tomography study of the upper mantle around the tesz based on passeq experiment data abstract we present a detailed velocity perturbation model of the earth s upper mantle in the area around the trans european suture zone tesz imaged by the teleseismic tomography the model is based on 12473 p wave arrival times measured on recordings of 273 stations of the passive seismic experiment passeq which was active during 2006 and 2008 station and teleseismic event distribution is sufficient to resolve the structure below the passeq array down to a depth of 350 km the velocity perturbation model clearly shows a 250 km thick uniform layer of positive velocity perturbations north east of the teisseyre tornquist zone ttz and 150 km thick layer south west of the ttz characterized by relatively lower velocity perturbations the former we associate with the precambrian mantle lithosphere of the european plate while the latter represents the much younger phanerozoic lithosphere in the uppermost layer of the model 40 km the boundary between the two regions closely follows the crustal trace of the ttz in deeper layers the boundary shifts south westward at a depth of approximately 120 km the region with positive perturbations reaches the northern part of the bohemian massif bm the shift suggests that the phanerozoic part of the european plate thrusts over the precambrian lithosphere the upper mantle below a depth of 250 km lacks the pronounced division between the two regions around the tesz which allows us to associate these depths with asthenospheric part of the upper mantle

is the teisseyre tornquist zone an ancient plate boundary of baltica the teisseyre tornquist zone ttz is generally regarded as a fossil plate boundary in europe that extends 2000 km from the baltic sea to the black sea we used an integrated approach merging potential fields and seismic data to explore crustal architecture across the ttz in central poland the aim of the study was to test whether the ttz coincides with an early paleozoic caledonian suture formed through the closure of the tornquist ocean along the sw baltica margin the suture is presumed to separate the east european craton eec from the paleozoic terranes of western europe two seismic reflection lines from the polandspan experiment were used to image the deep structure at the sw margin of the eec lines pl 5300 and pl 5400 run ne sw in central and northern poland respectively the seismic interpretation down to top of basement was integrated with 2 d gravity and magnetic modeling to highlight the structure of the deep crust both the gravity and magnetic models show a suture that welds together two blocks at the base of crust however top of basement above the suture dips uniformly to the sw and is overlain by undisturbed lower paleozoic and younger sediments by implication the suture must have developed in the precambrian and both crustal blocks amalgamated belong to the eec consequently the caledonian suture formed by the closure of the tornquist ocean between avalonia and baltica must be located farther southwest beneath thick upper paleozoic and mesozoic sediments

three dimensional seismic modelling of crustal structure in the tesz region based on polonaise 97 data abstract this paper reports the results of 3 d tomographic modelling of crustal structure in the trans european suture zone region tesz of poland eastern germany and lithuania the data are the product of a large scale seismic experiment polonaise 97 which was carried out in 1997 this experiment was designed to provide some 3 d coverage the tesz forms the boundary between the precambrian crustal terranes of the east european craton eec and the younger phanerozoic terranes to the southwest the 3 d results generally confirm the earth models derived by earlier 2 d analyses but also add some important details as well as a 3 d perspective on the structure the velocity model obtained shows substantial horizontal variations of crustal structure across the study area seismic modelling shows low

deep seismic reflection profile in central europe reveals complex pattern of paleozoic and alpine accretion at the east european craton margin 1 the first deep reflection seismic profile was acquired across the teisseyre tornquist zone ttz a major european suture zone southeast of the avalonia baltica collision zone portraying different tectonic deformation styles thick versus thin skinned and phanerozoic crustal accretion episodes over a relatively short distance 240 km the overall crustal structure preserves image of the neoproterozoic passive margin setting but with a significant overprint of the repetitive tectonic convergence cadomian to alpine acting at the baltica margin in contrast to the avalonia baltica collision zone here the polygenetic crustal accretion occurring at the cratonic margin was ultimately shaped by significant strike slip faulting ttz is imaged as a narrow 10 15 km transform zone separating the thinned east european cratonic crust from the malopolska block

thermochronology erosion surfaces and missing section in west greenland abstract in central west greenland palaeogene volcanic sequences deposited during post rift subsidence are exposed in mountains reaching 2 km above sea level a s l with palaeocene marine deposits within this section at elevations up to 1 2 km a s l this clearly shows that present day elevated topography of the west greenland margin is not a remnant of the rifting process but developed later integrating such geological constraints with landscape analysis and thermochronological data shows that mountain summits in central west greenland represent an oligocene miocene peneplain which is the counterpart of a correlative unconformity offshore separating eocene from middle miocene sedimentary units onshore the peneplain has been exhumed uplifted to its present altitude and progressively dissected since the late miocene redfield journal of the geological society london 167 261 271 2010 questioned numerous aspects of this interpretation suggesting that the aft model based hypothesis that the elevated topography of west greenland was constructed in purely neogene time remains an unproven speculation9 but as we illustrate here evidence for neogene uplift is provided by landscape analysis and geological evidence as well as thermochronology and integration of these independent lines of investigation provides a consistent synthesis that we regard as highly reliable the resulting history of episodic burial and exhumation cannot be simply dismissed and poses a major challenge to accepted tectonic and geomorphological models for the development of rifted continental margins how do mountains form along passive continental margins millions of years after rifting and breakup

upper crustal seismic structure of the mazury complex and mazowsze massif within east european craton in ne poland the large scale seismic experiment polonaise 97 polish lithospheric onsets an international seismic experiment was carried out in may 1997 in poland lithuania and germany its main purpose was to investigate the structure of the crust and the uppermost mantle in the region of the trans european suture zone tesz that lies between the east european craton eec and the palaeozoic platform this paper covers the interpretation of seismic data along the nw se trending 180 km long profile p5 located on the eec the recordings were of a high quality with seismic energy clearly visible along the whole profile we have not found waves refracted below the upper crust in first arrivals in the nw part of the profile we have delineated a high velocity body with the p wave velocity in the range of 6 5 6 75 km s in the upper crust it corresponds to the ketrzyn anorthosite massif within the mazury complex the mazowsze massif is rather uniformly characterized by p wave velocities 5 9 6 05 and 6 2 6 35 km s in two layers respectively sufficient s wave data were available to estimate the vp vs ratio as well as the poisson ratio being 1 80 0 277 in the high velocity body and 1 67 0 220 in the upper crust apart from the 2 d model along the profile results of 3 d modelling in the area of the p5 profile are presented using off line recordings we got p wave velocity field up to 8 km s below the p5 profile at the depth of about 40 km as well as horizontal extent of the high velocity body

reply to comment by m narkiewicz and z petecki on is the teisseyre tornquist zone an ancient plate boundary of baltica

electromagnetic images of the deep structure of the trans european suture zone beneath polish pomerania a large scale international electromagnetic experiment has been carried out in northwest poland and northeast germany the main goal was to study the deep conductivity structure across the trans european suture zone which is the most prominent tectonic structure of phanerozoic age in europe electromagnetic measurements were carried out mainly along seismic profiles p2 lt 7 and lt 2 crossing the suture zone and running in the northeastern direction strike and dimensionality analyses indicate that a geoelectrical strike of n60 degrees w common to both profiles lt 7 and p2 can be estimated this strike direction was used to project and rotate all transfer functions and both profiles were subjected to 2d inversion using three different approaches the results show the presence of highly conductive cenozoic mesozoic sedimentary cover reaching depths up to 3 km a significant conductivity anomaly beneath the central part of the tesz called the central polish anticlinorium has been well resolved at midcrustal depths the upper mantle of the precambrian east european craton is more resistive than adjacent to the west the younger paleozoic platform

palaeozoic amalgamation of central europe new results from recent geological and geophysical investigations abstract multidisciplinary studies of geotransects across the north european plain and southern north sea and geological reexamination of the variscides of the north bohemian massif permit a new 3 d reassessment of the relationships between the principal crustal blocks abutting baltica along the trans european suture zone tesz accretion was in three stages cambrian accretion of the bruno silesian lysogory and malopolska terranes end ordovician early silurian accretion of avalonia and early carboniferous accretion of the armorican terrane assemblage ata palaeozoic plume influenced metabasite geochemistry in the bohemian massif explains the progressive rifting away of peri gondwanan crustal blocks before their accretion to baltica geophysical data faunal and provenance information from boreholes and dated small inliers and cores confirm that avalonian crust extends beyond the anglo brabant deformation belt eastwards to northwest poland the location and dip of reflectors along the tesz and beneath the north european plain suggest that avalonian crust overrode the baltica passive margin marked by a high velocity lower crustal layer on shallowly southwest dipping thrust planes forming the heligoland pomerania deformation belt the variscan orocline of southwest poland masks two junctions between the armorican terrane assemblage ata and previously accreted crustal blocks to the east is a dextrally transpressive contact with the bruno silesian and malopolska blocks accreted in the cambrian while to the north is a thrust contact with easternmost avalonia deeply buried beneath younger sedimentary cover in the northeast bohemian and rhenohercynian massifs devonian early variscide deformation dominated by wnw and nw directed thrusting records closure of ordovician devonian seaways between detached islands of the ata and avalonia

numerical models of tectonic deformation at the baltica avalonia transition zone during the paleocene phase of inversion abstract predictions from dynamic modelling of the lithospheric deformation are presented for northern europe where several basins underwent inversion during the late cretaceous and early cenozoic and contemporary uplift and erosion of sediments occurred in order to analyse the evolution of the continental lithosphere the equations for the deformation of a continuum are solved numerically under thin sheet assumption for the lithosphere the most important stress sources are assumed to be the late cretaceous alpine tectonics localized rheological heterogeneities can also affect local deformation and stress patterns present day observations available in the studied region and coming from seismic structural interpretations and stress measurements have been used to constrain the model our modelling results show that lateral variation in lithospheric strength below the basin systems in central europe strongly controls the regional deformation and the stress regime furthermore we have demonstrated that the geometry of the boundary between baltica and avalonia together with different rheological characteristics of the two plates had a crucial role on local crustal deformation and faulting regime resulting in the baltica avalonia transition zone from the s n alpine convergence

lithospheric structure of the bohemian massif and adjacent variscan belt in central europe based on profile s01 from the sudetes 2003 experiment 1 the sudetes 2003 seismic experiment investigated the lithospheric structure of the eastern part of the variscan belt of central europe the key profile of this experiment s01 was 630 km long and extended southwestward from the margin of the east european craton across the trans european suture zone tesz and sudetes and across the bohemian massif that contains the active eger ohre rift which is an element of the european cenozoic rift system good quality first arrivals and later phases of refracted reflected p and s waves were interpreted using 2 d ray tracing techniques the derived seismic model shows large variations in the internal structure of the crust while the depth to the moho varies in the relatively narrow depth interval of 28 35 km except for the polish basin on the northeast end of the profile the sedimentary cover is thin the crystalline upper and middle crust with velocities of 5 9 6 4 km s 1 is about 20 km thick and the 7 10 km thick lower crust can be divided into three regions based on p wave velocities a low velocity region 6 5 6 6 km s 1 beneath eger rift and sudetes that is bounded on the southwest and northeast by regions of significantly higher velocity 6 8 7 1 km s 1 beneath the saxothuringian and moldanubian in the southwest and fore sudetic monocline and polish basin in the northeast high velocity bodies vp 6 5 km s 1 were delineated in the upper crust of the eger rift region the seismic structure along the s01 profile images a variscan orogenic wedge resting on the down warped margin of the plate margin containing the tesz this situation implies the northerly directed subduction of the rheic ocean that existed between the southern margin of the old red continent and the armorican terranes presently accreted into the variscan belt closure of this ocean produced the rheic suture between low velocity crust of the variscan orogenic wedge and higher velocity crust of the tesz

the mohorovicic discontinuity beneath the continental crust an overview of seismic constraints abstract the seismic signature of the moho from which geologic and tectonic evolution hypotheses are derived is to a large degree a result of the seismic methodology which has been used to obtain the image seismic data of different types passive source earthquake broad band recordings and controlled source seismic refraction densely recorded wide angle deep seismic reflection and normal incidence reflection using vibroseistm explosives or airguns have contributed to the description of the moho as a relatively complex transition zone of critical importance for the quality and resolution of the seismic image are the acquisition parameters used in the imaging experiments a variety of signatures have been obtained for the moho at different scales generally dependent upon bandwidth of the seismic source this variety prevents the development of a single universally applicable interpretation in this way source frequency content and source and sensor spacing determine the vertical and lateral resolution of the images respectively in most cases the different seismic probes provide complementary data that gives a fuller picture of the physical structure of the moho and its relationship to a petrologic crust mantle transition in regional seismic studies carried out using passive source recordings the moho is a relatively well defined structure with marked lateral continuity the characteristics of this boundary change depending on the geology and tectonic evolution of the targeted area refraction and wide angle studies suggest the moho to be often a relatively sharp velocity contrast whereas the moho in coincident high quality seismic reflection images is often seen as the abrupt downward decrease in seismic reflectivity the origin of the moho and its relation to the crust mantle boundary is probably better constrained by careful analysis of its internal details which can be complex and geographically varied unlike the oceanic moho which is formed in a relatively simple well understood process the continental moho can be subject to an extensive variety of tectonic processes making overarching conclusions about the continental moho difficult speaking very broadly 1 in orogenic belts still undergoing compression and active continental volcanic arcs the moho evolves with the mountain belt 2 in collapsed phanerozoic orogenic belts the moho under the collapse structure was formed during the collapse often by a combination of processes 3 in regions having experienced widespread basaltic volcanism the moho can result from underplated basalt and basaltic residuum in precambrian terranes the moho may be as ancient as the formation of the crust in others precambrian tectonic and magmatic processes have reset it we note that seismic reflection data in phanerosoic orogens as well as from precambrian cratonic terranes often show thrust type structures extending as deep as the moho and suggest that even where crust and mantle xenoliths provide similar age of formation dates the crust may be semi allochothonous

basin evolution of the northern part of the northeast german basin insights from a 3d structural model abstract a 3d structural model for the entire southwestern baltic sea and the adjacent onshore areas was created with the purpose to analyse the structural framework and the sediment distribution in the area the model was compiled with information from several geological time isochore maps and digital depth maps from the area and consists of six post rotliegend successions the upper permian zechstein lower triassic middle triassic upper triassic jurassic cretaceous and cenozoic this structural model was the basis for a 3d backstripping approach considering salt flow as a consequence of spatially changing overburden load distribution isostatic rebound and sedimentary compaction for each backstripping step in order to reconstruct the subsidence history in the region this method allows determination of the amount of tectonic subsidence or uplifting as a consequence of the regional stress field acting on the basin and was followed by a correlation with periods of active salt movement in general the successions above the highly deformed zechstein evaporites reveal a thickening trend towards the gluckstadt graben which also experienced the highest amount of tectonic subsidence during the mesozoic and cenozoic two periods of accelerating salt movement in the area has been correlated with the e w directed extension during the late triassic early jurassic and later by the late cretaceous early cenozoic inversion suggesting that the regional stress field plays a key role in halokinesis the final part of this work dealt with a neotectonic forward modelling in an attempt to predict the future topography when the system is in a tectonic equilibrium the result reveals that many of the salt structures in the region are still active and that future coastline will run with a wnw ese trend arguing that the compressional stresses related to the alpine collision are the prime factor for the present day landscape evolution

analysis of geomagnetic field along seismic profile p4 of the international project polonaise 97 abstract this paper presents relative secular variations of the total intensity of the geomagnetic field against a background of results of magnetic anomaly interpretation along seismic profile p4 profile p4 crosses a variscan folding zone in the paleozoic platform plz the trans european suture zone tesz and the polish part of the east european craton eec secular geomagnetic field variations t measured in 1966 2000 along a line adjacent to seismic profile p4 were analysed the study of secular variations reduced to the base recordings at the belsk magnetic observatory showed that the growth of geomagnetic field at the east european craton was slower than in the trans european suture zone and the paleozoic platform a 2d crustal magnetic model was interpreted as a result of magnetic modelling in which seismic geological and geothermal data were also used the modelling showed that there were significant differences in the magnetic model for geotectonic units which had been earlier determined based on deep seismic survey data it should be noted that a fundamental change of trend of the relative secular variations was observed at the slope of the precambrian platform after analysing the geomagnetic field observed along profile p4 the hypothesis that the contact between phanerozoic and precambrian europe lies in poland s territory can be proven

moho depth across the trans european suture zone from p and s receiver functions the mohorovicic discontinuity moho for short which marks the boundary between crust and mantle is the main first order structure within the lithosphere geodynamics and tectonic evolution determine its depth level and properties here we present a map of the moho in central europe across the teisseyre tornquist zone a region for which a number of previous studies are available our results are based on homogeneous and consistent processing of p and s receiver functions for the largest passive seismological data set in this region yet consisting of more than 40 000 receiver functions from almost 500 station besides we also provide new results for the crustal vp vs ratio for the whole area our results are in good agreement with previous more localized receiver function studies as well as with the interpretation of seismic profiles while at the same time resolving a higher level of detail than previous maps covering the area for example regarding the eifel plume region rhine graben and northern alps the close correspondence with the seismic data regarding crustal structure also increases confidence in use of the data in crustal corrections and the imaging of deeper structure for which no independent seismic information is available in addition to the pronounced stepwise transition from crustal thicknesses of 30 km in phanerozoic europe to more than 45 beneath the east european craton we can distinguish other terrane boundaries based on moho depth as well as average crustal v p v s ratio and moho phase amplitudes the terranes with distinct crustal properties span a wide range of ages from palaeoproterozoic in lithuania to cenozoic in the alps reflecting the complex tectonic history of europe crustal thickness and properties in the study area are also markedly influenced by tectonic overprinting for example the formation of the central european basin system and the european cenozoic rift system in the areas affected by cenozoic rifting and volcanism thinning of the crust corresponds to lithospheric updoming reported in recent surface wave and s receiver function studies as expected for thermally induced deformation the same correlation applies for crustal thickening not only across the trans european suture zone but also within the southern part of the bohemian massif

late cretaceous to recent tectonic evolution of the north german basin and the transition zone to the baltic shield southwest baltic sea abstract in this study we investigate the late cretaceous to recent tectonic evolution of the southwestern baltic sea based on a dense grid of seismic reflection profiles this area covers the baltic sea sector of the salt influenced north german basin and its transition to the salt free baltic shield across the tornquist zone the upper cretaceous to recent structural evolution is discussed by means of individual seismic sections and derived high resolution time structure maps of the main horizons i e the upper cretaceous tertiary and pleistocene the upper cretaceous and tertiary layers reveal numerous significant faults throughout the study area several of these faults propagate upwards across the unconsolidated pleistocene sediments and occasionally penetrate the surface the salt influenced north german basin reveals three major fault trends nw se n s and nne ssw several of these faults are located directly above basement sub salt faults and salt pillows the majority of these faults are trending n s to nne ssw and parallel the direction of the gluckstadt graben faults in the salt free tornquist zone we identify two major shallow fault trends which are nw se and ne sw the majority of these faults are located above basement faults following the direction of the tornquist zone we conclude that generally basement tectonics controls activation and trends of shallow faults if salt is present the ductile salt layer causes a lateral shift between the sub and supra salt faults major plate reorganisation related to the africa iberia europe convergence and the subsequent alpine orogeny caused reactivation of pre existing faults and vertical salt movement in the late cretaceous the change of stress orientation from ne sw to a nw se during neogene caused another phase of fault and salt tectonic reactivation we explain that the ice sheet loading and or present day stress field may have acted in combination causing the recent tectonics and upward extension of the faults

on the origin of the southern permian basin central europe abstract a detailed study of the structural and stratigraphic evolution of the southern permian basin during latest carboniferous to early jurassic times supported by quantitative subsidence analyses and forward basin modelling for 25 wells leads us to modify the conventional model for the rotliegend zechstein development of this basin the late permian early jurassic tectonic subsidence curves are typical for a permian to early triassic extensional stage that is followed by thermal subsidence however a purely extensional model is extremely problematic because active faulting during this time is minor and generally hard to document using inverse techniques to model the subsidence curves we quantitatively show that a significant component of late permian and triassic tectonic subsidence can be explained by thermal relaxation of early permian lithospheric thinning and by delayed infilling of paleo topographic depressions that developed during the early permian in this interpretation stephanian autunian wrenching resulted in thermal destabilisation of the lithosphere deep fracturing of the crust disruption and erosion of its sedimentary cover and regional uplift of the area of the future southern permian basin upon termination of wrench tectonics and associated volcanism towards the end of the autunian the southern permian basin began to subside in response to thermal contraction of the lithosphere the evolving basin was isolated from the world oceans and had subsided possibly up to some 700 m below their level at the beginning of upper rotliegend sedimentation after catastrophic flooding of this paleo topographic depression at the beginning of the zechstein changing sea level sedimentation and subsidence rates remained essentially in balance although the effects of triassic rifting overprinted parts of the southern permian basin its overall subsidence pattern persisted well into the jurassic in contrast to the remainder of the southern permian basin permian and triassic crustal extension contributed significantly to the subsidence of the polish trough

a late tournaisian synmetamorphic folding and thrusting event in the eastern variscan foreland 40 ar 39 ar evidence from the phyllites of the wolsztyn leszno high western poland a variscan foreland in western poland comprises two nw trending basement highs which are concealed under carboniferous through triassic strata of the fore sudetic monocline fsm both highs consist of multiply deformed quartz sericite albite chlorite phyllites of unknown protolith age 40ar 39ar laser probe dating of white micas in up to 0 5 mm thick mica layers which form the s2 axial plane foliation in phyllites of the wolsztyn leszno high yielded an age of 340 1 2 6 ma for the lower greenschists facies metamorphism and probably also for the f2 folding this deformation was associated and followed by thrusting which brought about the basement highs the latter delivered clasts to overlying late visean early namurian flysch basin that was mainly sourced from the saxothuringian sudetes in which most of the deformation occurred between 345 335 ma the fsm basement may represent an independent terrane referred to as the wielkopolska terrane belonging to the armorican terrane assemblage

from the variscan to the alpine orogeny crustal structure of the bohemian massif and the western carpathians in the light of the sudetes 2003 seismic data summary the variscan orogeny is the major middle to late palaeozoic tectonometamorphic event in central europe and the bohemian massif is the largest exposure of rocks deformed during this orogeny the bohemian massif consists of the saxothuringian barrandian and moldanubian units adjacent to this massif in the southeast the western carpathians form an arc shaped mountain range related to the alpine orogeny during the cretaceous to tertiary the complex crustal scale geological structure of the variscan bohemian massif and the western carpathians and especially their contact were analysed in this study employing the data of the sudetes 2003 international seismic refraction experiment the analysed seismic data were acquired along the 740 km long nw se oriented s04 profile that crossed the bohemian massif and the western carpathians before terminating in the pannonian basin the data were interpreted by 2 d trial and error forward modelling of p waves and additional constraints on crustal structure were provided by gravity modelling the complex velocity structure derived in our analysis included low velocities of 5 85 km s 1 at the contact of the saxothuringian and barrandian units that reflect the presence of low density granites there are distinct lateral variations in deep crustal structure in the transition between the bohemian massif and the western carpathians the abrupt change of the crustal thickness in this transition zone may be associated with the pieniny klippen belt a deep seated boundary between the colliding palaeozoic lithospheric plate to the north and the alcapa microplate to the south in the upper crust of this transition low velocities of 4 km s 1 extend to 6 km and represent the sedimentary fill of the carpathian flysch and foredeep that thins towards the foreland this basin is also expressed as a pronounced gravity low the moho in the carpathians reaches a depth of 32 33 km in contrast in the pannonian basin the moho rises to a depth of 25 km which corresponds to the pannonian gravity high

lower lithospheric structure beneath the trans european suture zone from polonaise 97 seismic profiles abstract the large scale polonaise 97 seismic experiment investigated the velocity structure of the lithosphere in the trans european suture zone tesz region between the precambrian east european craton eec and palaeozoic platform pp in the area of the polish basin the p wave velocity is very low vp 8 25 km s in the palaeozoic platform and 8 1 km s in the precambrian platform good quality record sections were obtained to the longest offsets of about 600 km from the shot points with clear first arrivals and later phases of waves reflected refracted in the lower lithosphere two dimensional interpretation of the reversed system of travel times constrains a series of reflectors in the depth range of 50 90 km a seismic reflector appears as a general feature at around 10 km depth below moho in the area independent of the actual depth to the moho and sub moho seismic velocity ringing reflections are explained by relatively small scale heterogeneities beneath the depth interval from 90 to 110 km qualitative interpretation of the observed wave field shows a differentiation of the reflectivity in the lower lithosphere the seismic reflectivity of the uppermost mantle is stronger beneath the palaeozoic platform and tesz than the east european platform the deepest interpreted seismic reflector with zone of high reflectivity may mark a change in upper mantle structure from an upper zone characterised by seismic scatterers of small vertical dimension to a lower zone with vertically larger seismic scatterers possible caused by inclusions of partial melt

seismic models of the lower lithosphere beneath the southern baltic sea between sweden and poland abstract based on recordings from the northern part of the baltic sea black sea profile and eugeno s profile 4 2 d seismic models have been constructed for a profile across the southwestern part of the east european platform from southern sweden to northern poland the thickness of the crust along the profile varies from 33 to 47 km the moho p wave velocity is 8 0 8 3 km s the uppermost mantle has a fine structure with alternating layers of higher and lower velocities down to a depth of about 120 km three alternating high and low velocity layers have been modelled the velocities vary between 8 2 and 8 7 km s in the high velocity layers and 8 0 and 8 5 km s in the low velocity layers a tendency of the depth of the moho and the depth of the uppermost mantle seismic boundaries to increase towards the southeast is observed

palaeozoic terranes and their lithospheric boundaries within the trans european suture zone tesz a review the trans european suture zone tesz is a broad and complex zone of terrane accretion separating ancient lithosphere of the baltic shield and east european craton eec from the younger lithosphere of western and southern europe there is debate about the number of terranes involved and their origins the most significant terrane boundaries originally oceanic sutures are poorly exposed and are defined using faunal provinciality prominent geophysical lineaments may represent sub terrane boundaries within composite terranes the avalonia composite terrane was amalgamated to baltica in latest ician time the provenance of the malopolska and moravo silesian terranes whose neoproterozoic basement is suspect with respect to baltica but with which they nonetheless share faunal affinities is still debated the extent of the variscide rhenohercynian zone defines the southern limit of the early palaeozoic accreted terranes terranes within the bohemian massif exhibit hp metamorphism recording subduction driven collision prior to incorporation in the tesz collage itself associated with a hp event in romania the saxothuringian zone and rheic suture are directly juxtaposed with the eec and the crustal structure of the tesz has been much modified by post palaeozoic tectonism deep seismic reflection data where available show that the oceanic sutures are frequently associated with inclined reflectivity zones irz in the lithospheric mantle here inferred to mark relict subduction zones interpreting the age of subduction is complicated by offset of originally coplanar mantle and crustal segments of the irz resulting from early orogenic lithospheric delamination at the moho interface and or post orogenic reordering processes the mantle irz appear to indicate a n directed polarity for early palaeozoic subduction apparently incompatible with the geological evidence which indicates subduction of the tornquist sea beneath avalonia and a large amount of underthrusting of avalonia by baltica possible explanations for these apparently incompatible observations are evaluated

crustal structure of the eastern alps and their foreland seismic model beneath the cel10 alp04 profile and tectonic implications summary the subject of this paper concerns the seismic modelling of the crustal structure in the transition zone from the bohemian massif across the molasse basin and the eastern alps to the southern alps mainly on the territory of austria the cel10 alp04 profile crosses the triple point of the european plate adriatic microplate and the recently identified pannonian fragment the seismic data along the presented profile originate from two large experiments celebration 2000 and alp 2002 the wavefield observed in the eastern alps is more complex than in the bohemian massif strong first arrivals pg are distinct up to 60 90 km offset and are characterized by large variations in apparent velocity and amplitude the contact between the molasse basin and the eastern alps represents a barrier for seismic waves midcrustal reflections pc are usually recorded at short distance intervals 20 50 km and are also characterized by variations in apparent velocity and amplitude the moho reflections are usually strong and well correlated while pn arrivals are only fragmentarily recorded detailed 2 d forward modelling of all refracted post critical and reflected phases identified in the correlation process was undertaken using a ray tracing technique the p wave velocity in the crystalline upper crust of the bohemian massif and molasse basin is about 6 15 km s 1 which is slightly higher than in the alpine area about 6 0 km s 1 below the northern accretionary wedge of the eastern alps low velocity sediments penetrate towards the southwest sw down to about 10 km depth in the middle crust of the alpine part a reflective zone was modelled by a lamellae structure with alternating high and low velocities and thicknesses of about 2 3 km the lower crust in this part of the model is more homogeneous with a velocity of about 6 9 km s 1 in the bohemian massif a high velocity hv body vp 7k m s 1 o f af ew kilometres thickness was delineated in the depth interval 18 23 km the crustal thickness along the cel10 alp04 profile changes from about 42 44 km in the sw alpine part to around 40 km in the central part of the profile molasse basin and 38 40 km in the ne bohemian massif the velocity in the uppermost mantle determined from pn wave traveltimes is about 8k m s 1 along the whole profile the interpretation of the seismic wavefield is supplemented by an existing 3 d p wave velocity model of the area main features derived by 2 d modelling low velocities beneath the accretionary wedge high velocities in the lower crust of the bohemian massif moho topography well correlate with the 3 d model furthermore the 3 d model allows assessing the lateral extent of significant features alongside the cel10 alp04 profile this area is affected by both collision and escape tectonics the high reflectivity zone

the mesozoic cenozoic structural framework of the bay of kiel area western baltic sea a dense grid of multichannel high resolution seismic sections from the bay of kiel in the western baltic sea has been interpreted in order to reveal the mesozoic and cenozoic geological evolution of the northern part of the north german basin the overall geological evolution of the study area can be separated into four distinct periods during the triassic and the early jurassic e w extension and the deposition of clastic sediments initiated the movement of the underlying zechstein evaporites the deposition ceased during the middle jurassic when the entire area was uplifted as a result of the mid north sea doming the uplift resulted in a pronounced erosion of upper triassic and lower jurassic strata this event is marked by a clear angular unconformity on all the seismic sections the region remained an area of non deposition until the end of the early cretaceous when the sedimentation resumed in the area throughout the late cretaceous the sedimentation took place under tectonic quiescence reactivated salt movement is observed at the cretaceous cenozoic transition as a result of the change from an extensional to compressional regional stress field the vertical salt movement influenced the cenozoic sedimentation and resulted in thin skinned faulting

heterogeneous tectonic inversion of the mid polish trough related to crustal architecture sedimentary patterns and structural inheritance abstract using a 3 d structural model we performed a basin scale analysis of the tectonically inverted mid polish swell which developed above the nw se oriented teisseyre tornquist zone the later separates the paleozoic west european platform from the precambrian east european craton the model permits a comparison between the present depths and sedimentary thicknesses of five layers within the permian mesozoic and cenozoic successions the inversion of the nw se trending mid polish trough during the late cretaceous paleogene resulted in uplift of a central horst the mid polish swell bounded by two lateral troughs these structural features are induced by squeezing of a weak crust along the teisseyre tornquist zone the swell is characterized by an inherited segmentation which is due to ne sw transversal faults having crustal roots from nw to se we distinguish the pomeranian kujavian and malopolska segments that are separated by two transversal faults during the inversion the zechstein salt occurring in the pomeranian and kujavian segments in the nw acted as decoupling level between the basement and the post salt cover leading to disharmonic deformation conversely because no salt occurs in the se both basement and cover were jointly deformed the vertical tectonic uplift at the surface is estimated to amount to 3 km in the malopolska segment the structural inheritance of the basement is expressed by the heterogeneous geometry of the swell and tectonic instability during mesozoic sedimentation the reasons for the inheritance are seen in the mosaic type paleozoic basement sw of the teisseyre tornquist zone contrasting the precambrian east european craton which acted as a stable buttress in the ne the horst and trough geometry of cenozoic sediments blanketing the mid polish swell reveals the ongoing intracontinental compressional stress in poland

deep temperature distribution along three profiles crossing the teisseyre tornquist tectonic zone in poland abstract the teisseyre tornquist tectonic zone is a large deep fracture zone separating the precambrian east european craton from the variscan system of central europe with the use of ample deep seismic sounding data the detailed crustal temperature distribution was calculated for three profiles crossing this zone in its northern central and southern segments the conversion technique of transforming the reported seismic velocities p into heat production values a was used together with the temperature dependent thermal conductivity structure and the observed surface heat flow pattern in addition to the obtained 2 d temperature distribution this work allowed a more reliable estimate of the crustal contribution to the surface heat flow and thus the characteristic moho heat flow q m 26 mw m 2 to be assessed in this region the results can also serve as an independent confirmation of the necessity of applying the p a conversion separately for phanerozoic and for precambrian rocks

deep resistivity structure of the trans european suture zone in central poland summary the deep resistivity structure was estimated along a 400 km profile in central poland crossing the malopolska massif mm the lysogory unit lu the trans european suture zone tesz and ending at the east european craton eec magnetotelluric transfer functions corresponding to 20 sites were supplemented by magnetovariational responses obtained at the geomagnetic observatories situated at the same tectonic units such a combination made it possible to extend the initial period range which is from fractions of a second to several hours up to months in order to reliably cover crustal and upper mantle depths the geoelectrical structures revealed using 2 d inversions do not contradict the known features of the lithosphere structure determined using seismic and gravity data along the profile the subsurface conductance varying from approximately 10 siemens at the inner part of the eec to about 600 siemens in the tesz is produced by sediments the deep part of which contains conductive highly mineralized water the existence of two crustal conductive faults at the southwest and northeast of the tesz were established mainly by the use of induction arrows it was also revealed that rather high mantle conductivity beneath the mm lu and tesz at depths of about 150 200 km contrasts with the resistive upper mantle of the eec this can be interpreted as the decrease of asthenosphere conductance and or as its submersion beneath the eec generally the results confirm the idea that the tesz forms not only specific seismic boundaries but also causes peculiar conductivity anomalies in the crust and upper mantle

crustal structure of the mid polish trough beneath the teisseyre tornquist zone seismic profile abstract a new seismic refraction and wide angle reflection experiment in the teisseyre tornquist zone ttz in poland was conducting during july 1993 as an international polish finnish german and swedish co operation the ttz profile running in an se nw direction was exactly located in the central part of the mid polish trough in the zone of maximum subsidence from upper permian to upper cretaceous 19 shot points were placed along the 450 km profile the interval between the shot points was about 25 km 31 explosions 90 to 1000 kg of dynamite were recorded in two deployments using 135 modern three component seismic stations with spacing of the recording sites of about 1 7 km in this area the depth of the consolidated basement with a velocity of about 5 7 5 8 km s is 5 to 12 km deep nevertheless the p wave velocity is very low vp

paleomagnetism of ordovician carbonate rocks from malopolska massif holy cross mountains se poland magnetostratigraphic and geotectonic implications abstract the structural and geodynamic history of the malopolska massif holy cross mountains poland situated within the trans european suture zone tesz is still a matter of debate recent provenance studies and biogeographical data indicate that the malopolska is a gondwana derived terrane accreted to baltica between late mid cambrian and tremadocian times existing paleomagnetic data however are equivocal they indicate either close proximity and coherence with baltica since silurian times or a significant variscan dextral strike slip displacement of malopolska with respect to the latter along the teisseyre tornquist line in order to address this problem a detailed paleomagnetic study of a condensed sequence of middle to upper ordovician carbonate rocks from the malopolska massif mojcza quarry has been undertaken samples were taken every 10 to 15 cm through the 4 5 m sequence which covers the upper llanvirnian and caradocian after detailed stepwise thermal demagnetization a high unblocking temperature direction of magnetization with mixed polarities is identified the directions pass the reversal test and yield an overall mean direction of dec 323 inc 63 k 16 6 95 5 8 after bedding correction this corresponds to a paleo south pole of 11 n 46 8 e d p 7 2 d m 9 1 which plots directly on the ordovician segment of the apparent polar wander path for baltica thus rendering major post ordovician rotations of the area relative to baltica unlikely the paleomagnetic results reveal three zones of each reversed r1 r3 and normal polarity n1 n3 the section starts with a reversed polarity interval in the mid llanvirnian stage r1 the transitions from r1 to n1 and from n1 to r2 in middle llanvirnian and from r2 to n2 during upper llanvirnian correspond well with previous paleomagnetic results based on graptolite biostratigraphy after a short normal polarity interval n2 the lower caradocian is dominated by inverse polarity r3 the following transition from r3 to n3 falls in the upper part of the amorphognathus tvaerensis conodont zone for this polarity change the misfit between the magnetostratigraphy of the mojcza section and previously published paleomagnetic results most likely reflects uncertainties of correlating between conodont and graptolite stratigraphies

the elbe fault system in north central europe a basement controlled zone of crustal weakness abstract the elbe fault system efs is a wnw striking zone extending from the southeastern north sea to southwestern poland along the present southern margin of the north german basin and the northern margin of the sudetes mountains although details are still under debate geological and geophysical data reveal that upper crustal deformation along the elbe fault system has taken place repeatedly since late carboniferous times with changing kinematic activity in response to variation in the stress regime in late carboniferous to early permian times the elbe fault system was part of a post variscan wrench fault system and acted as the southern boundary fault during the formation of the permian basins along the trans european suture zone sensu geol mag 134 5 1997 585 the teisseyre tornquist zone ttz most probably provided the northern counterpart in a pull apart scenario at that time further strain localisation took place during late mesozoic transtension when local shear within the elbe fault system caused subsidence and basin formation along and parallel to the fault system the most intense deformation took place along the system during late cretaceous early cenozoic time when the elbe fault system responded to regional compression with up to 4 km of uplift and formation of internal flexural highs compressional deformation continued during early cenozoic time and actually may be ongoing the upper crust of the elbe fault system which itself reacted in a more or less ductile fashion is underlain by a lower crust characterised by low p wave velocities low densities and a weak rheology structural seismic and gravimetric data as well as rheology models support the assumption that a weak stress sensitive zone in the lower crust is the reason for the high mobility of the area and repeated strain localisation along the elbe fault system

the uncertainty of 2d models along wide angle seismic profiles the estimation of uncertainty for any geophysical model is important for determining how reliable the model is it is especially important for subjective trial and error modelling techniques like forward ray tracing modelling of wide angle seismic data when the final result is very dependent on the interpreter s knowledge of the area and experience in this kind of modelling it is common to encounter over interpretation of the seismic data without checking the uncertainty of the result especially in the deep parts that are not constrained with other a priori knowledge in this paper we propose a method of estimating the uncertainty of the final models based on a one dimensional method of small error propagation generalized for 2d profiles with a simple approximation we estimate the uncertainty for published interpretative models of selected profiles from seismic experiments in the central europe we conclude that for typical wide angle seismic profiles we can reliably interpret four layered models of the earth s crust based on traveltimes fitting we also show how the number of layers influence obtained uncertainties estimated uncertainties for both the velocity fields and the boundaries between layers are important for future tectonic and geodynamic interpretation of those profiles

laminated structure of the lower crust in the fore sudetic region in poland derived from seismic data abstract the results of seismic studies of the crust of the palaeozoic platform in the fore sudetic region southwestern poland are presented the structure of the sedimentary cover and the boundary of the consolidated basement were determined from refraction profiles of a total length of about 1500 km and from seismic velocity profiling in deep boreholes interpretation of data from deep seismic sounding and wide angle reflection studies provided information on the structure of the lower crust and the crust upper mantle transition zone the results of the first deep seismic sounding measurements by the near vertical profiling method with recordings up to 18 s are also reported in the region under study the sedimentary cover thickness ranges from 3 to about 13 km and the moho discontinuity depth is from 28 to 35 km in the sedimentary cover and in the lower crust strong structural and physical inhomogeneities were identified in the 23 34 km depth range layers of 1 3 km thickness of increased and decreased velocity alternate they have velocity contrasts of 0 4 0 7 km s 1 and are shown by intense sequences of reflected waves which are observed both in the wide angle reflection studies and in the near vertical profiles

3d structure of the earth s crust beneath the northern part of the bohemian massif abstract the sudetes 2003 wide angle refraction reflection experiment covered the area of the south western poland and the northern bohemian massif the good quality data that were gathered combined with the data from previous experiments polonaise 97 celebration 2000 allowed us to prepare a 3d seismic model of the crust and uppermost mantle for this area we inverted travel times of both refracted and reflected p waves using the jive3d package this allowed us to obtain a model of p wave velocity distribution as well as the shape of major boundaries in the crust we also present a detailed uncertainty analysis for both the boundary depths and the velocity field in doing the uncertainty analysis we found an interesting strong dependence between uncertainty and inversion scheme order of used phases we also compared the model with surface geology and found good correlation between velocity inhomogeneities in the uppermost crust down to 2 km and major geological units the higher velocity lower crust 6 9 7 2 km s could result from remelting of the lower crust or magmatic underplating

geophysical characteristics of the tornquist fan area northwest trans european suture zone indication of late carboniferous to early permian dextral transtension

evaluation of nga west2 and chinese ground motion prediction equations for developing seismic hazard maps of mainland chinaevaluation of nga west2 and chinese gmpes for developing seismic hazard maps of mainland china

lithospheric structure of the trans european suture zone along the ttz cel03 seismic transect from nw to se poland abstract the large scale celebration 2000 seismic experiment investigated the velocity structure of the crust and upper mantle between western portion of the east european craton eec and the eastern alps this area comprises the trans european suture zone the carpathian mountains the pannonian basin and the bohemian massif this experiment included 147 chemical shots recorded by 1230 seismic stations during two deployments good quality data along 16 main and a few additional profiles were recorded one of them profile cel03 was located in southeastern poland and was laid out as a prolongation of the ttz profile performed in 1993 this paper focuses on the joint interpretation of seismic data along the nw se trending ttz cel03 transect located in the central portion of the trans european suture zone first arrivals and later phases of waves reflected refracted in the crust and upper mantle were interpreted using two dimensional tomographic inversion and ray tracing techniques this modelling established a 2 d quasi 3 d p wave velocity lithospheric model four crustal units were identified along the transect from northwest to southeast thickness of the crust varies from 35 km in the pomeranian unit nw to 40 km in the kuiavian unit to 50 km in the radom ysogory unit and again to 43 km in the narol unit se the first two units are thought to be proximal terranes detached from the eec farther to the southeast and re accreted to the edge of the eec during the early palaeozoic the origin of the remaining two units is a matter of dispute they are either portions of the eec or other proximal terranes in the area of the polish basin first two units the p wave velocity is very low vp

crustal structure along the egt profile across the tornquist fan interpreted from seismic gravity and magnetic data abstract the tornquist fan is a northwestward widening splay of late carboniferous to early permian fault zones in the danish area which emanates from the teisseyre tornquist zone in the baltic sea it is located over an area of deep sedimentary basins around denmark in the southwestern corner of the former baltica plate this paper presents an integrated model of seismic velocity density and magnetic properties along the egt profile across the tornquist fan between southern sweden and northern germany the model shows distinct features that may be related to the main tectonic events in the area the caledonian crustal suture between baltica and eastern avalonia is interpreted from changes in physical parameters at all crustal levels most noticeable as an abrupt lateral change in seismic velocity in the lowest crust at moho level from 6 9 km s in baltica to only 6 4 km s in eastern avalonia thick sedimentary successions beneath the mesozoic sequence are interpreted as palaeozoic sedimentary rocks which may have been deposited on the southern margin of the baltica plate in a deep caledonian foreland basin and in late carboniferous early permian rifts and extensional basins rift related magmatism is indicated by the presence of zones of high velocity density and magnetic susceptibility as well as strong remanent magnetization thermal subsidence following the emplacement of these bodies may be the origin of regional subsidence of the danish and north german basins of late paleozoic and mesozoic age late cretaceous to early cenozoic inversion of basin structures is detected at the sorgenfrei tornquist zone stz in the transition between shield and basin areas the stz coincides with a pronounced change in crustal thickness and the southwestern edge of a major magmatic intra crustal body significant abrupt changes in moho depth exist along the profile 26 30 km beneath the deep basins ca 35 km beneath the ringkobing fyn basement high and 48 km beneath the baltic shield around the sorgenfrei tornquist inversion zone the basement in the tornquist fan area is of proterozoic age the moho topography indicates strong thinning of the crust during its phanerozoic evolution the model supports the hypothesis that existing tectonic structures and weakness zones are continuously being reactivated during subsequent tectonic activity

structure and evolution of the northeastern german basin and its transition onto the baltic shield abstract the post permian sequence stratigraphical and structural evolution of the northeastern german basin and its transition onto the baltic shield has been studied in the bay of mecklenburg sw baltic sea by means of seismic interpretation five major sequences have been identified middle triassic upper triassic jurassic cretaceous and cenozoic time isochore maps allowed the identification of several phases of salt pillow growth the contemporaneity of active salt tectonics and the well studied tectonic evolution of the northeastern german basin suggest a causative correlation the e w directed extension during the triassic early jurassic marking the beginning break up of pangaea is seen as the trigger process for the first period of salt movement a fault system outside the limit of the zechstein evaporates is understood as the consequence of thin skinned faulting and brittle thick skinned deformation that accompanied this extension the observed pronounced erosion of upper triassic and lower jurassic strata is considered to result from the uplift due to the mid north sea doming event in middle jurassic times the seismic data show an undisturbed late cretaceous succession which reflects a period of rising sea level tectonic quiescence and no salt movement in contrast to the salt pillows which emerged above triassic fault systems in the westernmost baltic and western north german basin the cenozoic salt movement activity is the most pronounced this period of reactivated salt pillow growth started coevally with the onset of the alpine orogeny at the cretaceous cenozoic transition when the africa arabian plate collided with eurasia generally no significant faults were identified in the overburden of the salt floored southern bay of mecklenburg where ductile zechstein salt decouples deep rooted faulting from supra salt deformation

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

seismic structure of the palaeozoic platform along polonaise 97 profile p1 in northwestern poland abstract the deep seismic profile p1 was conducted in northwestern poland as part of the polonaise 97 project data acquisition involved 100 mobile seismographs which recorded seismic waves from 11 dispersed chemical controlled explosions along this 300 km long profile a variety of seismic modelling techniques were employed to derive a velocity model along the profile this model indicates that the mesozoic and palaeozoic sediments are 6 km thick in the northwest and 3 km thick in the southeast with the main thickness variation taking place in the palaeozoic succession an undulating basement surface indicates tectonic activity during deposition of the lower palaeozoic sequence the crust is 30 33 km thick along the profile thickening gradually to the southeast the p wave seismic velocities are low 1 down to a depth of 20 km along the whole profile which we interpret as evidence for their being of sedimentary or volcanic origin the lower crust has a high p wave velocity 6 7 7 5 km s 1 high vertical velocity gradient and strong ringing reflectivity the velocity of the sub moho mantle p n is high 8 2 km s 1 features similar to the ones below this profile have been interpreted for the area south of the caledonian deformation front in northern germany and southern denmark these similarities indicate that the crust between the southeastern north sea and poland has a common origin we therefore suggest that the deep crust beneath the profile is not of variscan origin despite its location south of the variscan deformation front we propose that variscan tectonism in the area was thin skinned while the deeper crust may originate from the caledonian microcontinent east avalonia or possibly from baltica

transcurrent nature of the teisseyre tornquist zone in central europe results of the polcrust 01 deep reflection seismic profile teisseyre tornquist zone ttz corresponds to a crustal boundary between the precambrian east european platform eep and the palaeozoic west european platform although the zone has been controlling phanerozoic evolution of large parts of central europe its course geometry and origin are still poorly constrained deep reflection seismic profile polcrust 01 recently acquired in se poland for the first time allowed a precise comparison of the ediacaran and later tectonic patterns to the deep crustal features of the ttz and adjacent areas the ttz corresponds to the subvertical tomaszow fault separating the radom kra nik elevation composed of the typical eep crust from the bilgoraj narol block bnb in the sw with a thinned crystalline basement showing affinities to the eep crust the bnb is a part of the larger caledonian ysogory terrane as evidenced by its lower palaeozoic stratigraphy and gravity data thus for the first time the proximal baltican affinity of this unit has been documented unambiguously the ysogory terrane is delimited from the sw by the subvertical cieszanow fault zone corresponding to the holy cross suture the adjacent malopolska terrane is characterized by a distinct early palaeozoic stratigraphy and lower middle crust exhibiting sw dipping reflective packages interpreted as ne verging thrust and shear zones of a neoproterozoic orogen the observations from the polcrust 01 profile and regional comparisons indicate that the ttz is a major caledonian transcurrent zone between poland and east romania in central poland the ttz likely forms a narrow subvertical contact between the eep and a proximal kuiavia terrane as constrained by the deep refraction seismic data to the nw the zone extends towards the pomeranian part of the caledonide fold and thrust belt related to the avalonia baltica collision zone thor suture south east of poland the ttz corresponds to the rava ruska fault zone established as a caledonian suture separating adjacent terrane probably of a baltican affinity the east romanian part of the ttz conforms with the sf ntu gheorghe fault separating reworked eep crust of the pre dobrogean depression from the north dobrogea unit bearing a strong variscan and cimmerian overprint

continental rift development in precambrian and phanerozoic europe europrobe and the dnieper donets rift and polish trough basins abstract upper crustal structure and lower crustal and mantle character of the european continental lithosphere differ significantly from west to east the processes of rifting of phanerozoic western europe s hotter thinner crust compared with the more stable thicker 45 vs 30 km proterozoic crust of the east european craton is being investigated by europrobe case studies of western and eastern european sedimentary basins the dnieper donets basin transects the southwestern part of the east european platform in a nw se direction lying between the ukrainian shield and the voronezh massif rifting took place from early frasnian until perhaps the late visean and was accompanied by major volcanic activity the distribution of both was affected by pre existing basement fault systems the syn and post rift sedimentary succession may be as thick as 20 km in the donets trough basin evolution and the present crustal geometry have been much affected by inversion during the permian in association with uralian orogenesis tectonic events of bathonian oxfordian 168 154 ma and turonian santonian 91 84 ma age are also recorded in the basin stratigraphy the polish trough lies along the boundary between the phanerozoic and proterozoic european crustal domains coincident with the trans european suture zone the presence of this rheological boundary may be paramount in structurally controlling the position of the trough tectonic subsidence analysis indicates an initial late rotliegendes early triassic syn rift phase of development subsequently episodes of increased tectonic subsidence rate occurred during the oxfordian tithonian 157 146 ma and beginning in the cenomanian 95 90 ma the oxfordian tithonian episode is likely the signature of a second extensional event correlated with intensification of rifting within the arctic north atlantic rift system while the cenomanian and later is a precursor to mild compressional intraplate orogenic movements present day crustal structure reflects the docking of phanerozoic crust against the proterozoic during palaeozoic orogenies permo carboniferous wrenching and transtensional modifications leading to formation of the polish trough as well as modifications during the late cretaceous early tertiary inversion process

the post glacial landscape evolution of the north german basin morphology neotectonics and crustal deformation the recent evolution of the north german basin ngb which is presently a low seismic area was partly affected by glacial loading and unloading of the ice masses major stresses acting within the ngb are induced by the north atlantic ridge push the ongoing alpine collision and the post glacial rebound of fennoscandia present day horizontal stresses within the ngb are directed generally nw se but fan and bend north of 52 n towards nne major basement faults are directed nw se minor faults ne sw and nne ssw and are clearly detectable in geomorphological and satellite lineaments furthermore the drainage pattern and the distribution of lakes in northern germany follow exactly block boundaries and hence mark zones of present day subsidence the understanding of the post glacial morphology and reactivation of faults requires a view into the very heterogeneous crust and upper mantle below the ngb the re adjustment of the individual fault blocks during post glacial relaxation of the lithosphere leads to differential crust dependent uplift and probably to the formation of urstrom valleys the urstrom valleys and terminal moraines in northern germany appear to parallel the major tectonic lineaments and lithospheric block boundaries the lithospheric memory is expressed in the post glacial landscape evolution of the ngb

ongoing tectonic reactivation of the outer carpathians and its impact on the foreland results of borehole breakout measurements in poland abstract the direction of present day maximum horizontal compression shmax tectonic stress was interpreted for 62 wells in poland using the method of borehole breakout analysis of 4 arm and 6 arm dipmeter logs the study area covers complex tectonic junction of the carpathian orogen and its foreland which comprises the east european craton eec divided by the teisseyre tornquist zone ttz from the palaeozoic platform of western poland for this area frequent deviation of the shmax direction from nw se characteristic for the atlantic ridge push has been interpreted in terms of the alcapa tectonic push in the upper silesian segment of the polish outer carpathians poc nne ssw oriented shmax in the accretionary wedge differs significantly from nnw sse shmax in the autochthonous basement the above discrepancy points to uncoupled type of the suture in this segment of the poc in this scenario the alcapa push involves the nappes and is compensated in the top of the basement which is expressed by systematic shmax rotations in the accretionary wedge of the eastern malopolska segment shmax follows the trend perpendicular to the strike of nappes it is in general agreement with nne ssw oriented shmax in the autochthonous basement that also parallels the alcapa push direction similarity in stress orientation between these structural levels implies coupled suture zone in this segment of the poc further to the north alcapa push is transmitted into the foreland plate where it causes n s orientation of shmax as determined for sedimentary cover of the eec within the baltic portion of the eec further shmax rotation towards the intermediate nnw sse position suggests balance between the alcapa push and the ridge push components within the ttz common shmax rotations from n s to nw se indicate structurally controlled accommodation of the alcapa push in the palaeozoic platform of western poland mesozoic complex of the fore sudetic monocline reveals nne ssw directed shmax that differs from nw se oriented shmax in the variscan accretionary wedge here mechanical decoupling along zechstein evaporates is likely presented set of breakout data from poland shows that recent compressive reactivation of the carpathians exerts strong impact on the stress field of the foreland plate at a distance of 700 km from the suture due to this effect the fore carpathian stress domain within the north european stress province can be discriminated

caledonian and proterozoic terrane accretion in the southwest baltic sea abstract a marine seismic reflection survey was carried out in 1996 by dekorp potsdam and bgr hannover in the sw baltic sea several tectonic lineaments were crossed nearly perpendicularly for example the caledonian deformation front which is assumed to mark the northern boundary of the terrane avalonia which accreted to baltica ca 400 ma here a bivergent collision is clearly observed confirming early ideas from the babel survey the ne dipping reflections in the uppermost mantle are interpreted as signs of the subducted tornquist ocean a similar tectonic style of compression and indentation is observed in the proterozoic crust northeast of bornholm where in addition a remarkable crustal thickening and a strong increase of reflection power is observed the three dekorp lines in this area provide a certain three dimensional control and allows extension of similar observations from the babel line a southward this proterozoic terrane accretion seems to be connected to major tectonic lineaments in southern sweden either to the gothian thrust or the sveconorwegian front

deep seismic expression of an ancient plate boundary in europe seismological results on the structure of the upper mantle below europe reveal a marked contrast in seismic properties between precambrian and younger parts of europe the precambrian craton in eastern europe is characterized by high shear wave velocities which can be explained by low temperatures the transition to low seismic velocities below phanerozoic europe coincides with the crustal boundary zone of the craton and exists to depths of at least 140 kilometers despite the long and complex tectonic history of the plate boundary zone the transition is remarkably sharp which rules out any significant lateral transport of asthenospheric material across the suture zone

lithospheric structure beneath trans carpathian transect from precambrian platform to pannonian basin celebration 2000 seismic profile cel05 1 in 2000 a consortium of european and north american institutions completed a huge active source seismic experiment focused on central europe the central european lithospheric experiment based on refraction or celebration 2000 this experiment primarily consisted of a network of seismic refraction profiles that extended from the east european craton along and across the trans european suture zone region in poland to the bohemian massif and through the carpathians and eastern alps to the pannonian basin the longest profile cel05 1420 km is the focus of this paper the resulting two dimensional tomographic and ray tracing models show strong variations in crustal and lower lithospheric structure clear crustal thickening from the pannonian basin 24 25 km thick to the trans european suture zone region 50 km together with the configuration of the lower lithospheric reflectors suggests northward subduction of mantle underlying carpathian pannonian plate under the european plate this however conflicts with strong geological evidence for southward subduction and we present three tectonic models that are to not totally mutually exclusive to explain the lithospheric structure of the area 1 northward old subduction of the pannonian lithosphere under the east european craton in the jurassic lower cretaceous 2 a collisional zone containing a crocodile structure where carpatho pannonian upper crust is obducting over the crystalline crust of the east european craton and the carpathian pannonian mantle lithosphere is underthrusting cratonic lower crust and 3 lithosphere thinning due to the effects of neogene extension and heating with the slab associated with young subduction southward in the miocene having been either detached and or rolled back to the east in the last case the northwestward dipping in the lithosphere can be interpreted as being due to isotherms that could represent the lithosphere asthenosphere boundary in the pannonian region

redistribution of recent collision push and ridge push in central europe insights from fem modelling summary 2 d elastic finite element models of the recent stress field of central europe are built to evaluate the loads exerted on the continental boundary and the magnitude of tectonic stresses within the continental part of the plate the models comprise 24 tectonic blocks their stiffness is either constant throughout the model or varies from block to block 16 fault zones and 12 geologically significant boundary segments we have obtained a relatively unique balance of external tectonic forces by 1 careful adjustment of calculated stress directions and regimes to complex pattern of stress from data and 2 by calibration with gravitational potential energy a high level of compression ca 9 10 12 nm 1 exerted to the short ionian side of the adriatic indenter is crucial for the stress field pattern in central europe the adria microplate rotates due to eccentricity between the africa push from the south and the alpine buttress to the north a free boundary of the apennines does not contribute significantly to this motion kinematics of this indenter is controlled by friction on the dinaric suture which in turn is decisive for strain energy distribution between the alpine and the pannonian domains the predicted pronounced extension in the greece aegean segment 2 5 10 12 nm 1 implies active pull transferred from the hellenic subduction zone this extension releases stress in the balkan pannonian region and enables the eastward escape of tectonic blocks in front of advancing adria significant changes of tectonic push trends are found along the black sea caucasus boundary segment and at the european passive margin from the north sea to the arctic ocean differential stresses in central europe are estimated in the range of 10 60 mpa when averaged over the 30 80 km thick mechanically heterogeneous lithosphere the maximum stiffness contrast across the model is predicted to be of one order of magnitude apparent friction coefficients of fault zones differ between the north european part of the plate 0 4 0 7 the pannonian region 0 15 0 25 and the dinaric suture 0 55

the moho depth map of the european plate summary the european plate has a 4 5 gy long and complex tectonic history this is reflected in the present day large scale crustal structures a new digital moho depth map is compiled from more than 250 data sets of individual seismic profiles 3 d models obtained by body and surface waves receiver function results and maps of seismic and or gravity data compilations we have compiled the first digital high resolution map of the moho depth for the whole european plate extending from the mid atlantic ridge in the west to the ural mountains in the east and from the mediterranean sea in the south to the barents sea and spitsbergen in the arctic in the north in general three large domains within the european plate crust are visible the oldest archean and proterozoic crust has a thickness of 40 60 km the continental variscan and alpine crust has a thickness of 20 40 km and the youngest oceanic atlantic crust has a thickness of 10 20 km

crustal structure at the easternmost termination of the variscan belt based on celebration 2000 and alp 2002 data abstract the eastern margin of the variscan belt in europe comprises plate boundaries between continental blocks and terranes formed during different tectonic events the crustal structure of that complicated area was studied using the data of the international refraction experiments celebration 2000 and alp 2002 the seismic data were acquired along sw ne oriented refraction and wide angle reflection profiles cel10 and alp04 starting in the eastern alps passing through the moravo silesian zone of the bohemian massif and the fore sudetic monocline and terminating in the tesz in poland the data were interpreted by seismic tomographic inversion and by 2 d trial and error forward modelling of the p waves velocity models determine different types of the crust mantle transition reflecting variable crustal thickness and delimiting contacts of tectonic units in depth in the alpine area few km thick lvz with the vp of 5 1 km s 1 dipping to the sw and outcropping at the surface represents the molasse and helvetic flysch sediments overthrust by the northern calcareous alps with higher velocities in the bohemian massif lower velocities in the range of 5 0 5 6 km s 1 down to a depth of 5 km might represent the se termination of the elbe fault zone the fore sudetic monocline and the tesz are covered by sediments with the velocities in the range of 3 6 5 5 km s 1 to the maximum depth of 15 km beneath the mid polish trough the moho in the eastern alps is dipping to the sw reaching the depth of 43 45 km the lower crust at the eastern margin of the bohemian massif is characterized by elevated velocities and high vp gradient which seems to be a characteristic feature of the moravo silesian slightly different properties in the moravian and silesian units might be attributed to varying distances of the profile from the moldanubian thrust front as well as a different type of contact of the brunia with the moldanubian and its northern root sector the moho beneath the fore sudetic monocline is the most pronounced and is interpreted as the first order discontinuity at a depth of 30 km

pomeranian caledonides nw poland a collisional suture or thin skinned fold and thrust belt abstract a main goal of this study was to understand the character of the caledonian deformation front in pomerania nw poland and its relationship to the adjoining teisseyre tornquist zone ttz in the context of the avalonia baltica early palaeozoic collision since the pomeranian caledonides are concealed beneath 1 4 km thick platform cover of upper palaeozoic and mesozoic sediments we used a combination of potential field seismic and well data to investigate the basement architecture and structure of the lower palaeozoic rocks starting from a qualitative review of gravity and magnetic data we built a 2d gravity and magnetic model upon the polandspan pl1 5600 seismic reflection line and applied 3d gravity inversion for a depth to basement study using well tops a top lower palaeozoic horizon and lower palaeozoic isopach map were created we found out that the pomeranian caledonides represent a thin skinned fold and thrust belt involving ordovician and silurian sediments of the caledonian foreland basin the deformation front was developed due to the buttressing effect of a basement ramp occurring directly above the ttz the latter corresponds to a precambrian suture zone overprinted by successive extensional tectonics and buried beneath the foreland basin in northern poland the suture is defined by a remnant crustal keel still preserved underneath the ttz probably resulting from precambrian collision during formation of the rodinia paleocontinent we propose that the extension of the thor suture separating baltica and avalonia must exist west from the ttz probably in the rugen area in our interpretation the ttz represents an intra cratonic crustal discontinuity comparable to its nw prolongation the sorgenfrei tornquist zone that runs across the baltic sea sweden and denmark consequently the basement underlying the palaeozoic platform in nw poland may be considered to have been part of baltica in early palaeozoic times

polonaise 97 an international seismic experiment between precambrian and variscan europe in poland abstract the trans european suture zone tesz comprises a series of sutures that developed by palaeozoic amalgamation of the phanerozoic central europe onto the proterozoic baltica and east european plate during the formation of pangea within tesz the permian basin in poland forms the easternmost part of the permian central european basin which is bordered on the east by the east european craton eec and on the southwest by the bohemian massif the axis of the basin the mid polish trough parallels the edge of the eec the teisseyre tornquist zone ttz is a geological inversion zone in the polish trough a large seismic experiment the polonaise 97 project was conducted in poland during may of 1997 and targeted the deep structure of the tesz and the complex series of upper crustal features associated with it it included contributions from the geophysical communities in poland denmark the usa lithuania germany finland sweden and canada this large lithospheric seismic experiment deployed 613 instruments to record 64 shots along five profiles with a total length of about 2000 km moreover five multichannel seismic reflection stations 90 and 120 channels recorded all signals from shots two dimensional velocity models were derived by p wave tomographic inversion these models provide an initial interpretation of this massive data set and allow us to present a few significant seismic and tectonic observations one of the most important is a very distinct asymmetry between the maximum thickness of the sedimentary cover in the polish trough 16 20 km and the crustal root 50 km associated with tesz ttz

thermal properties of the crust and the lithosphere asthenosphere boundary in the area of poland from the heat flow variability and seismic data high resolution 3d seismic p wave velocity model of poland grad et al tectonophysics 666 188 210 2016 and corrected for paleoclimate heat flow map majorowicz and wybraniec int j earth sci 100 4 881 887 2011 gridded to a common mesh are used together with four independent thermal models of the crust and upper mantle to calculate heat flow variation with depth and geotherms heat flow at moho depth are calculated and mapped and both confirm large variability with an elevated mantle heat flow circa 30 40 mw m2 in the paleozoic platform which is some 10 20 mw m2 higher than moho heat flow in the north eastern and south eastern poland which belong to a variety of tectonic terranes the oldest precambrian craton younger cadomian trans european suture zone carpathians temperatures calculated for the crust show consistent pattern higher temperatures beneath the paleozoic platform and lower temperatures beneath the precambrian and cadomian units at 10 km depth this difference is about 150 c about 300 c at 20 km depth and about 400 c at 50 60 km assuming the calculated isotherm 580 c as curie temperature the magnetic crust thickness was determined as 5 10 km only beneath the polish basin circa 20 km in carpathians circa 30 km in sudetes and 35 40 km beneath the precambrian and cadomian units such a thick magnetic crust results from a great depth of curie temperature thick crystalline crust and thin sediments mantle heat flow variability is mainly correlating with measured surface heat flow and influences geotherms calculated thermal lab depth follows patterns of heat flow and moho heat flow variability through poland with thinnest lithosphere in the high surface heat flow and high mantle heat flow areas comparison of this thermal lab depth estimates with seismic data based lab depth shows general coincidences when precambrian craton vs paleozoic platform are considered along the p4 seismic experiment data model circa 190 km depth vs some 90 km depth respectively however significant differences exist in many areas and especially for the se poland when compared with map for the whole of poland compiled from other seismic reported data

strain localization due to structural in homogeneities in the central european basin system the large scale crustal deformations observed in the central european basin system cebs are the result of the interplay between several controlling factors among which lateral rheological heterogeneities play a key role we present a finite element integral thin sheet model of stress and strain distribution within the cebs unlike many previous models this study is based on thermo mechanical data to quantify the impact of lateral contrasts on the tectonic deformation elasto plastic material behaviour is used for both the mantle and the crust and the effects of the sedimentary fill are also investigated the consistency of model results is ensured through comparisons with observed data the results resemble the present day dynamics and kinematics when 1 a weak granite like lower crust below the elbe fault system is modelled in contrast to a stronger lower crust in the area extending north of the elbe line throughout the baltic region and 2 a transition domain in the upper mantle is considered between the shallow mantle of the variscan domain and the deep mantle beneath the east european craton eec extending from the elbe line in the south till the tornquist zone the strain localizations observed along these structural contrasts strongly enhance the dominant role played by large structural domains in stiffening the propagation of tectonic deformation and in controlling the basin formation and the evolution in the cebs

p and s wave velocity model of the southwestern margin of the precambrian east european craton polonaise 97 profile p3 the large scale seismic experiment polonaise 97 investigated the seismic structure of the crust and the uppermost mantle in the polish region of the trans european suture zone this paper covers the interpretation of seismic data along the 300 km long p3 profile which is located in the precambrian east european craton eec parallel to the teisseyre tornquist zone the recordings were of high quality with seismic energy detectable out to 300 km ovsets the crustal model developed by two dimensional raytracing forward modelling and waveform analysis is characterized by a subhorizontal uniform structure although the boundaries of several large basement features are crossed the crystalline crust consists of three parts the upper middle and lower crust with p wave velocities of 6 1 6 4 km s 6 55 6 7 km s and 7 05 7 15 km s respectively the p m p wave can usually be correlated at distances beginning at about 100 km but it has variable reflection character moho depth increases from 38 km at the nw end of the profile to 44 km at the se end the p n velocity of 8 05 8 1 km s is less than that previously found in neighbouring areas of the eec the v p v s ratio was determined separately for the upper middle and lower crust to be 1 67 and 1 77 respectively following the p n wave another phase with an apparent velocity of about 8 3 km si s interpreted as a weak reflection from a low contrast discontinuity in the uppermost mantle 1999 elsevier science b v all rights reserved

seismic and geological structure of the crust in the transition from baltica to palaeozoic europe in se poland celebration 2000 experiment profile cel02 abstract the celebration 2000 together with the earlier polonaise 97 deep seismic sounding experiments was aimed at the recognition of crustal structure in the border zone between the precambrian east european craton baltica and palaeozoic europe the cel02 profile of the celebration family is a 400 km long sw ne transect running in poland from the upper silesia block usb across the malopolska block mb and the trans european suture zone tesz to the east european craton eec the structure along cel02 was interpreted using both 2d tomography and forward ray tracing techniques as well as 2d gravity modelling the crustal thickness along cel02 varies from 32 35 km in the usb to 45 47 km beneath the tesz and the eec the usb is a clearly distinctive crustal block with the characteristic high velocity lower crust 7 1 7 2 km s interpreted as a fragment of gondwana the krakow lubliniec fault is a terrane boundary produced by soft docking of the usb with the mb the malopolska crust fundamentally differs from the usb and has a strong connection with baltica it is a transitional 150 to 200 km wide unit composed of the extended baltican lower crust and the overlying low velocity 5 15 5 9 km s neoproterozoic metasediments in the up to 18 km thick upper crust the ysogory unit has its crustal structure identical with that of malopolska thus it is connected with baltica and cannot be interpreted as a gondwana derived terrane higher velocity and density bodies found below the mazovia lublin graben at a depth of 12 km and at the base of the lower crust might be a result of mantle derived mafic intrusions accompanying the extension of baltica by the preliminary 2d gravity modelling we have reconfirmed the need for considering the increased tesz mantle density in comparison to the eec and usb mantle

2 d seismic tomographic and ray tracing modelling of the crustal structure across the sudetes mountains basing on sudetes 2003 experiment data the seismic data obtained during sudetes 2003 experiment are analysed and detailed crustal structure for profiles s02 s03 and s06 is presented using three different 2 d techniques 1 smooth tomography of refracted waves travel times 2 ray tracing of reflected and refracted waves and 3 joint velocity and depth of reflector tomographic inversion in spite of different interpretation techniques used the models of the crustal structure show common characteristic features the low velocity vp 4 km s sedimentary layer was documented in the northeastern part of the study area the topmost basement has in general a velocity of 5 8 6 0 km s and velocities at ca 20 km depth are 6 15 6 25 km s the strong reflecting boundaries were found at 20 23 and 25 28 km depth with a velocity contrast about 0 4 km s and the highest velocities in the lowermost crust are 6 8 7 2 km s in general the crust of the bohemian massif is slightly thicker 33 35 km than in the northern part of the area velocities beneath moho are relatively low of 7 95 km s on the basis of well recorded reflected waves mantle reflectors were discovered in the depth interval ca 40 70 km apart of new results for the geology and tectonics of the area some conclusion could be made about different techniques used in the 2 d case the clasical ray tracing method with using all correlated phases gives the most adequate model of the structure because of full manual control of the model creation the smooth first arrival travel times tomography although very fast is not satisfactory enough to describe the complex structure so the best candidate in 3 d case seems to be travel time tomography for both refracted and reflected waves in multi layers models

inversion related features along the southeastern margin of the north german basin elbe fault system abstract a seismostratigraphic approach constrained by well data is used for the interpretation of the deformation style along the central elbe fault system efs within the sedimentary succession structural analysis allows to qualify to quantify and to date tectonic events the stratigraphic interpretation is complicated by the mobilized upper permian zechstein salt and by erosional events a first order quantification of the inversion related uplift is estimated from vertical fault offsets that reach up to 4 km the main uplift occurred during the maastrichtian paleocene amounts of erosion inferred from comparing the strata thickness on top of the flechtingen high with the surrounding basinal areas range from 3 to 4 km the data indicate a changing deformation style thick skinned deformation with southwest dipping thrusts that vertically offset the pre permian basement is observed along the flechtingen high in the central part of the efs thin skinned deformation occurs in the north german basin where salt detaches the post permian cover from the barely faulted basement it is concluded that during the late cretaceous early tertiary inversion the efs responded to regional compression with uplift and formation of an internal high the flechtingen high a stress sensitive crustal weak zone beneath the efs could be the reason for the repeated strain localization in the area

the southern margin of the east european craton new results from seismic sounding and potential fields between the north sea and poland abstract the extension of eastern avalonia from britain through the ne german basin into poland is in some sense a virtual structure it is covered almost everywhere by late paleozoic and younger sediments evidence for this terrane is only gathered from geophysical data and age information derived from magmatic rocks during the last two decades much geophysical and geological information has been gathered since the european geotraverse egt which was followed by the babel lt 7 mona lisa dekorp basin 96 and polonaise 97 deep seismic experiments based on seismic lines a remarkable feature has been observed between the north sea and poland north of the elbe line el the lower crust is characterised by high velocities 6 8 7 0 km s a feature which seems to be characteristic for at least a major part of eastern avalonia far eastern avalonia in addition the seismic lines indicate that a wedge of the east european craton eec or baltica continues to the south below the southern permian basin spb a structure which resembles a passive continental margin the observed pattern may either indicate an extension of the baltic crust much farther south than earlier expected or oceanic crust of the tornquist sea trapped during the caledonian collision in either case the data require a reinterpretation of the docking mechanism of eastern avalonia and the elbe odra line eol as well as the elbe fault system together with the intra sudedic faults appear to be related to major changes in the deeper crustal structures separating the east european crust from the paleozoic agglomeration of middle european terranes

moho topography and lower crustal wide angle reflectivity around the tesz in southern scandinavia and northeastern europe abstract the moho topography is strongly undulating in southern scandinavia and northeastern europe a map of the depth to moho shows similarities between the areas of the teisseyre tornquist zone ttz in poland and the fennoscandian border zone fbz which is partly coinciding with the sorgenfrei tornquist zone stz in denmark the moho is steeply dipping at these zones from a crustal thickness of approximately 32 km in the young palaeozoic platform and basin areas to approximately 45 km in the old precambrian platform and baltic shield the moho reflectivity pmp waveform in the polonaise 97 refraction wide angle seismic data from poland and lithuania is variable ranging from sharp to strongly reverberating signals of up to 2 s duration there is little or no lower crustal wide angle reflectivity in the thick precambrian platform whereas lower crustal reflectivity in the thin palaeozoic platform is strongly reverberating suggesting that the reflective lower crust and upper mantle is a young phenomena from stochastic reflectivity modelling we conclude that alternating high and low velocity layers with average thicknesses of 50 300 m and p wave velocity variations of 3 4 of the background velocity can explain the lower crustal reflectivity sedimentary layering affects the reflectivity of deeper layers significantly and must be considered in reflectivity studies although the reverberations from the deeper crust cannot be explained by the sedimentary layering only the reflective lower crust and upper mantle may correspond to a zone that has been intruded by mafic melts from the mantle during crustal extension and volcanism

crustal structure of the trans european suture zone region along polonaise 97 seismic profile p4 1 the large scale polonaise 97 seismic experiment investigated the velocity structure of the crust and upper mantle in the trans european suture zone tesz region between the precambrian east european craton eec and paleozoic platform that comprises terranes added during the caledonian and variscan orogenies 530 370 and 370 225 ma respectively this experiment included 64 shots recorded by 613 seismic stations during two deployments very good quality data were recorded along five profiles and the longest and most important one p4 is the focus of this paper clear first arrivals and later phases of waves reflected refracted in the crust and moho were interpreted using two dimensional 2 d tomographic inversion and ray tracing techniques the crustal thickness along the profile varies from 30 35 km in the paleozoic platform area to 40 km below and due northeast of the tesz to 43 km in the polish part of the eec and to 50 km in lithuania the paleozoic platform and eec are divided by the polish basin so the upper crustal structure varies considerably in the area of the polish basin the p wave velocity is very low vp 6 1 km s down to depths of 15 20 km indicating that a very thick sedimentary sequence is present we suggest two possible tectonic interpretations of the velocity models 1 baltica indented avalonia obducting its upper crust and underthrusting its lower crust in a tectonic flake structure and 2 a rifted margin of baltica underlies the polish basin this model is similar to other interpretations of seismic profiles recorded in the baltic sea the second model implies that the paleozoic platform solely consists of avalonian lithosphere and the eec of baltica lithosphere it offers a simple explanation of the difference in crustal thickness of the two platforms it also implies that the caledonian and variscan orogenies in this area were relatively soft collisions that left this continental margin largely intact

deep structure of the earth s crust in the contact zone of the palaeozoic and precambrian platforms in poland tornquist teisseyre zone abstract one of the major tectonic problems in europe concerns the southwest margin of the east european platform in the region of the so called polish danish trough in general this margin is assumed to be the tornquist teisseyre t t line running approximately from northwest to southeast in this part of europe determination of deep crustal structure of the contact zone between the precambrian platform and the palaeozoic platform was the main aim of the deep seismic sounding dss programme in poland in 1965 1982 deep seismic soundings of the earth s crust have been made in the t t line zone along nine profiles with a total length of about 2600 km the results of deep seismic soundings have shown that the crust in the marginal zone of the east european platform has highly anomalous properties the width of this zone ranges from 50 km in northwest poland to about 90 km in southeast poland the crustal thickness of the palaeozoic platform in poland is 30 35 km and of the precambrian platform 42 47 km while in the t t tectonic zone it varies from 50 to 55 km above the moho boundary in the t t zone at a depth of 40 45 km there is a seismic discontinuity with p wave velocities of 7 5 7 7 km s boundary velocities mean velocities and stratification of the earth s crust vary distinctly along the t t zone there are also observed high gravimetric and magnetic anomalies in the t t zone the t t tectonic zone determined in this manner is a deep tectonic trough with rift properties the deep fractures delineating the t t tectonic zone are of fundamental importance for the localization of the plate edge of the precambrian platform of eastern europe in the light of dss results the northeastern margin of the t t tectonic zone is a former plate boundary of the east european platform

seismic structure across the caledonian deformation front along mona lisa profile 1 in the southeastern north sea abstract seismic data from the mona lisa marine and onshore north sea acquisition for lithospheric seismic analysis project in the southeastern north sea image the caledonian deformation front cdf which is the collisional suture between baltica to the north and east and avalonia to the south and west the n s trending mona lisa normal incidence reflection profile 1 was recorded to 26 s twt coincident wide angle data were acquired on nine ocean bottom hydrophones and several onshore mobile seismographs along and off the profile the model of compressional seismic velocity shows three different crustal types a a typical three layered shield type crust below the ringkobing fyn high to the north b a highly complex transitional crust in the central part and c a two layered crust of caledonian origin to the south sharp and strong normal incidence and wide angle reflections from moho were recorded south of the caledonian deformation front in contrast to less distinct reflections further north s dipping crustal reflections from 4 to 11 s twt over 70 km horizontal distance terminate at moho and coincide with a change in the seismic velocity structure this indicates northward obduction of avalonian crust non migrated normal incidence seismic sections show crossing weak n dipping and stronger s dipping reflections to 20 s twt from the uppermost mantle we propose a tectonic model where the closure of the tornquist sea took place along a n dipping subduction zone which was later overprinted by a late or post caledonian s dipping shear zone sub moho velocities are 7 8 7 9 km s under 34 35 km thick baltica crust and 8 1 8 3 km s under 25 26 km thick caledonian crust the sub horizontal moho across the caledonian collision zone implies late or post caledonian re equilibration of the seismological moho we interpret the low velocity upper mantle 7 8 8 1 km s to the north as former baltica lower crust in eclogite facies after pressure induced metamorphism as a result of lithospheric flexure during the caledonian orogeny these rocks today appear as upper mantle that was uplifted to their present position during the middle devonian collapse of the north german polish caledonides