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Terra Nova, 22, 155–165, 2010 Abstract Sequence stratigraphy in the hinterland, kinematic analysis of thin‐skinned thrusting in the foreland and thermochronological tracking of exhumation in the orogenic core are combined to quantify the mechanics of an orogen with low topographic build‐up. The Carpathian system demonstrates that collisional deformation can couple and thicken the lower orogenic plate along reverse faults that dip more steeply than the subduction zone, defining a ‘foreland‐coupling’ type of collision. Near the surface, this is expressed by wide antiforms in the upper plate and the thin‐skinned orogenic wedge. A sequence stratigraphic analysis of the back‐arc Transylvanian Basin demonstrates that the sedimentary architecture records orogenic uplift pulses with both short and long wavelengths. These correspond to the activation of individual thrust sheets in the thin‐skinned wedge and to lower‐plate coupling events respectively.

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Late Miocene lacustrine clinoforms of up to 400 m high are mapped using a 1700 km 2 3-D seismic data set in the Dacian foreland basin, Romania. Eight Meotian clinoforms, constructed by sediment from the South Carpathians, prograded around 25 km towards southwest. The individual clinothems show thin (10-60 m thick), if any, topsets, disrupted foresets and highly aggradational bottomsets. Basin-margin accretion occurred in three stages with changing of clinoform heights and foreset gradients. The deltaic system prograded into an early-stage deep depocenter and contributed to high gradient clinoforms whose foresets were dominated by closely (100-200 m) spaced 1.5-2 km wide V-shaped sub-lacustrine canyons. During intermediate-stage growth, 2-4 km wide canyons were dominant on the clinoform foresets. From the early to intermediate stages, the lacustrine shelf edges were consistently indented. The late-stage outbuilding was characterised by smaller clinoforms with smoother foresets and less indentation along the shelf edge. Truncated and thin topsets persisted through all three stages of clinoform evolution. Nevertheless, the resulting long-term flat trajectory shows alternating segments of forced and low-amplitude normal regressions. The relatively flat trajectory implies a constant base level over time and was due to the presence of the DacianBlack Sea barrier that limited water level rise by spilling to the Black Sea. Besides the characteristic shelf-edge incision of the thin clinoform topsets and the resultant sediment bypass at the shelf edge, the prolonged regressions of the shelf margin promoted steady sediment supply to the basin. The high sediment supply at the shelf edges generated long-lived slope sediment conduits that provided sustained sediment transport to the basin floor. Clinothem isochore maps show that large volumes of sediment were partitioned into the clinoform foresets, and especially the bottomsets. Sediment predominantly derived from frequent hyperpycnal flows contributed to very thick, ca. 300-400 m in total, bottomsets. Decreasing subsidence over time from the foredeep resulted in diminishing accommodation and clinoform height, reduced slope channelization and smoother slope morphology.

The history of Middle to Late Miocene evolution of the Transylvanian Basin was determined by the bordering Carpathian orogen evolution, the tectonic events being well recorded by the sedimentary history. The basin evolved in a back-arc setting, under a regional, compressional stress field. The major tectonic events produced during the Late Sarmatian and Post-Pannonian were related to the reactivation of the pre-Badenian fault systems. The Transylvanian Basin got uplifted after the Late Pannonian (? during the Pliocene), and at least 500 m of sedimentary cover was eroded. Based on seismic and well-log interpretation, core and outcrop sedimentology, and microfauna, eight sequences were defined. The early Middle Miocene sequences are roughly synchronous to five 3rd order global sea-level cycles. Most of the recognized sequence boundaries are enhanced by regional tectonic events. The sedimentary evolution was also strongly influenced by salttectonics, active starting with the Late Sarmatian. Two sequences were identified in the Lower Badenian deposits. The third sequence (late Early Badenian to early Mid Badenian) preserves information about deeper shelf settings. The lowstand of the following sequence was responsible for the deposition of the salt formation (late Mid Badenian), an important lithostratigraphic marker in the sedimentary record of the basin. In general, the Upper Badenian deposits (parts of the 4th and 5th sequences) belong to deep marine submarine fan systems. The Sarmatian (partially 5th, 6th and partially 7th sequences) was characterized by diverse salinity conditions, stretching from brackish to hypersaline, and by high tectonic instability, which induced several significant relative sea-level falls. During that time, deltaic north) and fandeltaic (east) systems fed submarine fans, stacked between salt-related submarine heights ("channeled" deepmarine depocenters). Most of the Pannonian deposits (partially 7th and 8th sequences) belong to submarine fan systems, but shallower facies were also found in the western and eastern part of the basin.