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The Cenozoic evolution of the Barents Sea has been widely debated for its implications on hydrocarbon exploration. In this paper, we provide the first, for the area, apatite (U–Th)/He thermochronology data on Early-Middle Jurassic and Early Cretaceous sandstone reservoir samples obtained from three wells located on the western part of the Barents Shelf. A large range of grain ages have been detected, ranging from 1.58 to 50.65 Ma. These thermochronological data, initially integrated with vitrinite reflectance measurements to properly constrain the burial history evolution, have been modelled on the basis of estimated maximum temperature in order to evaluate the cooling path to present-day temperatures. Outputs from modelling indicate that: 1) the amount of net uplift and denudation is in the order of 1000 m, and 2) the last important phase of exhumation occurred during late Miocene-early Pliocene time, therefore challenging the prevailing idea of substantial uplift linked to the observed shelf-progradation along the margin as a result of the Plio-Pleistocene glaciations. The timing of the distinct exhumation event documented here may be, instead, attributed to different mechanisms. These may include basin inversion widespread on the NW European margin that is probably related to local changes in the North Atlantic spreading vector, while other mechanisms may include thermal and lithospheric-scale anomalies observed at the northwestern corner of the Barents-Svalbard Shelf. [ABSTRACT FROM AUTHOR]

The formation of the Transantarctic Mountains (TAM) is strictly related to the evolution of the West Antarctic Rift system, but the timing of their exhumation is still not fully assessed. In this work, we provide new apatite fission-track data collected on the region between the Royal Society Range and the Britannia Range. Cooling ages are late Eocene–Oligocene in the center of the region but they get older both northwards and southwards. We infer that exhumation was strictly controlled by TAM-parallel fault strands that were active after the Oligocene. The Royal Society Range and the Britannia Range represent transition zones corresponding to transverse structures, probably inherited from early basement crustal discontinuities and reactivated as transfer regions during rift propagation. The exhumation of the investigated region has been then modeled and predicted thermochronological ages have been compared with detrital data from the Miocene sedimentary succession drilled in the Victoria Land Basin. Results indicate that this sector of the TAM is the most probable candidate for the source of sediments and that during the Neogene 3 km (but up to 5 km) of rocks was exhumed. [ABSTRACT FROM AUTHOR]

Abstract: Apatite (U-Th)/He and fission-track analyses of both basement and sedimentary cover samples collected around the Marmara Sea point to the existence of a system of major E–W-trending structural discontinuities active at least from the Late Oligocene. In the Early Pliocene, inception of the present-day North Anatolian Fault (NAF) system in the Marmara region occurred by reactivation of these older tectonic structures. This is particularly evident across the Ganos fault in southern Thrace, as exhumation south of it occurred during the latest Oligocene and north of it during the mid-Miocene. In this area, large tectonic structures long interpreted as the results of Plio-Quaternary NAF-related transpressional deformation (i.e. the Ganos monocline, the Korudağ anticline, and the Gelibolu folds) were in fact produced during the Late Oligocene – Early Miocene. The overall lack of significant (U-Th)/He age differences across the NAF indicates that the Early Pliocene inception of strike–slip motion in the Marmara region represents a relatively minor episode. At the scale of the entire Marmara region, the geographic pattern of exhumation ages shown in this study results instead from the complex superposition of older tectonic events including: (i) the amalgamation of Sakarya and Anatolide–Tauride terranes and (ii) Aegean-related extension. [Copyright &y& Elsevier]

Abstract: Several tectonic processes have been proposed to be important in the Alpine to the recent evolution of the Polish Outer Carpathians, i.e., Paleogene–Neogene thrusting, post-thrusting extension, Quaternary reactivation of compression. This work tests the effect of these processes on exhumation of the wedge, in order to verify their timing and relative role in shaping the Polish Outer Carpathians. AFT, AHe and ZHe analyses were performed on samples collected along the study region. This allowed the reconstruction of their post-depositional minimum heating, depth of burial and timing of cooling and exhumation. After deposition samples from the innermost units were heated up to temperatures of ca. 60–120°C (ca. 4–9km), whereas samples from the outer units were heated to temperatures lower than 60°C (ca. 4km). Cooling and exhumation occurred progressively later from west to east (between ca. 25 and 10Ma in the western sector, between ca. 15 and 5Ma in the eastern sector). These results have been put in relationship with single structural features to understand the relative role of thrusts and normal faults. In the eastern sector of the study region samples at the footwall of significant normal faults show a higher degree of reset and younger ages than samples located at the hangingwall. This implies that, in this sector, extensional tectonics played an important role in exhumation. However, proper tectonic exhumation only had a minor role, the major exhumation mechanism being erosion, which is enhanced in the footwalls and reduced in the hangingwalls. In the western sector of the Polish Outer Carpathians only in few cases evidence of enhanced erosion to the footwall of major normal faults could be observed based on the present data. In this region the wedge exhumed mainly as a response to thrusting and normal faulting only played a minor role, locally modifying the pattern of erosion. Finally no major exhumation events occurred after Miocene, pointing to a minor relevance of recent compression. Unreset ZHe dates were used to estimate exhumation of source rocks through the ZHe PRZ and to outline the provenance of sediments forming the Polish Outer Carpathians. Exhumation occurred both in response to the Variscan (Late Devonian to Triassic) and Alpine (Late Jurassic to Early Paleocene) orogeneses, suggesting sedimentary provenance both from the southern margin and from the basement heights within the Outer Carpathian basin. [Copyright &y& Elsevier]

Application of different thermochronological methods to two areas of pronounced relief (Apuane Alps and Mt. Falterona ) of the Northern Apennines chain documents an average exhumation rate of about 0.7 mm/yr. This result suggests that the general exhumation of the chain is driven mainly by erosion. Nevertheless, the long-term exhumation trend seems to be perturbed by short-term events at higher exhumation rates. The time of increased exhumation rates coincides with onset of intramontane sedimentation, documenting a contribution of tectonics (local normal faulting?) to the surface uplift. The data indicate an eastward shifting of the onset of topographic relief, Early Pliocene in the Apuane Alps and Early Pleistocene in the Mt. Falterona area. [Copyright &y& Elsevier]

Paleo-thermometers in sedimentary basins often drive to misleading thermal modelling when applied alone or only on potentially productive Paleozoic source rocks. Different paleo-thermal and thermo-chronological data have been used as constraints to model the Silurian to Cenozoic succession of a recently drilled well in the onshore portion of the Baltic Basin, in northern Poland. This dataset provides an integrated platform for thermal maturity assessment contributing to the highly debated reconstruction of the thermal history of the Baltic Basin in the last decade. The well stratigraphy consists of a Lower Paleozoic marine clayey and arenaceous/calcareous succession, about 1000 m thick that is unconformably overlain by a 2000 m thick Permian to Cenozoic sequence, developed in a continental to shallow marine environment. Optical microscopy, FT-IR and Raman spectroscopy analysis of organic matter have been coupled with (U–Th)/He data to produce a robust vitrinite reflectance profile and constrain the 1D thermal modelling of the well. In addition, such a thermal maturity profile was validated by an independent thermal modelling calibrated by the smectite illitization kinetics. Both models identify high heat flow conditions (up to 1.7 HFU) at the end of Mesozoic. The Lower Paleozoic succession entered the late oil window of HC generation during this last heating event. • An original application to assess thermal maturity of sedimentary successions have been proposed. • We produced a thermal maturity profile validated by two independent thermal modelling approaches. • A section of Lower Silurian source rock in the Baltic Basin entered the oil window. • No potential for shale gas has been highlighted. [ABSTRACT FROM AUTHOR]