middle to late holocene storminess in brittany nw france part i morphological impact and stratigraphical record our study aims to understand the recurring climatic conditions prevailing during the largest storms reaching nw france brittany these storms are responsible for the breaching of coastal barriers and major flooding of lowlands in a first part of our work we examine the morphological impact and stratigraphic record of storm events along western brittany rocky coasts with a special focus on the southern coast of the bay of audierne the most exposed coast of the region in a second paper middle to late holocene storminess in brittany nw france part ii we shall focus on the chronology of storm events and their climate forcing conditions drilling transects and stratigraphic analyses were first undertaken to constrain chronology strength and wind direction during the main holocene storm events new dates observations and a relative sea level rsl curve were then used to inform discussion of the necessary climatic and morphologic conditions leading to destructive storm events most recorded events appear to be linked with cooling episodes of the holocene and a rsl close to present some storms are clearly responsible for breaching and dune building or remobilisation we demonstrate that storm frequency and intensity appear to rise in a stepwise manner during the late holocene maximum efficiency is reached during the little ice age with clustered events probably lasting several days but major storms also occurred immediately prior to the medieval warm period we suggest that recent coastal dune building from c ad 1100 until now despite a sea level close to present and continuously rising may be a direct consequence of the restoration of beaches after periods of recurrent storminess this building activity often occurred during dry negativ

the mesozoic and tertiary basins of the bohemian massif and their evolution abstract the bohemian massif is a major positive element within the structural framework of the alpine carpathian foreland its basement became consolidated during the variscan orogeny crustal thicknesses range between 32 5 km and 40 km during the late carboniferous and early permian the bohemian massif became dissected by a conjugate system of wrench faults which controlled the accumulation of a continental coal bearing series late permian red beds were deposited on intramontane topographic depressions in triassic to mid jurassic times the bohemian massif formed a high from which clastics were shed into adjacent basins during the late jurassic and late cretaceous it became transected by nw se trending sedimentary basins the sub hercynian and laramide phases of foreland compression resulted in deformation and uplift of the bohemian massif the eger graben a 350 km long volcanotectonic zone cutting across the bohemian massif in an ene wsw direction came into evidence during the oligocene and is at present inactive the crust of the bohemian massif forms the autochthonous substratum of the outer carpathians which are paralleled by the neogene carpathian foredeep the neogene intramontane neo autochthonous vienna basin is superimposed on the alpine carpathian nappe systems and developed under a tensional setting

subduction and volcanism in the iberia north africa collision zone from tomographic images of the upper mantle abstract new tomographic images of the upper mantle beneath the westernmost mediterranean suggest that the evolution of the region experienced two subduction related episodes first subduction of oceanic and or extended continental lithosphere now located mainly beneath the betics at depths greater than 400 km took place on a nw se oriented subduction zone this was followed by a slab tear process that initiated in the east and propagated to the west leading to westward slab rollback and possibly lower crustal delamination the current position of the slab tear is located approximately at 4 w and to the west of this location the subducted lithosphere is still attached to the surface along the gibraltar arc our new p wave velocity model is able to image the attached subducted lithosphere as a narrow high velocity body extending to shallow depths coinciding with the region of maximum curvature of the gibraltar arc the occurrence of intermediate depth earthquakes and anomalously thick crust this thick crust has a large influence in the measured teleseismic travel time residuals and therefore in the obtained p wave tomographic model we show that removing the effects of the thick crust significantly improves the shallow images of the slab and therefore the interpretations based on the seismic structure

physical properties of the lithosphere asthenosphere system in europe abstract all the geophysical fields considered evidence a clear structural difference between the adriatic sea ionian sea basin on one side and the tyrrhenian sea western mediterranean basin on the other the former displays continental type characteristics while the latter shows features definitely related to young ocean basins lateral variations in the thickness of the high velocity sub crustal layer the lid are clearly evidenced in the whole european area the lateral changes in the shear wave velocities of the lithosphere asthenosphere system are quite pronounced gravity data imply a positive density contrast 0 03 0 07 g cm 3 in the upper mantle related to almost aseismic high velocity lithospheric roots which seem to characterize many orogenic belts the analysis of a transect along the longitudinal axis of the alps seems to indicate that relevant lateral variations in density are present in the lithospheric part of the mantle

backward modeling of the rifting kinematics in the upper rhine graben insights from an elastic perfect contact law on the restoration of a multi bloc domain this paper addresses the problem of volume restoration for 3 d sedimentary basin kinematic deformation the primary purpose is methodological and concerns the use of contact mechanics with the finite element method in order to deform a geological multi bloc domain this approach is applied to backward model the later stage of rifting of a segment of the southern upper rhine graben france germany border preliminary results from our modeling demonstrate the ability of the method not only to handle complex geometries but also to successfully perform retro deformation of a complex geological domain in addition they provide or confirm crucial information on the rifting evolution and tectonic features of this segment of the upper rhine graben such as the distribution of deformation the asymmetry of the graben and a significant left lateral strike slip component of displacement

veins in clay rich aquitards as records of deformation and fluid flow events in northern switzerland abstract the jurassic clay rich aquitard sequence underlying the swiss molasse basin is locally penetrated by unusually frequent veins consisting of calcite celestite in particular in the schlattingen 1 and oftringen drill cores the veins are linked to extensional brittle structures with shear senses ranging between dip slip and strike slip deformation triggered transient and localised events of fluid flow within the aquitard followed by sealing of the structures by the vein minerals vein calcite was dated by la icp ms analysis using the u pb method while this was a demanding undertaking given the low u and high common pb contents of calcite 9 significant ages could be obtained two groups of ages can be distinguished namely 31 39 and 11 18 ma both age groups are consistent with the known regional tectonic evolution the older age group corresponds to the main phase of rifting in the upper rhine graben a major crustal discontinuity whose effects were not limited to the graben proper but affected large parts of the molasse basin the younger age group is linked to crustal tilting and related extensional deformation isotopic compositions of o and c in vein calcite from the schlattingen 1 core show substantial variability but do not discriminate between veins of the two age groups in contrast 87sr 86sr ratios in veins show different signatures the depth trend of 87sr 86sr ratios in veins fits well with that in pore water obtained by rock squeezing the two data sets define a trend of values increasing with depth connecting the current values in the embedding malm and keuper aquifer waters this trend is best explained as a near steady state diffusion profile while advective mixing of waters originating from the embedding aquifers to produce the veins implying structures that cross cut the whole low permeability sequence cannot be discarded on the basis of existing data it is considered more likely that the veins have local fluid sources these are mixtures of local pore water with a possible contribution of water from the nearest aquifer implying maximum vertical advection distances in the order of 50 100 m

the continental rift system of the rhinegraben structure physical properties and dynamical processes abstract the geophysical investigation of the continental rift system of the rhinegraben by various methods has progressed to such a stage that details of structure physical properties and seismic activity and relations between these features can be recognised differences in the nature of the crust mantle boundary inside and outside the graben proper seem to be a typical property of continental rifts asymmetries of structure seismic activity temperature in the crust and physical properties in the lithosphere are an important clue to the understanding of rift dynamics these asymmetries indicate that the formation of the rift cannot be explained by the updoming of an asthenolith alone but that taphrogenesis took place in the foreland of the continent continent collision in the alpine mediterranean zone a number of future key experiments is proposed

upper mantle structure below the european continent constraints from surface wave tomography and grace satellite gravity data 1 we here exploit fundamental mode rayleigh and love seismic wave information and the high resolution satellite global gravity model ggm02c to obtain a 1 1 3 d image of a upper mantle isotropic shear wave speeds b densities and c density vscoupling below the european plate 20 n 90 n 40 w 70 e the 3 d image of the density vscoupling provides unprecedented detail of information on the compositional and thermal contributions to density structures the accurate and high resolution crustal model allows us to compute a reliable residual topography to understand the dynamic implications of our models the correlation between residual topography and mantle residual gravity anomalies defines three large scale regions where upper mantle dynamics produce surface expression the east european craton the eastern side of the arabian plate and the mediterranean basin the effects of mantle convection are also clearly visible at 1 the eastern sirt embayment 2 the west african craton northern margins 3 the volcanically active region of the canarian archipelago 4 the northern edge of the central european volcanic province and 5 the northeastern part of the atlantic ocean between greenland and iceland strong connections are observed among areas of weak radial anisotropy and areas where the mantle dynamics show surface expression although both thermal and additional dependencies have been incorporated into the density model convective down welling in the mantle below the east european craton is required to explain the strong correlation between the estimated negative mantle residual anomalies and the negative residual topography

the maritime alps arc in the ligurian and tyrrhenian systems abstract after late eocene meso alpine collision between the european and adria plates the maritime alps underwent further deformations linked to the apennine orogenesis and consistent with a stress field developed during anticlockwise rotation the western limit of the rotated sector is east of the argentera massif and to the southwest represents the northwestern margin of the post eocene ligurian sphenochasm the sinistral rotation of the maritime alps initially occurred contemporaneous with the opening of the ligurian basin about 30 19 ma and probably continued during the subsequent opening of the tyrrhenian basin about 10 0 ma the rotating block comprises the northwestern part of the adria indenter and a part of the paleo european plate namely the maritime alps corsica and sardinia if a convenient configuration is assumed for the moho of the adria margin and suitable poles are chosen for subsequent rotations then a simplified model of rigid body can explain the rotation structures in the maritime alps the apennines and po plain subsurface compressional arcs the late foreland directed transport of nappes in the western alps the presence of extensional and dextral transcurrent structures and the general uplift of the lithospheric mantle between the ligurian sea and the ivrea body as to the causes of rotation two alternatives subduction or asthenosphere uplift are discussed chronological and mechanical arguments seem to favour the latter

the cenozoic evolution of the roer valley rift system integrated at a european scale the roer valley rift system rvrs is located between the west european rift and the north sea rift system during the cenozoic the rvrs was characterized by several periods of subsidence and inversion which are linked to the evolution of the adjacent rift systems combination of subsidence analysis and results from the analysis of thickness distributions and fault systems allows the determination of the cenozoic evolution and quantification of the subsidence during the early paleocene the rvrs was inverted laramide phase the backstripping method shows that the rvrs was subsequently mainly affected by two periods of subsidence during the late paleocene and the oligocene quaternary time intervals separated by an inversion phase during the late eocene during the oligocene and miocene periods the thickness of the sediments and the distribution of the active faults reveal a radical rotation of the direction of extension by about 70 80j counter clockwise integration of these results at a european scale indicates that the late paleocene subsidence was related to the evolution of the north sea basins whereas the oligocene quaternary subsidence is connected to the west european rift evolution the distribution of the inverted provinces also shows that the early paleocene inversion laramide phase has affected the whole european crust whereas the late eocene inversion was restricted to the southern north sea basins and the channel area finally comparison of these deformations in the european crust with the evolution of the alpine chain suggests that the formation of the alps has controlled the evolution of the european crust since the beginning of the cenozoic

hot spot activity and the break up of pangea abstract the mesozoic and cenozoic positions of the continents that formed pangea in the triassic jurassic were derived from paleomagnetic and intraplate volcanic data paleoclimatic observations such as reef and fossil flora distribution and geological observations major hot spots helped to determine the longitudinal position of pangea and to construct a model of plate motion during the pangean break up the position of the northern part of pangea was constrained using iceland and jan mayen hot spots the iceland hot spot was traced from its present day position to greenland in the paleocene to baffin bay in the late cretaceous to the alpha ridge in the early cretaceous to the chukchi borderland in the middle late jurassic to franz joseph land in the early jurassic the yenisei khatanga trough in the middle triassic and finally to west siberia in the late permian early triassic the hot spot activity is expressed by eastern and western greenland volcanics the siberian trap basalts and perhaps by alpha ridge and chukchi borderland volcanics the chukchi borderland volcanics are related to the early stage of the opening of the canadian basin the position of the southern part of pangea was constrained using the bouvet hot spot this hot spot was tracked from its present day position to western antarctica in the early cretaceous late jurassic and to south africa in the early jurassic late triassic this hot spot activity produced the ferrar and karoo volcanics the model of plate motion obtained agrees with other data on intraplate volcanics which are also related to hot spots at the time of the opening of the central atlantic the cape verde and canary island hot spots were located along the ocean s spreading axis the long lasting location of hot spot and associated mantle upwelling plumes could help to explain forces driving the tethys transit plates opening of the ligurian ocean and eastern mediterranean the european hot spots are related to the several mesozoic phases of rifting for example the rhine graben hot spot may have been located at the rifting axis in the north sea several authors have already discussed the contribution of hot spots to the opening of the south atlantic and indian oceans mantle plumes associated with hot spots play an active role in rifting and initial phases of spreading the lithospheric displacement caused by upwelling combined with sometimes remote collisional forces on the other side of continental plate may result in compression and basin inversion

discovery of the first quaternary maar in the bohemian massif central europe based on combined geophysical and geological surveys abstract based on results of previous investigations of tephra tuff volcaniclastic deposits and a geophysical survey in the surroundings of the elezna h rka quaternary volcano west bohemia we performed detailed geophysical surveys using gravimetry magnetometry and electrical conductivity techniques striking anomalies were revealed in a morphological depression near m tina west bohemia as a strong evidence of the assumed maar diatreme structure the sharp isometric gravity low of 2 30 mgal as well as the corresponding positive magnetic anomaly of 200 nt with a negative rim on its northern side indicate a steeply dipping geological body of low density and containing magnetic rocks minerals magnetic survey also showed pronounced local anomalies outside the depression that can reflect relicts of the tephra rim of the maar this geophysical evidence was then proven by an exploratory drilling near the centre of the gravity anomaly macroscopic on site evaluation of the core and more detailed sedimentological petrochemical palynological and microbiological laboratory analyses further confirmed the existence of a maar structure filled by 84 m of lake sediments reflecting a succession of several warm and cold climatic periods results of palynological analyses confirm the presence of a continuous palaeoclimate archive with at least three successive warmer periods of most probably interstadial character from the upper quaternary saalian complex therefore the recovered sediment sequence holds strong potential for in depth paleoclimate reconstruction and deep biosphere studies at the bottom of the m tina 1 my 1 borehole 84 85 5 m country rock debris was found containing also volcanic bombs and lapilli the discovered volcanic structure is considered to be the first known quaternary maar diatreme volcano on the territory of the bohemian massif because of hidden active magmatic processes in combination with earthquake swarm seismicity ca 20 30 km north of the m tina maar reconstruction of the palaeovolcanological evolution is important for evaluation of hazard potential of the ne and e part of the cheb basin

kinematic and geometric analysis of fault related folds in a rift setting the dannemarie basin upper rhine graben france abstract the upper rhine graben urg developed in the alpine foreland from mid eocene to pliocene as part of the west european rift system the dannemarie basin occupies the sw termination of the urg and is bordered by the vosges fault zone west and the illfurth fault zone east we constructed a 3d model of faults and principal pre and syn rift stratigraphic surfaces using all available subsurface and surface geological and geophysical data the model shows 1 syn rift strata thinning across kilometre scale fault parallel monoclinal flexures associated with basin margin faults and 2 major basin margin faults terminating laterally into major flexures sequential cross section restorations show that these flexures accommodated deposition of over 1300 m of syn rift strata salt series which is 42 63 of the basin fill these folds are interpreted as syn rift fault propagation folds that developed above normal faults their geometry is replicated in a trishear numerical model using reasonable parameter values fold development was controlled principally by 1 reactivation of favourably oriented basement faults 2 the presence of a thick viscous layer principally triassic evaporites allowing decoupling between crystalline basement and competent jurassic cover and 3 a relatively slow deformation rate

numerical modeling of simultaneous extension and compression the valencia trough western mediterranean a two dimesional kinematic model which incorporates lateral accommodation of extension and differential stretching is used to investigate the geodynamic evolution of the valencia trough this neogene basin located between the iberian peninsula and the balearic promontory underwent two rifting episodes the first one being coeval with compression model predictions are compared with observations of tectonic subsidence bouguer gravity anomaly surface heat flow and the present day crustal structure the best fitting model assumes three stages in the evolution of the basin during the first stage late oligocene early miocene extension is mainly restricted to the central and northwestern parts of the basin whereas its southeastern margin is locked by the alpine deformation front the material expelled from the axial area is partly accommodated under the balearic promontory producing compression and crustal thickening during the second rifting stage middle miocene extension affects a much broader area including the balearic promontory and the algero provencal basin the third stage late miocene to recent corresponds to a postrift thermal relaxation phase our results put further constraints on the geodynamic evolution of the area

crustal evolution of the rhinegraben area 1 exploring the lower crust in the rhinegraben rift by unified geophysical experiments abstract unified geophysical investigations of the lithosphere in the rhinegraben rift system have revealed new details of the lower crust and its role in the rifting process the new findings allow an assessment of the compatibility of four different geophysical notions and properties of the lower crust 1 1 the lower crust as the layer beneath the conrad discontinuity with a p wave velocity of about 6 5 km s or greater refraction seismics 2 2 the laminated band of reflections as seen in the near vertical reflection seismic experiments in many parts of the continents 3 3 the ductile part of the crust below the brittle ductile transition devoid of earthquakes in seismically active regions 4 4 the electrical conductivity of the lower crust indicative of dry or wet conditions or still unknown conduction phenomena in the rhinegraben area the lamination of the lower crust serves as an outstanding marker of deep tectonic activity during the rifting process in which the crust of the rhinegraben rift system has been subjected to three different natural dynamic processes 1 uplift by 2 to 3 km with subsequent erosion of the rhinegraben shoulders black forest and vosges mountains caused decompression possibly leading to the formation of a low velocity high electrical conductivity zone right on top of the laminated lower crust beneath the elevated shoulders of the black forest 2 the brittle crystalline wedge of the graben proper subsided nearly undeformed into the lower crust which became about 5 to 7 km thinner below the graben than below the shoulders 3 the deepest hypocentres in the black forest dinkelberg area if projected onto the neighbouring reflection profile would be located 7 to 8 km within the laminated lower crust beneath the southern black forest indicating a discrepancy between the top of the lower crust as defined by the brittle ductile transition as seen by the deepest earthquakes and by the top of the laminated reflection band the rhinegraben rift system reveals the properties and behaviour of the lower crust under a wide variety of tectonic situations

tectonic implications of transpression and transtension upper rhine graben 1 seismic reflection data from the upper rhine graben urg show a series of synclines along the linear eastern boundary faults from north of karlsruhe to the jura mountains similar structures do not characterize the northern segment of the graben the synclinal shape is portrayed by inversion related to transpression on the linear boundary faults coupled with the conserved easterly dip of the sediments farther inside the tilted hanging block the onset of transpression preceded the known early burdigalian unconformity but was also an early miocene event it suggests that the regional compression axis 1 in early miocene had a trend between 315 and 0 the continuous transtension in the northern segment suggests that at no time during the history of the urg was the regional 1 horizontal with a ne sw trend the lack of transpressional structures in the younger plio pleistocene sediments along the entire eastern boundary of the urg suggests a late change in the regional stress field the main eastern boundary faults and synclines north and south of baden baden are all continuous and have the same trend kinematically they form a single graben segment and respond to the regional stress in the same way

inversion tectonics along the western margin of the bohemian massif abstract the block faulted southwestern margin of the bohemian massif is superimposed on a permo carboniferous graben major faults of which became repeatedly reactivated during the mesozoic and cenozoic inversion of sedimentary basins associated with this fault system occurred during the early cretaceous and again during the latest cretaceous early cenozoic

late cretaceous cenozoic evolution of the north german basin results from 3 d geodynamic modelling abstract the late cretaceous cenozoic evolution of the north german basin has been investigated by 3 d thermomechanical finite element modelling the model solves the equations of motion of an elasto visco plastic continuum representing the continental lithosphere it includes the variations of stress in time and space the thermal evolution surface processes and variations in global sea level the north german basin became inverted in the late cretaceous early cenozoic the inversion was most intense in the southern part of the basin i e in the lower saxony basin the flechtingen high and the harz the lower crustal properties vary across the north german basin north of the elbe line the lower crust is dense and has high seismic velocity compared to the lower crust south of the elbe line the lower crust with high density and high velocity is assumed to be strong lateral variations in lithospheric strength also arise from lateral variations in moho depth in areas where the moho is deep the upper mantle is warm and the lithosphere is thereby relatively weak compression of the lithosphere causes shortening thickening and surface uplift of relatively weak areas tectonic inversion occurs as zones of preexisting weakness are shortened and thickened in compression contemporaneously the margins of the weak zone subside cenozoic subsidence of the northern part of the north german basin is explained as a combination of thermal subsidence and a small amount of deformation and surface uplift during compression of the stronger crust in the north the modelled deformation patterns and resulting sediment isopachs correlate with observations from the area this verifies the usefulness and importance of thermomechanical models in the investigation of intraplate sedimentary basin formation

tectonic implications of faulting styles along a rift margin the boundary between the rhine graben and the vosges mountains 1 seismic reflection data show the effects of the miocene strike slip environment on the boundary between the upper rhine graben urg and the vosges mountains vm the border fault zone exhibits three types of responses to the new nw se directed regional stress regime where it trends n s no new deformation is observed where it trends nne ssw transpression is evident and it develops into a few kilometers wide zone of intense deformation along the ne sw trending southern boundary of vm transpression intensifies with an increase in the perpendicular shortening component and the border fault zone turns into a reverse fault the uplift of the boundary relative to the graben is estimated to be no less than 1000 m near colmar and significantly more along the boundary with the dannemarie basin these estimates and kinematics considerations support the hypothesis that the vosges mountains are mostly a transpressional feature the rhine fault is mapped and suggested to be a lower miocene structure that was formed in response to the change in the regional stress regime

a two stage rifting in the basins of the corsica sardinian straits abstract a set of seismic and field data from the corsica sardinian straits allowed us to define three well separated oligocene deep basins the castelsardo and porto torres basins forming the northern end of the sardinian graben and the bonifacio basin on the continental shelf of the bonifacio straits a seismostratigraphic investigation of these three basins revealed two major tectonic events a first oligocene to middle aquitanian rifting phase followed by oceanic spreading in the western mediterranean and then a second rifting event between corsica and sardinia in lower burdigalian time the first rifting is noticed in the three basins but the second one only in the porto torres and castelsardo basins

from gullies to mountain belts a review of sediment budgets at various scales this paper reviews the state of the art in the concept as well as in the application of sediment budgets in sedimentary research sediments are a product of mass dispersal at the earth surface and take part in global cycles sediment budgets aim at quantifying this mass transfer based on the principle of mass conservation and are the key to determine ancient fluxes of solid matter at the earth surface this involves fundamental questions about the interplay of uplift climate and denudation in mountain belts and transfer of sediments from the continents to the oceans as well as applied issues such as soil and gully erosion reservoir siltation and coastal protection first after introducing basic concepts relevant scales and methodologies the different components of quaternary routing systems from erosion in headwaters river systems glacial and paraglacial systems lakes deltas estuaries coasts shelves epicontinental seas and deep sea fans are discussed in terms of their sediment budget most suitable are sedimentologically closed or semi closed depositional environments e g alluvial fans lakes deltas and deep sea fans in a second step the dynamics of passive active and collisional tectonic settings and sediment budgets in related sedimentary basins are explored and new concepts of sediment portioning at large geodynamic scales are introduced ancient routing systems are more or less incomplete and may be intensively fragmented or destroyed in active tectonic settings in terms of sedimentary basin types rifts intracontinental and epicontinental settings are preferred objects of sediment budgets because of their persistence and relatively simple overall sedimentary architecture however closing basins such as foreland forearc retroarc piggy back and wedge top basins may provide excellent snapshots of orogenic sediment fluxes in a third step the large long lived routing systems of the amazon the ganges brahmaputra and the rhine are reviewed for each system estimates of either sediment volumes mass or sediment fluxes of continental and marine subsystems have been compiled in order to receive a complete routing in terms of mass conservation for specific time periods since the late glacial maximum as well as the cenozoic following lessons can be taken from these case studies i depositional centers and fluxes show strong shifts in space and time and call for caution when simply looking at subsystems ii the response times of these large systems are within the milankovich time interval thus lower than predicted from diffusion models iii cyclic routing of sediments in continental basins is much more dominated by climate human control than by eustacy and iv at long time scales ultimate sinks win over intermittent storage it is concluded from this review that the quantitative understanding of global sediment cycling over historic and geologic time and its response to allogenic forcing is still in its infancy and further research is needed towards a holistic view of sediment routing systems at various temporal and spatial scales and their coupling with global biogeochemical cycles this includes i to better determine response times of large routing systems by linking quaternary with cenozoic sediment budgets and continental with marine sub systems ii to combine advanced provenance techniques with sediment budgets in order to reconstruct ancient systems iii to study sediment partitioning at the basin scale iv to reconcile continental supply dominated sequence stratigraphy with the eustatic dominated marine concept and iv to account for non actualism of ancient systems with respect to their erosion and transport mode in particular during glaciations and pronounced arid intervals glacial and eolian sediment routing may cross over hydrologic boundaries of drainage basins thus challenging the principle of mass conservation

introduction to special issue on integrated basin studies ibs a european commission dgxii project this issue contains papers issued from the integrated basin studies project ibs which is part of a larger program of the european commission dgxii entitled geosciences ii the ibs project ec contract jou2 ct92 0110 originated in geosciences consultation meetings the first of them being held in strasbourg in june 1989 under the auspices of mr hubert curien former french minister for research and technology and the subsequent meeting being held in brussels these consultation meetings have resulted in the conclusion that a main axis of future research in geosciences should be the study of sedimentary basins upstream of industrial activities mainly the oil and gas industry but also water resources management the mining industry the storage of undesirable products and coastal engineering they also resulted in the conclusion that future research on sedimentary basins should fulfill two requirements integration of disciplines and modelling such a conclusion may now seem trivial but was not so generally accepted at that time in this spirit the ibs project was designed to provide the oil and gas industry with a new generation of models for basin formation basin evolution and basin fill architecture from basin scale to reservoir scale its main objectives are the linkage of crust thermomechanical behaviour to basin formation and deformation mechanics and the corresponding modelling the quantification of tectonic control on the sedimentary record and the analysis of compaction and mass and heat transfer the ibs strategy is to link subsurface data to field data and an important part of the project is devoted to thematic field studies in european sedimentary basins of different tectonic styles taken as natural laboratories basin research has gone through a rapid evolution during the last decade in particular through the development of new acquisition and processing methods for seismic data and advances in drilling technology modelling provides an important tool to analyse different aspects of basin formation processes and find their tectonic expression in the basin fill the need for 3 d modelling techniques and models capable of linking processes operating on basinwide to subbasin scales is increasingly recognized and a significant effort has been made in the ibs project to develop a new generation of basin formation models coping with these needs see also cloetingh et al 1993a van wees and cloetingh 1994 as many data required to test these models reside in industrial companies ibs has promoted a closer link between academic research and basin studies carried out by industry the participation of the petroleum industry has been vital in this project and ibs has been able to establish a well functioning system of cooperation that not only facilitated data access but most important guaranteed the suitability of the end products of the project this has led to an intensive exchange of modelling concepts and data sets between industry and academia the ibs project has also used extensively the international lithosphere program task force origin of sedimentary basins see cloetingh sassi and task force team 1994 cloetingh et al 1993a b 1994 to implement planning and to discuss preliminary results it also builds partly on joint research through the european commission tempus and peco programs on pannonian basin studies horvath 1993 van balen and cloetingh 1995 van balen et al 1995 horvath and cloetingh 1995 a stimulating aspect of the activity of the ibs group is the creation of a research network in the corresponding field of knowledge which comprises now 30 teams belonging to eight european countries england france germany hungary norway spain switzerland and the netherlands this demonstrates the capacity of the procedures used by the dgxii of the european community to formulate a really european research space phd students and young researchers form an important component of the research groups

lithospheric cross sections of the european cenozoic rift system abstract the lithospheric structure of the european cenozoic rift system ecris is presented in transects through the southern rhine graben and the rhenish massif hessen depression emphasizing the geophysical structure of the lithosphere based on seismic refraction reflection investigations teleseismic tomography electromagnetic depth sounding models and gravity aeromagnetic earthquake uplift subsidence and heat flow data the rift is clearly expressed in the rhine graben but is not evident at the surface in the area of the rhenish massif where its existence is indicated by seismicity it is characterized by abnormal crustal and upper mantle structures which vary considerably in horizontal direction for example under the rhine graben the crust is thinned to 25 km but at 40 km depth anomalously high velocities are observed in contrast beneath the rhenish massif the crust is thickened to 35 37 km and under its eastern part a high velocity thin upper mantle slice is seen at 30 km depth within the lower crust which towards the hessen depression is gradually replaced by normal variscan mantle with the moho near 30 km depth under the western part of the rhenish massif p and s wave velocities are reduced below 50 km depth which is not seen east of the rhine river under the rhine graben the existence of a low velocity upper mantle above 100 km cannot be generalized but is restricted to confined regions

workflow for analysis of compositional data in sedimentary petrology provenance changes in sedimentary basins from spatio temporal variation in heavy mineral assemblages the field of provenance analysis has seen a revival in the last decade as quantitative data acquisition techniques continue to develop in the 20th century many heavy mineral data were collected these data were mostly used as qualitative indications for stratigraphy and provenance and not incorporated in a quantitative provenance methodology even today such data are mostly only used in classic data tables or cumulative heavy mineral plots as a qualitative indication of variation the main obstacle to rigorous statistical analysis is the compositional nature of these data which makes them unfit for standard multivariate statistics to gain more information from legacy data a straightforward workflow for quantitative analysis of compositional datasets is provided first 1 a centred log ratio transformation of the data is carried out to fix the constant sum constraint and non negativity of the compositional data next 2 cluster analysis is followed by 3 principal component analysis and 4 bivariate log ratio plots several 5 proxies for the effects of sorting and weathering are included to check the provenance significance of observed variations and finally a 6 spatial interpolation of a provenance proxy extracted from the dataset can be carried out to test this methodology available heavy mineral data from the southern edge of the miocene north sea basin are analysed the results are compared with available information from literature and are used to gain improved insight into miocene sediment input variations in the study area

3 d structure of the lithosphere beneath the southern rhine graben area abstract the 3 d velocity structure of the lithosphere asthenosphere system beneath the southern rhine graben area is imaged by inverting p wave traveltime residuals of teleseismic events recorded by a dense network of short period stations the upper part of the lithosphere marked by velocity anomalies orientated along the graben strike can be related to the development of the graben these upper 50 km display stronger lateral heterogeneities than the weak anomalies observed at deeper levels which show roughly an e w orientation the teleseismic inversion models yield no indications for significantly reduced seismic p wave velocities in the upper mantle as could be expected from an actively upwelling mantle diapir located beneath the southern rhine graben area the observation of generally weak p wave velocity variations at greater depth indicates a rather smooth transition from the lower lithosphere to the upper asthenosphere the observed heterogeneities in the 25 50 km depth range may be related to partial melts which intruded the mantle lithosphere during the middle and late miocene these melts cooled and solidified since that intrusion the rifting and thermal doming stage of the rhine graben ceased at the end of the miocene

comparative study of geophysical and soil gas investigations at the hartousov czech republic natural co2 degassing site our study at this natural analog site contributes to the evaluation of methods within a hierarchical monitoring concept suited for the control of co2 degassing it supports the development of an effective monitoring concept for geological co2 storage sites carbon capture and storage as one of the pillars of the european climate change efforts this study presents results of comprehensive investigations along a 500 m long profile within the hartousov czech republic natural co2 degassing site and gives structural information about the subsurface and interaction processes in relation to parameters measured measurements of co2 concentrations and investigation of the subsurface using electrical resistivity tomography and self potential methods provide information about subsurface properties for their successful application it is necessary to take seasonal variations e g soil moisture temperature meteorological conditions into consideration due to their influence on these parameters locations of high co2 concentration in shallow depths are related to positive self potential anomalies low soil moistures and high resistivity distributions as well as high 13c values and increased radon concentrations co2 ascends from deep geological sources via preferential pathways and accumulates in coarser sediments repetition of measurements which includes the effects of seasonal variations revealed similar trends and allows us to identify a clear prominent zone of anomalous values coarser unconsolidated sedimentary layers are beneficial for the accumulation of co2 gas the distribution of such shallow geological structures needs to be considered as a significant environmental risk potential whenever sudden degassing of large gas volumes occurs

palaeocene oligocene tectonics of nw europe s u m m a r y during the palaeogene in nw europe a gallic subplate was very nearly created this plate was almost entirely bordered by plate boundaries although not of equivalent ages to the n the n atlantic began to open about 56 ma ago the alpine convergent boundary extended southwestwards to the pyrenean subduction zone on the ne side a n british pataeocene early eocene fracture dyke boundary appears to pass southeastwards across the north sea into a lutetian to burdigalian rift system there is an age disparity between the fracturing and nw dyke intrusion in britain and the fracturing and formation of the rhine graben the last dykes in britain ypresian were intruded not long before the important subsidence of the rhine graben earliest lutetian but their causes were different the british dyke fractures propagated southeastwards via the cleveland dyke towards the north sea whereas the rhine graben propagated northwards towards the zuider zee depression however the structures from both sides converged in the sole pit basin in the north sea with the result that a continuous though not coevally originated fracture system developed from nw scotland to the alps during the early tertiary there was a wide range of tectonic activity throughout nw europe fig 1 in nw britain lavas were extruded and plutonic complexes and extensive dyke swarms were intruded in the north sea tufts were deposited as a result of volcanism along the rockall faeroe rift reactivation of faults con trolled magmatism localization of gas fields devolatilization of coal and inversion of basins caused uplift deformation and erosion along the rhine graben doming subsidence and rift propagation took place in association with alka line volcanism and plutonism coevally with the meso alpine compressive deformations that oc curred in the alps faulting controlled sedimen tation patterns during inversion of basins in southern england the english channel northern france and holland old rift faults were reacti vated in the western approaches basin thrust faults formed in the southern bay of biscay contemporaneously with thrusting in the pyre nees and variscan massifs were tilted and uplifted along steep reverse faults the main tectonic activity lasted from about 60 ma to about 30 ma but it was diachronous generally earlier in the nw and later in the se the igneous activity in northern britain was related to the opening of the n atlantic in the late palaeocene but the formation of the rhine graben and the inversion of sedimentary basins in the north sea and near the english channel were caused by major orogenic events in the alpine region in the late eocene to mid oligocene frisch 1981 tectonic phenomena in the north sea provide the link between those in northern britain and those in the rhine graben the aim of this paper is to demonstrate that these movements from the atlantic and alpine sides almost fragmented the lithospheric plates of nw europe during the creation of a gallic sub block an earlier northern boundary from nw scotland to northern germany being transected by a later eastern boundary along the rhine graben

recent surface displacements in the upper rhine graben preliminary results from geodetic networks abstract datasets of the gnss upper rhine graben network gurn and the national levelling networks in germany france and switzerland are investigated with respect to current surface displacements in the upper rhine graben urg area gurn consists of about 80 permanent gnss global navigation satellite systems stations the terrestrial levelling network comprises 1st and 2nd order levelling lines that have been remeasured at intervals of roughly 25 years starting in 1922 compared to earlier studies national institutions and private companies made available raw data allowing for consistent solutions for the urg region we focussed on the southern and eastern parts of the investigation area our preliminary results show that the levelling and gnss datasets are sensitive to resolve small surface displacement rates down to an order of magnitude of 0 2 mm a and 0 4 mm a respectively the observed horizontal velocity components for a test region south of strasbourg obtained from gnss coordinate time series vary around 0 5 mm a the results are in general agreement with interseismic strain built up in a sinistral strike slip regime since the accuracy of the gnss derived vertical component is insufficient data of precise levelling networks is used to determine vertical displacement rates more than 75 of the vertical rates obtained from a kinematic adjustment of 1st order levelling lines in the eastern part of urg vary between 0 2 mm a and 0 2 mm a indicating that this region behaves stable higher rates up to 0 5 mm a in a limited region south of freiburg are in general agreement with active faulting we conclude that both networks deliver stable results that reflect real surface movements in the urg area we note however that geodetically observed surface displacements generally result from a superposition of different effects and that a separation in tectonic and non tectonic processes needs additional information and expertise

evidence for the permutation of stresses σ1 and σ2 in the alpine foreland the example of the rhine graben abstract the orientation of the principal stresses 1 2 and 3 and the ratio r 2 3 1 3 which characterizes the shape of the stress tensor can be calculated using earthquake focal mechanisms in the rhine graben area two types of stress tensor can be determined one of them is an extensional stress state subvertical 1 horizontal 2 n130 in the northern part of the rhine graben the other is a strike slip stress state horizontal 1 n150 in the southern part these results show that the maximum horizontal stress is constant in an approximately n130 150 direction 1 in the south 2 in the north this permutation of the stresses 1 and 2 may be imputed to the interaction between the decrease in alpine pressure and the asthenospheric uprise under the rhenish massif the superficial in situ stresses measured from the alps to the lower rhine embayment showing a decrease in maximum horizontal stress h max support this hypothesis

recent stress field and neotectonics in the eastern jura mountains switzerland the regional stress field and its local variation were determined for the northern part of central switzerland fig 1 by using overcoring techniques doorstopper triaxial strain cell and observations of breakouts in deep boreholes the results are compared with fault plane solutions of earthquakes and with the orientation of horizontal stylolites in the northern part of central switzerland the nw se orientation of the maximum horizontal stress sh which is characteristic for central europe was observed only in the crystalline basement in the folded jura and south of it in one well the greatest principal horizontal stress above the triassic decollement horizon is oriented approximately in a n s to nne ssw direction this direction persists into the western tabular jura and the southernmost rhine graben only in the eastern part of the tabular jura the greatest principal horizontal stress shows a nnw sse to nw se orientation comparison of the near surface stress field as determined by in situ stress measurements and borehole breakouts with the directions of horizontal stylolites generated during the evolution of the folded jura indicates that the orientation of the recent stress field near the earth s surface is the same as that which prevailed during the upper miocene to lower pliocene the central part of northern switzerland is therefore the first area in central europe where it is possible to demonstrate that the near surface stress field is decoupled from that in the crystalline basement the difference in the orientation of the greatest principal horizontal stress is about 50

late quaternary tectonic switching of siliciclastic provenance in the strike slip dominated foreland of the western carpathians upper morava basin bohemian massif abstract this study is focused on the lithology and provenance of late quaternary fluvial deposits of the upper morava basin a pull apart basin situated at the contact of the bohemian massif and western carpathians late cenozoic tectonic convergence between these two units caused differential subsidence along strike slip faults of the elbe odra zone leading to a distinct horst and graben morphology of the upper morava basin the pleistocene fluvial deposits are preserved in several terrace levels and partly buried under the present day floodplain of the morava river this study is based on four cores 11 25 m deep drilled in the floodplain of two major depocentres of the basin the lutin graben and the upper morava basin sensu stricto the drill cores were analysed for grain size pebble and heavy mineral composition chemical composition of detrital garnets bulk magnetic susceptibility sediment colour visible light spectral reflectance and bulk element geochemistry age interpretations are based on eight optically stimulated luminescence osl analyses the upper pleistocene sediments were deposited in a gravelly braided to transitional braided meandering river in both the upper morava basin s s and the lutin graben the oldest osl age is 161 5 ka corresponding to the late saalian between the end of the saalian and late weichselian glaciations the morava river abandoned the lutin graben for the upper morava basin s s where it flows up to the present day the pleistocene fluvial style contrasts with the present day meandering to anastomosing fluvial style of the morava river the pleistocene deposits were sourced from areas corresponding to the present day morava river catchment including crystalline units of the eastern bohemian massif and the moravo silesian carboniferous basin they also contain a considerable input from the bohemian cretaceous basin the composition of late weichselian deposits from the dub nad moravou core 34 53 3 42 ka and younger differs from the older fluvial deposits representing the other cores it indicates that a major provenance change occurred between the latest saalian and the late weichselian in the late weichselian the morava river started to recycle loess deposits which cover large areas of its catchment based on osl dating it may be assumed that the morava river turned from degrading between 92 6 8 03 and 34 53 3 42 ka to aggrading in style from 34 53 3 42 ka to the present day due to coeval tectonic movements in the umb which are indirectly indicated by present day seismicity geomorphic faults and palaeoseismic evidence both the tectonic context and fluvial deposition styles of the upper morava basin show similar features to the upper rhine graben of the alpine foreland

the evolution of the south hunsruck and taunus borderzone abstract the main fabric development of the south hunsruck and taunus borderzone htb occurred during late variscan homoaxial backfolding of an early variscan stack of thrust sheets in a narrow wsw ene trending zone several hundred kilometres long rotation and uplift of the southern rhenohercynian zone was accompanied by the subsidence of the southward adjacent northernmost parts of the saxothuringian zone and the development of the saar nahe basin during the latest carboniferous changing stress conditions gave rise to the development of normal faults along the htb and an extensive tholeiitic and rhyolitic volcanism contemporaneous uplift of the hunsruck is reflected by coarse elastics in the saar nahe basin subsequently the htb became covered by latest carboniferous early permian and mesozoic sediments cretaceous uplift of the rhenish shield caused their erosion the faultzone separating the rhenohercynian hunsruck and taunus from the permo carboniferous saar nahe basin is characterised by reverse and normal faults conjugate shear indicated by slickensides on steep oblique fracture planes as well as slight folding and small scale thrusting in post variscan sediments may be attributed to compressional foreland deformation reactivating variscan joint fabrics and fault systems timing of these deformations is ambiguous and could partly be related to dextral shear during the cenozoic subsidence of the rhine graben cenozoic sediments of the upper rhine graben overstep the northeastern parts of the htb seismic investigations indicate that the htb is associated with a system of southeast hading listric planes extending beneath the moho occasional dip slip earthquakes occur along these fractures

the lithosphere asthenosphere boundary in the western mediterranean from 3d joint gravity and geoid modeling tectonic implications abstract a new integrated three dimensional 3d gravity and geoid forward modeling was used to investigate the lithospheric structure of the northwestern mediterranean basins namely the gulf of lyons liguro provencal basin valencia trough and south balearic basin available geological and geophysical data were used to construct preliminary maps of the thickness of the sediments and the base of the crust and lithosphere which were further refined by 3d modeling our model results show that the base of the crust thins from 22 km in the sw areas of the valencia trough to less than 12 km at its ne transition to the oceanic domain of the provencal basin and from 28 km in the shelf area of the gulf of lyons to about 12 km in the deep oceanic part of the basin upper mantle densities vary from 3240 kg m 3 beneath the valencia trough where p wave velocities are anomalously low suggesting the presence of an anomalous uppermost mantle to 3320 kg m 3 beneath the gulf of lyons and the provencal basin where normal p wave velocities are recorded the base of the lithosphere rises from 75 80 km at the shoreline of the valencia trough and gulf of lyons to 60 km in the northern part of the valencia trough and 55 60 km at the center of the provencal basin the structure of the crust and lithospheric mantle obtained from the 3d modeling indicates differential thinning moreover other geophysical observations e g the uneven distribution of heat flow values suggest an asymmetric extensional model

interplay between tectonic fluvial and erosional processes along the western border fault of the northern upper rhine graben germany abstract the northern upper rhine graben situated in the central part of the european cenozoic rift system is currently characterized by low intra plate seismicity historical earthquakes have not been large enough to produce surface rupturing moreover the records of quaternary surface processes and human modifications are presumably better preserved than the record of the relatively slow tectonic deformation in order to gain information on the neotectonic activity and paleoseismicity in this setting the geological and geomorphological records of fault movements along a segment of the western border fault wbf were studied using an integration of techniques in paleoseismology structural analysis and shallow geophysics the wbf segment investigated follows a 20 km long linear scarp of unclear origin a series of geophysical measurements were performed and the results suggested that near surface deformation structures are present at the segments southern end several trenches opened at this location revealed fault structures with consistent extensional style and a maximum vertical displacement of 0 5 m in one trench the deformation structures were dated between 19 and 8 ka assuming the deformation has been caused by an earthquake a m w 6 5 earthquake would be implied aseismic deformation would point to a fault creep rate 0 04 mm yr a reconstruction of the sequence of events at the trench site from middle pleistocene to present demonstrates that the morphology at the base of the scarp is the result of interplay between tectonic activity and fluvial and erosional processes at the regional scale a mixed origin for the wbf scarp is proposed combining the effects of fluvial dynamics erosion regional uplift and localized tectonic activity on the wbf

refraction seismic investigations of the northern massif central france abstract new refraction seismic data have been obtained in the northern french massif central seven shots were recorded simultaneously on two parallel nnw sse i e perpendicular to the surface structures oriented profiles allowing for inline and fan interpretations the results of a 2d interpretation reveal a large scale updoming of the moho of about 2 km compared to average western europe corresponding to the cenozoic uplift of the massif central local crustal thinning of up to 20 is restricted to the cenozoic grabens as seen at the surface beneath the volcanic area of cantal one of the largest cenozoic european shield volcanoes which was active in miocene to recent times significant crustal thickening of 2 3 km is observed velocities in the upper mantle are generally in the range of 7 9 8 1 km s beneath the limagne graben and surrounding undisturbed areas underneath the volcanic area of cezallier however velocity is reduced to about 7 7 km s corresponding to the area of crustal thickening therefore the low velocity in this zone is explained by the remainders of cooling magma chambers and heating by ascending hot plume material the cenozoic tectonic evolution of the massif central has affected crust and upper mantle in different ways oligocene rifting corresponds well to local crustal thinning but no correlation is detected to velocities of the upper mantle in contrast the volanic event occurring since miocene times is related to upper mantle velocity reduction and crustal thickening due to underplating

the glueckstadt graben a sedimentary record between the north and baltic sea in north central europe abstract the glueckstadt graben is one of the deepest post permian structures within the central european basin system and is located right at its heart at the transition from the north sea to the baltic sea and from the lower saxony basin to the rynkoebing fyn high the mesozoic to recent evolution is investigated by use of selected seismic lines seismic flattening and a 3d structural model a major tectonic event in the latest middle late triassic keuper was accompanied by strong salt tectonics within the glueckstadt graben at that time a rapid subsidence took place within the central part which provides the core of the glueckstadt graben the post triassic tectonic evolution of the area does not follow the typical scheme of thermal subsidence in contrast it seems that there is a slow progressive activation of salt movements triggered by the initial triassic event starting with the jurassic the subsidence centre partitioned into two parts located adjacent to the triassic core in comparison with other areas of the central european basin system the glueckstadt graben was not strongly affected by additional jurassic and cretaceous events during the late jurassic to early cretaceous the area around the glueckstadt graben was affected by relative uplift with regional erosion of the elevated relief however subsidence was reactivated and accelerated during the cenozoic when a strong subsidence centre developed in the north sea during paleogene and quaternary neogene the two centres of sedimentation moved gradually towards the flanks of the basin the data indeed point toward a control of post permian evolution by gradual withdrawal of salt triggered by the initial exhaustion along the triassic subsidence centre in this sense the glueckstadt graben was formed at least partially as basin scale rim syncline during post permian times the present day hamburger east and westholstein troughs are the actual final state of this long term process which still may continue and may play a role in terms of young processes and e g for coastal protection

determination of displacements in the upper rhine graben area from gps and leveling data the upper rhine graben is a north northeast trending rift system which belongs to the european cenozoic rift system today the southern part of the graben is seismically still active earthquakes of magnitude 5 have a recurrence time of approximately 30 years in order to monitor and to determine the displacements in the study area gps measurements have been carried out in two campaigns 1999 and 2000 and observations of the available permanent stations have been processed in 2002 owing to the small size of deformations expected high accuracy requirements must be met by the gps processing in order to achieve these requirements precise antenna modeling has been introduced into the processing as expected the short time span has not enabled to detect significant displacements from the gps measurements the deformation analysis shows that the horizontal displacement rates do not exceed 1 mm year which is compatible with the geological information owing to the fact that the accuracy of positioning with gps for the vertical coordinates is lower than for the horizontal coordinates the determination of vertical displacements has been carried out using the leveling technique in the area of freiburg first order and second order leveling lines have been chosen for the detection of local displacements on the weinstetten on the lehen schonberg and on the main border fault mbf some sections of these faults are still active today significant vertical displacements have been observed at the weinstetten fault in the area of bad krozingen and on the mbf in freiburg the displacement rates 1925 1984 are 0 17 0 01 mm year and 0 25 0 02 mm year respectively the results agree very well with the results of seismotectonic investigations and show that ongoing displacements can be found on the northern part of the lehen schonberg fault in the vicinity of eichstetten and on the mbf in the vicinity of freiburg

stress field changes in the rhone valley from the miocene to the present abstract study of the deformation of neogene and quaternary deposits in the rhone valley shows that the end miocene e w greatest principal compression 1 that deformed the western alps did not continue into the quaternary at least between vienne and montelimar the middle to upper miocene molasse on the east side of the rhone valley was affected by e w compression at the end of the miocene causing reverse faulting and n s folding st lattier and varacieux anticlines in contrast the pliocene sands and clays of the rhone valley are unaffected by folding and show only small normal faults with a maximum throw of l m trending between n s and nw se these were caused by e w to ne sw extension which is incompatible with the e w compression that characterises the latest miocene alpine phase these structures are the surface expression of extension that was probably induced locally by the overall compressive regime that exists to the present day in this part of western europe the transcurrent extensional regime of philip 1983 ustl thesis montpellier this stress field results from the collision of the african and european plates that began in the tertiary west of the frontal pennine thrust the present day direction of compression which is deduced from calculated focal mechanisms and from in situ stress measurements varies between n s and nw se in the grenoble region and the northern massif central the focal mechanisms indicate transcurrent movement with 1 horizontal and oriented between n s and nw se and with 2 vertical in the southwestern massif central and the vendee however they indicate an extensional tectonic regime with 1 vertical and 2 horizontal and oriented nw se 3 trends ne sw this orientation is similar to that which would have caused the small pliocene normal faulting observed in the rhone valley between vienne and montelimar in this part of the rhone valley west of the frontal pennine thrust the e w stress resulting from the collision of apulia italy with the west european plate has not been in evidence since the pliocene the e w compression has been replaced by n s to nw se compression resulting directly from the collision between the african and european plates transmitted through the straits of gibraltar and the iberian microplate in the west and the corsica sardina block in the east the piercing effect of the apulian block is no longer dominant in the rhone valley

shear wave splitting around the eifel hotspot evidence for a mantle upwelling summary we present the results of a shear wave splitting analysis across the eifel hotspot in westcentral europe our data set includes 18 permanent european broadband stations and 102 temporary eifel broadband and short period stations we observe variations in splitting at most permanent stations but are not able to model them reliably with unique dipping axis or two layer anisotropy models we prefer instead a single layer model with a horizontal fast axis to approximate the first order anisotropy which varies smoothly between stations we observe a first order parabolic pattern in fast polarization azimuth around the hotspot which suggests that a lattice preferred orientation lpo of olivine fast axes exists in the asthenosphere as a result of the interaction between the slowly wsw moving eurasian plate and a mantle upwelling beneath the eifel volcanic fields the minority of the variation not explained by this model correlates with rapid lateral changes in splitting and is interpreted as a result of additional anisotropy and or the effects of dynamic recrystallization associated with lpo development in the region of corner flow near the conduit our parabolic asthenospheric flow paf interpretation is consistent with eifel geological tomographic receiver function global absolute plate motion electrical conductivity anisotropy and geochemical studies as well as with splitting studies in the great basin and around hawaii we suggest that the eifel upwelling is sporadic and a result of a low excess upwelling temperature and or varying crustal stresses that periodically shift and facilitate eruption the paf pattern we observe neither suggests nor rules out anisotropy in the conduit associated with a wet eifel upwelling we use our optimum pa f model parameters to calculate a eurasian plate speed of 12 km ma 1 w hich is consistent with the recent hs3 nuvel1a speed of 19 14 km ma 1

eocene oligocene tectonics and kinematics of the rhine saone continental transform zone eastern france a tectonic analysis of brittle deformaton was performed in the rhine saone transform in order to decipher and understand the deformation processes in a typical continental hansfer zone cenozoic major and minor fault patterns are described and brittle structures are interpreted in terms of paleostress orientations the eocene n s compression related to africa eurasia convergence is marked mainly by strike slip faults it was followed by a major phase of crustal extension mainly oligocene in age related to the west european rifting this extensional phase is expressed by normal faults tension gashes and extensional strike slip faults which are especially abundant in the transform zone these two events are found to be quite different in terms of distribution of horizontal shess trajectories the trend of ol axes is very homogeneous for the n s compression whereas o3 orientations associated with the major extension vary from e w in most of the rift system to i v se within the transform zone finally the mio pliocene tectonic emplacement of the jura fold and thrust belt is marked in the field by strike slip faults associated with a well defined trend of ol oriented w iiw e se to nw se the preexisting basement fracture pattern between the grabens was also considered in order to estimate which faults were likely to have been reactivated during the oligocene transform kinematics and the theoretical shear motion on these inherited fault surfaces when submitted to e w extension was calculated left laterauextensional reactivation of a preexisting 60 n trending fault system in the brittle upper crust is likely to have accommodated the shear strain arising between the rift segments in response to crustal stretching two independent numerical modelings based on distinct element and finite element analyses respectively enabled us to verify and to refine the hypothesis of transform kinematics related to e w extension and inducing regional perturbations of extensional stress trajectories the overall mechanism and the transtensional kinematics of the rhine saone transform zone are thus tightly conshained the inherited crustal anisotropy the large scale perturbations of extensional stress trajectories and the development of distributed brittle deformation within the sedimentary cover are found to play a major role in the tectonic evolution of continental rift transform systems

successive post variscan stress fields in the french massif central and its borders western european plate comparison with geodynamic data abstract structural analysis and particularly microtectonic methods have made it possible to define the different stages of brittle deformation of the massif central basement and the surrounding sedimentary cover from the end of the hercynian orogeny to the end of the tertiary during the stephanian a compressional tectonic regime prevailed regional faults appeared or were react vated reactivation as a result of initial n s compression becoming nw then e w these regional strike slip faults caused local extension which led to the formation of small coal bearing basins this compressional regime which marked the end of the formation of pangea was followed by a series of extension episodes permian triassic extension oscillating around n s e w to nw se extension in the early and middle jurassic and finally n s to ne sw extension in the late jurassic to cretaceous the normal faults formed during these episodes strongly influenced the distribution of emerging continents and sedimentary basins from the campanian 75 ma to the present the convergence of africa and eurasia involved the distribut on of stresses in the west european plate several tectonic episodes are distinguished in the massif central during the eocene approximately n s compression predominated general e w extension in the late eocene oligocene resulted in grabens with general northerly strike mainly in the centre of the massif central and on its east and southeast borders lastly compression varying from nw se to e w in the north and south of the massif central prevailed during the alpine orogenic phase at the end of the miocene these successive stages of brittle deformation are interpreted in the context of the evolution of the west european plate and its displacement in relation to the african plate the correspondences between the major geodynamic periods and the distribution of stresses over the west european continent are noted as well as the problems which remair to be resolved

subsidence analysis and modelling of the roer valley graben se netherlands abstract the roer valley graben southeastern netherlands forms the most northern branch of the european cenozoic rift system sedimentary backstripping of exploration wells provides control on vertical tectonic motions during the complex post paleozoic geodynamic evolution of the area the roer valley graben evolved by repeated reactivation of permo carboniferous fracture systems at least three episodes of extension related subsidence are recorded these occurred during the late permian early triassic 255 240 ma the middle jurassic 168 165 ma and the late cenozoic 36 0 ma a late jurassic early cretaceous stretching phase is weakly inferred from incomplete data crustal stretching values calculated from the tectonic subsidence curves can account for the reflection seismic controlled crustal configuration of the roer valley graben area results demonstrate a close relationship between the roer valley graben and the basins in the north sea during the mesozoic in contrast the cenozoic evolution of the roer valley graben is independent from that of the north sea and is related to the development of the rhine graben

thermal maturity and petroleum kitchen areas of liassic black shales lower jurassic in the central upper rhine graben germany in the central upper rhine graben urg several major oil fields have been sourced by liassic black shales in particular the posidonia shale lias e lower toarcian acts as excellent and most prominent source rock in the central urg this study is the first comprehensive synthesis of liassic maturity data in the urg area and sw germany the thermal maturity of the liassic black shales has been analysed by vitrinite reflectance vrr measurements which have been verified with t max and spore coloration index sci data in outcrops and shallow wells 600 m the liassic black shales reached maturities equivalent to the very early or early oil window ca 0 50 0 60 vrr this maturity is found in liassic outcrops and shallow wells in the entire urg area and surrounding swabian jura mountains maximum temperatures of the posidonia shale before graben formation are in the order of 80 90 c these values were likely reached during late cretaceous times due to significant upper jurassic and minor cretaceous deposition and influenced by higher heat flows of the beginning rift event at about 70 ma in this regard the consistent regional maturity data vrr t max sci of 0 5 0 6 vrr for the posidonia shale close to surface suggest a major burial controlled maturation before graben formation these consistent maturity data for liassic outcrops and shallow wells imply no significant oil generation and expulsion from the posidonia shale before formation of the urg a detailed vrr map has been created using vrr values of 31 wells and outcrops with a structure map of the posidonia shale as reference map for a depth dependent gridding operation highest maturity levels occur in the area of the rastatt trough ca 1 5 vrr and along the graben axis with partly very high vrr gradients e g well scheibenhardt 2 in these deep graben areas the maximum temperatures which were reached during upper oligocene to miocene times greatly exceed those during the cretaceous

recent crustal movements in the southern black forest western germany precise levelling data are examined in the southern black forest massif by comparing them analytically along levelling profiles instead of generalizing regional vertical motion trends the method emphasizes the current activity of accurately located individual structural elements measured recent crustal movement rates range from 0 2 to 1 1 mm year for the 1930 1961 1972 period the inferred motions corresponding to aseismic fault creep based on the near infrared band image of a landsat mss scene a lineament map of the study area is compared with the recent crustal movement rcm map the upper rhine graben eastern border fault between badenweiler and freiburg displays the highest rcm these displacements are consistent with the geological motion and the topographic expression of that structure within the massif both the lineament map and the rcm map demonstrate the predominant role played by wnw ese to nw se striking structures in accommodating the deformation moreover with the seismic dislocations in the southern black forest taking place also mainly on n120 and n20 faults it is most probable that these active structures are deep reaching zones of crustal weakness to some extent seismicity and rcm appear however to be mutually exclusive in their spatial distribution the seismic black forest flexure and dinkelberg block being opposed to the aseismically moving eastern and northern parts of the study area

the stromboli volcano landslides of december 2002 a seismological description 1 we analyse seismograms of the slump episodes at stromboli on december 30 2002 using a simple single force model we estimate the volume involved in the individual subevents and attempt a chronological reconstruction of the whole process our results indicate the occurrence of two main events that could be interpreted as a submarine slump which caused the observed tsunami and a subaerial slump which did not produce destructive sea waves a total volume of about 20 106 m3 results for the submarine event which developed over about 2 minutes with several distinct detachments the first and largest displacing a volume of 10 8 106 m3 the second subaerial slump involved at least 2 5 106 m3 in about 90 s a large long period pulse is also recognizable in the seismograms of the stromboli station we tentatively interpret this feature as tilt caused by the water load associated with the inundation in the ficogrande area on the northeastern side of the island

seismic stratigraphy of the post breakup succession offshore northeast greenland links to margin uplift abstract the timing of the continental breakup between norway and greenland and the subsequent plate tectonic motions are well understood however due to the remote location of the northeast greenland shelf relatively few details about the tectonosedimentary response to the tectonism following the breakup have previously been published this article gives new insights into the structural and sedimentary history of the northeast greenland shelf with an emphasis on the post breakup tectonics using state of the art 2d seismic data the results of this study clearly shows a highly dynamic post breakup tectonic setting with pronounced kilometre scale fault offsets tilting of the danmarkshavn basin and pronounced progradational events the tectonosedimentary events are linked with the passage of the icelandic mantle plume south of the northeast greenland shelf based on tectonostratigraphic interpretations and integration of data from odp 913 this study constructs a temporally robust model for the post breakup succession significant post breakup uplift and tectonism related to thermal uplift is present on the margin it is observed that the icelandic hot spot passes relatively close by the northeast greenland shelf

subduction triggered magmatic pulses a new class of plumes article i nfo a variety of atypical plume like structures and focused upwellings that are not rooted in the lower mantle have recently been discussed and seismological imaging has shown ubiquitous small scale convection in the uppermost mantle in regions such as the mediterranean region the western us and around the western pacific we argue that the three dimensional return flow and slab fragmentation associated with complex oceanic subduction trajectories within the upper mantle can generate focused upwellings and that these may play a significant role in regional tectonics the testable surface expressions of this process are the outside arc alkaline volcanism topographic swell and low velocity seismic anomalies associated with partial melt using three dimensional simplified numerical subduction models we show that focused upwellings can be generated both ahead of the slab in the back arc region though five times further inward from the trench than arc volcanism and around the lateral edges of the slab in the order of 100 km away from slab edges vertical mass transport and by inference the associated decompression melting in these regions appears strongly correlated with the interplay between relative trench motion and subduction velocities the upward flux of material from the depths is expected to be most pronounced during the first phase of slab descent into the upper mantle or during slab fragmentation we discuss representative case histories from the pacific and the mediterranean where we find possible evidence for such slab related volcanism

compression and right lateral strike slip movement at the southern hunsruck borderfault southwest germany abstract compressional tectonic structures have been known from the southern hunsruck borderzone since the end of the last century in the western part of the borderzone the saar nahe syncline is upthrown whereas in the eastern part the hunsruck is upthrown against the saar nahe syncline folds with axes parallel and oblique to the 60 trending fault zone have been described in the past in the area between idar oberstein and kirn permian lava sheets are displaced in such a way that their recent distribution can be explained by a right lateral strike slip movement of 5 8 km the block of the saar nahe basin between the southern hunsruck borderfault and the saarbrucken anticline has been tilted to the ene since the late palaeozoic the transcurrent movement can only be related to the opening of the upper rhine graben ne sw and nne ssw trending folds in the rotliegend sediments are considered to be transpression structures related to strike slip movement in early tertiary times recent seismicity along the southern hunsruck borderzone indicates that this zone is still active

high resolution imaging of the pyrenees and massif central from the data of the pyrope and iberarray portable array deployments the lithospheric structures beneath the pyrenees which holds the key to settle long standing controversies regarding the opening of the bay of biscay and the formation of the pyrenees are still poorly known the temporary pyrope and iberarray experiments have recently filled a strong deficit of seismological stations in this part of western europe offering a new and unique opportunity to image crustal and mantle structures with unprecedented resolution here we report the results of the first tomographic study of the pyrenees relying on this rich data set the important aspects of our tomographic study are the precision of both absolute and relative traveltime measurements obtained by a nonlinear simulated annealing waveform fit and the detailed crustal model that has been constructed to compute accurate crustal corrections beneath the massif central the most prominent feature is a widespread slow anomaly that reflects a strong thermal anomaly resulting from the thinning of the lithosphere and upwelling of the asthenosphere our tomographic images clearly exclude scenarios involving subduction of oceanic lithosphere beneath the pyrenees in contrast they reveal the segmentation of lithospheric structures mainly by two major lithospheric faults the toulouse fault in the central pyrenees and the pamplona fault in the western pyrenees these inherited hercynian faults were reactivated during the cretaceous rifting of the aquitaine and iberian margins and during the cenozoic alpine convergence therefore the pyrenees can be seen as resulting from the tectonic inversion of a segmented continental rift that was buried by subduction beneath the european plate

european cenozoic rift system abstract the european cenozoic rift system extends from the coast of the north sea to the mediterranean over a distance of some 1100 km it finds its southern prolongation in the valencia trough and a plio pleistocene volcanic chain crossing the atlas ranges development of this mega rift was paralleled by orogenic activity in the alps and pyrenees major rift domes accompanied by subsidence reversal of their axial grabens developed 20 40 ma after beginning of rifting uplift of the rhenish shield is related to progressive thermal lithospheric thinning the vosges black forest and the massif central domes are probably underlain by asthenoliths emplaced at the crust mantle boundary evolution of this rift system is thought to be governed by the interaction of the eurasian and african plates and by early phases of a plate boundary reorganization that may lead to the break up of the present continent assembly

seismic refraction investigation of the black forest abstract within the framework of site surveys of the deep continental drilling program ktb deep seismic sounding experiments were carried out in the black forest southwest germany in august 1984 these site surveys comprised seismic refraction as well as seismic reflection measurements this paper will concentrate on the interpretation of the refraction data which were observed along a 240 km long line approximately following the morphological axis of the black forest in a n s direction and extending in the south into the swiss molasse basin from the available seismic refraction data a detailed velocity depth model of the crust and uppermost mantle was derived a clear phase refracted in the basement with a velocity of 5 9 km s is observed for all shots this phase is followed by a reflection from the upper boundary of a low velocity zone this zone is very accentuated under the northern and central black forest and is characterized by a velocity decrease from 6 2 to 5 4 km s between depths of about 8 and 14 km towards the south the velocity inversion gradually loses its intensity under the center of the southern black forest velocities of about 6 km s prevail throughout the upper crust the lower crust which starts at the lower boundary of the low velocity zone shows a very complicated response in the record sections due to long reverberations between travel times of 1 5 3 5 s reduced by 6 0 km s at an epicentral distance of approximately 30 70 km a classical phase correlation is not possible based on a combined interpretation of near angle and wide angle reflection data the lower crust is characterized by a stack of thin layers with alternating high and low velocities the average velocity of the laminated zone is 6 7 km s the reflection from the moho at a depth of 25 26 km is the most prominent phase at epicentral distances greater than 60 km

u pb dating of geodic calcite new insights on western europe major tectonic events and associated diagenetic fluids this study presents the first application of the u pb dating method to highly pb depleted diagenetic geodic calcites of the jurassic formations of the paris basin that leads to a reappraisal of the palaeohydrological history of this region composite u pb ages from multiple geodes combined with 18 o analyses reveal two main phases of diagenetic fluid circulations linked with major regional tectonic events dogger formations recorded a first diagenetic fluid episode at 147 8 3 8 ma i e at the very beginning of the emersion of the basin during the tithonian period and 30 ma earlier than previously assumed 18 o results confirmed that most of the calcitic cement phases that closed the porosity of these formations precipitated at the beginning of the cretaceous period oxfordian formations recorded another major meteoric fluid circulation at 33 5 2 8 ma related to the initial stage of the european cenozoic rift system ecris consequently the porosity of the mesozoic formations of the studied area may have been closed sooner than previously thought before the main ecris rifting phase of oligocene age this study shows that u pb dating of secondary geodic calcite offers a new powerful way for reconstructing the coupled palaeohydrological and diagenetic history of sedimentary basins supplementary material pb pb diagrams 238 u and 235 u series isochron diagrams and effect of blank correction on u and pb isotopic compositions and on ages calculation are available at https doi org 10 6084 m9 figshare c 3886885

a three dimensional crustal model of southwest germany derived from seismic refraction data abstract from densely covered seismic refraction data obtained in 1978 urach experiment and 1984 schwarzer zollern wald experiment and from seismic reflection data and results from previous refraction investigations a three dimensional crustal model of southwest germany was derived travel time and amplitude information of seismic refraction data were interpreted with two dimensional forward modeling ray tracing to calculate two crustal cross sections in southwest germany these results fill a gap in the existing data and enabled the construction of a detailed three dimensional crustal model while seismically the upper crust is laterally homogeneous 5 9 6 0 km s throughout the area the middle and lower crust show pronounced lateral variations in thickness velocity and reflectivity the moho is a flat surface at a relatively shallow depth 25 26 km we classify the middle and lower crust of southwest germany into two characteristic crustal types type i consists of a mid crustal low velocity zone 5 4 5 8 km s overlying a thick 10 km high velocity 6 6 6 8 km s lower crust type ii has no prominent mid crustal low velocity zone and a thin

thermochronological evolution of an intra plate magmatic event inferred from an integrated modeling approach a case study in the westerwald germany abstract a lava sample from the tertiary westerwald volcanic field was selected for a detailed study using various analytical techniques in combination with petrological thermodynamic and diffusion modeling to extract information related to the thermochronological evolution of a magmatic event before eruption the lava sample contains large olivine phenocrysts which are compositionally zoned and two coexisting but chemically distinct melts a host melt with basaltic composition and small spherical pockets of a less abundant trachytic melt globules the sample was analyzed by electron microprobe x ray fluorescence xrf x ray diffraction xrd and electron backscatter diffraction ebsd the primary melt of the host lava was determined using the program primelt2 xls partial fractional crystallization of olivine was modeled using the program alphamelts timescale and cooling rate were retrieved by fitting the measured fe mg zoning along two directions in four olivine grains from the host lava using a 3 d numerical diffusion model the measured variation of ca is also consistent with a chemical diffusion process while a numerical growth model applied to the same olivines does not appear to explain the fe mg zoning chemical zoning of major elements in the melt globules were reproduced with a multicomponent diffusion model the results of this study show that the host magma fractionated about 9 of olivine in a first stage then the crystallization proceeded without further separation of mineral phases modeling of diffusion in the olivine crystals suggests that this second stage lasted at least 5 yrs and the temperature of the melt decreased from 1120 1150 c to 1090 c during this time according to the results of the multicomponent diffusion model applied to the melt globules the coexistence of the two melts was extremely short less than few hours possibly recording the assimilation of the globules during eruption or cooling of the whole system on the surface

cenozoic block rotation according to a conjugate shear system in central europe indications from palaeomagnetic measurements abstract results of palaeomagnetic measurements in the middle tertiary volcanic provinces of siebengebirge and westerwald northeastern rhenish massif germany indicate that block rotation of the northeastern rhenish massif of the order of 10 to 16 has occurred since the late oligocene contemporaneous subsidence in the upper rhine graben neuwied basin and lower rhine basin and intensive faulting in the hessian depression document a new period of intraplate tectonism in central europe in the tertiary presumably from the eocene to the miocene the axis of maximum horizontal stress rotated from the nne ssw to the nnw sse and the nw se direction respectively the new stress conditions may be responsible for the development of a conjugate shear system in central europe north of the alps a model of a conjugate shear system is presented a sinistral divergent strike slip fault extends ssw nne from the upper rhine graben to the north the fault splits up into two branches in the area of the hessian depression a conjugate dextral wrench fault system develops from the bavarian pfahl zone southeastern germany to the rhenish massif about 200 km to the northeast a parallel dextral strike slip fault is known from the southern lower saxony basin to the north of the osning zone and harz mountains the northeastern block of the rhenish massif was created between dextral strike slip faults the block began clockwise rotation presumably in the late oligocene due to small changes in direction of the maximum horizontal compressive stress from nnw to nw and contemporaneous extension of the western european crust to the southwest it is assumed that the block rotation is responsible for the v shaped opening of the lower rhenish basin and anticlockwise micro block rotation within the hessian depression opening between the rotating and nonrotating crust along the recent rhine river in the central part of the rhenish massif formed triangular transrotational basins basin of neuwied due to movements of crustal blocks in the western rhenish massif bounded by wnw ese dextral faults fault plane solutions from recent earthquakes in the rhine system support the model of block rotation and related crustal movements due to rotation of the northeastern rhenish massif the continuation of the upper rhine graben development to the north is prevented

a multi scale approach to study the lithospheric structure of the southern upper rhine graben from seismic tomography through reflection seismics to surface geology this paper integrates the results of different techniques local and regional travel time tomography reflection seismics and surface geology with this integration of different techniques working on different scales it is possible to derive a comprehensive picture of the present day structures in the lithosphere of the upper rhine graben it is shown that the stucture of the lithosphere is dominated by structures related to the variscan orogeny late stage strike slip reactivation of the internal faults of the rhine graben is observed in the field this reactivation is of dominant influence on the geomorphology in the southern end of the upper rhine graben

seismotectonic model for the earthquake swarm of 1985 1986 in the vogtland west bohemia focal area abstract after decades of minor seismic activity an intensive earthquake swarm occurred in 1985 1986 with a maximum activity in december 1985 and january 1986 in the well known narrow focal zone of swarm quakes in the border region of the g d r and czechoslovakia local seismic networks recorded more than 8000 events during this swarm the strongest local magnitude being 4 6 nearly all of these swarm events were located within a relatively small focal volume 3 5 km in length 1 5 km in width and at depths of 6 8 km fault plane solutions could be determined for 17 of the strongest events they provided the basis for seismotectonic modelling in connection with 1 detailed tectonic data including faults indicating conditions at the seismogenic depths and recent active faults 2 crustal stress data and 3 studies on recent horizontal movements of crustal micro blocks according to detailed local micro earthquake monitoring since 1962 all epicentral areas of swarms are aligned along the n153 e striking marianske lazn fault mlf which trends approximately in the azimuth of maximum compressive stress the mlf is intersected by a bundle of recent active lamellar n s to nne ssw fault elements the fault plane solutions of 14 of the events studied show strikes in this direction the others strike along the mlf tectonic evidence for the conjugate planes is lacking both the mlf and the n s fault elements show a tendency to dextral creep according to neotectonics and recent horizontal crustal movements whereas a generally sinistral elastic rebound has been derived for the focal process of the swarm this reflects alternating block movements which could also be deduced from repeated geodetic measurements probably the mlf system provides a suitable setting for the foci only whereas the faulting process itself occurs mainly on secondary faults within the system moreover a splay structure along the mlf immediately south of the 1985 1986 epicentral area and connected with a right stepping offset along a n s fault element substantiates the proneness to the occurrence of swarm like seismic activity

estimation of small surface displacements in the upper rhine graben area from a combined analysis of ps insar levelling and gnss data the intra plate deformation of the upper rhine graben urg located in central europe is investigated using geodetic measurement techniques we present a new approach to calculate a combined velocity field from insar levelling and gnss measurements as the expected tectonic movements in the urg area are small less than 1mma 1 the best possible solutions for linear velocity rates from single technique analyses are estimated in a first step second we combine the velocity rates obtained from insar line of sight velocity rates in ascending and descending image geometries levelling vertical velocity rates and gnss horizontal velocity rates using least squares adjustment lsa focusing on the northern urg area we analyse sar data on four different image stacks ers ascending ers descending envisat ascending envisat descending using the persistent scatterer ps approach the linear velocity rates in ascending and descending image geometries respectively are estimated in an lsa from joint time series analysis of ers and envisat data vertical velocity rates from levelling are obtained from a consistent adjustment of more than 40 000 measured height differences using a kinematic displacement model horizontal velocity rates in east and north direction are calculated from a time series analysis of daily coordinate estimates at 76 permanently operating gnss sites in the urg region as the locations at which the measurement data of ps insar levelling and gnss reside do not coincide spatial interpolation is needed during several steps of the rigorous processing we use ordinary kriging to interpolate from a given set of data points to the locations of interest with a special focus on the modeling and propagation of errors the final 3 d velocity field is calculated at a 200 m grid which carries values only close to the location of ps points resulting in a mean horizontal and vertical precision of 0 30 and 0 13 mm a 1 respectively the vertical component of the combined velocity field shows a significant subsidence of about 0 5 mm a 1 in the northern part of the graben coinciding with a well known quaternary basin structure horizontal displacement rates of up to 0 8 mm a 1 in southeast direction are observed outside the graben in reasonable alignment with the average direction of maximum horizontal stress within the graben the velocity directions rotate toward east in the non subsiding part while an opposite trend is observed in the subsiding part of the graben the complexities of the observed velocity field are compatible to the geomechanical situation in our investigation area which is characterized by a transition from a restraining to a releasing bend setting glacial isostatic adjustment is another potential source influencing the observed velocity field as well as anthropogenic signals due to mining oil exploration and groundwater usage that have been identified in some places

towards the determination of displacements in the upper rhine graben area using gps measurements and precise antenna modelling abstract the upper rhine graben is a north northeast trending rift system which belongs to the european cenozoic rift system today the southern part of the graben is seismically still active earthquakes of magnitude 5 have a recurrence time of approximately 30 years the eucor urgent project focuses on the seismic hazards and neotectonics in the upper rhine graben and the surrounding areas within the framework of this project five institutions have created and have been maintaining a gps network in the upper rhine graben and the surrounding area in order to monitor horizontal and vertical displacements in the study area two gps campaigns have been carried out in the network to monitor and to determine the horizontal and vertical displacements in the study area the first one was observed in 1999 and the second one in 2000 in 2002 2 weeks of data of the available permanent gps reference stations in the area have also been included in the investigations these permanent stations belong to the european reference frame permanent network international gps service network satellite positioning service of baden wurttemberg reseau gps permanent france rgp reseau gps permanent dans les alpes regal and the agnes operated by the swiss positioning service due to the small size of the displacements expected high accuracy requirements must be met in the gps processing in order to achieve this the results of the available absolute antenna calibrations have been considered in the data processing too the results have shown that the application of absolute antenna calibration models is crucial for the derivation of a highly accurate displacement field without these models large discrepancies on the level of few centimetres can be observed at those stations where the observations were carried out by different antennas in the various campaigns as expectedly due to the short time span no significant displacement could be detected in the study area however the deformation analysis shows that the horizontal displacements do not exceed the level of 1 mm yr this value agrees with the results of other investigations

styles of extension in the pannonian basin abstract structural interpretation of reflection seismic profiles reveals distinct modes of upper crustal extension in the pannonian basin while some subbasins in the pannonian basin complex show little extension planar rotational normal faults others are characterized by large magnitude of extension detachment faults metamorphic core complexes gravitational collapse of the intra carpathian domain combined with subduction zone roll back is thought to be the driving mechanism of the neogene back arc extension the very heterogeneously distributed extension is accommodated by transfer faults which bound regions characterized by different polarity direction or amount of extension in cross section these transfer faults are characterized by flower structures typical for strike slip faults seismic stratigraphic interpretations indicate that the non marine post rift sedimentary fill of the pannonian basin can be described in terms of sequence stratigraphy the exceptionally good seismic sequence resolution allows recognition of third order and also fourth order depositional sequences which may reflect the interplay of tectonics and eustasy and milankovitch scale climatic variations respectively

the role of precursory structures on tertiary deformation in the black forest hegau region structural inheritance of preexisting crustal discontinuities is widely accepted to have played a crucial role during the cenozoic tectonic evolution of the northern alpine foreland it is recognised as a process that can strongly influence local fault kinematics and strain patterns the case study presented herein is dedicated to the tectonic analysis of the freiburg bonndorf bodensee fault zone fbbfz located at the external margin of the northern alpine molasse basin and extending into the crystalline black forest massif the structure and kinematics of this crustal scale fault zone are investigated by means of a regional analysis of locally mapped faults kinematic analysis of outcrop scale fractures and slip vector modelling the exceptional possibility of analysing the fault zone exposed from basement to cover allowed for an evaluation of interaction between precursory structures and subsequent deformation features the results of this study show that the crystalline basement structures exposed along the fbbfz had a strong imprint on the map scale fault pattern observable in the mesozoic and tertiary sequences kinematic analysis of outcrop scale fracture systems in the latter units yields evidence for local multi directional extension and strike slip faulting during miocene to recent times while these observations may evoke the interpretation of a multistage palaeostress history along the fbbfz slip vector modelling of a very well exposed fbbfz segment suggests that the various strain records can alternatively be explained by one single regional stress tensor and be related to superordinate deep seated strike slip deformation

the deep thermal field of the glueckstadt graben with this paper we assess the present day conductive thermal field of the glueckstadt graben in nw germany that is characterized by large salt walls and diapirs structuring the graben fill we use a finite element method to calculate the 3d steady state conductive thermal field based on a lithosphere scale 3d structural model that resolves the first order structural characteristics of the graben and its underlying lithosphere model predictions are validated against measured temperatures in six deep wells our investigations show that the interaction of thickness distributions and thermal rock properties of the different geological layers is of major importance for the distribution of temperatures in the deep subsurface of the glueckstadt graben however the local temperatures may result from the superposed effects of different controlling factors especially the upper sedimentary part of the model exhibits huge lateral temperature variations which correlate spatially with the shape of the thermally highly conductive permian salt layer variations in thickness and geometry of the salt cause two major effects which provoke considerable lateral temperature variations for a given depth 1 the chimney effect causes more efficient heat transport within salt diapirs as a consequence positive thermal anomalies develop in the upper part and above salt structures where the latter are covered by much less conductive sediments in contrast negative thermal anomalies are noticeable underneath salt structures 2 the thermal blanketing effect is caused by thermally low conductive sediments that provoke the local storage of heat where these insulating sediments are present the latter effect leads to both local and regional thermal anomalies locally this translates to higher temperatures where salt margin synclines are filled with thick insulating clastic sediments for the regional anomalies the cumulative insulating effects of the entire sediment fill results in a long wavelength variation of temperatures in response to heat refraction effects caused by the contrast between insulating sediments and highly conductive crystalline crust finally the longest wavelength of temperature variations is caused by the depth position of the isothermal lithosphere asthenosphere boundary defining the regional variations of the overall geothermal gradient we find that a conductive thermal model predicts observed temperatures reasonably well for five of the six available wells whereas the steady state conductive approach appears not to be valid for the sixth well

the deep crust of the southern rhine graben reflectivity and seismicity as images of dynamic processes abstract the rhine graben part of the european cenozoic rift system deserves special attention because of its location in the foreland of the alpine orogen the phanerozoic evolution of the lithosphere in this region is defined by a set of major geodynamic events ranging from the variscan orogeny late orogenic crustal re equilibration to the interference of rifting and alpine orogeny in tertiary times the rhine graben is one of the most detailedly studied continental grabens prospecting for hydrocarbons in its sedimentary fill and intensive pre site studies for the continental deep drilling program ktb on its eastern crystalline flank black forest provided a comprehensive set of geoscience data seismic investigations ranging from a deep seismic network of near vertical reflection to concurrent wide angle refraction experiments were accompanied by seismological and geological surveys therefore a direct observational comparison between the two depth definitions of crustal subdivisions elastic vs strength rheological was possible in large parts of western europe deep seismic sounding dss investigation distinguishes between a crystalline upper crust of comparatively low p wave velocities 5 9 6 0 km s with little and discrete reflectivity and a strongly reflective lower crust with higher p wave velocities about 6 4 6 8 km s both are separated by the conrad discontinuity in contrast strength and rheological considerations define a brittle upper crust and a ductile lower crust the boundary between these two realms is usually referred to as the brittle ductile transition zone which in seismically active regions is imaged by the deepest crustal hypocentres the present brittle ductile transition in the rhine graben region as defined by the deepest hypocentres does not necessarily coincide with the structural separation in an upper and lower crust as seen in deep seismic studies this suggests that the laminated lower crust developed during the crustal re equilibration phase at the end of the variscan orogeny the second part of this paper concentrates on evidence of recent tectonic activities related to rifting processes impacting on the variscan lower crust a remarkable concentration of deep crustal earthquakes reaching to the top of an asymmetrical thinned lower crust is observed at or near the eastern border fault of the southern rhine graben and is possibly induced by the young rifting process we suggest that this asymmetry could be a consequence of the uppermost mantle detaching from the upper crust in collision with the alpine orogen this allows us to propose the distinction between the influence of compression extension continental subduction and intra crustal detachment during graben formation the dynamic interference of rifting and foreland compression shown by structural and seismological observations leads to the notion of small scale collisional escape tectonics associated with an intra continental transform fault at the southern end of the rhine graben the rhine sao ne transform zone

interactions between thin and thick skinned tectonics at the northwestern front of the jura fold and thrust belt eastern france 1 this study investigates spatial and temporal interactions of thin and thick skinned tectonics in a classical foreland setting located at the front of the jura fold and thrust belt in eastern france the working area coincides with the intracontinental rhine bresse transfer zone and represents the most external front of the deformed alpine foreland the investigation combines analyses of largely unpublished and newly available subsurface information with our own structural data including an exhaustive paleostress analysis and geomorphologic observations results are provided in the form of a new tectonic map and a series of regional cross sections through the study area the besancon zone forming the most external part of the thin skinned fold and thrust belt encroached onto the eo oligocene rhine bresse transfer fault system until early pliocene times thrust propagation was largely controlled by the late paleozoic to paleogene preexisting fault pattern that characterizes the rhine bresse transfer zone thick skinned deformation dominant throughout the avant monts zone located farther to the west was associated with compressional to transpressional reactivation of such faults overprinting and crosscutting criteria of fault slip data allow distinguishing between systematically fanning maximum horizontal stress axes that define the front of the thin skinned jura fold and thrust belt and consistently nw se directed maximum horizontal stress axes that characterize deformation of the autochthonous cover of the foreland which is affected by thick skinned tectonics tectonic and geomorphic analyses indicate that thick skinned tectonics started at a very late stage of foreland deformation post early pliocene geomorphic observations imply that deformation between mesozoic cover and basement is locally still decoupled however overprinting relationships and recent seismicity suggest that present day tectonic activity is thick skinned which probably reflects ongoing tectonic underplating in the alpine foreland

deep crustal structure of the rhine graben from dekorp ecors seismic reflection data a summary abstract results of two deep reflection seismic lines crossing the northern and southern part of the rhine graben which were recorded in 1988 by the french ecors and the german dekorp teams indicate that the asymmetry of this rift persists to the base of the crust the brittle ductile transition zone approximately coincides with the top of the lower crust ductile shear zones appear to affect the crust mantle boundary upper crustal extension by faulting accounts for a divergence of the graben flanks by 5 7 km whereas the crustal configuration of the rhine graben suggest an extension value of some 17 km

asthenospheric flow and origin of volcanism in the baikal rift area the origin of low volume hotspot like volcanism often observed in continental rift areas is debated as is the nature of the flow in the mantle beneath in this paper we assemble seismic constraints on the mantle flow below the baikal rift zone we combine new evidence from upper mantle tomography and from a radially anisotropic shear velocity profile measured beneath and se of the rift with published shear wave splitting constraints on azimuthal anisotropy fast directions of azimuthal anisotropy are perpendicular to the rift on both of its sides stable siberian platform lithosphere on the northern side extends down to 200 km on the southern side the lithosphere is only 60 70 km thick this asymmetry with the thick cratonic root forming a barrier to convective flow inhibits a mid ocean ridge like flow pattern the radially anisotropic profile yields evidence for horizontal flow in the upper asthenosphere 60 100 km se of the rift but no evidence for vertical flow these results are consistent with horizontal asthenospheric flow nw to se perpendicular to the rift from beneath the thick siberian towards the thin baikal mongolian lithosphere when asthenosphere ascends from the 200 km depth beneath the craton to shallower depths beneath the rift decompression melting of embedded veins of enriched rock can produce the hotspot like basaltic volcanism observed the occurrence of such veins of enriched mantle in sub cratonic asthenosphere has been predicted by geochemical mantle models we propose that sub horizontal asthenospheric flow from beneath cratons is a common cause for hotspot like volcanism in continental rift zones

structural control of geothermal reservoirs in extensional tectonic settings an example from the upper rhine graben abstract in extensional tectonic settings major structural elements such as graben boundary faults are typically oriented subparallel to the maximum horizontal stress component shmax they are often structurally accompanied by transfer zones that trend subparallel to the extension direction in the upper rhine graben such transfer faults are typically characterized by strike slip or oblique slip kinematics a major re orientation of the regional stress field by up to 90 of the upper rhine graben in the early miocene led to the present day normal and strike slip faulting regimes in the north and south of the upper rhine graben respectively and a transition zone in between consequently conditions for fault frictional failure changed significantly moreover it has been observed during tracer and stimulation experiments that such transfer faults may be of major importance for the hydraulic field of geothermal reservoirs under the present stress condition especially when located between production and injection well in this context we have investigated slip and dilation tendencies ts and td of major structural elements at reservoir scale for two representative geothermal sites bruchsal germany and riehen switzerland located close to the eastern main boundary fault of the upper rhine graben we have evaluated the quality and uncertainty range of both tendencies with respect to potential variation in shmax orientation despite significant differences in orientation of the structures and the stress regimes the resulting variation of ts and td reveal major similarities concerning the reactivation potential of both the graben parallel structures and the transfer faults the conditions of criticality for tensile failure and non criticality for shear failure suggest that transfer faults are most likely naturally permeable structures with low stimulation potential this is in agreement with the absence of both immediate tracer recovery and seismicity in the studied geothermal sites

the valencia trough western mediterranean an overview abstract the valencia trough located between the spanish mainland and the balearic islands corresponds to a late oligocene to recent sedimentary basin that is characterized by a highly attenuated continental crust its northwestern part evolved in response to a late oligocene to early miocene rifting phase that was followed by a period of post rift subsidence and a late miocene pleistocene phase of renewed crustal extension and magmatism its southeastern part is characterized by late oligocene to mid miocene compressional deformation and subsequent extension in the axial parts of the basin the crust has been thinned by a factor of 3 whereby the lower crust is either absent or very thin upper crustal extension appears to be considerably smaller than indicated by the crustal configuration of the basin a major problem in understanding the evolution of the valencia trough is the lack of knowledge about the physical state and structure of the lithosphere before late oligocene extension evolution of the northwestern part of the basin appears to be linked with the development of the oceanic provencal basin middle miocene compressional deformation of the balearic fold belt forming the southeastern margin of the valencia trough appears to have interfered with the tensional evolution of the latter which only resumed after crustal shortening in the balearic domain had given way to extensional tectonics during the late miocene

tsunamis as geomorphic crises lessons from the december 26 2004 tsunami in lhok nga west banda aceh sumatra indonesia abstract large tsunamis are major geomorphic crises since they imply extensive erosion sediment transport and deposition in a few minutes and over hundreds of kilometres of coast nevertheless little is known about their geomorphologic imprints the december 26 2004 tsunami in sumatra indonesia was one of the largest and deadliest tsunamis in recorded human history we present a description of the coastal erosion and boulder deposition induced by the 2004 tsunami in the lhok nga bay located to the west of banda aceh northwest sumatra the geomorphological impact of the tsunami is evidenced by beach erosion some beaches have almost disappeared destruction of sand barriers protecting the lagoons or at river mouths numerous erosion escarpments typically in the order of 0 5 1 5 m when capped by soil and more than 2 m in dunes bank erosion in the river beds the retreat along the main river is in the order of 5 15 m with local retreats exceeding 30 m large scars typically 20 50 cm deep on slopes dislodgement of blocks along fractures and structural ramps on cliffs the upper limit of erosion appears as a continuous trimline at 20 30 m a s l locally reaching 50 m the erosional imprints of the tsunami extend to 500 m from the shoreline and exceed 2 km along riverbeds the overall coastal retreat from lampuuk to leupung was 60 m 550 000 m 2 and locally exceeded 150 m over 276 000 m 3 of coastal sediments were eroded by the tsunami along the 9 2 km of sandy coast the mean erosion rate of the beaches was 30 m 3 m of coast and locally exceeded 80 m 3 m the most eroded coasts were tangent to the tsunami wave train which was coming from the southwest the fringing reefs were not efficient in reducing the erosional impact of the tsunami the 220 boulders measured range from 0 3 to 7 2 m large typically 0 7 1 5 m with weights from over 50 kg up to 85 t we found one boulder less than 1 m large at 1 km from the coastline but all the others were transported less than 450 m 30 m and the moderate tsunamis height

palaeoenvironmental reconstructions during the meso to neolithic transition 9 2 5 3 cal ka bp in northwestern france palynological evidences sedimentological palynological and micropalaeontological studies carried out throughout the first half of the holocene during the mesolithic neolithic transition in the bay of brest i e 9200 9