the effects of a lateral variation in lithospheric strength on foredeep evolution implications for the east carpathian foredeep abstract lateral variations in lithospheric strength have been adopted often in flexural modeling both 2d and 3d to better fit the observed basement deflections typically supported by gravity data this approach provides essentially a snap shot of the role of lithosphere strength in determining the present day geometry in contrast we investigate and quantify the effects of a lateral change in lithospheric strength on the evolution of the foredeep in front of an advancing orogen transitions in lithospheric strength are common in the foreland of orogens and show large variations in the width of the transition zone and the strength difference former passive margins for instance will display strength changes distributed over several tens to hundreds of kilometers other transitions may originate from juxtaposition or accretion of pieces of lithosphere with different properties and may be characterized by a much smaller width than former passive margins in our modeling a constant load representing an advancing orogenic belt is displaced towards and across a transition from a weak to a strong plate in a 2d elastic thin plate model the effect of different transition widths and strength contrasts on foredeep geometry and bending stress is investigated interference of flexural wavelengths across the transition affects foredeep geometry by causing rapid basin widening oscillation of the bulge and volume increase the bending stresses are found to concentrate and amplify around the strength transition large transition gradients i e large strength contrast or small transition width cause the highest rates of change basin widening caused by the orogenic load advancing towards the transition between the east european craton and the moesian platform appears to control the sarmatian transgression over the east carpathian foreland in romania

cretaceous sedimentation in the outer eastern carpathians implications for the facies model reconstruction of the moldavide basin abstract the mid cretaceous is characterized by high eustatic sea levels with widespread oxic conditions that made possible the occurrence of globally correlated oceanic red beds however very often these eustatic signals have been overprinted by local tectonics which in turn resulted in lower cretaceous closed and anoxic basins as in the eastern carpathians there the black shale to red bed transition occurs in the latest albian up to the early cenomanian although earlier studies discussed the large scale basin configuration no detailed petrography and sedimentology study has been performed in the eastern carpathians this paper describes the hauterivian to turonian lithofacies and interprets the depositional settings based on their sedimentological features the studied sections crop out only in tectonic half windows of the eastern carpathians part of the vrancea nappe the lithofacies comprises black shales interbedded with siderites and sandstones calcarenites marls radiolarites and red shales the siliciclastic muddy lithofacies in general reflects accumulation by suspension settling of pelagites and hemipelagites in anoxic black shale to dysoxic dark gray and gray to green shales and oxic red shales conditions the radiolarites alternate with siliceous shales and are considered as evidence of climate changes the sandstones represent mostly low and high density turbidite currents in deep marine lobes as well as channel levee systems the source area is an eastern one e g the eastern carpathians foreland given the abundance of low grade metamorphic clasts the hauterivian lower albian sediments are interpreted as deep marine linear and multiple sourced mud dominated systems deposited in a mainly anoxic to dysoxic basin the anoxic conditions existed in the early to late albian but sedimentation changed to a higher energy mud sand dominated submarine channels and levees this coarsening upwards tendency is interpreted as the effect of the aptian to albian compressional tectonics of the carpathians the deepening of the moldavide basin from the cenomanian is most probably linked to a significant sea level rise

stratigraphic and geochemical study of the organic rich black shales in the tarcău nappe of the moldavidian domain carpathian chain romania an integrated stratigraphic analysis has been made of the tarc u nappe moldavidian domain eastern romanian carpathians coupled with a geochemical study of organic rich beds two main sequence boundaries early oligocene and near to the oligocene aquitanian boundary respectively divide the sedimentary record into three depositional sequences the sedimentation occurred in the central area of a basin supplied by different and opposite sources the high amount of siliciclastics at the beginning of the miocene marks the activation of the foredeep stage the successions studied are younger than previously thought and they more accurately date the deformation of the different miocene phases affecting the moldavidian basin the intervals with black shales identified are related to two main separate anoxic episodes with an age not older than late rupelian and not before late chattian the most important organic rich beds correspond to the lower menilites bituminous marls and lower dysodilic shales members interval 2 these constitute a good potential source rock for petroleum with homogeneous type ii oil prone organic matter highly lipidic and thermally immature the deposition of black shales has been interpreted as occurring within a deep periodically isolated and tectonically controlled basin

stratigraphic and kinematic modeling of thrust evolution northern apennines italy we present a quantitative kinematic model of thrust evolution that allows detailed interpretation of the stratigraphic record of foreland basins simulation of thrusting and syntectonic sedimentation shows that changes in the relative rate of thrusting and mode of thrust activation can be determined by their expression in basin stratigraphy truncations and offlaps reflect thrust activity and hinterland migration of basin depocenters indicates out of sequence thrusting forward modeling of the stratigraphic record of the pliocene quaternary po basin italy enables the quantitative reconstruction of the displacement sequence of the thrust sheets prograding into the basin during the pliocene deep seated middle pliocene thrusting accompanied by out of sequence thrusting provides a consistent explanation for the observed stratigraphic record of the po piggyback basins

paleomagnetic and magnetic fabric data from lower triassic redbeds of the central western carpathians new constraints on the paleogeographic and tectonic evolution of the carpathian region in the central western carpathians cwc most published paleomagnetic results from permo mesozoic rocks document extensive remagnetizations and come from thin skinned thrust units that have undergone multistage deformation we present results from lower triassic redbeds from the autochthonous cover overlying the basement that carry a primary magnetization petromagnetic results indicate that the dominant ferromagnetic carrier is hematite while magnetic susceptibility and its anisotropy are controlled by both ferromagnetic and paramagnetic minerals magnetic fabrics document weak deformation related to late cretaceous shortening the directions of the high unblocking temperature remanence components pass both reversal and fold tests attesting to their primary nature paleomagnetic inclinations are flatter than expected from reference datasets suggesting small latitudinal separation between the cwc and stable europe paleomagnetic declinations are mostly clustered within individual mountain massifs implying their tectonic coherence they show only minor differences between the massifs indicating a lack of significant vertical axis tectonic rotations within the studied central parts of the cwc the paleomagnetic declinations are therefore representative of the whole of the cwc in terms of regional paleogeographic interpretations and imply moderate counterclockwise rotations c 26 of the region with respect to stable europe since the early triassic

automated coregistration of repeat digital elevation models for surface elevation change measurement using geometric constraints a large archive of digital elevation model dem data spanning more than a decade is now available for a wide range of earth surface process studies precise coregistration is a critical step for obtaining accurate elevation change measurements from repeat dems we present an algorithm for coregistering stereoscopic gridded dems that includes an automatic detection of control surfaces a reliable estimation technique for defining a geometric relationship between dems through a 3 d conformal transformation and a quality check qc for the confidence of the coregistration for the control surface detection we use a geometric constraint approach that uses similarities in slope aspect and height undulation as observation weights in an iterative transformation model solution the qc is possible through the evaluation of the geometric similarities and the amount of detected relatively unchanged surfaces we test our algorithm using a sample of repeat stereoscopic gridded dems from multiple sources over a rapidly changing glacier in greenland the algorithm results on average in a 24 decrease in the standard error as obtained from elevation over stationary surfaces the result is not sensitive to the distribution of the control surface the qc metric provides a simple and effective criterion for parsing result quality in large data sets surface height decreases of 110 and 200 m at the up glacier and down glacier ends of kangerdlugssuaq glacier in greenland are observed between april 2001 and june 2010 respectively

geometry and kinematics of the north monagas thrust belt venezuela abstract the complex geometry and structural evolution of the north monagas thrust belt were investigated and new exploration trends in this part of eastern venezuela considered the pirital thrust and related structures of the maturin basin are used to discuss the sequence of thrusting and to illustrate the constant balance between erosion and thrust reactivation in a recent fold and thrust belt a careful analysis of the chronostratigraphy and the internal geometry of the foredeep and piggy back syntectonic deposits has been used to constrain balanced cross sections and to establish the kinematics of each individual structure basement involvement is postulated for the pirital thrust which remobilizes previously emplaced cover structures such as the el furrial or orocual structural units it thus probably relates to the pinch out of a shallow decollement level coal measures of the barranquin formation older late jurassic to lower cretaceous evaporites or other mesozoic plastic horizons and to the reactivation of a deeper basement fault the westward emergence of the pirital and el furrial thrusts in a complex transfer area the urica fault is also analysed according to transverse profiles the surficial urica fault does not connect directly to a basement fault but instead acts as a lateral ramp for the el furrial cover unit and as a tear fault for the pirital thrust reactivation of ancient thrust faults also occurs at the rear of the pirital thrust in the west in areas where the topographic profile of the eastern venezuelan ranges has recently been modified by the pirital thrust emplacement these out of sequence thrusts resulting from fault reactivation in the inner parts of the prism are discussed in terms of the preservation of the critical taper they effectively relate directly to erosional processes which significantly decrease the load applied on this portion of the wedge the influence of the sequence of thrusting on the potential plays is considered

the evolution of the carpathians pannonian system interaction between neotectonics deep structure polyphase orogeny and sedimentary basins in a source to sink natural laboratory abstract the carpathians pannonian basin system provides a natural laboratory for analysing lithospheric to surface controls on tectonic topography development in a coupled source to sink environment to link processes taking place at depth and at the surface recent research focused on the interplay between basin evolution active tectonics topography evolution and intraplate folding mechanisms neotectonic processes control landscape development and natural hazards in particular the seismicity during the late stage late neogene quaternary evolution of both the carpathians pannonian basin system and its interaction with the adjacent dinarides and balkans the deep structure of the se carpathians exerts a strong control on the post collisional evolution of the system new constraints are available from seismic tomography deep seismic reflection and refraction profiling and detailed studies of the vreancea seismicity inherited orogenic fabric and structure of the active black sea sink has a strong influence on the localisation of the neogene sediment pathways a close relationship has been established between the timing and mechanisms of stress changes in the pannonian and transylvania basins and structural episodes in the surrounding thrust belts pointing to an intrinsic mechanical coupling with these basins the orogen and its foredeep basin inversion taking place during the pliocene quaternary times in the entire carpathians pannonian system is related to changes in the regional stress field leading to differential vertical movements associated with a laterally variable folding mechanism active in the entire system short crustal folding patterns alternate with lithospheric wavelengths in the se carpathians foreland east and south carpathians transylvania and pannonian basins the lateral variability is the result of a marked contrast in rheology between these areas directly related to the crustal configuration thermal properties and late stage collision kinematics with the carpathians foreland lateral variations in the properties of the downgoing plates largely control the collision mode in the carpathians and the post collisional evolution of the entire system

consequences of foreland basin development on thinned continental lithosphere application to the aquitaine basin sw france abstract we present an analysis of the consequences of foreland basin development on thinned continental lithosphere inherited from pre orogenic phases of extension bathymetry at the transition from pre orogenic extensional basin to foreland basin and compaction of pre orogenic sediments contribute to the accommodation space for foreland basin sediments and thrust loads in addition the extension induced transient thermal state of the lithosphere results in ongoing thermal subsidence and a flexural rigidity which changes through time quantitative modelling of the phase of extension and the foreland basin stage of the aquitaine basin southern france shows that the inherited transient thermal state of the lithosphere contributes significantly to 1 the total foreland basin depth and width 2 the post compressional subsidence history and 3 the cratonward onlap pattern accounting for the thermo mechanical effects of pre orogenic extension significantly reduces the estimates of both the flexural rigidity 30 43 for the aquitaine basin and the required topographic or thrust load 40 for the aquitaine basin at foreland basins emplacement of thrust loads below sea level as expected in a pre orogenic extensional basin setting further reduces the required topographic load this sheds light on the wide range of flexural rigidity values reported for continental lithosphere from foreland basin modelling studies and explains in many instances the inferred hidden load or subsurface load in flexural modelling studies at foreland basins the present study has shown that pre orogenic extension phases significantly affect the record of vertical motion and the stratigraphy of the aquitaine basin and is probably important for foreland basin evolution in general

computerized x ray tomography analysis of sandbox models examples of thin skinned thrust systems computerized x ray tomography applied to analog sandbox experiments performed in a normal gravity field makes possible the analysis of the kinematic evolution as well as the three dimensional geometry of models that simulate tectonic deformations most of the plastic or viscous analog materials generally used in a normal gravity field for such models have x ray attenuations compatible with medical scanner images models using soft cohesionless granular materials were studied faults in granular materials corresponding to dilatant zones with lower by 30 50 x ray attenuation are thus clearly visible in the tomography images kinematic analysis was done on imbricate thrust propagation in materials with an internal friction angle of 30 thrust propagation is controlled mainly by a triangular pop up structure resulting from the nucleation of two conjugate thrusts at the basal decollement the pop up structure is created immediately in front of the previous thrust three dimensional geometry analysis was tested on lateral ramps parallel to the transport direction lateral ramps were induced by changing the frictional boundary conditions at the bottom of the model though the lateral ramps strike almost parallel to the transport direction their dip angle is comparable to the dip angle of frontal ramps

lower cretaceous provenance and sedimentary deposition in the eastern carpathians inferences for the evolution of the subducted oceanic domain and its european passive continental margin

neogene quaternary magmatism and geodynamics in the carpathian pannonian region a synthesis in the carpathian pannonian region in neogene times westward dipping subduction in a land locked basin caused collision of two lithospheric blocks alcapa and tisia with the southeastern border of the european plate calc alkaline and alkaline magmatism was closely related to subduction rollback collision and extension from the spatial distribution of the magmatic activity four segments can be defined western segment magmatism occurring on the alcapa block central segment magmatism occurring on both alcapa and the tisia blocks south eastern segment and interior segment both on the tisia block most calc alkaline magmatism in the region resulted from melting of a heterogeneous asthenospheric mantle source modified by addition of fluids and sediment assimilation and fractionation processes at shallow crustal levels occurred in most of the segments strongly masking the deeper source processes long term subduction rollback and or delamination led to contamination of the asthenosphere beneath the western segment here large volume partial melts of the contaminated mantle caused underplating and crustal anatexis leading to mixing of mantle derived calc alkaline magmas with crustal melts in the central segment calc alkaline magmas were formed by subduction and rollback followed by back arc extension and slab breakoff avariable mantle source is indicated in the back arc setting and larger amount of fluid induced metasomatism source enrichment and assimilation nearer to the trench in the interior segment evolution from typical calc alkaline magmas to adakite like ones was related to extension due to fast rotations and transtensional tectonics here calc alkaline magmas formed by decompression melting of a heterogeneous crust mantle lithosphere while adakite like melts resulted from fliud dominated melting of the lithosphere along the south eastern segment slab breakoff was responsible for the generation of typical calcalkaline magmas but in the extreme south of the segment shallow level tearing of the slab followed breakoff strike slip tectonics allowed the rise of hot asthenosphere and generation of adakite like magmas via slab melting along the torn edge of the east european plate alkalic basaltic volcanism with an oib like asthenosphere source followed the calc alkaline stage

on late oligocene to pliocene depocentre migrations and the evolution of the carpathian pannonian system abstract the late oligocene to pliocene evolution of foredeep basins of the eastern alps carpathians fold and thrust belt is marked by pronounced internal to external and lateral depocentre shifts the latter shifts covering a present along arc distance of 1700 km portray accelerating rates of foredeep depocentre migration particularly so in the late early and in the middle miocene from about 7 to about 45 cm yr lateral depocentre migration came to a close at the beginning of the late miocene the subsequent late miocene to pliocene foredeep infill history was characterized by exponentially increasing accumulation rates in the intersection area of the east european ukrainian and moesian platforms successive steps in the evolution of the foredeep basins had pronounced counterparts in the intra carpathian area the beginning of acceleration of foredeep depocentre migration in latest early miocene times was coeval with the inception of intra carpathian extensional tectonics the extremely rapid middle miocene depocentre shift coupled with a change in direction of foredeep depocentre migration corresponded with maximum extension in the intra carpathian area the ensuing end of foredeep depocentre migration around the middle late miocene transition was coeval with the end of extension of the intra carpathian area which in turn was followed by the inception of overall thermal subsidence at about 11 5 ma the timing of and spatial relationships between discrete coeval events in arc and intra arc evolution put unambiguous geological constraints on geodynamic modelling of the evolution of the carpathian pannonian system it is speculated that the geological observations may best be understood in terms of the surficial effects of lateral migration of slab detachment such effects would mirror the dominant role of a concentrating slab pull taken to result in e g a time progressive acceleration of foredeep depocentre migration

late cretaceous and cenozoic intra plate compressional deformations in the alpine foreland a geodynamic model abstract the mesozoic grabens and wrench induced troughs of western and central europe developed in response to triassic early cretaceous intra plate tensional stresses which affected the arctic north atlantic and the tethys borderlands during the rifting phase preceding the opening of the respective oceans this resulted in the fragmentation of the continental crust of the alpine foreland during the late cretaceous and tertiary alpine orogeny collision related compressive stresses exerted on the foreland induced the reactivation of these fracture systems causing the inversion of mesozoic grabens and the uplifting of major basement blocks at distances up to 1300 km to the north of the present alpine deformation front the structural style of these inverted basins and basement uplifts is indicative of compressional and transpressional deformations the total amount of crustal shortening associated with these deformations is unlikely to exceed a few tens of kilometres these displacements require a coupling between the foreland and the orogen at the alpine a subduction zones and within the foreland a decoupling at intra crustal levels between the crust and mantle and or at deeper lithospheric levels the example of the alpine foreland indicates that compressive stresses inducing major deformations can be transmitted from a collisional plate boundary through continental lithosphere over distances of up to 1300 km circumstantial evidence suggests that collision related compressive stresses not large enough to give rise to significant deformations can be transmitted through continental lithosphere over even greater distances

the neogene evolution of the outer carpathian flysch units poland ukraine and romania kinematics of a foreland fold and thrust belt system abstract various techniques of geometric and kinematic analyses including cross section balancing and forward modeling have been applied successfully to the outer carpathian flysch units along regional geologic profiles crossing the belt from its undeformed foreland to the pieniny klippen belt western carpathians poland or to the central east carpathian allochthon eastern carpathians ukraine and romania the amounts of neogene shortening as well as the mode and the location of basement consumption are discussed on the basis of balanced cross sections compiled along the three most representative regional traverses in addition the complete kinematic evolution of complex carpathian structures such as the fore dukla triangle zone southeastern poland the borislav pokut duplexes ukraine and the marginal folds romania are described in more detail by using a forward modeling approach major results concern the tectonic heritage of laramian inverted structures mesozoic normal faults reactivated as reverse faults during the late cretaceous paleocene compression or transpression in the development of the neogene outer carpathian edifice pre eocene deformation and erosion effectively induce discontinuities in the mid cretaceous blackshale detachment horizon and help to localize the neogene deformations in complex triangle zones the thrust sequence itself evolves alternatively in a piggyback or in an out of sequence mode clearly the critical taper of the outer carpathians is preserved by a constant balance between erosion and thrust reactivations in the inner part of the wedge and sedimentation and tectonic accretion at its front

the link between tectonics and sedimentation in back arc basins new genetic constraints from the analysis of the pannonian basin the architecture of sedimentary basins reflects the relationship between accommodation space and sediment supply their rates and localization being variable during basin evolution the mechanisms driving the interplay between tectonics and sedimentation in extensional back arc basins overlying rheological weak zones inherited from an earlier orogenic evolution are less understood a typical example is the pannonian back arc basin of central europe it is floored by continental lithosphere and was affected by large amounts of extension driven by the subduction rollback that took place in the carpathians and or dinarides a novel kinematic and seismic sequence stratigraphic interpretation calibrated by wells allows the quantification of the link between the formation of half grabens and coeval sedimentation in the great hungarian plain part of the basin while the lower order tectonic induced cycles characterize the main phases of extension in various subbasins the higher order cyclicity and associated unconformities define individual moments of fault re activation our novel interpretation of a temporal and spatial migration of extension during miocene times explains the contrasting present day strike of various subbasins as a result of their gradual clockwise rotation incorporating the observed asymmetry in particular the associated footwall exhumation infers that the amount of extension is much larger than previously thought the quantitative link between tectonics and sedimentation has allowed the definition of a novel model of sedimentation in asymmetric basins that can be ported to other natural scenarios of similarly hyperextended back arc basins observed elsewhere

building and exhumation of the western carpathians new constraints from sequentially restored balanced cross sections integrated with low temperature thermochronometry western carpathian orogeny has been the subject of intense scientific debate due to the occurrence of enigmatic features leading several authors to provide contrasting geological models in this paper a new interpretation for the tectonic evolution of the western carpathians is provided based on i an analysis of the stratigraphy of the mesozoic tertiary successions across the thrust belt domains ii a reappraisal of the stratigraphy and sedimentology of the tectonic melange i e the so called pieniny klippen belt marking the suture between the inner and outer carpathians and iii the construction of a series of balanced and restored cross sections validated by 2d forward modeling our analysis provides a robust correlation of the stratigraphy from the outer to the inner carpathians independently of the occurrence of oceanic lithosphere in the area and allows for the reinterpretation of the tectonic relationships among the inner carpathians the outer carpathians and the pieniny klippen belt and the exhumation mechanisms affecting this orogenic belt in order to constrain the evolution during the last 20 ma our model also integrates previously published and new apatite fission track and apatite u th sm he data these latter indicate a middle late miocene exhumation of the pieniny klippen belt in this study the recent regional uplift of the pieniny klippen belt is described for the first time using a 2d kinematic model for the tectonic evolution of the western carpathians

architecture and orogenic evolution of the northeastern outer carpathians from cross section balancing and forward modeling abstract new balanced and restored cross sections and a 2d kinematic model illustrate the present geometry of the northeastern outer carpathians and quantify their orogenic evolution between the late eocene and the late miocene 35 3 to 11 0 ma the balanced cross section is built on extensive surface and subsurface data and depicts an imbricate fan internally stacked along high displacement out of sequence thrusts section restoration yielded 507 km of minimum orogenic shortening at least 230 km more than proposed in previous studies our shortening estimate relies on accurate thicknesses of lithostratigraphic units in most cases thinner than applied before the average convergence rate between 35 3 and 11 0 ma is estimated at 20 8 km my the forward model constrained by lower and upper ages of syn orogenic deposits traces the advance of the outer carpathian accretionary wedge and proves kinematic admissibility of the balanced and restored cross sections progradation rates of the foreland basin depositional sequences evolving from 9 11 km my between 41 5 and 21 1 ma to 22 39 km my between 21 1 and 11 0 ma suggest a two phase dynamics of the orogenic system the acceleration of foreland migration at 21 1 ma likely reflects the onset of northward subduction retreat linked to the rollback of the european lower plate that gave rise to coeval back arc extension in the pannonian basin

magmagenesis in a subduction related post collisional volcanic arc segment the ukrainian carpathians abstract calc alkaline magmatism in the south west ukraine occurred between 13 8 and 9 1 ma and formed an integral part of the neogene subduction related post collisional carpathian volcanic arc eruptions occurred contemporaneously in two parallel arcs here termed outer arc and inner arc in the ukrainian part of the carpathians outer arc rocks mainly andesites are characterized by lile enrichment e g k and pb nb depletion low compatible trace element abundances high 87sr 86sr high 18o and low 143nd 144nd isotopic ratios 0 7085 0 7095 7 01 8 53 0 51230 0 51245 respectively inner arc rocks are mostly dacites and rhyolites with some basaltic and andesitic lavas they also show low compatible element abundances but have lower 87sr 86sr 18o and higher 143nd 144nd ratios 0 7060 0 7085 6 15 6 64 0 5125 0 5126 respectively than outer arc rocks both high nb and low nb lithologies are present in the inner arc based on the lile enrichment especially pb a higher fluid flux is suggested for the outer arc magmas compared with those of the inner arc combined trace element and sr nd o isotopic modelling suggests that the factors which controlled the generation and evolution of magmas were complex compositional differences between the inner and outer arcs were produced by introduction of variable proportions of slab derived sediments and fluids into a heterogeneous mantle wedge and by different extents of upper crustal contamination degrees of magmatic fractionation also differed between the two arcs the most primitive magmas belong to the inner arc isotopic modelling shows that they can be produced by adding 3 8 subducted terrigenous flysch sediments to the local mantle wedge source up to 5 upper crustal contamination has been modelled for fractionated products of the inner arc the geochemical features of outer arc rocks suggest that they were generated from mantle wedge melts similar to the inner arc primitive magmas but were strongly affected by both source enrichment and upper crustal contamination assimilation of 10 20 bulk upper crust is required in the afc modelling assuming an inner arc parental magma we suggest that magmagenesis is closely related to the complex geotectonic evolution of the carpathian area several tectonic and kinematic factors are significant 1 hydration of the asthenosphere during subduction and plate rollback directly related to collisional processes 2 thermal disturbance caused by ascent of hot asthenospheric mantle during the back arc opening of the pannonian basin 3 clockwise translational movements of the intracarpathian terranes which facilitated eruption of the magmas

modelling of piggyback basin stratigraphy record of tectonic evolution abstract the tectono stratigraphic evolution of foreland basins is influenced by processes acting on local regional and global scale in this paper the effects of these processes on the basin evolution are investigated using a forward reconstruction model based on the principles of balanced cross section the modelling incorporates the consequences of thrust deformation sedimentation erosion basement subsidence and sealevel changes on the basin stratigraphy basement subsidence due to lithospheric loading is the main cause of foreland basin formation but appears to have minor implications for the occurrence of angular unconformities in the stratigraphie record of piggyback basins thrusting is probably the dominant factor in the control of the stratigraphie evolution of piggyback basins overprinting the effect of eustasy detailed analyses of stratigraphie data enable the reconstruction of the structural evolution of the underlying thrust system modelling of the northern apenninic po basin shows that neogene stratigraphie sequences of the proximal part of the basin can be explained by tectonic activity of the apenninic fold and thrust belt strong basement subsidence accompanied with deep seated mid pliocene thrusting controls the stratigraphie record of the po piggyback basins

tertiary evolution of the intra carpathian area a model abstract the outer carpathian flysch nappes encircle an intra carpathian domain which can be divided into two megatectonic units north pannonian and tisza mostly on the basis of contrasting mesozoic and palaeogene facies development we see two major kinematic problems to be solved 1 1 the present distribution of the mesozoic and palaeogene facies is mosaic like and some belts form exotic bodies within realms of austroalpine affinity 2 2 late eocene palinspastic reconstruction of the outer carpathian flysch nappes suggest that the entire intra carpathian area must have been located several hundreds of kilometres to the south and to the west of its present position neogene extension can account for shortening in the external carpathian nappes but is unable to explain mesozoic facies anomalies and offsets of palaeogene formations we suggest that evolution of the intra carpathian area involved first late palaeogene early miocene juxtaposition of the north pannonian and tisza megatectonic units accompanied by the closure of the external carpathian flysch troughs thereafter extension of this amalgamated unit occurred which was compensated by thrusting of flysch nappes onto the european foreland and formation of molasse foredeeps eastward escape of the north pannonian unit from the alpine collisional belt involved left lateral shear along the pieniny klippen belt and right lateral shear along the mid hungarian zone parts of the late palaeogene basin and an early miocene volcanic edifice were dissected offset and elongated by several 100 kms the driving mechanism of the eastward escape of the intra carpathian area can be related to the collision of apulia and europe and the subduction of the external carpathian crust under the pannonian units the escape ceased gradually in the early miocene when oblique collision between the north pannonian unit and european continent occurred neogene extension of the pannonian region was an areal deformation the extension at locally variable rate resulted in the break up of the heterogenous floor of the neogene basin the driving mechanism of basin extension and contemporaneous compressional deformation of the external carpathians is thought to be related to ongoing subduction involving the marginal part of the attenuated european continental crust tectonic activity in the carpathians and basin subsidence and volcanism shifted in time and in unison from the west toward the east southeast

classification of rifted sedimentary basins of the pannonian basin system according to the structural genesis evolutionary history and hydrocarbon maturation zones abstract we apply the concept that sedimentary basins can be classified according to their structural genesis and evolutionary history to the tertiary rifts of the pannonian basin of eastern europe we have approached the classification by breaking the basins down into the cycles or stages that they comprise this approach helps us to understand the basin evolution better and allows us to compare the basins more easily the drivers that define the cycles of basin history are 1 basin forming tectonics 2 sedimentary processes and 3 basin modifying tectonics we link common elements of petroleum systems and plays to these natural cycles or stages in basin evolution to improve the prediction of which plays could be expected to occur in a particular basin or region this concept is constructed through several steps these steps are 1 to identify standard evolutionary patterns related to geodynamic drivers 2 to group the basins with similar tectono stratigraphic evolution and correlate these with petroleum system development 3 to relate basin trap types to basin history and 4 to calculate characteristic hydrocarbon maturation zones by thermal modeling we present an application to the pannonian basin system of eastern europe an area formed by miocene back arc extension and affected by compressional reactivation during its late stage evolution the sub basins of the pannonian basin system appear to have experienced comparable magnitudes of deformation to have developed similar trap types and to have experienced a characteristic hydrocarbon maturation history in a way that supports play prospectivity

revised crustal architecture of the southeastern carpathian foreland from active and passive seismic data 1 integration of active and passive source seismic data is employed in order to study the nature of the relationships between crustal seismicity and geologic structures in the southeastern se carpathian foreland of romania and the possible connection with the vrancea seismogenic zone vsz of intermediate depth seismicity one of the most active earthquake prone areas in europe crustal epicenters and focal mechanisms are correlated with four deep industry seismic profiles the reprocessed danube and carpathian integrated action on process in the lithosphere and neotectonics dacia plan profile and the deep reflection acquisition constraining unusual lithospheric activity ii and iii dracula profiles in order to understand the link between neotectonic foreland deformation and vrancea mantle seismicity projection of crustal foreland hypocenters onto deep seismic profiles identifies several active crustal faults in the se carpathian foreland and suggests a mechanical coupling between the mantle located vsz and the overlying foreland crust the coupled associated deformation appears to take place on the trotus fault the sinaia fault and the newly detected ialomita fault seismic reflection imaging reveals the absence of west dipping reflectors in the crystalline crust and a slightly east dipping to horizontal moho in the proximity of the vrancea area these findings argue against previously purported mechanisms to generate mantle seismicity in the vsz including oceanic lithosphere subduction in place and oceanic slab break off furthermore suggesting that the vrancea seismogenic body is undetached from the overlying crust in the foreland

thermal evolution and geometry of the descending lithosphere beneath the se carpathians an insight from the past abstract mantle heterogeneities imaged by seismic tomography in the se carpathians contain information on the present thermal state of the mantle based on p wave seismic velocity anomalies we develop a model of the present mantle temperature beneath the region and combine the model with a model of crustal temperature constrained by heat flow data the modeled temperatures are assimilated into the geological past using the information on the regional movement in the early and middle miocene prominent thermal states of the lithospheric slab descending in the region are restored from its diffuse present state in miocene times the slab geometry clearly shows two portions of the sinking body the northwest southeast oriented portion of the body is located in the vicinity of the boundary between the east european and scythian platforms and this portion of the sinking body may be a relic of cold lithosphere that has traveled eastward another portion has a northeast southwest orientation and is related to the present descending slab above a depth of 60 km the slab had a concave thermal shape confirming the curvature of the carpathian arc and a convex surface below that depth the slab maintained its convex shape until it split into two parts at a depth of about 220 km we propose that this change in the slab geometry which is likely to be preserved until the present can cause stress localization due to the slab bending and subsequent stress release resulting in large mantle earthquakes in the region also we hypothesize that either the processes of dehydration and partial melting of the descending lithospheric slab or dragging down of hotter rocks from the adjacent uppermost mantle by the slab are possible causes of the reduction in seismic velocities beneath the transylvanian basin

quantitative reconstruction of orogenic convergence in the northeast carpathians abstract the ne outer carpathians form a fold and thrust belt of large displacement this mainly consists of deformed cretaceous tertiary deep water clastics and can be divided into an imbricate stack of four major supracrustal nappes the magura dukla silesian and skole nappes an extensive reflection seismic surface geological and drillhole database is used to constrain the deformed geometry of the two uppermost and southernmost allochthonous units the magura and dukla nappes a retro deformable cross section shows that the cretaceous tertiary sediment piles are detached along a single large decollement at about 5 7 km depth the rear and frontal parts of the magura nappe show steep imbricate fan geometries while the central part has a duplex structure with long thrust horses to the ne the dukla nappe is a stack of imbricate slices and is separated from the subjacent silesian nappe by a large thrust flat reverse modelling of deformation reveals that the magura nappe was horizontally shortened by at least 80 km and the dukla nappe by about 20 km in the ne sw direction together with previously published estimates of shortening in the silesian and skole nappes the total orogenic contraction in the ne outer carpathians is at least 260 km shortening was accumulated between the middle oligocene and the middle miocene almost all of the shortening can be balanced against contemporaneous back arc extension and eastward extrusion of rock masses from the eastern alps

subsidence analysis and tectonic evolution of the external carpathian moesian platform region during neogene times abstract the miocene pliocene subsidence of the tectonic platforms in the romanian carpathians foreland is analysed using standard 1d backstripping techniques for individual wells combined in two regional sections and six contour maps the subsidence patterns were integrated together with previous paleostress and kinematic studies in order to derive the tertiary kinematics of the buried faults in the carpathians lower plate the study revealed accelerated subsidence during the early miocene in the western part of the moesian platform getic depression in direct relationship with the opening of a wsw ene trending extensional basin the largest subsidence recorded in the front of the carpathians took place during the late miocene due to final e ward emplacement of the thrust sheets the late miocene subsidence showed anomalous high values between the intramoesian and trotus faults as a result of the orogenic collision with the east european platform northward and acceleration of the subduction process in the se carpathians corner further pliocene subsidence continued only in the latter region the depocenter being shifted southward near the junction with the south carpathians foreland

stratigraphic modeling of foreland basins interpreting thrust deformation and lithosphere rheology the authors incorporate the processes of erosion and deposition in a numerical model to predict the stratal geometries and facies patterns produced during episodic thrusting in a nonmarine foreland basin the resultant stratigraphic record is characterized by a stairstepped facies package in which each retrogradation of facies toward the thrust marks the onset of a thrusting event the retrogradation of facies coincides with the migration of the forebulge toward the thrust and the generation of an erosional unconformity in the past changes in basin wavelength during basin evolution have been interpreted to record viscoelastic relaxation of the lithosphere this model suggests that changes in basin wavelength are a natural consequence of the interplay between thrust and sediment loading on an elastic lithosphere

kinematics of an arcuate fold thrust belt the southern eastern carpathians romania abstract flysch and molasse nappes of the eastern carpathians strike mainly n s and were folded and imbricated since the late early cretaceous boundaries of stratigraphic and structural units and calculated fold trend axes from the southern part of the eastern carpathians indicate a curvature of the orogen by 80 kinematic data from fault slip analysis of all nappe systems exposed in the arc document an overall nw se contraction nappes of the external moldavides nappe complex underwent deformation since the late cretaceous peaking in the miocene and exhibit fanning subhorizontal contraction axes from e w in the n striking part of the eastern carpathians through wnw ese and nw se in the northern part of the arc to nnw sse in its southwestern part geometric relations between faults and folds indicate that this fan pattern reflects an extended interval and was contemporaneous to nappe stacking and subsequent continental collision statistical analysis reveals correlation between orientation of the fanning kinematic axes and the structural trend where fanning of subhorizontal contraction axes is systematically smaller than change of strike of fold thrust structures orogen parallel extension in the tarcau nappe of the moldavides nappe complex is estimated to be 20 this low value of orogen parallel extension indicates a primary arc in contrast to bending of a previously straight fold thrust belt low orogen parallel extension and the observed pattern of structural and kinematic axes can be simulated in sand wedge indentation models where the indenter moves oblique to its margins in these models thrust traces and fold axes are curved around the arc but are parallel to the margins of the indenter away from the corner area the movement directions of the thrust faults in the models are deflected from normal to fault strike towards the movement direction of the indenter leading to fanning contraction directions similar to those observed in the eastern carpathian arc thus the main controlling factors on arc formation were the plate margin geometry i e the shape of the upper plate and the movement direction of the upper plate relative to the orientation of its margins the influence of the geometry of the continental margin in the lower plate was mainly by imposing constraints on the movement direction of the upper plate

aircraft observations of boundary layer rolls off the coast of california abstract large scale horizontal rolls can have a significant influence on turbulent transport across the atmospheric boundary layer the formation and maintenance of such rolls is dependent on the thermal and dynamic stability of the boundary layer bl the authors present aircraft observations of boundary layers both with and without roll circulations off the coast of california the contribution of the rolls to the turbulent fluxes of heat moisture and momentum and the variances of the three velocity components are determined for four cases the fractional roll contributions to the u and w variances and the sensible heat and along wind momentum fluxes show a near linear increase with altitude from less than 10 at 30 m to more than 70 at the top of the bl the variance in and crosswind momentum flux are more scattered although the variance shows a slight increase with altitude from about 40 to 60 the latent heat flux also shows a great deal of scatter especially in the lower third of th

sedimentary basins formed and carried piggyback on active thrust sheets small sedimentary basins that formed on the apennine southern margin of the po basin complex northern italy have been studied using borehole and seismic reflection information and their evolution can be dated using the largely marine biostratigraphy of the miocene to quaternary sediments these studies show that the basins formed and were filled while being carried on moving thrust sheets and they are therefore named piggyback basins each of these basins corresponds to the active phase of a different thrust front ramp on the pyrenean northern margin of the ebro basin complex northern spain similar piggyback basins formed between eocene and mid miocene time they have since been uplifted and eroded and may therefore be studied in outcrop in northern spain much of the basin fill sediment was deposited in nonmarine environments

large scale deformation in a locked collisional boundary interplay between subsidence and uplift intraplate stress and inherited lithospheric structure in the late stage of the se carpathians evolution 1 the interplay between slab dynamics and intraplate stresses in postcollisional times creates large near surface deformation particularly in highly bent orogens with significant lateral variations in mechanical properties this deformation is expressed through abnormal foredeep geometries and contrasting patterns of vertical movements intraplate folding is often the controlling mechanism particularly when the orogenic belt is locked the study of these tectonic processes in the se carpathians indicates a generalized subsidence period during latest miocene pliocene times driven by the slab pull and an intraplate folding due to an overall quaternary inversion the latter accommodates 5 km ese ward movement of this area with respect to the neighboring units which creates complicated three dimensional deformation patterns potentially driven at a larger scale by the interaction between the adriatic indentor and the entire carpathians system the lithospheric anisotropy inherited from the subduction times concentrates strain and induces large scale deformation far away from the active plate margins this anisotropy is dynamic because of deep mantle processes related to the subducted slab during postcollisional times such as thermal reequilibration or increase in slab dip

late pliocene quaternary tectonics in the frontal part of the se carpathians insights from tectonic geomorphology abstract the romanian east carpathians display large scale heterogeneities along the mountain belt unusual foredeep geometries significant post collisional and neotectonic activity and major variations in topography mostly developed in the aftermath of late miocene sarmatian 11 ma subduction underthrusting and continental collision between the east european scythian moesian foreland and the inner carpathians tisza dacia unit in particular the se corner of the arcuate orogenic belt represents the place of still active large scale differential vertical movements between the uplifting mountain chain and the subsiding focsani foredeep basin in this key area we have analysed the configuration of the present day landforms and the drainage patterns in order to quantify the amplitude timing and kinematics of these post collisional late pliocene quaternary vertical movements a river network is incising in the upstream a high topography consisting of the external carpathians nappes and the pliocene lower pleistocene sediments of the foreland further eastwards in the downstream this network is cross cutting a low topography consisting of the middle pleistocene holocene sediments of the foreland geological observations and well preserved geomorphic features demonstrate a complex succession of geological structures the late pliocene holocene tectonic evolution is generally characterised by coeval uplift in the mountain chain and subsidence in the foreland at a more detailed scale these vertical movements took place in pulses of accelerated motion with laterally variable amplitude both in space and in time after a first late pliocene uplifting period subsidence took place during the earliest pleistocene resulting in a basal quaternary unconformity this was followed by two quantifiable periods of increased uplift which affected the studied area at the transition between the carpathians orogen and the focsani foreland basin in the late early pleistocene and the late middle to late pleistocene both large scale deformation events affected the western focsani basin flank tilting the entire structure with 9 during the late early pleistocene and uplifted it as a block during the early late pleistocene the late early pleistocene tilting resulted in 750 m uplift near the frontal monocline and by extrapolation in a presumed 3000 m uplift near the central parts of the carpathians the late middle to late pleistocene cumulative uplift reaches 250 m and correlates with a contemporaneous progradation of the uplifted areas towards the focsani basin the uplifting events are separated by a second quaternary unconformity on the whole the late pliocene quaternary evolution of the carpathians orogen focsani basin structure indicate large scale differential uplift during the latest stages of a continuous post collisional orogenic evolution

out of sequence thrusts out of sequence thrusts oost are those thrusts which do not obey the foreland propagating or in sequence deformation style they include both isolated thrusts which develop hindward of the thrust front and sequences of break back thrusts which propagate from the foreland to the hinterland two end members of a series of oost types are recognized 1 older in sequence thrusts which are reactivated along their entire length and 2 completely new thrusts which propagate through already deformed thrust sheets between the two end members are thrusts composed partially of reactivated in sequence thrust sequences and partially of new entirely out of sequence segments oosts can be initiated for a variety of reasons including 1 keeping the orogenic wedge at critical taper 2 break back sequences from the suture zone in the overriding plate 3 ramping to overcome a sticking point which inhibits in sequence thrust propagation and 4 during simultaneous displacement along two stacked thrusts culminations which bow up segment of the upper thrust may be chopped through to permit continued displacement on the upper thrust many different types of thrust behavior including gravity sliding plucking and derivation of isolated horses from ramps may mimic some of the characteristics of oosts consequently it may be difficult to conclusively prove an oost origin for a complex thrust geometry

new data on the vrancea nappe moldavidian basin outer carpathian domain romania paleogeographic and geodynamic reconstructions a study has been performed on the cretaceous to early miocene succession of the vrancea nappe outer carpathians romania based on field reconstruction of the stratigraphic record mineralogical petrographic and geochemical analyses extra basinal clastic supply and intra basinal autochthonous deposits have been differentiated appearing laterally inter fingered and or interbedded the main clastic petrofacies consist of calcarenites sub litharenites quartzarenites sub arkoses and polygenic conglomerates derived from extra basinal margins an alternate internal and external provenance of the different supplies is the result of the paleogeographic re organization of the basin margins system due to tectonic activation and exhumation of rising areas the intra basinal deposits consist of black shales and siliceous sediments silexites and cherty beds evidencing major environmental changes in the moldavidian basin organic matter rich black shales were deposited during anoxic episodes related to sediment starvation and high nutrient influx due to paleogeographic isolation of the basin caused by plate drifting the black shales display relatively high contents in sub mature to mature type ii lipidic organic matter good oil and gas prone source rocks constituting a potentially active petroleum system the intra basinal siliceous sediments are related to oxic pelagic or hemipelagic environments under tectonic quiescence conditions although its increase in the oligocene part of the succession can be correlated with volcanic supplies the integration of all the data in the progressive reorientation of convergence direction carpathian model and their consideration in the framework of a foreland basin led to propose some constrains on the paleogeographic geodynamic evolutionary model of the moldavidian basin from the late cretaceous to the burdigalian

partial delamination of continental mantle lithosphere uplift related crust mantle decoupling volcanism and basin formation a new model for the pliocene quaternary evolution of the southern east carpathians romania abstract a geodynamic model is proposed for the mid miocene to quaternary evolution of the southern east carpathians in order to explain the relationships between shallow and deep geological phenomena that occurred synchronously during late collision tectonics in this area an active volcanic zone cross cuts since 2 my the suture between the overriding tisza dacia and subducting european continental plates mafic calc alkaline and alkaline magmas south harghita and persani volcanoes erupted contemporaneously these magmas were supplied by partial melting of the mantle lithosphere of the subducting and not of the overriding plate in an effort to decipher this geodynamically a typical setting of magma generation the spatial and temporal distribution of shallow and deep phenomena was successively examined in order to establish the degree of their interdependence our model indicates that intra mantle delamination of the subducting european plate is the principal cause of a succession of events it caused upwelling of the hot asthenosphere below a thinned continental lithosphere of the carpathians inducing the uplift of the lithosphere and its internal decoupling at the moho level by isostatic and mostly thermal effects during this uplift the crust deformed flexurally whilst the mantle deformed in a ductile way this triggered decompressional partial melting of the uppermost mantle lithosphere flexural deformation of the crust induced its fracturing allowing for the rapid ascent of magmas to the surface as well as reactivation of an older detachment horizon at the base of the carpathian nappe stack above which the brasov ciuc and gheorghieni hinterland basins formed by extension and gravity spreading the rapid subsidence of the focsani foreland basin is controlled by the load exerted on the lithosphere by the delaminated mantle slab that is still attached to it in this model crust mantle decoupling magma genesis and volcanism local near surface hinterland extension are consequences of uplift induced by asthenospheric upwelling triggered by intra mantle delamination this model enables to conceive that delamination induced decoupling began to be efficient 9 4 my ago at the northern end of the east carpathians when the mantle slab dipped westwards since then intra mantle delamination migrated laterally normal to the slab strike and follows the arcuate shape nw se sw of the carpathians nowadays whereas the mantle slab is still actively foundering below the vrancea seismic zone to the se of the most recent volcanic area south harghita persani a significant southwestward shift of the delamination process can be discerned

post rift compressional reactivation potential of passive margins and extensional basins poly phase deformation of a compressional nature is a common feature in the post rift evolution of passive margins and rifts the compressional mode of deformation in these sedimentary basins originally formed by extension in an intraplate setting is characterized by a spectrum of spatial wavelengths spanning several tens of kilometres up to several hundreds of kilometres the actual mode of compressional deformation appears to be strongly affected by the rheological structure of the underlying lithosphere the level of the regional intraplate stress field and the geometry of the rifted basin configuration prior to late stage compressional reactivation the interplay of plumes and intraplate compressional deformation can lead to temporal transitions from basin inversion to lithospheric folding these modes of deformation lead to substantial differential vertical motions late stage anomalies in subsidence and uplift patterns the development of innovative combinations of numerical and analogue modelling techniques is the key to differentiating different modes of compressional deformation of passive margins and extensional basins the geological society of london 2008

a forward modeling strategy for balancing cross sections 1 a strategy to balance cross sections of complex structures is documented and illustrated by the interpretation of a compressional structure in the deep water gulf of mexico the strategy is applicable to structures formed in sedimentary rocks under low temperatures in both compressional and extensional environments and involves the comparison of the observed structure with simple balanced forward models forward models generated using fault related fold theory help in understanding the processes and kinematics involved in the deformation further forward models are completely constrained and easy to balance whereas it is difficult to balance data therefore forward models are useful in evaluating ideas without completely solving the structure models are constructed assuming parallel behavior preservation of layer thickness no net distortion where layers are horizontal and conservation of bed length unmetamorphosed sedimentary rocks are generally observed to deform obeying the assumptions of parallel behavior in field map well and seismic data

flexure of lithosphere beneath apennine and carpathian foredeep basins evidence for an insufficient topographic load the pliocene foredeep basin external to the apennine thrust belt and the late miocene foredeep basin external to the outer east carpathians are considered typical molassic foredeeps that formed contemporaneously with thrusting in the adjacent mountain belts a simple mechanical model in which the response of the lithosphere to loading was approximately by a semi infinite broken elastic plate overlying a weak fluid was used to analyze the deflection of the foreland lithosphere beneath the apennine and outer east carpathian foredeep basins along three transects perpendicular to the thrust belts comparison between the calculated and observed depth to basement suggests that the emplacement of thrust sheets onto the foreland lithosphere during mountain building failed to pr duce a sufficient load to create the observed foredeep basins and observed topography regardless of the position of the slab end or the flexural rigidity assumed for the foreland lithosphere we infer that an additional subsurface load must be present and that its magnitude must be roughly equal to the load created by that part of the thrust belt that is above sea level for the two apennine transects an acceptable fit to the shape and size of the observed foredeep basin was generated by assuming effective elastic plate thicknesses of 8 and 15 km 4 9 and 9 3 mi and applied vertical forces of 2 1015 dynes cm and 1 3 1015 dynes cm at the slab end for the carpathian transect an effective plate thickness of 30 km 18 6 mi and an applied force of 1 5 215 1015 dynes cm generated an acceptable fit this study suggests a method whereby an estimate of the depth to autochthonous basement rocks beneath overthrust belts can be made in some areas where this information is not available from seismic or drilling data such an approach may enable exploration geologists to determine if crystalline rocks encountered in drilling overthrust terranes are a part of the autochthonous basement or if they are part of an overthrust sheet in the latter situation oil bearing sequences of sedimentary rocks might lie below crystalline rocks contained in the allochthonous sheet