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Extensional basins often show along‐strike variability in terms of fault geometries, basement structures, subsidence, and thermal evolution. This is particularly pronounced when extension reactivates preexisting suture zones with opposing dip directions, that is, opposite polarities, which creates wide strike‐slip transfer zones. We have studied this extensional variability by means of thermomechanical lithospheric‐scale 3‐D numerical modeling. We conducted a series of experiments to model the extension of a thick lithosphere simulating a young orogenic area containing segmented suture zones inherited from former opposing subduction polarities, implemented as rheologically weak inclined layers with opposite dips. Numerical experiments demonstrate that the initial subduction sutures are reactivated by two long‐lived lithospheric‐scale detachment faults, which remain active until the onset of oceanic spreading. The opposite polarity of these faults causes their migration toward each other by asymmetric mantle lithosphere extension and thermal accretion. Crustal kinematics shows the formation of extensional detachment faults and high‐offset listric normal faults. These structures undergo gradual tilting during their footwall exhumation, while the rheological weak suture layers are redistributed beneath the crust. The results demonstrate an active interaction along the strike of the system between the two opposite dipping weak zones, where fault segments mechanically interact. During extension, the maximum horizontal fault offset switches the apparent sense of shear in the separating strike‐slip transfer zone. This kinematics explain the rapid change in the sense of shear in major strike‐slip transfer zones or transform faults, such as observed during the extension of the Pannonian back‐arc basin. Key Points: We have conducted 3‐D lithospheric‐scale numerical modeling of rift interactionExtensional reactivation of lithospheric‐scale suture zones has been analyzedStrike‐slip transfer faults evolve and change their sense of shear with time [ABSTRACT FROM AUTHOR]

Sedimentary basins are affected by a large number of forcing factors during their evolution and as a result, it is often difficult to isolate the contribution of each individual factor. Many forcing factors are temporally and spatially heterogeneous; they do not affect all parts of the basin in the same way and at the same time. We show that this heterogeneity can be used to identify the contributions of forcing factors by comparing various parts of a basin. This approach is applied to the Pannonian Basin, a back-arc basin located in Central Europe. In the basin, the amounts of crustal extension, tectonic inversion and sediment influx varied in space and time, while the connection with the marine realm fluctuated. In this study we focus on two currently unresolved issues: firstly, we establish by what processes and from what directions the basin was filled in, and secondly, we investigate whether the basin was affected by the Messinian Salinity Crisis. The analysis of seismic and well data in the previously less studied SE part of the basin demonstrate that progradation occurred from the southern and eastern basin margins, complementing the previously described progradation from the northwestern and northern basin margins. Elsewhere in the basin, an unconformity observed in the progradational basin infill is intensely debated to be the result of either the Messinian Salinity Crisis ( MSC) or basin inversion. Having the advantage of minor Pliocene-Quaternary amounts of inversion in the studied part of the basin we show that no regional unconformity is present in the studied stratigraphic interval, which implies that the effects of the MSC on the basin were minor. We infer that being aware of the fact that the effects of relative sea/lake-level fluctuations may vary significantly across a basin is critical for understanding the evolution of semi-enclosed basins. [ABSTRACT FROM AUTHOR]

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. [Copyright &y& Elsevier]

The coupled tectonic and depositional history of extensional basins is usually described in terms of stratigraphic sequences linked with the activity of normal faults. This depositional-kinematic interplay is less understood in basins bounded by major extensional detachments or normal fault systems associated with significant exhumation of footwalls. Of particular interest is the link between tectonics and sedimentation during the migration of normal faulting in time and space across the basin. One area where such coupled depositional-kinematic history can be optimally studied is the Late Oligocene - Miocene Sarajevo-Zenica Basin, located in the Dinarides Mountains of Bosnia and Herzegovina. This intra-montane basin recorded Oligocene – Pliocene sedimentation in an endemic and isolated lake environment. We use field kinematic and sedimentological mapping in outcrops correlated with existing local and regional studies to derive a high-resolution evolutionary model of the basin. The novel results demonstrate a close correlation between moments of normal faulting and high-order sedimentological cycles, while the overall extensional basin was filled by a largely uni-directional sediment supply from the neighbouring mountain chain. The migration in time and space of listric NE-dipping normal faults was associated with a gradual shift of the sedimentological environment. Transgressive-regressive cycles reflect sequential displacements on normal faults and their footwall exhumation, defining a new sedimentological model for such basins. This Early - Middle Miocene extension affected the central part of the Dinarides and was associated with the larger opening of the neighbouring Pannonian Basin. The extension was preceded and followed by two phases of contraction. The Oligocene - Early Miocene thrusting took place during the final stages of the Dinarides collision, while the post-Middle Miocene contraction is correlated with the regional indentation of the Adriatic continental unit. This latter phase inverted the extensional basin by reactivating the inherited basal listric detachment. [ABSTRACT FROM AUTHOR]

Abstract: This finite element modelling study addresses the contraction of rheologically layered and laterally heterogeneous lithosphere representative for the Pannonian Basin and its surroundings. The time interval and strain rate adopted in the experiments reflect the Pliocene–Quaternary inversion of the basin. Several sets of fully coupled elastoviscoplastic thermo-mechanical, plane strain 2D models explore the evolution of buckling, and stress/strain changes across the lithosphere. The viscous rheology of the asthenosphere allows for a detailed simulation of isostatic rebound during deformation. The numerical models predict the successive development of surface undulations, caused by crustal and/or lithosphere folding, at three different characteristic wavelengths. Among these, the longest wavelength folds occur systematically at the rim of the basin as marginal bulges, while the short wavelength folds overprint the earlier folds and are observed at a later stage during compression. The thermo-mechanical evolution of the lithosphere in response to progressive horizontal contraction is described in terms of a characteristic delay of the changes in the stress regime and a reduction of elastic strain in the strong crustal layers. The models predict a change in stress state along the flanks of the basin, caused by the development of weak basin lithosphere in their vicinity. Comparing the modelling results with tectonic features of the Pannonian Basin has resulted in the identification of three different stages in the Pliocene–Quaternary basin inversion of the Pannonian–Carpathian system. [Copyright &y& Elsevier]

Abstract: Results are presented from GPS measurements performed in the Southeastern Carpathians between 1997 and 2004. Data from 25 stations observed during 13 campaigns were analyzed by the Department of Earth Observation and Space Systems (DEOS) of Delft University of Technology. The repeatabilities of the solutions are on the order of 1–4 mm for the horizontal, and 4–8 mm for the vertical component. The resulting velocity estimates have an uncertainty of <1 mm/yr and <3 mm/yr, respectively. The region southeast of the Carpathian bend zone shows a horizontal movement towards SSE of ∼2.5 mm/yr, while the Transylvanian Basin shows very small motions with respect to Eurasia. The vertical velocity field indicates the existence of uplift and subsidence domains in the SE Carpathians, in good agreement with Pliocene–Quaternary orogen and basin studies. Another 29 GPS stations installed in the last 3 yr will generate a denser velocity field in the coming years for this region. [Copyright &y& Elsevier]

It has been widely documented that the depth of foredeeps does not always reflect the topography of the neighboring orogens. In many cases, the topographic load is insufficient to explain basin subsidence. Such is the case of the SE Carpathians where an anomalously deep (almost 13 km) foreland basin has evolved since the Middle Miocene (Badenian). A peculiar feature of this basin is its position relative to the orogen. In contrast to typical foredeeps, which deepen towards the belt, the maximum depth of this basin is 10–20 km out of the orogen. The subsidence in the Carpathians Bend foreland is characterized by two stages: the first is Middle Miocene (Badenian) in age and is related to NE–SW extension when fault-bounded basins were formed. Modeling shows that the foreland underwent small pre-orogenic uniform thinning. The modeling also predicts <100 m post-rift subsidence in accordance with the regional unconformity observed at the Middle/Upper Miocene (Badenian/Sarmatian) boundary. The second subsidence stage follows rifting and is caused by flexural loading of the Carpathians nappes. According to the planform flexural modeling results, the location of depocenter in front of the Carpathians Bend in the latter contractional stage can be accounted for by the present topography if lateral variations in lithospheric strength are taken into account. Since the depth of the predicted basin is half of what is actually observed, an extra-load is required, which is equivalent to 500–800 m in terms of extra topography. In this case, the predicted basin corresponds with the observed geometry in terms of position/shape and depth, the latter depending on the magnitude of intraplate stresses as well. The modeling also suggests that the flexural fore-bulge of the Carpathians system is represented by the uplifted Dobrogea. Our explanation for the large subsidence recorded by the SE Carpathians foredeep highlights the control exerted by lateral changes in lithospheric strength on 3-D subsidence patterns in arcuate orogenic belts. [Copyright &y& Elsevier]