recruitment and deposition dynamics in a large gravel bed braided river tagliamento river italy we used a combination of field measurements automatically repeated ground images and remotely sensed surveys to quantify wood input through bank erosion and associated downstream deposition two sites were investigated where floods caused the erosion of vegetated island edges a lidar survey preceding the erosion events provided data on the morphology and vegetation structure of the eroded areas allowing estimation of the number of trees that were uprooted sequences of ground based images acquired automatically and supported by field measurements showed the time number and location of deposited trees results show that the complex morphology of braided rivers induces specific deposition patterns we observed wide dispersal of wood on gravel bars with jams characterised by a small number of logs on average 2 3 and in many cases only a single log a large proportion of the eroded trees up to 40 were deposited on the nearest downstream bar this illustrates significant wood retention close to the recruitment site with the remaining wood dispersed widely downstream differences in the observed level of local wood retention were associated with the proximity of the erosion site to the main channel and differences were also observed in retention between the peak and the falling limb of flood events confirming that water depth and probably flow velocity are the crucial parameters controlling wood deposition

mid cretaceous primitive alkaline magmatism in the northern calcareous alps significance for austroalpine geodynamics basanitic dykes local name ehrwaldite occur over a distance of at least fifty kilometres in a narrow east west trending zone within the lechtal nappe of the northern calcareous alps the dykes crosscut mesozoic sedimentary strata up to the lower cretaceous the sedimentary rocks show contact metamorphism in the immediate vicinity of the dykes the ehrwaldites vary in mineral content from olivine fo 91 87 titanian augite basanites to basanites containing also kaersutite titanian biotite and zeolites minor phases are titanian magnetite picotite llmenite carbonate and sulfides mantle derived xenoliths and xenocrysts form up to five percent of the rock bulk chemical analyses show the typical characteristics of nepheline basanites ne 11 17 wt mg number 74 78 and demonstrate that the ehrwaldites are primitive mantle derived melts trace element contents of the dykes are in excellent agreement with those for basanites and olivine nephelinites from tertiary and quaternary european provinces the same is true for the isotope characteristics of the dykes with average initial esr and end values of 8 2 and 4 7 respectively these data demonstrate similarities in the mantle source rocks and in the melting characteristics with european alkaline rocks and thus similarities in the european subcontinental mantle at different localities for the last 100 ma these data are in clear contrast with the value for the penninic suboceanic mantle geochemical constraints and piston cylinder experiments indicate a depth of origin of 80 kilometres at temperatures of at least 1250 c for the ehrwaldites potassium argon bulk rock data of petrographically different samples of the dykes from different localities yield consistent ages around 100 ma upper albian after emplacement the ehrwaldites underwent conditions of the zone of diagenesis with temperatures around 120 c which the late magmatic zeolites survived

kinematics of the inntal shear zone sub tauern ramp fault system and the interpretation of the transalp seismic section eastern alps austria abstract a new interpretation of the inntal tauern sector of the transalp seismic section is presented one of the most prominent contrasts in reflectivity in the transalp seismic section is the contact between the bajuvaric unit in the footwall and the overlying tirolic unit and its basement across a moderately south dipping interface we trace this contact from the surface at the southern margin of the inn valley to a depth of 5 km there the contact is deformed or cut by the tauern window northern margin we define the contact between bajuvaric and tirolic units as brixlegg thrust which is older than miocene tauern window exhumation and has a paleogene age the sub tauern ramp connects with the inntal fault system at the surface and roots below the tauern window oblique thrust movements across this fault system in the miocene caused exhumation of the hanging wall where the fault has a ramp geometry which is in the area of the transalp cross section and west of it east of the transalp cross section the fault system merges with alpine basal thrust which is a flat no miocene exhumation occurred above the flat

input storage and distribution of large woody debris along a mountain river continuum the drome river france abstract large woody debris lwd input storage and distribution were studied along the drome river a french alpine river with an active shifting channel and a well developed riparian forest lwd input from the floodplain is low 669 6 mg year 1 between 1948 and 1971 and 569 3 mg year 1 between 1971 and 1991 based on estimates of average lwd mass per study plot a range of 766 2122 mg year 1 of lwd were stored within the active channel e g unvegetated bars and low flow channel 60 km course covering 492 ha lwd accumulations are mainly observed on gravel bars at a limited number of preferential sites they are relatively rare and are randomly distributed in the low flow channel consequently lwd location is mainly associated with the decrease of flow level in shallow sectors in the low flow channel lwd stop en route is primarily caused by in channel structures such as boulders or vegetated islets general geomorphological factors e g pattern slope etc provide less explanation of lwd distribution moreover the residence time of lwd accumulations on the drome river is short lwd storage 1 3 3 7 times the annual lwd input from the floodplain and their morphogenic role is negligible few of the accumulations are buried or characterized by vegetation shoots and associated pools

eastern alpine tectono metamorphic evolution constraints from two dimensional p t t modeling we use two dimensional 2 d p t t modeling to constrain the thermal and rheological aspects of different scenarios for the late mesozoic and cenozoic tectonic evolution of the eastern alps inferred from excellent data sets from the tauern window tw models invoking subduction of the south penninic sp oceanic lithosphere during thrusting and subsequent erosion of the austro alpine aa upper plate nappe stack are inconsistent with the observed thermal evolution within the aa and penninic units in these models predictions for the aa peak thermal conditions are lower than observed after exhumation and cooling to midcrustal levels and subduction of the continental middle penninic mp block the aa undergoes a phase of renewed heating to almost the previous peak temperatures simultaneously the penninic units experience a phase of heating upon subduction followed by cooling after onset of subduction of the north penninic np basin the model predictions are inconsistent with the observed nearly isothermal uplift path of the sp after subduction and cannot explain observed inverted metamorphic peak conditions in the deeper aa amphibolite facies down to the higher penninic unit greenschist facies a model with the beginning of subduction of the sp occurring after crustal thickening of the aa and subsequent return to normal crustal thicknesses is compatible with the p t t data in this model peak temperature conditions are higher in the aa followed by a phase of strong cooling in the aa upper plate with the onset of underthrusting this model also explains successfully nearly isothermal exhumation of the mp and inverted metamorphic peak conditions in the deeper aa material accreted to the hanging wall from the oceanic crust sp experiences a phase of cooling during ongoing subduction of oceanic lithosphere and begins to heat up to its thermal climax after the subduction of trailing continental lithosphere the subsequent pt path of the penninic units strongly depends on the timing and rates of underthrusting by the foreland observed pt paths in the mp within the tw require continuous subduction of the np and the trailing european foreland under the exhuming mp block documented rapid cooling in the final uplift phase of the penninic units in the tw requires exhumation rates up to approximately 4 mm yr predictions of slightly elevated present day geothermal gradients in the tw area are consistent with available heat flow data as a result of mesozoic rifting followed by late mesozoic crustal thickening of the aa paleorheological reconstructions are characterized by a contrast between relatively strong oceanic lithosphere and adjacent weak continental lithosphere predicted decoupling of weak continental and oceanic lithosphere during subsequent subduction of the penninic units can explain observed late cretaceous crustal extension in the aa units in terms of gravitational spreading ongoing subduction leads to an overall strength increase due to underthrusting of cool oceanic lithosphere whereas subduction of continental lithosphere causes a strength decrease in the upper levels of the lithosphere continuous crustal thickening and relaxation of the depressed isotherms reduce the strength of the lower lithospheric mantle beneath the central orogen further enhanced by rapid late stage uplift predictions for the present day rheological structure of the eastern alps support the existence of a strong upper crustal layer two wedge shaped strong upper mantle layers to the north and the south of the orogen and a weak upper mantle underlying the central orogen

orogenic structure of the eastern alps europe from transalp deep seismic reflection profiling abstract the transalp group comprising of partner institutions from italy austria and germany acquired data on a 340 km long deep seismic reflection line crossing the eastern alps between munich and venice although the field work was split into four campaigns between fall 1998 and summer 2001 the project gathered for the first time a continuous profile across the alps using consistent field acquisition and data processing parameters these sections span the orogen itself at its broadest width as well as the editor fred davey and the two adjacent basins vibroseis and explosion data complementary in their depth penetration and resolution characteristics were obtained along with wide angle and teleseismic data the profile shows a bi vergent asymmetric structure of the crust beneath the alpine axis which reaches a maximum thickness of 55 km and 80 100 km long transcrustal ramps the southward dipping sub tauern ramp and the northward dipping sub dolomites ramp strongly reflective patterns of these ramps can be traced towards the north to the inn valley and towards the south to the valsugana thrust belt both of which show enhanced seismicity in the brittle upper crust the seismic sections do not reveal any direct evidence for the presence of the periadriatic fault system the presumed equivalent to the insubric line in the western alps according to our new evolutionary model the sub tauern ramp is linked at depth with remnants of the subducted penninic ocean the crocodile type model describes an upper lower crustal decoupling and wedging of both the european and the adriatic african continents

cretaceous to neogene cooling and exhumation history of the oetztal stubai basement complex eastern alps a structural and fission track study the central austroalpine oetztal stubai basement complex osk of the eastern alps together with its overlying sedimentary brenner mesozoic bmz and tectonic units upper austroalpine nappes underwent extension and exhumation during the cretaceous before its incorporation into the hanging wall of the neogene brenner normal fault during this late cretaceous to early tertiary deformation the brenner mesozoic and the immediately underlying uppermost part of the osk developed a strong stretching lineation within a near horizontal and often mylonitic foliation related to consistent top to ese directed transport quartz and calcite behaved ductilely throughout the area whereas dolomite shows a transition from brittle fracture in the north to plastic flow in the south consistent with the known cretaceous metamorphic temperature gradient the transition to crystal plastic flow of dolomite occurs at 480 c quartz textures indicate an increase in the contribution of prism glide together with a decrease in basal glide toward the south also consistent with the temperature gradient in the osk and bmz fission track analysis of both zircon and apatite along a n s profile in combination with existing data from the literature allows a continuous cooling path to be constructed for the osk cooling of the eastern osk started at 90 ma the thermal peak of metamorphism and ended some 30 myr later at near surface temperatures at 60 ma the northern region had already cooled below the upper limit of the apatite partial annealing zone whereas in the south cooling related to this exhumation phase stopped at temperatures between 100 and 200 c the ese directed shearing is interpreted as late cretaceous to early tertiary normal faulting that exhumed the osk and brought the upper austroalpine blaser and steinacher nappes into contact with the underlying brenner mesozoic the pattern of alpine metamorphic isograds established in the osk directly reflects the geometry and kinematics of this late cretaceous early tertiary exhumation due to low angle normal faulting

the tertiary dynamics of the northern eastern alps austria changing palaeostresses in a collisional plate boundary abstract six tertiary deviatoric palaeostress tensor groups from 165 stations in the calcareous alps describe the upper crustal dynamics of the leading edge of the adriatic plate during protracted continental collision with the european lower plate palaeostress changes are correlated to the kinematic evolution of the plate boundary and to independently derived plate kinematic data of the alpine carpathian pannonian area each palaeostress direction is defined by 32 to 89 individual tensors which constrain 1 late eocene to oligocene nw directed compression during thrusting and dextral shearing on wnw striking faults nw directed compression along the northern margin of the adriatic plate is correlated to its n directed translation combined with a counterclockwise rotation 2a late eocene to early miocene n directed compression during n directed thrusting of penninic and helvetic units and the molasse 2b early to middle miocene n directed strike slip compression during the onset of eastward lateral extrusion the change from nw to n directed compression is interpreted to result from strain partitioning at the periadriatic fault which has formed the new adriatic plate boundary since the oligocene dextral shearing on this fault accommodated continued anticlockwise rotation and decoupled the northern eastern alps from the rotational component n directed compression in the calcareous alps paralleled the n directed translation of the adriatic plate 3 middle miocene ne directed compression of thrust and strike slip type during lateral extrusion ne directed compression in the calcareous alps resulted from the drag of the eastward extruding central eastern alps sinistral shear stress was transmitted across the ene trending salzach ennstal fault ne oriented 1 axes include 45 with the e w striking zone of distributed sinistral shear in the calcareous alps 4 middle miocene e directed extension associated with orogen parallel normal faulting of the central eastern alps e directed extension paralleled the direction of mass transfer towards the pannonian basin during lateral extrusion normal faulting was induced by reduced lateral confinement due to removal of material east of the alps on the large scale eastward motion was enabled by the e directed retreat of the eastern carpathian subduction zone 5 late miocene e directed compression orogen parallel compression obstructed lateral extrusion the stress change from extension to e directed compression was caused by the end of subduction retreat in the eastern carpathians due to dynamic changes in the subduction zone 6 n directed extension late to post miocene extension paralleled recent topographic slopes in the foothill of the eastern alps palaeostresses changes correspond to distinct phases in the kinematic evolution of the northern eastern alps and to the systematic formation and reactivation of major fault zones wnw striking faults changed deformation styles from dextral shear to dextral transpression reverse faulting and finally to sinistral shear the early to middle miocene salzach ennstal fault which formed the northern boundary of the extruded central eastern alps changed from sinistral transpression to sinistral shear sinistral transtension and finally to dextral shear

critical taper analysis reveals lithological control of variations in detachment strength an analysis of the alpine basal detachment swiss alps although evidence for weak detachments underlying foreland thrust belts exists very little is known about the lateral variations in effective strength as well as the geological nature of such variations using critical taper analysis we show that a detailed and systematic measurement of surface slope of the central european alps reveals variations in strength parameter f along the detachment based on the argument that the alps are close to the critical state we show that the basal detachment is very weak near the deformation front but strengthens toward the hinterland very low f effective coefficient of friction plus normalized cohesion values of 0 54 but may also require additional mechanisms of dynamic weakening

interannual kinetics 2010 2013 of large wood in a river corridor exposed to a 50 year flood event and fluvial ice dynamics abstract semi alluvial rivers of the gaspe peninsula quebec are prone to produce and transport vast quantities of large wood lw the high rate of lateral erosion owing to high energy flows and noncohesive banks is the main process leading to the recruitment of large wood which in turn initiates complex patterns of wood accumulation and reentrainment within the active channel the delta of the saint jean river sjr has accumulated large annual wood fluxes since 1960 that culminated in a wood raft of 3 km in length in 2014 to document the kinetics of large wood on the main channel of sjr four annual surveys were carried out from 2010 to 2013 to locate and describe 1000 large wood jams lwj and 2000 large wood individuals lwi along a 60 km river section airborne and ground photo video images were used to estimate the wood volume introduced by lateral erosion and to identify local geomorphic conditions that control wood mobility and deposits video camera analysis allowed the examination of transport rates from three hydrometeorological events for specific river sections results indicate that the volume of lw recruited between 2010 and 2013 represents 57 of the total lw production over the 2004 2013 period volumes of wood deposited along the 60 km section were four times higher in 2013 than in 2010 increases in wood amount occurred mainly in upper alluvial sections of the river whereas decreases were observed in the semi alluvial middle sections observations suggest that the 50 year flood event of 2010 produced large amounts of lw that were only partly exported out of the basin so that a significant amount was still available for subsequent floods large wood storage continued after this flood until a similar flood or an ice breakup event could remobilise these lw accumulations into the river corridor ice jam floods transport large amounts of wood during events with fairly low flow but do not contribute significantly to recruitment rates ca 10 to 30 early it is fairly probable that the wood export peak observed in 2012 at the river mouth where no flood occurred and which is similar to the 1 in 10 year flood of 2010 is mainly linked to such ice break events that occurred in march 2012

new evidence for block and thrust sheet rotations in the central northern calcareous alps deduced from two pervasive remagnetization events 1 we present 81 paleomagnetic sites early triassic to early cretaceous from the central sector of the northern calcareous alps nca eastern alps austria and germany stepwise thermal demagnetization defines three magnetic directions mostly carried by low unblocking temperature and low coercivity minerals j3 350 j2 500 j1 575 and 680 j3 and j2 show positive inclinations whereas j1 very seldom is of dual polarity the fold tests show that a j3 can be interpreted as a postfolding and posttilting remagnetization and j2 as a postfolding and pre syn tilting j1 can be considered as primary because of the occurrence of two polarities and evidence presented by other authors in the area all three components show a systematic and significant clockwise rotation after comparing with the expected european references j2 or j1 are marked by higher rotation values than j3 j2 shows different inclinations depending on the structural position north or southward dips considering the structural evolution and the observed inclinations the first postfolding and pretilting remagnetization event j2 could have taken place between late cretaceous and eocene times but certainly before the thrusting of the nca over the rhenodanubian flysch and northward tilting caused by the stacking of the lower austroalpine nappes the second postfolding and posttilting remagnetization j3 would have been acquired after the final thrusting of the nca over penninic units from then the nca behaved as a set of rigid blocks recording the main stage of vertical axis clockwise rotation 65 in average associated with the continental collision the variable degree of rotation in the different positions from 40 to 134 can be explained by individual vertical axis rotation in a block system trying to adjust to space problems the constant declination differences between j2 and j3 25 in average would reflect the rotation related with the lateral differences of shortening during the oblique thrust of the austroalpine units over the penninic units

north atlantic blocking during january 1979 linear theory the second half of january 1979 was a time of persistent and large scale blocking in the north atlantic region in this study we examine the instability properties of the flow during this period and relate the growing modes to the development that occurs we have analysed the growth rates phase frequencies and structures of the ten fastest growing modes within a five level quasi geostrophic model incorporating spherical geometry on each day for the period between 10 and 30 january 1979 large scale equivalent barotropic dipole or multipole instability modes are prevalent in the north atlantic during the second half of january these modes are stationary or slowly propagating and grow rapidly with efolding times as short as 1 7 days in some cases we find that there is a close connection between these modes and the dynamical developments observed subsequently a few days later associated with the early stages of block formation there are large scale eastward propagating westward tilting onset of blocking wave train modes the onset of blocking modes also appear to be associated with rapid cyclogenesis off the east coast of north america the formation of the north atlantic blocking system and diffluent flow also produces corresponding changes in the storm tracks during the early parts of this period the fastest growing monopole cyciogenesis instability modes have regions of preferential development in the climatological storm tracks over the pacific atlantic and siberian regions subsequently however the atlantic cyclogenesis modes split into wave trains poleward and equatorward of the block in the developments during this period we also examine the roles of the adjoint eigenmodes and of optimal perturbations which produce the largest initial tendency of the l2 norm squared of the streamfunction

growing folds and sedimentation of the gosau group muttekopf northern calcareous alps austria analysis of the three dimensional geometry of upper cretaceous clastics in the muttekopf area northern calcareous alps austria indicate fold and fault structures active during deposition coniacian continental to neritic sedimentation lower gosau subgroup was contemporaneous with displacements on nw trending faults and minor folding along ne trending axes from the santonian onwards sedimentation of the deep marine upper gosau subgroup the nw trending faults were sealed and large folds with wsw trending axes developed the direction of contraction changed to n s after the end of gosau deposition in the danian paleocene synorogenic sedimentation patterns indicate continuous contraction from the coniacian to the late maastrichtian danian therefore large scale extension as observed in the central part of the eastern alps cannot be documented in the western parts of the northern calcareous alps a combination of subduction tectonic erosion for the frontal parts and gravitational adjustment of an unstable orogen after nappe stacking for the internal parts possibly accounts for the different development of gosau basins in the frontal and trailing regions of the austroalpine wedge

slab breakoff a model for syncollisional magmatism and tectonics in the alps slab breakoff is the buoyancy driven detachment of subducted oceanic lithosphere from the light continental lithosphere that follows it during continental collision in a recent paper davies and von blanckenburg 1994 have assessed the physical conditions leading to breakoff by quantitative thermomechanical modeling and have predicted various consequences in the evolution of mountain belts breakoff will lead to heating of the overriding lithospheric mantle by upwelling asthenosphere melting of its enriched layers and thus to bimodal magmatism breakoff will also lead to thermal weakening of the subducted crustal lithosphere thereby allowing buoyant rise of released crustal slices from mantle depths in this paper we present a test of this model in the tertiary evolution of the european alps in the alps both basaltic and granitoid magmatism occur between 42 and 25 ma following the closure of oceanic basins by subduction and continental collision the granitoids are now well established to result from mixing of basalt with assimilated continental crust to identify the tectonically crucial origin of the partial mantle melts we have compiled all published geochemical and isotopic data of numerous mafic dykes occurring throughout the whole alpine arc their trace element and isotopic composition suggests that they have been formed by low degree melting of the mechanically stable lithospheric mantle we see no evidence for melting of asthenospheric mantle it was thus not decompressed to depths shallower than 50 km once initiated rapid lateral migration of slab breakoff will result in a linear trace of magmatism in locally thermal weakened crust this explains why all alpine magmatic rocks intruded almost synchronously along a strike slip fault the periadriatic lineament a compilation of ages from penninic high pressure rocks subducted to depths of up to 100 km shows that subduction took place at circa 55 40 ma followed by uplift at 40 35 ma from the short time interval between their uplift and the onset of magmatism we infer that both processes have been induced by the breakoff the slab breakoff model fulfills its predictions in the case of the alps and therefore supports the assumptions made in the theoretical model on a geological basis we believe that the characteristic association of magmatic activity with the return of high pressure rocks to the surface allows the identification of this process in the earth s mountain belts

bridging the gaps an overview of wood across time and space in diverse rivers abstract nearly 50 years of research focused on large wood lw in rivers provide a basis for understanding how wood enters rivers how wood decays breaks and is transported downstream and how at least temporarily stable wood influences channel geometry fluxes of water sediment and organic matter and the abundance and diversity of aquatic and riparian organisms field based studies have led to qualitative conceptual models and to numerical stimulations of river processes involving wood numerous important gaps remain however in our understanding of wood dynamics the majority of research on wood in rivers focuses on small to medium sized rivers defined using the ratio of wood piece size to channel width as channels narrower than the locally typical wood piece length small and slightly narrower than the longer wood pieces present medium although diverse geographic regions and biomes are represented by one or a few studies in each region the majority of research comes from perennial rivers draining temperate conifer forests regional syntheses most commonly focus on the pacific northwest region of north america where most of these studies originate consequently significant gaps in our understanding include lack of knowledge of wood related processes in large rivers dryland rivers and rivers of the high and low latitudes using a wood budget as an organizing framework this paper identifies other gaps related to wood recruitment transport storage and how beavers influence lw dynamics with respect to wood recruitment we lack information on the relative importance of mass tree mortality and transport of buried or surficial downed wood from the floodplain into the channel in diverse settings knowledge gaps related to wood transport include transport distances of lw and thresholds for lw mobility in small to medium rivers with respect to wood storage we have limited data on longitudinal trends in lw loads within unaltered large and great rivers and on fluctuations in lw load over time intervals greater than a few years other knowledge gaps relate to physical and ecological effects of wood including the magnitude of flow resistance caused by lw patterns of wood related sediment storage for diverse river sizes and channel geometry quantification of channel floodplain lw interactions and potential threshold effects of lw in relation to physical processes and biotic communities finally knowledge gaps are related to management of large wood and river corridors including understanding the consequences of enormous historical reductions in lw load in rivers through the forested portions of the temperate zone and how to effectively reintroduce and manage existing lw in river corridors which includes enhancing public understanding of the importance of lw addressing these knowledge gaps requires more case studies from diverse rivers as well as more syntheses and metadata analyses

the deep lithosphere in the alps a model inferred from p residuals abstract the tomographic studies of the alps and their surroundings based on the relative p residuals indicated two lithosphere roots attaining depths over 200 km separated by an upwelling of the lithosphere asthenosphere transition beneath the central part of this mountain range the directional dependence of relative p velocities indicates an anisotropic wave propagation in the subcrustal lithosphere beneath the alps and their surroundings the presented model of the deep lithosphere structure suggests several phases of the tectonic development of this region collision of a tip of the adriatic plate with europe in the eastern alps and dextral strike slip movement of the adriatic ending with underthrusting of europe beneath the western alps and counterclockwise rotation the latter contributes to a steep plunge of both plates beneath the eastern alps and to stress accumulation in the friuli region a model with delamination of the rigid upper crust and its rotation resolves some of the inconsistencies between the near surface and deep tectonics and also explains the distribution of seismicity

quantification of fluvial wood using uavs and structure from motion abstract fluvial wood is recognized as one of the key elements of riverine environments its importance role and potential related risks are widely considered and analysed still to characterize and measure wood elements in the field a large investment in terms of time and cost is normally required these activities are often carried out in complex and potentially dangerous environments in this context the use of unmanned aerial vehicles uavs provides a powerful alternative technology to traditional approaches in this work we propose a novel approach combining uav surveys with structure from motion sfm photogrammetry to quantify fluvial wood the proposed methodology was tested in the blanco river southern chile which was severely affected by the chaiten volcanic eruption in 2008 that delivered large quantities of wood to the channel an area of about 1 2 ha was surveyed using uav and field measurements a comparative analysis between the traditional field based and uav surveys was carried out to quantify the accuracy of the latter and to better understand the strengths and potential limitations of the proposed methodology results showed that differences between the two methodologies were about 13 for both single large wood elements and wood jam volumes moreover a sensitivity analysis applied to 12 different scenarios allowed us to define the measurement precision achieved using the orthomosaics and dems our results showed that the proposed approach is effective in terms of field and laboratory activities saving around half the time this study demonstrates that the combination of uav and sfm can yield accurate results covering large areas in less time and providing a powerful tool for performing repeated surveys and thus acquiring relevant information for wood budgets and wood dynamics in rivers

exhumed fault bounded alpine blocks along the periadriatic lineament the eder unit carnic alps austria the eder unit in the carnic alps which is situated immediately south of the periadriatic lineament pl represents a fault bounded block consisting of a low grade up to 400 c indicated by epizonal illite crystallinity values recrystallized quartz and non recrystallized white mica metamorphic paleozoic metasedimentary sequence until now it has been assumed to represent a separate variscan nappe the rocks of the eder unit show a strong e to w oriented stretching lineation on steep foliation planes d1 subparallel to the pl d1 structures originated near the temperature peak of metamorphism and shear sense indicators show dextral ductile shear parallel to the pl tight mesoscale d2 folds formed on the cooling path k ar and ar ar ages from newly formed white mica cluster around 32 28 and 18 13 ma and suggest a two stage tertiary history of the eder unit we interpret the eder unit as a fault bounded block formed during oligocene large scale dextral shearing along the pl near tmax and exhumed in mid miocene times during another phase of activity along the pl its nature as a separate variscan nappe is questioned

the pulse of driftwood export from a very large forested river basin over multiple time scales slave river canada this study presents a case study of large wood transport on the great slave river in northern canada with the objective to better understand the processes of and variability in pulsed wood fluxes from large forested catchments we use a varied approach integrating field characterization of wood historical anecdotes repeat aerial imagery of stored wood and time lapse imagery of moving wood for a robust analysis and synthesis of processes behind pulsed wood flux from yearly uncongested export to rare congested wood floods repeat monitoring of known sites of temporary storage with new or historic imagery proved to be a very useful tool for constraining wood flux histories pulsed wood export on the slave river is not an artifact of episodic recruitment from major up basin disturbances but rather reflects decadal to half century scale discharge patterns that redistribute wood recruited from channel migration and bank slumping we suggest that the multiyear flow history is of paramount importance for estimating wood flux magnitude followed in declining importance by the yearly sequence of peaks and the magnitude and characteristics of the rising limb of individual floods

frequency of large in channel wood in eastern oklahoma ecoregions and its association with channel morphology abstract regional climate geology vegetation and land use influence hydrogeomorphic processes which influence stream channel form and the recruitment and transport of wood in streams we studied relationships between channel morphology and frequencies of large in channel wood in three upland ecoregions of eastern oklahoma where streams contain high fish diversity and valuable sport fisheries we surveyed 138 streams for wood within the boston mountains n 30 ozark highlands n 30 and ouachita mountain n 78 ecoregions our study investigated whether 1 the frequency of large wood differed among ecoregions 2 channel morphology influenced the distribution of large wood within and among ecoregions and 3 a relationship existed between the frequency and size of trees in the riparian zone and the frequency of large wood within and among ecoregions the frequency of single large wood pieces did not differ among ecoregions or vary with drainage area however the presence of one or more wood accumulation 2 to 4 pieces increased with drainage area and increased at a higher rate in the boston mountains and ozark highlands than in the ouachita mountains the frequency of single wood pieces decreased in narrower channels with larger substrates but increased in larger stream channels overall no association existed between riparian tree density and in channel wood in study reaches we discuss these results in the context of wood recruitment and transport and highlight key questions that remain regarding wood in eastern oklahoma streams

on the patterns and processes of wood in northern california streams abstract forest management and stream habitat can be improved by clarifying the primary riparian and geomorphic controls on streams to this end we evaluated the recruitment storage transport and the function of wood in 95 km of streams most drainage areas 2 in northern california crossing four coastal to inland regions with different histories of forest management managed less managed unmanaged the dominant source of variability in stream wood storage and recruitment is driven by local variation in rates of bank erosion forest mortality and mass wasting these processes are controlled by changes in watershed structure including the location of canyons floodplains and tributary confluences types of geology and topography and forest types and management history average wood storage volumes in coastal streams are 5 to 20 times greater than inland sites primarily from higher riparian forest biomass and growth rates productivity with some influence by longer residence time of wood in streams and more wood from landsliding and logging sources wood recruitment by mortality windthrow disease senescence was substantial across all sites mean 50 followed by bank erosion 43 and more locally by mass wasting 7 the distances to sources of stream wood are controlled by recruitment process and tree height ninety percent of wood recruitment occurs within 10 to 35 m of channels in managed and less managed forests and upward of 50 m in unmanaged sequoia and coast redwood forests local landsliding extends the source distance the recruitment of large wood pieces that create jams mean diameter 0 7 m is primarily by bank erosion in managed forests and by mortality in unmanaged forests formation of pools by wood is more frequent in streams with low stream power indicating the further relevance of environmental context and watershed structure forest management influences stream wood dynamics where smaller trees in managed forests often generate shorter distances to sources of stream wood lower stream wood storage and smaller diameter stream wood these findings can be used to improve riparian protection and inform spatially explicit riparian management

tectonics of the dolomites southern alps northern italy abstract in post variscan times the dolomites underwent a number of tectonic events which may be summarized as follows permian and triassic rifting phases broke the area into n s trending basins with different degrees of subsidence a middle triassic transpressive event then deformed the region along a n70 e axis generating flower structures within the basement volcano tectonic domal uplift and subsequent caldera formation occurred at the same time as the late ladinian magmatism early jurassic rifting also controlled the subsidence which increased eastward this long period of deformation was followed by a pre neogene late cretaceous palaeogene e w ene wsw compression which generated a w vergent belt possibly equivalent to the folded foreland of the dinaric chain a 70 km e w section of the dolomites indicates shortening of at least 10 km during the neogene the dolomites as far north as the insubric lineament were the innermost part of a s vergent thrust belt the basement of the dolomites was thrust southwards along the valsugana line onto the sedimentary cover of the venetian prealps for at least 10 km this caused a regional uplift of 3 5 km the valsugana line and its backthrusts on the northern side of the central dolomites generated a 60 km wide pop up in the form of a synclinorium within which the sedimentary cover adapted itself mainly by flexural slip often forming triangle zones the shortening linked to this folding is about 5 km with neogene thrusts faulting and folding pre existing thrust planes on the north eastern side of the dolomites neogene deformation is apparently more strictly controlled by the transpressive effects of the insubric lineament and shortening of the sedimentary cover may be greater than in the central dolomites minor deformation linked to the giudicarie belt is present in the western dolomites the present structure of the dolomites is thus the result of a number of tectonic events of different significance and different strike only a 3 dimensional restoration can unravel the true structure of the dolomites

temporal variations of large wood abundance and mobility in the blanco river affected by the chaiten volcanic eruption southern chile abstract the aim of this study is to analyze the temporal variation in abundance and transport of in channel wood along a river affected by a volcanic eruption considering the mobility and retention rates in detail the 2008 eruption of chaiten volcano southern chile severely affected the blanco river basin causing changes in channel morphology and large wood lw dynamics along the fluvial corridor of the river a fourth order stream on the southern slope of the volcano temporal dynamics of lw were investigated from january 2015 until march 2016 in three 80 m long study reaches of the active channel in the lower course of the river every wood element 1 m in length and 0 1 m in diameter within the active channel of each reach was georeferenced measured tagged and characterized wood mobility rate defined as the number of tagged wood pieces repositioned or not found within each study reach to total tagged lw in the same reach and retention rate defined as the number of tagged lw pieces found within each study reach to total tagged wood pieces in the same reach were calculated considering two periods one in summer and one in autumn winter a regional flood frequency analysis estimated flood magnitude defining a recurrence interval of 1 year for summer floods and 10 25 years for autumn winter floods results highlighted how eight years after the eruption the types of lw are still influenced by the impacts of pyroclastic density currents on riparian vegetation the characteristics and abundance of monitored lw are typical of a river system with frequent wood transport the mobility rate ranges between 42 and 94 during the summer and autumn winter period respectively while the wood volume decreases during the summer and increases in autumn winter large wood mobility was also found to vary according to the predominant morphological settings with lower values in narrower channels compared to wider wetted areas in this context the greatest abundance of lw was detected after the higher floods corresponding to an input of lw up to 285 35 m3 ha 1 along the blanco river ordinary floods deliver lw mainly through fluvial transport and bank erosion during higher floods appears as an additional and important wood recruitment process the bank erosion processes with up to 5200 m2 of eroded area confirmed the widening tendency occurring in river systems following volcanic disturbances as there are dead riparian trees along the easily erodible banks it is reasonable to suppose that the blanco river will continue to widen for a long period recruiting and transporting downstream huge volumes of lw in this context these analyses appear of fundamental importance to better manage the river system also for decreasing hazards to the downstream village of chaiten

the response of braided planform configuration to flow variations bed reworking and vegetation the case of the tagliamento river italy morphological features of braided rivers bars channels and pools experience major changes in area shape and spatial distribution as a response to i the pulsation of discharge during a flood and ii the bed evolution induced by floods in this work at a station relationships between water level and planform configuration were investigated on the tagliamento river a large gravel bed braided river in northeast italy over a 2 year study period comprising three bankfull events and several small to medium floods the analysis was performed on two 1 km long reaches characterized by different riparian vegetation cover ground based images with an hourly temporal resolution were acquired using software controlled digital cameras bars channels pools and vegetated patches were manually digitized on more than 100 rectified images sequences of constant level images spanning the study period were used to quantify the impact of floods on the stability of at a station relationships and on the turnover rate of water bodies the analysis shows that wetted area increased almost linearly with water level in both reaches the average number of branches per cross section peaked at intermediate flow levels increasing from 2 at low flow up to 6 7 the number of branches displayed the largest fluctuations over time with significant changes produced also by moderate floods turnover rates were high in both reaches with more than 30 of wetted areas at low flow converting into bare gravel in less than 2 months vegetation colonization was found to limit the mobility of the low flow channels over time by concentrating the flow in fewer deeper anabranches the number of channels per cross section was 30 40 less in the vegetated reach and the proportion of low flow water bodies in the same position after 12 months increased from 3 to 14 copyright 2012 john wiley sons ltd

a 400 km long piggyback basin upper aptian lower cenomanian in the eastern alps piggyback basins ori and friend 1984 comprise sedimentary basins that formed on active thrust sheets based on basin geometry and depositional systems two end member types of piggyback or thrust top basins have been distinguished type 1 basins are deep water basins that occur mainly as elongated synsedimentary deforming troughs in the footwall of thrusts in the early stages of orogenic wedge development and under lled foreland basins e g ori and friend 1984 lash 1990 type 2 piggyback basins are terrestrial to shallow marine intramontane basins that are formed predominantly during late orogenic stages e g ori and friend 1984 nijman 1998 this paper describes the geometry and evolution of an early deepmarine piggyback trough that formed on the cretaceous orogenic wedge of the eastern alps and the western carpathians the narrow basin extended over a considerable horizontal distance as suggested by similarities in stratigraphy and the timing of deformation the basin characterized a signi cant stage in the cretaceous evolution of the austroalpine northern boundary

large wood recruitment and transport during large floods a review large wood lw elements transported during large floods are long known to have the capacity to induce dangerous obstructions along the channel network mostly at bridges and at hydraulic structures such as weirs however our current knowledge of wood transport dynamics during high magnitude flood events is still very scarce mostly because these are locally rare and thus unlikely to be directly monitored therefore post event surveys are invaluable ways to get insights although indirectly on lw recruitment processes transport distance and factors inducing lw deposition all aspects that are crucial for the proper management of river basins related to flood hazard mitigation this paper presents a review of the quite limited literature available on lw transport during large floods drawing extensively on the authors own experience in mountain and piedmont rivers published and unpublished the overall picture emerging from these studies points to a high catchment specific variability in all the different processes affecting lw dynamics during floods specifically in the lw recruitment phase the relative floodplain bank erosion vs hillslope landslide and debris flows contribution in mountain rivers varies substantially as it relates to the extent of channel widening which depends on many variables itself but also to the hillslope channel connectivity of lw mobilized on the slopes as to the lw transport phase within the channel network it appears to be widely characterized by supply limited conditions whereby lw transport rates and thus volumes are ultimately constrained by the amount of lw that is made available to the flow indeed lw deposition during floods was mostly in terms of volume observed at artificial structures bridges in all the documented events this implies that the estimation of lw recruitment and the assessment of clogging probabilities for each structure for a flood event of given magnitude are the most important aspects for the prediction of lw transport magnitude at any cross section along the river network finally the review discusses the optimal strategies to manage lw related hazard which should consider riparian vegetation and in channel dead wood as key components of river ecosystems and thus should interfere with lw as well as with sediment transport dynamics only for limited spatial and temporal scales

kinematics of the alpine plate margin structural styles strain and motion along the penninic austroalpine boundary in the swiss austrian alps a structural and kinematic analysis of parts of the alpine suture zone i e the arosa zone and the edges of the overlying austroalpine and underlying penninic units is presented the arosa zone is interpreted as part of an accretionary wedge formed by the overriding of the austroalpine units the northern part of the adriatic plate over the penninic units structures strain and stretching trajectories indicate that two main deformation events followed each other discontinuously the earlier event was a wsw to nw directed thrusting under noncoaxial deformation and led to melange type structures the second event less penetrative in the arosa zone and with a downward increase in strain and noncoaxial flow formed n to ne verging folds and imbrication zones west directed displacement commenced in the early cretaceous and the motion changed to a prevailing northerly direction during the eocene as revealed by sediments involved in thrusting and by radiometric dating of the mylonites the kinematic history deduced from structural analysis agrees with the history obtained by recent work on plate margin sediments we correlate the anticlockwise rotation of the adriatic plate relative to europe between about 130 and 60 ma with the west directed motion in the arosa zone a change to relative n s motion during the lower tertiary led to the n to ne directed displacements a direct relationship thus exists between the motion of the adriatic plate and the resulting deformation along its northern margin during the early history of the eastern alps partitioning in brittle and ductile deformation and structural slicing under noncoaxial deformation is responsible for the melange type structures

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

transpressional collision structures in the upper crust the fold thrust belt of the northern calcareous alps abstract two major structural events characterize the tectonic evolution of the northern calcareous alps nca 1 late early cretaceous to late eocene nw directed dextral transpressional stacking of nappes as an expression of the formation of the austroalpine orogenic wedge and 2 miocene sinistral wrenching due to eastward lateral extrusion of crustal wedges along the central eastern alps three first order detachment horizons are defined by differences of competence within areas of facies transition preexisting normal faults control the thrust architecture transpressional contraction in the nca is indicated by a nw directed thrusting oblique to both the long axis of the nca and the edge of the orogenic foreland b the occurrence of en echelon arrays of thrusts and folds laterally displaced by dextral strike slip faults the thrusts and strike slip faults are kinematically connected to each other and dissect the nca into rhomboidal blocks c ne directed extension parallel to fold and ramp axes and the internal strike of the nca and d clockwise rotation 30 of the entire nca around a vertical axis kinematic and dynamic analysis of mesoscale fault striae data related to transpressional stacking indicates a nw trend of contraction directions and in general a ne trend of the extension directions parallel to fold axes and branch lines of thrusts before rotation the average contraction direction was probably parallel to the generally w directed shear direction recorded in the crystal plastically deformed central part of the eastern alps three balanced cross sections across the nca yield a minimum of 54 65 total shortening

transport and deposition of large woody debris in streams a flume experiment abstract large woody debris lwd is an integral component of forested streams of the pacific northwest and elsewhere yet little is known about how far wood is transported and where it is deposited in streams in this paper we report the results of flume experiments that examine interactions among hydraulics channel geometry transport distance and deposition of floating wood these experiments were carried out in a 1 22 m wide 9 14 m long gravel bed flume using wooden dowels of various sizes as surrogate logs channel planforms were either self formed or created by hand and ranged from meanders to alternate bars floating pieces tended to orient with long axes parallel to flow in the center of the channel pieces were deposited where channel depth was less than buoyant depth typically at the head of mid channel bars in shallow zones where flow expanded and on the outside of bends we hypothesize that the distance logs travel may be a function of the channel s debris roughness a dimensionless index incorporating ratios of piece length and diameter to channel width depth and sinuosity travel distance decreased as the ratio of piece length to both channel width and radius of curvature increased but the relative importance of these variables changed with channel planform large pieces can move further than our debris roughness models predict if greater than 50 of the active channel area is deeper than the buoyant depth of the piece or if momentum is high enough to carry pieces across shallows our debris roughness model allows first order prediction of the amount of wood transport under various channel geometries

time calibration of a pt path from the western tauern window eastern alps the problem of closure temperatures new hornblende k ar and 39ar 40ar and mica rb sr and k ar ages are used to place specific timemarks on a well constrained pressure temperature path for the late alpine metamorphism in the western tauern window after identification of excess 40ar the closure behavior of ar in hornblende is compared with that of sr and ar in phengite and biotite samples were collected in three locations whose maximum temperatures were 570 c zemmgrund 550 c pfitscher joch and 500 540 c landshuter hutte

deep structure and kinematics of the northern calcareous alps transalp profile the northern calcareous alps nca of southern bavaria and northern tyrol constitute a carbonate dominated polyphase fold thrust wedge together with its grauwacken zone basement it is the northernmost part of the far travelled upper austroalpine thrust complex of the eastern alps the present geometry developed in several kinematic stages jurassic extensional faults that affected large parts of the nca and their basement originated when the main part of the nca was still located southeast of the central alpine otztal silvretta complex these faults and related facies transitions influenced the later style of detachment of the nca thrust sheets mid to late cretaceous detachment thrust sheet stacking and motion over the central alpine complex are registered in clastic deposits of syntectonic basins the latest cretaceous to cenozoic nne to n directed motion of the nca towards europe in front of the central alpine complex created another set of significant contraction structures which at depth overprinted all previous structures during cretaceous to cenozoic deformation the nca experienced about 80 km of shortening i e about 73 along the transalp profile the european basement and autochthonous mesozoic cover beneath the allochthonous nca thrust sheets and flysch complexes seem to have remained relatively undeformed

evaluating short term morphological changes in a gravel bed braided river using terrestrial laser scanner abstract braided rivers are dynamic and complex environments shaped by the balance of the flow and sediment regimes and by the influence of the riparian vegetation and disturbances such as floods in particular the balance between sediment supply and transport capacity can determine the morphological evolution of a river for instance aggrading and widening trends are distinctive of reaches where sediment supply is higher than transport capacity in contrast incising and narrowing tendencies are dominant the aim of the present study is to analyze the short term morphological dynamics and the processes of erosion and sediment deposition along a small reach of a relatively unimpacted gravel bed braided river tagliamento river northeast italy using a terrestrial laser scanner tls the study area is around 23 ha and has been surveyed before after two periods with relevant flood events two of which were higher than the bankfull level and occurred between september 2010 and september 2011 the very high point clouds density allowed us to derive three high resolution digital elevation models dems with 0 125 0 125 m pixel size scan data cloud merging was achieved with an overall high degree of accuracy and resolution subcentimeter topographic data were more accurate for exposed surfaces than those collected in wet areas a detailed net of dgps control points allowed us to verify the high quality of the dems derived from the surveys rmse of about 5 cm two dems of difference dod were computed revealing different and consistent episodes of erosion and deposition within the analyzed area and changes in morphology of channel and bars could also be detected such as bar edge accretion and bank erosion demonstrating a strong dynamicity of the tagliamento river moreover a very detailed estimation of the surface roughness in the study area has been carried out permitting a large scale analysis of the roughness values distribution the results of the analysis on the tls collected data show that along a river with a high natural character i e tagliamento river the dynamic processes are also common during low magnitude events

patterns and processes of wood debris accumulation in the queets river basin washington field surveys in the 724 km 2 queets river basin on the west slope of the olympic mountains in nw washington reveal basin wide patterns of distinctive wood debris wd accumulations that arise from different mechanisms of wd recruitment hydraulic geometry and physical characteristics of wd individual pieces of wd in an accumulation or jam can be separated into key racked and loose members ten types of wd accumulations are identified based on the mode of recruitment and the orientation of key racked and loose debris relative to the channel axis although some types of wd accumulation have few geomorphic effects others form stable in stream structures that influence alluvial morphology at both subreach and reach length scales ranging from less than 1 to greater than 10 channel widths in the queets river stable accumulations of wd directly influence channel anabranching planform geometry flood plain topography and establishment of long term riparian refugia for old growth forest development the classification of wood debris accumulations in the queets river basin is based on physical observations that offer a template potentially applicable to other forested mountain regions d 2002 elsevier science b v all rights reserved

transform faulting extension and subduction in the carpathian pannonian region the carpathian arc formed during the cretaceous to miocene continental collision of europe with a smaller continental fragment following southward and westward subduction of an oceanic terrane during and after the last stages of thrusting in the outer carpathians a set of discrete basins opened up inside the carpathian loop these basins are regions of local extension which appear to be associated with strike slip faults in general northeast and northwest trending sets of conjugate shears reflect east west extension of the intra carpathian region during the middle and late miocene palinspastic reconstruction of the basins indicates approximately 75 to 100 km of extension comparable to the magnitude of synchronous crustal shortening in the east carpathians extension may have occurred to accommodate continued westward a type subduction after plate convergence was prohibited by geometrical constraints and suggests that in this region miocene subduction is driven by forces acting on the downgoing plate

nonlinear instability and error growth in northern hemisphere three dimensional flows cyclogenesis onset of blocking and mature anomalies abstract the nonlinear interactions of an initial small amplitude instability mode with a three dimensional climatological flow for northern hemisphere january 1978 an which it is growing are studied in a multilevel nonlinear primitive equation model incorporating spherical geometry numerical experiments in which there is either constant or no forcing are considered for the forced runs the forcing is such that the climatological flow is an exact steady state solution which however is unstable when perturbed by the normal mode disturbance for the unforced runs we examine the divergence of two forecasts one of which has the climatological flow as initial conditions and the other the climatological flow perturbed by the instability solution the structural changes that occur in the total and disturbance streamfunctions and kinetic energies and in the disturbance momentum and heat fluxes are examined the initially small scale shallow disturbance increases in wale and penetrates into the upper t

entrainment displacement and transport of tracer gravels the mass and size distribution of grain entrainment per unit bed area may be measured by replacing a volume of the bed with tracer gravels and observing the mass difference before and after a transport event this measure of spatial entrainment is relevant to any process involving size selective exchange of sediment between transport and bed and may be directly used in calculations of sediment transport rate using an elementary relation for fractional transport components presented here this relation provides a basis for evaluating tracer data collected by different methods and may be used to provide physical insight regarding the expected behaviour of tracer grains the variation with grain size of total displacement length l ti depends on the degree of mobilization of the individual fractions on the bed surface l ti is independent of d i for smaller fully mobile sizes and decreases rapidly with d i for larger fractions in a state of partial transport in which a portion of the surface grains remain immobile through the flow event the boundary between fully and partially mobile grain sizes increases with flow strength these inferences are supported by values of l ti calculated from flume experiments and provide a physical explanation for a summary relation between l ti and d i based on field data 1997 john wiley sons ltd

log transport and deposition in incised channelized and multithread reaches of a wide mountain river tracking experiment during a 20 year flood abstract distance of large wood transport during floods and conditions for wood deposition in wide mountain rivers are still insufficiently understood tracking of logs tagged with radio transmitters was used to investigate differences in depositional conditions and the length of log displacement during a 20 year flood between channel reaches of different morphology in the czarny dunajec river polish carpathians during the rising limb of the flood logs were placed into the river at three locations at the beginning of an incised reach close to the beginning of a channelized reach and 1 km upstream from the beginning of a wide multithread reach the incised channelized and multithread reaches retained 12 5 33 and 94 of tagged logs introduced to these reaches respectively and of the logs retained in the multithread reach all were deposited in its upstream half significant differences in the length of displacement existed between the logs delivered to the river at the three locations with logs placed into the river at the beginning of the incised reach moving the longest distance and those delivered just upstream from the multithread reach moving the shortest distance before deposition one fourth of the logs were deposited in a low flow channel or on a channel margin one fifth on the floodplain and more than half on gravel bars after the flood river cross sections with deposited logs and a set of cross sections without any wood deposits were surveyed to collect data for one dimensional modelling of hydraulic conditions at the flood peak the cross sections with deposited logs were typified by significantly greater flow width and flow area and by significantly smaller mean flow depth mean velocity froude number mean bed shear stress and unit stream power principal component analysis of the hydraulic parameters in the analysed cross sections grouped the two types of cross sections in distinct clusters indicating that multithread cross sections differed in hydraulic parameters from all the other cross sections the experiment confirmed findings from the previous wood inventory and numerical modelling of wood transport and deposition in the river indicating that in a wide mountain river wood can be transported long distances in a narrow single thread channel it is however preferentially deposited in a wide multithread channel that functions as a natural wood trap preventing or considerably limiting further transfer of large wood to vulnerable sites therefore it is crucial to avoid channelization of multithread reaches that would eliminate their functioning as natural wood traps the hydraulic modelling provided a physical justification for the observed differences in wood behaviour between the distinct channel morphologies

present day lithospheric strength of the eastern alps and its relationship to neotectonics 1 we calculate the present day lithospheric strength of the eastern alps along the new reflection seismic profile transalp to examine vertical and lateral strength variations and their implications on neotectonic activity of the eastern alps the large scale geometry of the eastern alps and the spatial distribution of upper and lower crustal layers and the lithospheric mantle is constrained by the deep seismic line two rheological models coupled to a kinematic thermal model that accounts for the thermal evolution of the eastern alps for the last 30 myr are investigated for the present day lithospheric configuration in the eastern alps models with strong model a and weak model b crustal rheologies predict the european and the adriatic plates to be stronger than the central zone of the orogen comprising the region between the inntal fault and the periadriatic fault model a is characterized by a brittle ductile boundary between 14 and 9 km depth and strong coupling of the mechanically strong lower crust to the upper mantle whereas model b suggests the presence of a thick decoupling zone between the upper crust and the upper mantle and a shallower brittle ductile boundary 7 10 km of these end member scenarios model a is in better agreement with neotectonic data including seismicity down to the upper lower crust boundary within the adriatic plate uplift of the central zone of the eastern alps and the southern alps and eastward escape of fault bound blocks such deformation pattern is best explained by lateral extrusion upon north south compression supporting a strong weak strong configuration of tectonic units along the transalp line

model experiments on the impact of pacific sea surface temperature anomalies on blocking frequency abstract sensitivity experiments with a perpetual january version of a low resolution general circulation model are conducted to investigate the influence of pacific sea surface temperature sst anomalies on blocking in the northern hemisphere six 1200 day integrations each of which contains a different specified sst anomaly superimposed upon a fixed climatological sst distribution are compared with a 1200 day control simulation to examine the impact of both equatorial pacific and midlatitude north pacific anomalous forcing an ensemble of eight independent 90 day realizations is extracted from each simulation distributions of the ensemble mean differences in the total number of blocking days from the control simulation are presented along with estimates of the statistic significance of these differences pacific sst anomalies do not strongly affect the total number of days in which a block is present anywhere over the north pacific basin but they apparently can affect the preferred regions over th

p t t history of the lower austroalpine nappe complex in the tarntaler berge nw of the tauern window implications for the geotectonic evolution of the central eastern alps new petrologic and 40ar 39ar geochronologic data constrain conditions of alpine metamorphism along the northwestern border of the tauern window the p t estimations based on phengite barometry were determined for samples from units of the lower austroalpine nappe complex exposed above the southpenninic interior of the tauern window and from upper parts of the southpenninic bundner schiefer sequence results suggest that both mesozoic metasedimentary nappe units reckner and hippold nappes and an ophiolitic nappe reckner complex of the lower austroalpine nappe complex have been metamorphosed at pressures between 8 and 10 5 kbar and temperatures around 350 c the structurally highest lower austroalpine unit quartzphyllite nappe was not affected by high pressure metamorphism and records maximum p t conditions of approximately 4 kbar and 400 c highest parts of the structurally underlying southpenninic bundner schiefer sequence were metamorphosed at intermediate pressures 6 7 kbar temperatures increased in all structural units during decompression whole rock 40ar 39ar plateau ages of silicic phyllites and cherts with abundant high si phengites record ages around 50 ma in the reckner nappe and 44 37 ma in the hippold nappe and southpenninic bundner schiefer sequence these ages are interpreted to date closely the high pressure metamorphism

wood storage within the active zone of a large european gravel bed river wood storage within the active zone of the dynamic gravel bed fiume tagliamento italy was investigated at eight sites along the river s main stem the quantity nature and mode of wood storage revealed a number of trends related to active zone morphology cover type and distance from the river s source relatively small quantities of wood were stored on open gravel surfaces estimates ranged from 1 to 21 t ha 1 intermediate quantities were associated with established islands 24 186 t ha 1 and large quantities were associated with pioneer islands 293 1664 t ha 1 thus variations in the geomorphological style of the river which are associated with changes in these three cover types are reflected in variations in the amount of wood that is stored in different reaches in addition although wood was found in many locations within the active zone it was preferentially stored in three specific locations i bar crests the main open gravel location for wood accumulations and pioneer islands ii the margins and iii surfaces of established islands the proportion of the stored wood that was living sprouting increased downstream and was higher on the open gravel than in association with established islands there was a downstream gradient in the dominant type of wood accumulation individual logs predominated at the most upstream site thereafter on the open gravel whole shrubs and trees dominated the more confined sites in the headwaters and middle reaches whereas jams were the most frequent form of accumulation in the downstream reaches jams were the most frequent type of accumulation associated with established islands throughout the river in contrast to small streams where debris dams constitute the major type of wood accumulation complex patterns and trends of wood storage were revealed along the tagliamento although further studies are needed it is clear that erosion of woody vegetation its subsequent transport and deposition play a major role in structuring the geomorphological and ecological character of this relatively natural large european river system insight into the mechanisms underlying the observed spatial patterns will contribute to a better understanding of the dynamic processes involved and is essential for more effective management of river ecosystems

assessment of transfer patterns and origins of in channel wood in large rivers using repeated field surveys and wood characterisation the isere river upstream of pontcharra france abstract when and whence does wood enter large mountain alluvial rivers how stable through time are characteristics and quantities of wood deposited in a reach these simple questions related to the complex practice of wood budgeting are explored on the isere river in france we hypothesise that i the wood originates from the riparian zone all along the alluvial reach and that ii the characters and quantity of wood in the reach can vary through time according to flood occurrence and provenance in order to validate these hypotheses two complementary approaches were performed i wood pieces were surveyed along 190 km river length and taxonomy in channel wood macromorphology and dendrochemistry were used to infer wood origin local vs upstream respective subbasin contributions and transport conditions ii wood movement was monitored using both tracking techniques in specific sampling plots and with an experiment orchestrated using wood placement coupled with a significant artificial flood surveys were done over a period of 3 years so as to include two distinct sampling events to explore wood deposition and mobilisation within a channel network under different flood conditions one of the subbasins the arly river underwent a 1 in 30 year flood in 2004 allowing us to assess its effect on in channel wood quantity and characteristics results confirm that wood is primarily introduced by erosion from river banks but they are not always as close as expected from the sites of deposition temporal variability of wood introduced deposited and transferred downstream is also significant in terms of abundance and origin as shown by dendrochemical and macromorphological signatures the types of wood observed along the channel length changes through time large flood signature can be detected from wood characteristics and uplands make a slight contribution but in average wood characteristics do not change much no significant difference between years and tributaries in wood characteristics based on discriminant analysis data suggest that the interannual variability is fairly low so that the diversity of wood characteristics is maintained by the complex and multiple sources of wood in the network further research is needed to better understand such patterns and to study physical breakage in space and time to better infer distance between sources and depositional zones

distorted froude scaled flume analysis of large woody debris this paper presents the results of a movable boundary distorted froude scaled hydraulic model based on abiaca creek a sand bedded channel in northern mississippi the model was used to examine the geomorphic and hydraulic impact of simplified large woody debris lwd elements the theory of physical scale models is discussed and the method used to construct the lwd test channel is developed the channel model had bed and banks moulded from 0 8 mm sand and flow conditions were just below the threshold of motion so that any sediment transport and channel adjustment were the result of the debris element dimensions and positions of lwd elements were determined using a debris jam classification model elements were attached to a dynamometer to measure element drag forces and channel adjustment was determined through detailed topographic surveys the fluid drag force on the elements decreased asymptotically over time as the channel boundary eroded around the elements due to locally increased boundary shear stress total time for geomorphic adjustment computed for the prototype channel at the q2 discharge discharge occurring once every two years on average was as short as 45 hours the size depth and position of scour holes bank erosion and bars created by flow acceleration past the elements were found to be related to element length and position within the channel cross section morphologies created by each debris element in the model channel were comparable with similar jams observed in the prototype channel published in 2001 john wiley sons ltd

structural synthesis of the northern calcareous alps transalp segment the northern calcareous alps nca are the site of very large top to north convergent movements during cretaceous tertiary alpine mountain building to determine the amount of shortening the depth of detachment and the style of deformation we retro deformed an approximately 40 40 km area comprising the lechtal and allgau nappes on the basis of all available geological data and processed sections of the transalp reflection seismic experiment coherent 3d models were constructed by splining lines from n s cross sections integration of 3d kinematic modeling and field data shows the following the structure of the lechtal nappe is controlled by the triassic hauptdolomit four main thrusts link to a detachment at 2 6 km depth below sea level shortening estimates vary from 25 east to 42 west additional contraction is accommodated by folding in the east the subjacent allgau nappe can be traced about 10 km down plunge and is shortened by about one third in the western part the downplunge width is at least 15 20 km with restorable shortening of one third the triple inntal lechtal allgau nappes nca nappe system was moved uniformly n s to produce laterally heterogeneus shortening of 40 90 km or 50 67 we suggest that the nca are underlain by substantial amounts of buried molasse sediments and or overthrust units of helvetic and rheno danubian flysch indicating post eocene n s shortening of at least 55 km restored to an initial configuration the basin topography of the nca reveals strong e w thickness variations of the triassic wettersteinkalk and hauptdolomit platform carbonates such variations may pertain to n s trending growth faults which were important precursors to later jurassic extension of the austroalpine passive margin such structures are unlikely to be seen in the conventional n s cross sections but form an essential geometrical and mechanical element in later convergent mountain building

paleomagnetism and paleogeography of the northern calcareous alps austria prefolding magnetization components have been resolved at 38 sites of liassic adnet limestones in the central northern calcareous alps nca and at one site in the drauzug the site mean directions are northeasterly and down and are closer to coeval european directions than to southern alpine african directions the western end of both the nca and of the drauzug yield different site mean directions and negative fold tests indicating remagnetization the sampling localities have been rotated relative to one another during thrusting however comparison of paleomagnetic poles with the european apparent polar wander path implies an average clockwise rotation of about 30 for the nca relative to europe larger scale clockwise rotations in excess of 80 relative to the southern alps are implied by comparison with the southern alpine african polar wander path facies analysis of jurassic and lower cretaceous basinal sediments in the central part of the nca suggests that liassic subsidence was related to presently e w sinistral strike slip faults whereas malm berriasian subsidence was controlled by presently e w south dipping normal faults both paleomagnetic and facies data tend to indicate that the nca did not undergo the african rotation seen in southern alpine paleomagnetic data this implies the existence of a short lived tract of triassic jurassic ocean floor between the nca and the southern alps which linked the pindos ocean to the ligurian trough and allowed adria to rotate independently from the nca during the late jurassic eo alpine deformation and metamorphism are associated with the early cretaceous closure of this hallstatt trough

measuring river velocities using gps river flow tracers grifters existing methods of measuring flow velocities in natural rivers are largely based on series of point measurements acquisition of these data can be time consuming and difficult especially in high flow conditions this paper introduces the use of gps drifters termed grifters to measure surface flow velocities in a 400 m reach of the river swale uk over 10 000 measurements were made in a 3 hour period and aggregated over a 2 m grid to generate a genuine distributed representation of flow across the reach the technique shows great promise to provide new insights into flow patterns over long reaches of rivers over a range of flow conditions and may also provide valuable data for numerical model validation copyright 2007 john wiley sons ltd

islands in a european mountain river linkages with large wood deposition flood flows and plant diversity abstract vegetated islands are characteristic landforms of braided mountain rivers long term observations and recent morphological and botanical surveys conducted in the gravel bed czarny dunajec polish carpathians were used to determine the processes and patterns governing initiation and development of islands and their floristic complexity moreover dendrochronologically estimated years of island inception were compared with the timing and magnitude of flood flows in the period 1970 2011 to infer about controls on the formation and persistence of islands in the river in the high energy braided river islands originate as a result of deposition of large vegetative particles mostly large wood on gravel bars and the associated vegetative regeneration of living wood or the growth of seedlings and saplings in the shelter of wood accumulations tree ring dating of the largest trees growing in particular zones of building and established islands indicated a predominant upstream island growth in the river it results from repeated accumulation of living wood on the head of islands and its subsequent regeneration and contrasts with the progressive downstream growth of islands in the rivers supplied with large stable logs of the tree species without the capability to re sprout the lack of islands from the years 1982 1996 most likely reflects the removal of relatively young islands by two major floods in the 1990s which were however unable to destroy older and larger islands after 1997 the occurrence of low to moderate floods facilitated the formation and persistence of islands the plant inventory demonstrated that species richness increased non linearly with the increasing age area and shoreline length of islands islands supported more plant species than the riparian forest and attained comparable species richness at an early stage of development fast developing dynamic and supporting rich plant communities islands contribute highly to the overall floristic complexity of the river corridor and their re establishment should be viewed as an important factor in the restoration of hydromorphologically degraded mountain rivers

large wood lw 3d accumulation mapping and assessment using structure from motion photogrammetry in the laboratory abstract a structure from motion sfm photogrammetry based methodology for precise mapping of large wood lw accumulations in fluvial systems is presented the technique may be useful for routine inventory and rapid volume estimation of complex lw structures that tend to divert or obstruct flow in rivers our methodology is validated by means of laboratory experiments ranging from elementary to complex arrangements of lw components and organic fine material ofm seven experimental setups were used as the basis for i manual approximations of 2 5d and 3d geometric reference volumes ii 2 5d volume models based on mesh geometry iii a closed watertight 3d mesh from an unorganized point cloud and iv estimates of porosity a commercially available sfm photogrammetry software package pix4dmapper was used for point cloud and simplified mesh generation in order to obtain more precise volumes 3d surface models are required accordingly we generated 3d watertight mesh models of the unorganized point cloud using the screened poisson surface reconstruction psr technique the pix4d volume tool 2 5d resulted in an overestimation 2 9 to 52 7 of the geometric volume 3d due to the convex hull approximation of the geometry normal to the surface plane psr 3d resulted in more precise volumes showing deviations from the geometric volume 3d in a range of 15 9 to 10 6 as the algorithm could capture concavities and involuted surfaces on the accumulation assuming that the difference between 3d and 2 5d volume models represents many of the voids visible within or on the surface of the deposit this volume can be used as an estimate of porosity our assessment suggests that image based sfm methodology is well suited for further investigations in lw research due to its time and cost efficiency in comparison with other conventional surveying techniques the methodology can be used to generate high quality point cloud and mesh models of log jam formations these may be used by river managers and researchers to quantify accumulation volume and thus gain a better understanding of lw composition and the influence of wood geometry on hydraulic flow conditions

riparian vegetation and island formation along the gravel bed fiume tagliamento italy after more than 300 years of river management scientific knowledge of european river systems has evolved with limited empirical knowledge of truly natural systems in particular little is known of the mechanisms supporting the evolution and maintenance of islands and secondary channels the dynamic gravel bed fiume tagliamento italy provides an opportunity to acquire baseline data from a river where the level of direct engineering intervention along the main stem is remarkably small against a background of a strong alpine to mediterranean climatic and hydrological gradient this paper explores relationships between topography sediment and vegetation at eight sites along the active zone of the tagliamento a conceptual model of island development is proposed which integrates the interactions between large woody debris and vegetation geomorphic features sediment calibre and hydrological regime islands may develop on bare gravel sites or be dissected from the floodplain by channel avulsion depositional and erosional processes result in different island types and developmental stages differences in the apparent trajectories of island development are identified for each of the eight study sites along the river the management implications of the model and associated observations of the role of riparian vegetation in island development are considered in particular the potential impacts of woody debris removal riparian tree management regulation of river flow and sediment regimes and changes in riparian tree species distribution are discussed

a natural and controlled source seismic profile through the eastern alps transalp abstract the combined passive and active seismic transalp experiment produced an unprecedented high resolution crustal image of the eastern alps between munich and venice the european and adriatic mohos em and am respectively are clearly imaged with different seismic techniques near vertical incidence reflections and receiver functions rfs the european moho dips gently southward from 35 km beneath the northern foreland to a maximum depth of 55 km beneath the central part of the eastern alps whereas the adriatic moho is imaged primarily by receiver functions at a relatively constant depth of about 40 km in both data sets we have also detected first order alpine shear zones such as the helvetic detachment inntal fault and sub tauern ramp in the north apart from the valsugana thrust receiver functions in the southern part of the eastern alps have also observed a north dipping interface which may penetrate the entire adriatic crust adriatic crust interface aci deep crustal seismicity may be related to the aci we interpret the aci as the currently active retroshear zone in the doubly vergent alpine collisional belt

geomorphic and stream flow influences on large wood dynamics and displacement lengths in high gradient mountain streams chile understanding large wood lw 1 m long and 10 cm in diameter dynamics in rivers is critical for many disciplines including those assessing flood hazard and risk however our understanding of wood entrainment and deposition is still limited mainly because of the lack of long term monitoring of wood related processes the dataset presented here was obtained from more than 8 years of monitoring of 1264 tagged wood pieces placed in four low order streams of the chilean mountain ranges and is used to further our understanding of key factors controlling lw dynamics we show that lw displacement lengths were longer during periods when peak flow water depths hmax exceeded the bankfull stage hbk than in periods with hmax hbk and that these differences were significantly higher for smaller wood pieces lw length and length relative to channel dimensions were the main factors governing lw entrainment lw displacement lengths were inversely related to the ratio of piece length to h15 i e the level above which the flow remains for 15 of the time and to the ratio of h15 to bankfull width unrooted logs and lw pieces located at the bankfull stage travelled significantly longer distances than logs with attached rootwads and those located in other positions within the bankfull channel a few large logjams were broken during the period of observation and in all occasions lw from these broken logjams did not travel over longer distances than other pieces of lw moved in the same periods and in the same stream segments most importantly our work reveals that lw dynamics tend to be concentrated within a few reaches in each stream and that reaches exhibiting high wood dynamics extensive entrainment deposition or repositioning of lw are significantly wider and less steep than less dynamic reaches

reconciling plate tectonic reconstructions of alpine tethys with the geological geophysical record of spreading and subduction in the alps article a new reconstruction of alpine tethys combines plate kinematic modelling with a wealth of geological data and seismic tomography to shed light on its evolution from sea floor spreading through subduction to collision in the alps unlike previous models which relate the fate of alpine tethys solely to relative motions of africa iberia and europe during opening of the atlantic our reconstruction additionally invokes independent microplates whose motions are constrained primarily by the geological record the motions of these microplates adria iberia alcapia alkapecia and tiszia relative to both africa and europe during late cretaceous to cenozoic time involved the subduction of remnant tethyan basins during the following three stages that are characterized by contrasting plate motions and driving forces 1 131 84 ma intra oceanic subduction of the ligurian part of alpine tethys attached to iberia coincided with eo alpine orogenesis in the alcapia microplate north of africa these events were triggered primarily by foundering of the older 170 131 ma neotethyan subduction slab along the ne margin of the composite african adriatic plate subduction was linked by a sinistral transform system to e w opening of the valais part of alpine tethys 2 84 35 ma subduction of primarily the piemont and valais parts of alpine tethys which were then attached to the european plate beneath the overriding african and later adriatic plates nw translation of adria with respect to africa was accommodated primarily by slow widening of the ionian sea 3 35 ma recent rollback subduction of the ligurian part of alpine tethys coincided with western alpine orogenesis and involved the formation of the gibraltar and calabrian arcs rapid subduction and arc formation were driven primarily by the pull of the gravitationally unstable retreating adriatic and african slabs during slow convergence of africa and europe the upper european iberian plate stretched to accommodate this slab retreat in a very mobile fashion while the continental core of the adriatic microplate acted as a rigid indenter within the alpine collisional zone the subducted lithosphere in this reconstruction can be correlated with slab material imaged by seismic tomography beneath the alps and apennines as well as beneath parts of the pannonian basin the adriatic sea the ligurian sea and the western mediterranean the predicted amount of subducted lithosphere exceeds the estimated volume of slab material residing at depth by some 10 30 indicating that parts of slabs may be superposed within the mantle transition zone and or that some of this subducted lithosphere became seismically transparent

floods in mountain environments a synthesis floods are a crucial agent of geomorphic change in the channels and valley floors of mountains watercourses at the same time they can be highly damaging to property infrastructure and life because of their high energy mountain watercourses are highly vulnerable to environmental changes affecting their catchments and channels many factors have modified and frequently still tend to modify the environmental conditions in mountain areas with impacts on geomorphic processes and the frequency magnitude and timing of floods in mountain watercourses the ongoing climate changes vary between regions but may affect floods in mountain areas in many ways in many mountain regions of europe widespread afforestation took place over the twentieth century considerably increasing the amounts of large wood delivered to the channels and the likelihood of jamming bridges at the same time deforestation continues in other mountain areas accelerating runoff and amplifying the magnitude and frequency of floods in foreland areas in many countries in channel gravel mining has been a common practice during recent decades the resultant deficit of bed material in the affected channels may suddenly manifest during flood events resulting in the failure of scoured bridges or catastrophic channel widening during the past century many rivers in mountain and foreland areas incised deeply the resultant loss of floodplain water storage has decreased attenuation of flood waves hence increasing flood hazard to downstream river reaches on the other hand a large amount of recent river restoration activities worldwide may provide examples of beneficial changes to flood risk attained as a result of increased channel storage or reestablished floodplain water storage relations between geomorphic processes and floods operate in both directions which means that changes in flood probability or the character of floods e g increased wood load may significantly modify the morphology of mountain rivers but morphological changes of rivers can also affect hydrological properties of floods and the associated risk for societies this paper provides a review of research in the field of floods in mountain environments and puts the papers of this special issue dedicated to the same topic into context it also provides insight into innovative studies methods or emerging aspects of the relations between environmental changes geomorphic processes and the occurrence of floods in mountain rivers

provenance of cretaceous synorogenic sandstones in the eastern alps constraints from framework petrography heavy mineral analysis and mineral chemistry abstract the detrital components of cretaceous sedimentary rocks in the northern calcareous alps reflect the early alpine geodynamic evolution of the austroalpine microplate two contrasting source areas are distinguished on the base of light and heavy mineral analysis the first source area is located at the southeastern margin of the austroalpine and is composed of palaeozoic sediments and metamorphic rocks mesozoic carbonate rocks and ultrabasic rocks derived from the suture zone of the vardar meliata ocean the second source area is located in the northwest in a lower austroalpine position near the transpressive plate margin that juxtaposes austroalpine and penninic units this source area comprises palaeozoic low grade metamorphic rocks including high pressure hp rocks late palaeozoic meta sediments mesozoic carbonate rocks and ultrabasic rocks from obducted slices of penninic oceanic crust chemical analyses of detrital white mica amphibole and garnet support the discrimination between the two source areas tourmaline chemistry calls for a significant amount of metasedimentary rocks in the source area granitoid rocks and high grade metamorphic rocks are rare blue amphibole phengite and chloritoid composition suggest the erosion of lower blueschist facies rocks in the northwestern source area we suggest a modified model of austroalpine valanginian to coniacian tectono sedimentary evolution which is based on 1 an onset of subduction of the penninic ocean no earlier than late cretaceous 2 deposition of the analyzed sedimentary rocks in piggyback basins and 3 a reconstruction of provenance as proposed in this study

evidence for east west crustal extension in the eastern alps implications for the unroofing history of the tauern window the contact between the western border of the tauern window and the overlying austroalpine nappes austria and italy is marked by a structural petrologic and geochronologic discontinuity that developed in the early stages of unroofing of the window within the window pressure temperature time paths j selverstone 1985 indicate that significant ductile thinning occurred shortly after the cessation of thrusting paleocene eocene sense of shear indicators rotated porphyroblasts asymmetric augen and pressure shadows s c fabrics associated with a west plunging stretching lineation indicate that this thinning occurred in response to top to the west low angle normal shear during metamorphism the same sense of normal shear is present in the mesozoic members of the austroalpine sequence west of the window in these rocks however west directed shear occurred at low temperatures 300 c after the thermal peak of metamorphism structural data and the regional geometry imply that the western end of the tauern window is a low angle normal fault brenner line that juxtaposed brittlely deformed rocks of the austroalpine nappes against more ductilely deformed rocks from the window biotite k ar and rb sr data suggest a miocene age for final movement on the brenner line these data indicate a prolonged history of east west extension in the eastern alps that affected all crustal levels early ductile thinning of lower crust followed by mid to upper crustal low angle normal faulting a model is presented that relates the young east west extension to displacement transfer from dextral movement on the periadriatic lineament in this model the brenner line and by analogy the simplon line can be thought of as detachment faults that tectonically unroofed the tauern window and lepontine thermal highs respectively

tracking log displacement during floods in the tagliamento river using rfid and gps tracker devices large pieces of in channel wood can exert an important role on the ecological and morphological properties of gravel bed rivers on the other side when transported during flood events large wood can become a source of risk for sensitive structures such as bridges however wood displacement and velocity in river systems are still poorly understood especially in large gravel bed rivers this study focuses on log transport in a valley reach of tagliamento river italy log displacement during flood events of different magnitudes recorded from june 2010 to october 2011 has been analysed thanks to the installation of 113 radio frequency identification rfid tags and 42 gps tracker devices in logs of different dimensions recovery rates of logs equipped with rfid and gps trackers were about 43 and 42 respectively the gps devices allowed us to analyse in details the log displacement and transport overtime indicating a higher log entrainment during rising limb of hydrographs the threshold for the entrainment of logs from low bars is around 40 of bankfull water stage no clear relationship was found between the peak of flood and log displacement length and velocity however log displacement length and velocity appear significantly correlated to the ratio between the peak of flow and the water stage exceeding the flow duration curve for 25 of time i e the ratio hmax h25 ratio log deposition was observed to occur at the peak flow and logs transported during ordinary events are preferably deposited on low bars this study reveals the potentials of gps tracker devices to monitor the entrainment and movements of logs in large gravel bed rivers during floods these observations could be useful for better planning of river management practices and strategies involving the use of large wood pieces and could help for calibrating wood budgets at the reach scale

using structure from motion photogrammetry to assess large wood lw accumulations in the field abstract river systems in forested catchments are strongly influenced by wood and sediment loading from both natural e g mass wasting and anthropogenic forestry sources in order to effectively manage impacts on property infrastructure and the broader ecosystem as well as to better assess the interactions between large wood lw channel morphology and flow hydraulics more efficient and accurate surveying techniques are required we present an evaluation of structure from motion sfm photogrammetry and point cloud based techniques for capturing the geometry and volume of lw in the field wood accumulations can be notoriously complex 3d objects with multi scalar features and thus difficult to quantify with photogrammetric methods we introduce a novel workflow to generate volumetric information of organic material accumulations using sfm and a suite of meshing algorithms the volumes of two accumulations are assessed individually using several meshing techniques and are compared with more conventional volume estimates results show volumetric variations of

rules of the road a qualitative and quantitative synthesis of large wood transport through drainage networks abstract to effectively manage wood in rivers we need a better understanding of wood mobility within river networks here we review primarily field based and some numerical studies of wood transport we distinguish small medium large and great rivers based on wood piece dimensions relative to channel and flow dimensions and dominant controls on wood transport we suggest further identification and designation of wood transport regimes as a useful way to characterize spatial temporal network heterogeneity and to conceptualize the primary controls on wood mobility in diverse river segments we draw analogies between wood and bedload transport including distinguishing eulerian and lagrangian approaches exploring transport capacity and quantifying thresholds of wood mobility we identify mobility envelopes for remobilization of wood with relation to increasing peak discharges stream size and dimensionless log lengths wood transport in natural channels exhibits high spatial and temporal variability with discontinuities along the channel network at bankfull flow and when log lengths equal channel widths although median mobilization rates increase with increasing channel size maximum mobilization rates are greatest in medium sized channels most wood is transported during relatively infrequent high flows but flows under bankfull can transport up to 30 of stored wood we use conceptual models of dynamic equilibrium of wood in storage and of spiralling wood transport paths through drainage networks as well as a metaphor of traffic on a road to explore discontinuous wood movement through a river network the primary limitations to describing wood transport are inappropriate time scales of observation and lack of sufficient data on mobility from diverse rivers improving models of wood flux requires better characterization of average step lengths within the lifetime travel path of a piece of wood we suggest that future studies focus on i continuous or high frequency monitoring of wood mobility ii monitoring changes in wood storage iii using wood characteristics to fingerprint wood sources iv quantifying volumes of wood buried within river corridors v obtaining existing or new data from unconventional sources such as citizen science initiatives and vi creating online interactive data platforms to facilitate data synthesis

pre oceanic rifting in the alps abstract a review of mesozoic mainly earliest jurassic to mid jurassic rifting in the western and central alps normal faults with throws up to a few kilometers are moderately inclined and involve rotation of crustal blocks the amount of stretching and thinning of the crust by jurassic rifting is discussed the rifting 200 165 m y pre dates the opening of the alpine oceans by spreading and transform movements 165 110 m y

timing of metamorphism in the tauern window eastern alps rb sr ages and fabric formation the peripheral schieferhulle of the tauern window of the eastern alps represents post hercynian penninic cover sequences and preserves a record of metamorphism in the alpine orogeny without the inherited remnants of hercynian events that are retained in basement rocks the temperature time deformation history of rocks at the lower levels of these cover sequences have been investigated by geochronological and petrographic study of units whose p t evolution and structural setting are already well understood the eclogite zone of the central tauern formed from protoliths with penninic cover affinities and suffered early alpine eclogite facies metamorphism before tectonic interposition between basement and cover it then shared a common metamorphic history with these units experiencing blueschist facies and subsequent greenschist facies conditions in the alpine orogeny the greenschist facies phase associated with penetrative deformation in the cover and the influx of aqueous fluids reset sr isotopes in metasediments throughout the eclogite zone and cover schists recording deformation and peak metamorphism at 28 30 ma the peripheral schieferhulle of the south east tauern window yields rb sr white mica ages which can be tied to the structural evolution of the metamorphic pile early prograde fabrics pre date 31 ma and were reworked by the formation of the large north east vergent sonnblick fold structure at 28 ma peak metamorphism post dated this deformation but by contrast to the equivalent levels in the central tauern peak metamorphic conditions did not lead to widespread homogenization of the sr isotopes localized deformation continued into the cooling path until at least 23 ma partially or wholly resetting sr white mica ages in some samples these isotopic ages may be integrated with structural data in regional tectonic models and may constrain changes in the style of crustal deformation and plate interaction however such interpretations must accommodate the demonstrable variation in thermal histories over small distances

relating orogen width to shortening erosion and exhumation during alpine collision we investigate along strike width changes of the thickened accreted lower plate talp in the central and in the eastern alps we set the width of the talp in relation to the inferred amount of collisional shortening and exhumation along six orogen scale cross sections taking the present day along strike gradients in the amount of collisional shortening to represent the temporal evolution of the collisional wedge it may be concluded that the cross sectional area of the talp diminishes during ongoing shortening indicating that the erosional flux outpaced the accretionary flux higher amounts of collisional shortening systematically coincide with smaller widths of the talp and dramatic increases of the reconstructed eroded rock column higher amounts of shortening also coincide with larger amplitudes of orogen scale upright folds with higher exhumation and with higher exhumation rates hence erosion did play a major role in reducing by 30 km the vertical crustal thickness in order to accommodate and allow shortening by folding long term climate differences cannot explain alternating changes of width by a factor of almost 2 along straight segments of the orogen on length scales less than 200 km as observed from the western central alps to the easternmost eastern alps sedimentary or paleontological evidences supporting such paleo climatic differences are lacking suggesting that erosional processes did not directly control the width of the orogen