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With proven reserves of 9.836 × 1010 m3, the largest known natural gas reservoir among terrigenous basement rocks has been discovered within the granitoids of the northern Qaidam Basin. Due to their high heterogeneity, the genesis of basement reservoirs remains unknown. Herein, the structure of the weathering crust in granitoids and their potential controlling factors on the reservoir development mechanism are discussed using a multidisciplinary approach based on data from cores, thin sections, scanning electron microscopy (SEM), conventional and imaging logs, and physical property and major elements analyses. Moreover, the classification standard of the weathering crust structure is established. The dissolution belt holding diverse reservoir spaces accounts for more than 50% of the total porosity, while the disintegration belt is the main context for the development of cleavage fractures and crack fractures. The original pores exist mainly among the crystal grains of quartz and mica, while the secondary pores and fractures were generated by the alteration of aluminosilicate minerals as well as biotite or hornblende. The quality of these reservoirs is controlled by their mineral composition, tectonic uplift, faulting, and paleogeomorphology. The femic granitoid is the main reservoir-forming lithology in the case of dissolution, while the felsic granitoid is more likely to develop cracks. The formation of the disintegration belt is significantly linked to the presence of faulting. These belts were mostly induced by tectonic deformation along the Altyn fault belt from the late Oligocene to the early Miocene. The diversity in paleogeomorphology influences the extent of the weathering. The exhumation in the Altyn terrane from the late Jurassic to the Cenozoic corresponds to the weathering and hypergene leaching period of the weathering crust within granitoids. Three types of reservoirs are present in the rocks: fractured-porous (Type Ⅰ); porous (Type Ⅱ); and fractured (Type Ⅲ). The fractured-porous and fractured reservoirs were developed mainly in the granitic gneiss and granite, while the porous reservoir was formed in granitic diorite and granitic gneiss. The reservoirs that developed in the weathering crust of granitoids are dominated by Type Ⅰ and Type Ⅱ. The highest quality reservoir, which is the fractured-porous type, developed mainly in the dissolution belt of the weathering crust, and has a porosity ranging from 1.56% to 8.48% and a permeability ranging from 0.03 mD to 14.48 mD. The mechanisms of the development of weathering crust reservoirs provide further information for the hydrocarbon exploration of basement rocks worldwide.

In the southern Apennines fold-and-thrust belt, thermal indicators record exhumation of sedimentary units from depths locally in excess of 5 km. The thrust belt is made of allochthonous sedimentary units that overlie a 6-8-km-thick, carbonate footwall succession. The latter, continuous with the foreland Apulian PlatForm, is deformed by reverse faults involving the underlying basement. Therefore, a switch from thin-skinned to thick-skinned thrusting occurred as the Apulian Platform carbonates - and the underlying thick continental lithosphere-were deformed during the latest shortening stages. Apatite fission track data, showing cooling ages ranging between 9.2 ± 1.0 and 1.5 ± 0.8 Ma, indicate that exhumation marks these late tectonic stages, probably initiating with the buttressing of the allochthonous wedge against the western margin of the Apulian Platform. Pliocene-Pleistocene foreland advancing of the allochthonous units exceeds the total amounts of slip that, based on cross-section balancing and restoration, could be transferred to the base of the allochthon from the underlying thick-skinned structures. This suggests that emplacement of the allochthon above the western portion of the Apulian Platform carbonates was followed by gravitational readjustments within the allochthonous wedge, coeval - and partly associated with - thick-skinned shortening at depth. The related denudation processes are interpreted to have played a primary role in tectonic exhumation.

Apatite fission-track analysis and thermochronologic statistical modeling of Precambrian–Oligocene plutonic and metamorphic rocks from the Lesser Caucasus resolve two discrete cooling episodes. Cooling occurred during incremental crustal shortening due to obduction and continental accretion along the margins of the northern branch of the Neotethys. (1) The thermochronometric record of a Late Cretaceous (Turonian–Maastrichtian) cooling/exhumation event, coeval to widespread ophiolite obduction, is still present only in a relatively small area of the upper plate of the Amasia-Sevan-Akera (ASA) suture zone, i.e. the suture marking the final closure of the northern Neotethys during the Paleogene. Such area has not been affected by significant later exhumation. (2) Rapid cooling/exhumation occurred in the Early-Middle Miocene in both the lower and upper plates of the ASA suture zone, obscuring previous thermochronologic signatures over most of the study area. Miocene contractional reactivation of the ASA suture zone occurred contemporaneously with the main phase of shortening and exhumation along the Bitlis suture zone marking the closure of the southern branch of the Neotethys and the ensuing Arabia-Eurasia collision. Miocene collisional stress from the Bitlis suture zone was transmitted northward across the Anatolian hinterland, which was left relatively undeformed, and focused along preexisting structural discontinuities such as the eastern Pontides and the ASA suture zone. Keywords: Lesser Caucasus, Low-temperature thermochronology, Apatite fission-track analysis, Structural reactivation, Far-field tectonics

International audience; The Admiralty Mountains region forms the northern termination of the northern Victoria Land, Antarctica. Few quantitative data are available to reconstruct the Cenozoic morpho-tectonic evolution of this sector of the Antarctic plate, where the Admiralty Mountains region forms the northern termination of the western shoulder of the Mesozoic-Cenozoic West Antarctica Rift System. In this study we combine new low-temperature thermochronological data (apatite fission-track and (U-Th-Sm)/He analyses) with structural and topography analysis. The regional pattern of the fission-track ages shows a general tendency to older ages (80–60 Ma) associated with shortened mean track-lengths in the interior, and younger fission-track ages clustering at 38–26 Ma with long mean track-lengths in the coastal region. Differently from other regions of Victoria Land, the younger ages are found as far as 50–70 km inland. Single grain apatite (U-Th-Sm)/He ages cluster at 50–30 Ma with younger ages in the coastal domain. Topography analysis reveals that the Admiralty Mountains has high local relief, with an area close to the coast, 180 km long and 70 km large, having the highest local relief of >2500 m. This coincides with the location of the youngest fission-track ages. The shape of the area with highest local relief matches the shape of a recently detected low velocity zone beneath the northern TAM, indicating that high topography of the Admiralty Mountains region is likely sustained by a mantle thermal anomaly. We used the obtained constraints on the amount of removed crustal section to reconstruct back-eroded profiles and calculate the erosional load in order to test flexural uplift models. We found that our back-eroded profiles are better reproduced by a constant elastic thickness of intermediate values (Te = 20–30 km). This suggests that, beneath the Admiralty Mountains, the elastic properties of the lithosphere are different with respect to other TAM sectors, likely due to a stationary Cenozoic upper mantle thermal anomaly in the region.

Located in the foreland domain of the Alpine and Pyrenean mountain belts, the French Massif Central presents enigmatic topographic features—reaching elevations of ∼1700 m above sea level and ∼1000 m of relief—that did not originate from Alpine compressional nor from extensional tectonics. Similar to other Variscan domains in Europe, such as the Bohemian, Rhenish, and Vosges/Black Forest Massifs, a Cenozoic uplift has been postulated, although its timing and quantification remain largely unconstrained. With respect to the other Variscan Massifs, the French Massif Central is wider and higher and shows a more intense late Cenozoic volcanism, suggesting that deep-seated processes have been more intense. In this study, apatite fission-track and (U-Th)/He thermochronometry were applied to investigate the long-term topographic evolution of the Massif Central. Our new thermochronological data come from the eastern flank of the massif, where sampling profiles ran from the high-elevation region down to the Rhône River valley floor with a total elevation profile of 1200 m. Age-elevation relationships, mean track-length distributions, and thermal modeling indicate a two-step cooling history: (1) a first exhumation event, already detected through previously published thermochronology data, with an onset time during the Cretaceous, and (2) a more recent Cenozoic phase that is resolved from our data, with a likely post-Eocene onset. This second erosional event is associated with relief formation and valley incision possibly induced by a long-wavelength domal uplift supported by mantle upwelling.

Fluid-rock interaction occurring within high-permeability conduits represented by fault-fracture meshes is well known to control the development of hydrothermal ore deposits. In this study we document the fundamental role of four sets of precursor joints, reactivated as dilational faults displaying variable normal dip-slip and strike-slip components of motion, in the formation of epithermal Au-Ag deposits of economic interest. Paleostress analysis unravels how all the resulting four sets of hybrid extension-shear fractures are kinematically compatible with an extensional stress field characterized by multiple permutations between the σ3 and the σ2 axes. Such permutations are interpreted to be associated with dominantly normal fault reactivation of suitably oriented early joint sets as a result of continued regional extension, and by orthogonal stretching produced by differential downthrow of the hanging-wall blocks of laterally-terminating Jurassic normal faults. Later fault reactivation appears to be associated with far field propagation of Andean stresses, marked by superposed strike-slip and reverse fault slip components recording roughly E-W horizontal compression. This late fault reactivation could be related with a late Early Cretaceous shortening event known to have affected the studied sector of the Deseado Massif. The subsequent tectonic evolution of the study area occurred within the general framework of a slow Cretaceous to Tertiary exhumation recorded by apatite fission track cooling ages. Our new thermochronometric results, recording steady-state cooling at a rate of c. 1 °C/Ma during the last 90 Ma, shed new light onto the post-Jurassic geodynamic evolution of the foreland of the southern Patagonian Andes. Fil: Fernandez, Maria Lis. Universidad Nacional del Comahue. Facultad de Ingeniería. Departamento de Geología y Petróleo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Confluencia; Argentina Fil: Mazzoli, Stefano. Universita Degli Di Camerino; Italia Fil: Zattin, Massimiliano. Università di Padova; Italia Fil: Savignano, Elisa. Università di Padova; Italia Fil: Genge, Marie Catherine. Università di Padova; Italia Fil: Tavani, Stefano. Università degli Studi di Napoli Federico II; Italia Fil: Garrone, Alejandro. Minera Don Nicolás S.A.; Argentina Fil: Franchini, Marta Beatriz. Universidad Nacional del Comahue. Facultad de Ingeniería. Departamento de Geología y Petróleo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Confluencia; Argentina

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 Korudag 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.

Thermal indicators record exhumation of sedimentary units from depths in excess of 6 km over most of the Outer Carpathian fold and thrust belt in Poland. Apatite fission track data, showing cooling ages ranging between 32.1 ± 4.8 and 7.0 ± 0.8 Ma, indicate that exhumation was partially coeval with shortening. However, new thermochronometric information obtained as part of this study allowed us to unravel a previously undetected, post-thrusting exhumation stage. The integration of new field data and structural analysis with low-T thermochronometry suggests that termination of thrusting – at ca. 11 Ma in the area of the present study – was followed by gravity disequilibria within the orogenic wedge. The related extension and denudation phenomena appear to have played a primary role in the recent (< 10 Ma) tectonic evolution of the Western Outer Carpathians, exerting a major control on exhumation processes in this key area of the Alpine–Carpathian mountain system.

The collision between the Eurasian and Arabian plates along the 2400-km-long BitlisZagros thrust zone isolated the Mediterranean from the Indian Ocean and has been linked to extension of the Aegean, rifting of the Red Sea, and the formation of the North and East Anatolian fault systems. However, the timing of the collision is poorly constrained, and estimates range from Late Cretaceous to late Miocene. Here, we report the fi rst apatite fi ssiontrack (AFT) ages from the Bitlis-Zagros thrust zone. The AFT samples are distributed over the 450 km length of the Bitlis thrust zone in southeast Turkey and include metamorphic rocks and Eocene sandstones. Despite the disparate lithology and large distance, the AFT ages point consistently to exhumation between 18 and 13 Ma. The AFT ages, along with a critical appraisal of regional stratigraphy, indicate that the last oceanic lithosphere between the Arabian and Eurasian plates was consumed by the early Miocene (ca. 20 Ma). The results imply that Aegean extension predated the Arabia-Eurasia collision.

Diachronous deformation and exhumation of the Dinaric, eastern Southern Alps, and Northern Apennine belts caused a complex pattern of sedimentation and dispersal in the Venetian–Friulian Basin. Our dataset provides, for the first time, a comprehensive picture of the Cenozoic evolution across the whole basin. Growth and erosion of the three chains feeding the Venetian–Friulian Basin are here traced by combination of multiple analytical techniques. We examine the terrigenous and intrabasinal supply to the basin by using arenite petrography (gross composition, heavy minerals) and apatite fission-track analysis framed in an updated stratigraphy. Data come from both outcropping and subsurface Eocene to Pleistocene strata and are compared with the modern river sediments of the study area. On the basis of this approach, we present a schematic temporal and paleogeographic evolution of the Venetian–Friulian Basin from the Eocene to Present. During the Eocene most sediments were derived from erosion of carbonate successions within the growing Dinaric thrust belt to the east, and from its peripheral bulge to the west, where some carbonate factories were active. Oceanic rocks, probably located in the Vardar suture zone to the north, contributed little. Once Dinaric thrusting ceased, most of the detritus was derived from the northern basement of the Austroalpine realm. An abrupt paleogeographic variation caused by activation of southward-verging thrusts in the Southalpine domain occurred during the Serravallian. The drainage divide moved southward and most of the detritus was derived from the basement and related sedimentary covers of the Southern Alps. Sand composition of modern river sediments and of the Plio-Pleistocene deposits indicates that the modern hydrographic pattern of this area was already established in the Pleistocene.

In this paper, we merge more than 200 new apatite and zircon (U-Th)/He analyses and 21 apatite fission-track analyses from 71 new samples with previous published thermochronologic data using the same systems to understand the growth and large-scale kinematics of the central Andes between 21°S and 28°S. In general, minimum dates decrease and the total range of dates increases from west to east across the range. Large variations in thermochronometer dates on the east side reflect high spatial gradients in depth of recent erosional exhumation. Almost nowhere in this part of the Andes has Cenozoic erosion exceeded ~6–8 km, and in many places in the eastern half of the range, erosion has not exceeded 2–3 km, despite these regions now being 5–6 km above sea level. This means that west of the rapidly deforming and eroding eastern range front, uplift and erosion are largely decoupled as a result of meager precipitation, relatively low relief, internal drainage, and volcanic burial. We interpret the west-to-east pattern of decreasing minimum dates across the range as recording the time-transgressive eastward migration of a focused zone of deformation, erosion, and convergence between the South American plate and the eastern edge of the Andean orogenic plateau. At this scale, the thermochronologic data do not suggest major changes in rates of plateau propagation or shortening/convergence with time. We use the thermochronometer date-distance trend and a simple kinematic model to infer a rate of eastward propagation of deformation and plateau growth of 6–10 km/m.y. This plateau propagation model balances horizontal convergence, erosion, and crustal thickening and predicts rates of shortening and convergence between the Andes block and South American plate that are consistent with geologic and geodetic observations.

The Carpathian-Pannonian region is made up of the wide extensional Pannonian Basin surrounded by the Carpathian mountain belt. The Pannonian Basin formed in the Miocene by extension in a retro-wedge position while thrusting was still active at the Carpathian front. The Ukrainian region is an ideal area to reconstruct the relationship between the Pannonian Basin and the Carpathians, due to the relatively simple structural setting and to the progressive but neat transition between the two domains. This study uses low-temperature thermochronometry and vitrinite refl ectance analysis to investigate the effect of the opening of the Pannonian Basin on the thermal and burialexhumation histories of the Ukrainian Carpathians. The results show heating and burial maxima in the central units of the wedge (up to ~170 °C and 6 km, respectively), tapering out toward both the innermost and the outermost thrust sheets. Cooling and exhumation occurred by means of a fi rst rapid stage between ca. 12 and 5 Ma (exhumation rates of up to ~1 mm/yr), followed by a slower stage from ca. 5 Ma to the present (exhumation rates within 0.5 mm/yr). Timing and spatial pattern of exhumation are compatible with post-thrusting erosion enhanced by isostatic uplift. The extent of exhumation progressively decreases toward the Pannonian Basin, characterized by a thinned crust. No further signifi cant infl uence of the Pannonian Basin opening on the thermal and burial history of the Ukrainian Carpathians may be inferred based on our results, whereas the comparison of the tectonothermal evolution of the two domains suggests that they are both controlled by the same lithospheric processes.

New zircon fission-track (ZFT) ages from Corsica record multiple thermal events that can be tied to the structural evolution of the western Mediterranean region. The Corsican zircons have a wide scatter of ZFT grain ages (243–14 Ma), which together define several age domains. Western Corsica consists largely of stable Hercynian basement characterized by ZFT ages in the range 161–114 Ma. We interpret these ages (Late Jurassic–Early Cretaceous) as the product of a long-lived Tethyan thermal event related to continental rifting and subsequent drifting during the separation of the European and African plates and the formation of the Liguro–Piemontese ocean basin. In contrast to Hercynian Corsica, Alpine Corsica (northeast Corsica) experienced widespread deformation and metamorphism in Late Cretaceous(?)–Tertiary time. Dated samples from Alpine Corsica range in age from 112 to 19 Ma and all are reset or partially reset by one or more Alpine thermal events. The youngest ZFT grain ages are from the northernmost Alpine Corsica and define an age population at ∼ 24 Ma that indicates cooling after Tertiary thermal events associated with the Alpine metamorphism and the opening of the Liguro–Provencal basin. A less well-defined ZFT age population at ∼ 72 Ma is present in both Alpine Corsica and Hercynian basement rocks. The thermal history of these rocks is not clear. One interpretation is that the ZFT population at ∼ 72 Ma reflects resetting during a Late Cretaceous event broadly synchronous with the early Alpine metamorphism. Another interpretation is that this peak is related to variable fission-track annealing and partial resetting during the Tertiary Alpine metamorphic event across central to north-eastern Corsica. This partial age resetting supports the presence of a fossil ZFT partial annealing zone and limits the peak temperature in this area below 300 °C, for both the affected pre-Alpine and Alpine units.

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.

The results of apatite fission-track analyses of the Western Pontides of NW Turkey point to three discrete episodes of Cenozoic exhumation correlatable with major supraregional tectonic events. (1) Paleocene–early Eocene exhumation reflected the closure of the İzmir–Ankara ocean. (2) Late Eocene–earliest Oligocene exhumation was the result of renewed tectonic activity along the İzmir–Ankara suture. (3) Late Oligocene–early Miocene exhumation recorded the onset of northern Aegean extension. Samples collected north and south of the tectonic contact between the two terranes forming the Western Pontides (i.e. İstanbul and Sakarya terranes) record the same cooling events, suggesting that such terranes were amalgamated in pre-Cenozoic times.

Unraveling the deformation pattern characterizing the transition from final oceanic subduction stages to early stages of deformation of a foreland continental margin is crucial for a better understanding of the geodynamic processes taking place at convergent plate boundaries. In particular, the combined role of internal wedge dynamics and continental-margin architecture in controlling the tectonic evolution of an accretionary complex during its final emplacement onto the foreland continent is discussed in this study. To this purpose, we conducted integrated structural, stratigraphic, and low-temperature thermochronometric analyses on the Ligurian accretionary complex units exposed in the Campania region (Italy) and on continental-margin successions located in their footwall, as well as on related foredeep and wedge-top basin deposits. Our results point out a series of late early Miocene (Burdigalian) shortening events, also involving buttressing of the accretionary wedge against the crustal ramp of the foreland continental margin. Emplacement of the overthickened accretionary complex onto the distal part of the continental margin was followed by horizontal extension and wedge thinning, aiding the development of wedge-top depocenters. Extension may have been either related to reduced subduction rates during the middle Miocene, or to a period of subduction erosion (known to have occurred in the Northern Apennines in the same time frame). Early Miocene NW-SE shortening recorded by Ligurian accretionary complex units was completely unrelated to later (late Miocene to Pleistocene) NE-directed thrusting in the Apennines, which was coeval with backarc extension in the Tyrrhenian Sea. Therefore, our results emphasize the occurrence of a major discontinuity in the Neogene geodynamic evolution of the Southern Apennines, the tectonic history of which may be clearly subdivided, from a kinematic point of view, into pre- and syn-Tyrrhenian backarc extension stages.

(U–Th)/He and fission-track analyses of apatite along deep-seated tunnels crossing high-relief mountain ranges offer the opportunity to investigate climate-tectonic forcing on topographic evolution. In this study, the thermochronologic analysis along the Simplon tunnel (western-central Alps; Italy and Switzerland) constrains in detail the mechanisms controlling the topographic evolution of the Simplon Massif. Cooling rates vary from about 10°C/Ma at about 10 Ma to about 35°C/Ma in the last 3 Ma. Such increase in cooling rates corresponds to the inception of glacial cycles in the northern hemisphere. Age patterns show correlation with faults distribution until 2 Ma, suggesting that tectonics-controlled rocks exhumed up to that age. After 2 Ma thermo-chronometric data show that the Simplon area has experienced primarily erosional exhumation. All age patterns provided are not affected by topographic effects, thus indicating that present-day topography has been carved in the last 2 Ma, most likely controlled by glacial erosion.

This paper investigates the applicability of organic and inorganic thermal parameters in a range of thermal conditions, from diagenesis to epizone, and in HP–LT settings within the framework of continental subduction and exhumation in the southern Apennines, where independent thermobarometric constraints are available. Two juxtaposed tectonic units, the HP–LT Lungro–Verbicaro Unit (in the hanging wall) and the non-metamorphic Pollino–Ciagola Unit (in the footwall) have been analysed. For the Lungro–Verbicaro Unit, clay mineral thermal parameters and vitrinite reflectance underestimate metamorphic conditions (constrained by petrology), suggesting that, in relatively HP units, these indicators are ‘retarded9 and strongly depend on P – T evolution through time. On the other hand, the K-white mica b cell dimension provides a robust estimate of peak pressure. Fluid inclusion textures indicate a fast isothermal decompression during exhumation. Two-phase inclusions from early stage syntectonic veins were trapped after isothermal exhumation at a pressure of 0.3 GPa. For the Pollino–Ciagola Unit, the correlation of analysed parameters effectively unravels the thermal evolution, with maximum palaeotemperatures of c . 150 °C. Apatite fission tracks provide details of the final stages of exhumation, indicating that both units were coherently exhumed in the Late Miocene, following the tectonic emplacement of the Lungro–Verbicaro Unit on top of the Pollino–Ciagola Unit. Supplementary material: X-ray diffraction data (whole-rock composition, quantitative analysis of the b cell dimension) are available at http://www.geolsoc.org.uk/SUP18416.

We review the burial-exhumation history of sedimentary units along the Apennines, focussing on paleo-thermal and thermochronological data derived from organic matter optical analyses, X-ray diffraction of clay-rich sediments, fission-track and (U-Th)/He dating. In the Northern Apennines, burial conditions and timing of exhumation progressively decreases eastwards from the inner towards the outer zones and through the nappes from the lowermost to the uppermost unit. Apart from large outcrops of metamorphic rocks well exposed in Tuscany, most of the rocks of the Northern Apennines reached only diagenetic conditions. In the Central Apennines paleo-thermal and thermochronological data indicate a substantial low sedimentary and tectonic burial testifying minor amounts of orogenic shortening with a prevailing thick-skinned structural style and scarce exhumation when compared to the Northern and Southern Apennines. In the Southern Apennines, thermal indicators record exhumation of sedimentary units in the axial zone of the chain from depths locally in excess of 4 km (Lagonegro Unit and Monte Alpi structure). Apatite fission-track data indicate that exhumation marks the late tectonic stages (younger than 10 Ma) of chain evolution, probably initiating with the buttressing of the allochthonous wedge against the thickening passive margin of Adria microplate. On the other hand, higher structural units (derived from Apenninic platform deformation) show variable amounts of burial along the strike of the chain (increasing from Lucania to North Calabria border). In Eastern Sicily thermal maturity decreases from hinterland to foreland as a result of less severe thermal evolution and/or tectonic loading apart from the Peloritani Mts. in the hinterland that subdued two different phases of exhumation: the first between 35-20 Ma and the second younger than 15 Ma. Accretionary prism made up of Sub-ligurian unit (namely Sicilidi) in the footwall of the Peloritani Mts. mainly exhumed in Burdigalian times (17-19 Ma) from depths of a few kilometers. Frontal thrust stack derived from late deformation of Mesozoic passive margin successions mainly exhumed in Tortonian-Pliocene times from depths of about three kilometers. Syn-orogenic siliciclastics (mainly thrust-top basins) generally show low thermal maturity testifying scarce burial apart from those at the rear of the chain (on top of the Peloritani Mts) that are thermally imprinted by out-of-sequence reactivation in Serravalian times followed by fast exhumation in extensional regime.

The Uludag Massif in northwest Turkey represents an exhumed segment of an Oligocene ductile strike-slip shear zone that is over 225 kin long and has similar to 100 km of right-lateral strike-slip displacement. It forms a fault-bounded mountain of amphibolite-facies gneiss and intrusive Oligocene granites. A shear-zone origin for the Uludag Massif is indicated by: (1) its location at the tip of the active Eskisehir oblique-slip fault, (2) pervasive subhorizontal mineral lineation in the gneisses with a right-lateral sense of slip, (3) foliation with a consistent strike, (4) the presence of a subvertical synkinematic intrusion, and (5) the alignment of the Eskisehir fault, synkinematic metagranite, and the strike of the foliation and mineral lineation. The shear zone nucleated in amphibolite-facies gneisses at peak pressure-temperature (P-T) conditions of 7.0 kbar and 670 degrees C, and it preserves Eocene (49 Ma) and Oligocene (36-30 Ma) Rb/Sr muscovite and biotite cooling ages. The shear zone was active during the latest Eocene and Oligocene (38-27 Ma), as shown by the crystallization and cooling ages from synkinematic granite. A 27 Ma postkinematic granite marks the termination of shear-zone activity. The 20-21 Ma apatite fission-track (AFT) ages indicate rapid exhumation during the early Miocene. A 14 Ma AFT age from an Uludag gneiss clast deposited in a neighboring Neogene basin shows that the shear zone was on the surface by the late Miocene. Results of this study indicate that during the Oligocene, crustal-scale right-lateral strike-slip faults were transporting crustal fragments from Anatolia into the north-south-extending Aegean; this implies that the westward translation of Turkey, related to the Hellenic slab suction, started earlier than the Miocene Arabia-Eurasia collision.

Compositional control on the annealing kinetics of fission-tracks (FT) in apatite requires routine measurement of sample grain composition. However, for practical reasons the bulk composition of analysed grains is not routinely measured and instead grain chlorine content or etch-pit dimensions are used to characterise a samples annealing behaviour. A more desirable approach is to measure crystallographic parameters (i.e. unit cell dimension) of a grain as these represent the summed effect of all substitutions and crystal defects. We show how Raman microspectrometry can be used as a routine non-destructive tool to obtain rapid measurement of the crystallographic structure of apatite grains etched for FT analysis. Variations of unit cell parameter a are found to correspond to a systematic variation of Raman shift in the range of 452–440 cm− 1 for measurements made on c-parallel sections of apatite where the direction of the polarized incident beam is parallel to the c axis.

The Dolomite region is located in the Southern Alps, which were affected by Mesozoic extensional tectonics and by consequent thermal perturbations. In this work, vitrinite reflectance and apatite fission-track analysis are used to estimate the thermal evolution. These methodologies have been applied to the Permo-Mesozoic succession, which crops out along the TRANSALP seismic profile. The regional distribution of the organic matter maturity seems to be mainly controlled by different burials reached during the Norian-Liassic extensional phase, in connection with high heat flow values. The best solutions obtained from thermal modelling of both vitrinite and fission-track data suggest that peak of high heat flow occurred during Bajocian–Bathonian ages, when western Tethys was characterized by intrusions of gabbros and plagiogranites and extrusion of tholeiite basalts. This time coincides with the onset of the drifting phase and related thermal subsidence. The following thermal relaxation occurred during continuous sedimentation and the maximum burial does not coincide with peak temperatures. Cooling history has been carefully analysed through apatite fission-track data on samples collected close to the Valsugana overthrust, which document an important exhumation event at about 10 Ma. The related erosion has been analysed through the combined use of arenite petrography and fission-track analysis on detrital samples of the Veneto foredeep succession, which represents the storage of detritus during Tertiary. These data confirm that after Serravalian the Southalpine domain and related covers were affected by subaerial erosion.

The reconstruction of the thermal history of folded and thrust units is crucial to define the pattern of tectonic loading and the time-space evolution of an orogen where tectonic exhumation processes occurred at shallow crustal levels. In the present study, a well-constrained reconstruction of the thermal maturity in the axial zone of the southern Apennines has been achieved by the combined use of different thermal indicators in diagenesis. The major results are: (i) documentation of a jump in thermal maturity from the Apenninic Platform derived tectonic unit (from immature to early mature stages of hydrocarbon maturation) to the Lagonegro Basin derived tectonic units (late diagenetic zone); (ii) documentation of along-strike slighter variations in the Lagonegro units, concerning thermal maturity (thus maximum burial temperatures). This can be related to changes in amounts of tectonic burial and erosion/ exhumation because of the lack of cylindricity of contractional structures; (iii) recognition of an independent thermal evolution of the allochthonous chain compared with the Apulian Platform tectonic unit with Mt Alpi area (in the late mature stage of hydrocarbon generation) interpreted as a sector of localized, intense exhumation within the External Zone of the orogen.

[1] The long-term erosional evolution of relief is revealed by low-temperature thermochronometric data, whereas geomorphic features give constraints on the short-term evolution. We discuss the topographic evolution of northeastern Corsica by fission track and (U-Th)/He dating of apatite, the provenance of Neogene alluvial sediments, an analysis of uplifted strath terraces, and the shape of river profiles. Cooling ages indicate high cooling rates of up to 40°C/Myr during the early-middle Miocene, when this region was affected by extensional tectonics. Cooling rates are less than 7.5°C/Myr from the middle Miocene to the present, when topographic perturbations are detected by variations in the source areas of middle-to-late Miocene alluvial sediments and by the presence of large-scale irregularities along modern river longitudinal profiles. We suggest that the contrast of slow long-term erosion rates and the high local relief in the present Corsican landscape require that the landscape be in a transient state in response to a recent tectonic event.

Post-nappe brittle structures across the Austroalpine–Penninic wedge are representative of two principal deformation stages. The former (D1) developed during the Late Oligocene, the latter (D2) from the Miocene to the Present. Major D1 features are the E–W Aosta–Ranzola half-graben and the NE–SW Ospizio Sottile subvertical normal fault system. Oligocene extension was also characterized by hydrothermal activity and intrusion of calc-alkaline to ultra-potassic dikes. From the Miocene onwards (D2), the Ospizio Sottile system was re-activated as a SE sinistral boundary of the Pennine–Graian Alps block of nappes, bodily moving away from the Simplon detachment to the SW. Inside the escaping block, a number of D2 slightly diverging sublatitudinal splays (Aosta–Piccolo San Bernardo system) was generated, as well as a regular set of NW-trending normal faults from the Simplon to the Gran Paradiso massif. Instead, the Aosta–Ranzola system was poorly reworked in that time. More generally, the short-lived Oligocene extension (D1) was associated to slab break-off of lower plate, wedge rebound, rapid uplift and thermal perturbation. From the Early Miocene onwards the Oligocene extension was replaced by renewed compression, allowing the vertical extrusion of the Lepontine dome and lateral escape of the overlying Pennine–Graian Alps block.

In the southern Apennines fold and thrust belt, thermal indicators record exhumation of sedimentary units from depths locally in excess of 5 km. The belt is made of allochthonous sedimentary units that overly a 6–8 km thick, carbonate footwall succession. The latter is deformed by reverse faults involving the underlying basement. Therefore, a switch from thin-skinned to thick-skinned thrusting occurred as the Apulian Platform carbonates - and the underlying continental lithosphere - were deformed during the latest shortening stages. Apatite fission track data, with cooling ages ranging between 9.2 ± 1.0 and 1.5 ± 0.8 Ma, indicate that exhumation marks these late tectonic stages, probably initiating with the buttressing of the allochthonous wedge against the western margin of the Apulian Platform. Pliocene-Pleistocene foreland advancing of the allochthonous units exceeds the total amount of slip that could be transferred to the base of the allochthon from the underlying thick-skinned structures. This suggests that emplacement of the allochthon above the western portion of the Apulian Platform carbonates was followed by gravitational readjustments within the allochthonous wedge, coeval - and partly associated with - thick-skinned shortening at depth. The related denudation processes have played a primary role in tectonic exhumation.

A multidisciplinary approach for thermo-baric data acquisition is proposed along the southern Appennines, a key region of the Alpine orogen in the central Mediterranean area, including the remnants of a Cretaceous to Palaeogene accretionary complex. Ophiolite-bearing HP-LT tectonic units occur on top of the thrust pile. The underlying outcropping thrust sheets consist of Mesozoic and Cenozoic rocks derived from the sedimentary cover of the foreland plate (Apennine carbonate platform and Lagonegro pelagic units). These latter suffered, in some parts, HT-LT metamorphic conditions. We integrated independent thermal and thermo-chronological methods such as XRD analyses of clay mineral assemblages, fluid inclusion micro-thermometry, apatite fission tracks and vitrinite reflectance analyses, sampling both metamorphic and non methamorphic low-temperature successions. Our results indicate that a significant part of the sedimentary rocks exposed in the southern Apennines experienced substantial tectonic burial (locally in excess of 5 km), and confirm that, besides kinetics factors, a combination of methods allow to define thermo-cronological and, subordinately, pressure characteristics also for the HP-LT successions. Finally, in the northern sector of the area (Lucania), a break in thermal maturity from the Apennine carbonate platform and Lagonegro pelagic derived units has been documented, and along-strike variations of thermal maturity also emerged.