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The present work provides a combined structural and paleothermal (fluid inclusions, illite content in mixed layers illite–smectite, Kubler index and vitrinite reflectance) investigation of the Alpine cleavage domain affecting the western South Pyrenean Zone (Central Pyrenees). Integration of structural and paleothermal data allows us (i) to determine the position of the cleavage front in the sedimentary sequence and (ii) to define mechanisms and temperature conditions for cleavage development. Cleavage in the eastern part of the study area is approximately limited to the forelimb of the Gavarnie hanging wall anticline, but to the West it extends progressively southwards, affecting younger turbiditic units. At regional scale, the cleavage front is oblique to the strike of bedding and the overall trend of macrostructures. Pressure-solution is the main mechanism for cleavage development, and a strong thermal control on the position of the cleavage front is inferred. The transition between sedimentary and tectonic, compressional fabric is marked by vitrinite reflectance values of 1.12–1.14%, Kubler index values between 0.71 and 0.74°Δ2θ and the transition between R1 and R3 mixed layers illite–smectite. A lower thermal boundary of 140–160 °C is suggested for incipient cleavage development in the shaly beds of the turbiditic sequence, as well as an upper boundary constrained by a maximum measured value of about 215 °C.

[1] Obtaining constraints on maximum earthquake energy from fossil geological evidence has a primary importance for complementing historical information toward the proper mitigation of seismic hazard in a region. In this paper, we describe a newly discovered extensional fault zone in the western L'Aquila basin (Italy), associated with large paleofluidization structures. Paleofluidization-bearing Calabrian sediments provide evidence for very shallow burial from mineralogical, organic matter thermal maturity, and flat dilatometer test data, whereas density of organic matter shows anomalously high values. We propose that all these pieces of information can be reconciled into a paleoseismological scenario where sediment liquefaction and fluidization in early middle Pleistocene times, as well as dewatering and overconsolidation, were coseismically triggered by strong earthquakes with magnitude approaching or slightly exceeding 7.0.

Vitrinite reflectance is considered one of the most reliable indicators of thermal maturity in sedimentary basins and is widely used to calibrate numerical models that assess hydrocarbon generation/expulsion from source rocks. Nevertheless, ambiguities in vitrinite reflectance can occur from variations in composition and preservation state of organic facies, temperature/pressure conditions and the abundance of organic matter resulting in incorrect or uncertain assessments of petroleum systems. This study presents an original application of Raman spectroscopy to assess the diagenesis - catagenesis of kerogen between the immature and mid-mature stages of hydrocarbon generation. Kerogens were isolated from 33 intervals of drill cuttings from a 5km thick Oligocene-Miocene siliciclastic section of the Malembo Formation (Lower Congo Basin, Angola). Their Raman spectra were obtained and derived parameters were compared to depth and to previously reported equivalent vitrinite reflectance values. The best correlations between thermal maturity and Raman parameters were found for D-G band distance; FWHM of the G band; D/G area ratio; RA2 ratio (calculated as S+Dl+D/Dr+Gl+G band ratio) and the D/G width ratio. The Raman parameters were not influenced by varying kerogen composition (mixed type II/III). The technique offers the potential to reduce the risk of source rock thermal maturity assessment even when organic facies rich in amorphous organic matter are present.

Poland is considered the most prospective country for shale gas production in Europe. Hydrocarbon generation/expulsion scenarios, drawn in the latest intensive exploration phases, tend to overestimate maturation levels when compared with brand new data acquired after recent drillings. We tested an integrated workflow to correlate published and original thermal maturity datasets for the Paleozoic to Jurassic successions cropping out in the Holy Cross Mountains. These successions, when preserved in subsurface, host the major source rocks in the area. The application of the workflow allowed us to highlight the burial and thermal evolutionary scenarios of the two tectono-stratigraphic blocks of the Holy Cross Mountains (Łysogory and Kielce blocks) and to propose this approach as a tool for reducing levels of uncertainty in thermal maturity assessment of Paleozoic successions worldwide. In particular, published datasets including colour alteration indexes of Paleozoic microfossils (conodont, acritarchs) and vitrinite and graptolite reflectance data, show differences in levels of thermal maturity for the Łysogory (mid mature to overmature) and Kielce (immature to late mature) blocks. Original data, derived from optical analysis, pyrolysis, and Raman spectroscopy on kerogen, and X-Ray diffraction on fine-grained sediments, mostly confirm and integrate published data distribution. 1D thermal models, constrained by these data, show burial and exhumation events of different magnitude, during the Late Cretaceous, for the Łysogory (maximum burial depths of 9 km) and Kielce (burial depths of 6 km) blocks that have been related to the Holy Cross Fault polyphase activity. In the end, Palynomorph Darkness Index and Raman spectroscopy on kerogen, for Llandoverian and Cambrian rocks, turned out to be promising tools for assessing thermal maturity of Paleozoic organic facies devoid of vitrinite macerals.

This study presents new stratigraphic, structural and hydrogeological data on the Tocomar geothermal volcanic area (Puna plateau, Central Andes, NW Argentina), together with preliminary geochemical and magnetotelluric data. The main geothermal reservoir is located within the fractured Pre-Palaeozoic-Ordovician units. The reservoir is recharged by meteoric waters. Geothermal fluids upwell where main regional structures intersect secondary structures associated with the development of the Tocomar basin. Preliminary data indicate a reservoir temperature of ∼ 200°C and a local geothermal gradient of ∼ 130°C/km associated with the Quaternary volcanic activity in the Tocomar area. Fil: Giordano, G.. Universita Degli Studi Roma Tre; Italia Fil: Ahumada, Maria Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina. Universidad Nacional de Salta; Argentina Fil: Aldega, L.. Università degli studi di Roma "La Sapienza"; Italia Fil: Baez, Walter Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina. Universidad Nacional de Salta; Argentina Fil: Becchio, Raul Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina. Universidad Nacional de Salta; Argentina Fil: Bigi, S.. Università degli studi di Roma "La Sapienza"; Italia Fil: Caricchi, C.. Universita Degli Studi Roma Tre; Italia Fil: Chiodi, Agostina Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina. Universidad Nacional de Salta; Argentina Fil: Corrado, S.. Universita Degli Studi Roma Tre; Italia Fil: De Benedetti, A.A.. Universita Degli Studi Roma Tre; Italia Fil: Favetto, Alicia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Filipovich, Ruben Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina. Universidad Nacional de Salta; Argentina Fil: Fusari, A.. Universita Degli Di Camerino; Italia Fil: Groppelli, G.. Istituto Per la Dinamica Dei Processi Ambientali; Italia Fil: Invernizzi, C.. Universita Degli Di Camerino; Italia Fil: Maffucci, R.. Universita Degli Studi Roma Tre; Italia Fil: Norini, Gianluca. Istituto Per la Dinamica Dei Processi Ambientali; Italia Fil: Pinton, A.. Universita Degli Studi Roma Tre; Italia Fil: Pomposiello, Maria Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Tassi, F.. Università degli Studi di Firenze; Italia Fil: Taviani, S.. Universita Degli Studi Roma Tre; Italia Fil: Viramonte, Jose Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina. Universidad Nacional de Salta; Argentina

Cap rock characterization of geothermal systems is often neglected despite fracturing may reduce its efficiency and favours fluid migration. We investigated the siliciclastic cap rock of Rosario de La Frontera geothermal system (NW Argentina) in order to assess its quality as a function of fracture patterns and related thermal alteration. Paleothermal investigations (XRD on fine-grained fraction of sediments, organic matter optical analysis and fluid inclusions on veins) and 1D thermal modelling allowed us to distinguish the thermal fingerprint associated to sedimentary burial from that related to fluid migration. The geothermal system is hosted in a Neogene N-S anticline dissected by high angle NNW- and ENE-striking faults. Its cap rock can be grouped into two quality categories: • rocks acting as good insulators, deformed by NNW–SSE and E–W shear fractures, NNE-SSW gypsum- and N-S-striking calcite-filled veins that developed during the initial stage of anticline growth. Maximum paleo-temperatures (< 60 °C) were experienced during deposition to folding phases.• rocks acting as bad insulators, deformed by NNW-SSE fault planes and NNW- and WNW-striking sets of fractures associated to late transpressive kinematics. Maximum paleo-temperatures higher than about 115 °C are linked to fluid migration from the reservoir to surface (with a reservoir top at maximum depths of 2.5 km) along fault damage zones.This multi-method approach turned out to be particularly useful to trace the main pathways of hot fluids and can be applied in blind geothermal systems where either subsurface data are scarce or surface thermal anomalies are lacking. Fil: Maffucci, R.. Universita Degli Studi Della Tuscia; Italia. Universita Degli Studi Roma Tre; Italia Fil: Corrado, Sveva. Universita Degli Studi Roma Tre; Italia Fil: Aldega, L.. Instituto de Investigaciones Universitarias Roma la Sapienza; Italia Fil: Bigi, S.. Instituto de Investigaciones Universitarias Roma la Sapienza; Italia Fil: Chiodi, Agostina Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones en Energía no Convencional. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Física. Instituto de Investigaciones en Energía no Convencional; Argentina Fil: Di Paolo, L.. Eni E&P Division; Italia Fil: Giordano, G.. Universita Degli Studi Roma Tre; Italia Fil: Invernizzi, C.. Universita Degli Di Camerino; Italia

Shale gas is envisaged to contribute in the next future to the European energy mix in the prospective of lowering CO2 emissions. Poland is by far one of the most perspective countries in Europe. In the “Golden Belt”, potential productive levels are Early Paleozoic in age and the reliable assessment of their thermal maturity is crucial for evaluating hydrocarbon generation/expulsion scenarios. When exploring Lower Paleozoic targets that are devoid of vitrinite macerals, uncertainties in thermal maturity evaluation can occur according to commonly adopted parameters (e.g., vitrinite reflectance). These uncertainties can negatively influence targets assessment. We adopted a multi-method approach to assess thermal maturity of the Silurian sections encountered in three wells deep between 2.9 and 3.3 km, recently drilled in the Polish Baltic Basin. The methodological strategy consists of: ( i ) measurement of organoclasts (mainly graptolites) reflectance; ( ii ) FT-IR spectroscopy on bulk dispersed organic matter; ( iii ) X-ray diffraction on

Vitrinite reflectance has been always considered the most reliable thermal maturity indicator in sedimentary basins. Nevertheless the reliability of vitrinite reflectance measurements can be affected by many external factors that change from basin to basin (e.g. organic facies, temperature and pressure conditions) leading to wide uncertainties in thermal modelling calibration and thus in the evaluation of timing and amount of hydrocarbons generation. We demonstrate that in case of vitrinite suppression and/or retardation in siliciclastic successions, the classical Sweeney and Burnham kinetics do not match the actual thermal evolution of the basin. In these cases, thermal evolution can be successfully modelled using a complementary approach based on smectite illitization kinetics or more appropriate kinetics (e.g., PresRo TM and T-P-Ro) to evaluate the effect of pressure on organic matter maturation where pressure data are available. This approach was applied in the Lower Congo Basin where 32 cuttings from a 5 km-deep well drilled in the Upper Oligocene-Miocene Malembo formation have been analysed to derive organic and inorganic constraints to model the basin thermal evolution. Vitrinite and bitumen reflectance measurements show values between 0.3 and 1.0% along the well, whilst the illite content of mixed layer I-S ranges between 35 and 88%, passing from R0 to R1 to R3 stacking order with increasing depth. Present-day temperature distribution through the well indicates a geothermal gradient of about 40 °C/km and measured pressures show an overpressured interval between 3 and 4 km depth. Retardation and suppression phenomena affected vitrinite reflectance in this interval but did not influence smectite illitization. The comparison between thermal maturity scenarios constrained by organic and inorganic thermal indicators shows differences in the calculation of the depth of the onset of hydrocarbon generation that is overestimated of about 500 m in the Lower Miocene interval when only suppressed/retarded vitrinite reflectance values are used to calibrate models.

Geological records from the Antarctic margin offer direct evidence of environmental variability at high southern latitudes and provide insight regarding ice sheet sensitivity to past climate change. The early to mid-Miocene (23-14 Mya) is a compelling interval to study as global temperatures and atmospheric CO2 concentrations were similar to those projected for coming centuries. Importantly, this time interval includes the Miocene Climatic Optimum, a period of global warmth during which average surface temperatures were 3-4 degrees C higher than today. Miocene sediments in the ANDRILL-2A drill core from the Western Ross Sea, Antarctica, indicate that the Antarctic ice sheet (AIS) was highly variable through this key time interval. A multiproxy dataset derived from the core identifies four distinct environmental motifs based on changes in sedimentary facies, fossil assemblages, geochemistry, and paleotemperature. Four major dis-conformities in the drill core coincide with regional seismic discontinuities and reflect transient expansion of grounded ice across the Ross Sea. They correlate with major positive shifts in benthic oxygen isotope records and generally coincide with intervals when atmospheric CO2 concentrations were at or below preindustrial levels (similar to 280 ppm). Five intervals reflect ice sheet minima and air temperatures warm enough for substantial ice mass loss during episodes of high (similar to 500 ppm) atmospheric CO2. These new drill core data and associated ice sheet modeling experiments indicate that polar climate and the AIS were highly sensitive to relatively small changes in atmospheric CO2 during the early to mid-Miocene.

In the Northern Apennines of Italy the Ligurian and Subligurian Units (LSU) represent far-travelled/allochthonous units which, since early Miocene to Recent, migrated towards NE, above the Tuscan-Umbrian foredeep deposits, reaching the present-day frontal ranges of the chain. In the NE-facing side of the western Northern Apennines the present-day geometry of the LSU does not reflect the shape they acquired during the late Oligocene, when the early orogenic collisional phases produced a wedge whose geometry tapered out towards the foreland area, i.e. to the E-NE. In fact, at present, geological evidences indicate that the LSU are characterized by a doubly-tapering geometry, whose thickness ranges from less than 1 km at the main ridge zone (SW) up to more than 4 km along the NE slope of the chain and then tips out again few km N of the Northern Apennines topographic front, underneath the late Messinian to Recent marine and continental deposits of the Po Plain foredeep. These data imply that since late Oligocene the LSU geometry has been deeply reshaped inside a context of overall growth of the orogenic wedge. Therefore the reshaping of the LSU is related to their post-early Miocene progressive emplacement over the foredeep units and to the late orogenic evolution of the Northern Apennines, characterized by the coeval activity of extensional and compressional tectonics. In order to put new constraints on the relationships existing between timing and modes of reshaping of the LSU and the Miocene to Recent evolution of the western Northern Apennines, we adopted a multidisciplinary approach which took into account field evidences, low temperature thermal and thermochronological data (vitrinite reflectance, clay mineral analyses, apatite fission track dating), numerical modelling of the AFT cooling ages through the use of Pecube finite element code, recently published works on the evolution of the external slope of the chain, and a new interpretation of seismic lines and boreholes data. This multidisciplinary approach allowed us to: 1) build a 3D representation of the LSU present-day geometry; 2) highlight two main stages of reshaping of the LSU, first during late Miocene (10 to 6 Ma), and subsequently during Pliocene to Recent (?) time (6 to 0 (?) Ma); 3) relate, during the first stage, the LSU thinning processes, achieved by means of low-angle extensional faults, to the tectonic denudation of the foredeep units; 4) envisage the importance of coupled tectonic (high-angle extensional tectonics) and progressively increased surface erosion processes as responsible for the denudation of the foredeep units during the second stage; 5) define estimates of the exhumation/erosion rates characterizing the investigated area during the last 10 My. These results allowed us to give new insights, temporal and spatial constraints on the morphostructural evolution of the western Northern Apennines, which has been mainly affected initially (10-6 Ma) by the interplay between deep compressional and coeval shallow extensional tectonics (< 20 and < 4 km, respectively), and subsequently by the progressively more relevant onset of surface erosion processes.

Coeval extensional and contractional tectonics are a common feature in orogenic belts, especially in post-collisional phases. The attempt to constrain their relative timing and the responsible mechanisms led to several models taking into account different geodynamic contexts of various mountain chains. In peri-Mediterranean collisional orogens, extension and compression are commonly associated and coeval to the emplacement of far-travelled/allochthonous units. Therefore their internal deformation acquired during the translation across collisional belts is likely imprinted by the extensional and contractional tectonics affecting the orogen.In the western portion of the Northern Apennines of Italy, one of the northernmost peri-Mediterranean Tertiary orogens, the far-travelled/allochthonous units, i.e., the Ligurian and Subligurian units, are widely exposed. The present study integrates published and newly acquired surface geological data (geological maps, cross-sections), subsurface boreholes data, and paleothermal (vitrinite reflectance, mixed layer illite-smectite and Kübler index) and thermochronological data (apatite fission-tracks) in order to investigate the deformation history and, consequently, the record of the extension-compression relationships within these far-travelled/allochthonous units.The study of modes and timing of reshaping of the far-travelled/allochthonous units allowed us to strengthen the hypothesis that extensional and contractional tectonics were coeval in the Northern Apennines and tightly connected by a cause/effect relationship. In particular, the late orogenic low- and high-angle extensional tectonics represent the response to an overall contractional regime which induced episodes of gravitational instability in the orogenic wedge. © 2013 Elsevier B.V.

Combined structural and geophysical investigations were carried out in the Matese Massif at the boundary between the Central and the Southern Apennines. The aim of this research was to define the structural geometry and the kinematics of Neogene deformation in order to validate the applicability of either thin-skinned or thick-skinned compressive styles in the Apennines of Italy. On the basis of two surface N–S cross-sections, integrated with recently acquired magnetotelluric data, the Matese structure appears as a single thrust sheet limited at the bottom by a low-angle thrust fault with sense-of-displacement towards the North. The structure was later deformed by footwall thrusts carrying Molise–Sannio Pelagic Basin Units and Apulian Carbonate Platform Units. The structure of the Matese Massif is composed mainly of Mesozoic carbonates of inner platform to by-pass and slope facies, separated within the thrust sheet by high-angle faults with low reverse horizontal displacement. These faults acted as normal faults in the Mesozoic and Cenozoic and controlled the carbonate facies distribution. During Neogene compression, these structures were tilted and then truncated by the basal short-cut thrust fault that cut from pre-Triassic units to Jurassic dolostone towards the foreland. Finally, Quaternary extensional tectonics dissected the whole structure with fault-related displacement values of up to 1000 m. This resulted in the present-day structural setting of the Matese Massif as a horst bounded to the SW and NE by fault-controlled basins, filled with continental deposits. This revised structural scenario is discussed within the framework of the structural style of external zones of the Apennines.

The emplacement temperatures of three ignimbrites belonging to the 4.6-ka Fogo A plinian eruption sequence in São Miguel Island (Azores, Portugal) were determined using partial thermal remanent magnetization (pTRM) of lithic clasts and reflectance (Ro%) of charcoal fragments embedded within the deposits and collected at the same localities close to each other. The Fogo A sequence is characterised by a complex stratigraphy consisting of a thick plinian deposit interbedded with two intraplinian ignimbrites (here named “pink” and “black” intraplinian ignimbrite, respectively) and capped by a final ignimbrite (here named “dark brown” ignimbrite). A total of 140 oriented lithic clasts from the three ignimbrites were collected from 15 localities distributed along the northern and southern flanks of the volcano. The pTRM analyses show different paleomagnetic behaviours, which correspond to different emplacement temperatures of the ignimbrites. The emplacement temperatures of the pink and black intraplinian ignimbrites inferred from pTRM analysis were respectively ≥400 and ≥600 °C; the temperatures of the dark brown ignimbrite are lower, estimated between 300 and 350 °C. Thermal estimations of three key sites were compared with the results of the analysis of reflectance (Ro%) measured on eight specimens derived from charcoal fragments collected from the pink intraplinian ignimbrite and the dark brown ignimbrite. Results indicate Ro% values between 1.61 and 1.37 for the pink intraplinian ignimbrite, whereas fragments collected from the dark brown ignimbrite show Ro% values between 0.85 and 0.50. No charred wood was found in the black intraplinian ignimbrite. Ro% values indicate that charcoal fragments in the pink intraplinian ignimbrite reached temperatures of 380–460 °C, whereas the Ro% values of the dark brown ignimbrite indicate slightly lower temperatures of 330–350 °C. TRM and Ro% results are comparable and validate the use of both methods. Greatest accuracy in the determination of emplacement temperatures of ignimbrites is achieved when both methods can be applied at the same locations.

A multi-method approach (palaeothermal and thermochronological analyses; thermal modelling) is applied to reconstruct the exhumation history of the Altotiberina Fault (ATF), a representative example of crustal-scale active low-angle normal faulting in the Northern Apennines (Italy). Thermal maturity and thermochronological data yield similar burial histories but different exhumation patterns for the sedimentary successions in the hangingwall and the footwall of the ATF. Since 3.8 Ma, the ATF footwall has exhumed at rates of 0.90 mm a-1. Exhumation led to bending and deactivation of the ATF uppermost portion as a result of tectonic unloading and isostatic adjustment, followed by migration of extension and the development of a set of domino-like, east-dipping normal faults, rooting on the buried portion of the ATF. ATF activity and isostatic rebound exhumed Triassic rock units from depths of about 4 km. We suggest that isostatic instability is accommodated at shallow crustal levels, in a similar way to what is observed on larger structures at mid-low crustal levels.

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.

A new data set of temperature-dependent clay mineral parameters and vitrinite reflectance of the Tuscan successions in the Northern Apennines (Italy) displays decreasing levels of thermal maturity from hinterland to foreland, and abrupt changes parallel to the strike of the chain which are structurally controlled by northeast-southwest–trending faults (e.g., Marecchia valley lineament). To the southeast of the Marecchia valley lineament, paleothermal indicators show deep diagenetic conditions in the hinterland and early diagenetic conditions in the foreland (R o % ranges from 0.80% to 0.30%; illite content in mixed-layer illite-smectite [I-S] from 86% to 38%). To the northwest of the Marecchia valley lineament, in the hinterland, R o % is up to 0.95% and mixed-layer I-S have an illite content of ~87%–88%, both gradually decreasing toward the northeast (to R o % of 0.33%, and illite in I-S of 50%). Thermal models allowed us to constrain the geometry of the Miocene thrust wedge with special regard to the original thickness and distribution of its allochthonous uppermost structural unit (Ligurian unit) across northeast-southwest–trending tectonic lineaments. The thickness of the Ligurian unit ranges from 1 to 1.5 km to the south of the Marecchia valley lineament, to 3 km to the north-northwest. This tectonic lineament affected wedge geometry, amounts of tectonic transport, and thickness of the uppermost structural unit, and, possibly, Neogene–Quaternary levels of exhumation.

This paper focuses on the boundary area between the Central and Southern Apennines thrust belt of the Italian peninsula, which separates two different patterns of distribution of active faults and strong earthquakes along the Apennines chain. In order to reduce the remarkable lack of data on this area, part of this boundary has been investigated. The study area corresponds to the surroundings of the town of Isernia, an important centre of the Molise region, and contains the Carpino and Le Piane (CLP) intermountain Basins of Quaternary age. The research was based on unpublished data, consisting of 65 well logs drilled in the CLP Basins, integrated with detailed field surveys (scale 1:10,000), mesoscale structural analysis and aerial photograph interpretation. This study allowed to define the geometry and kinematics of the CLP Basins. They result to be asymmetric halfgrabens partially filled with fluvio-lacustrine deposits, where the sedimentation is controlled by the activity of a set of normal faults striking N30jW and NE dipping. This set of faults, which developed mainly during the Late Pleistocene–Holocene, is about 10 km long and is located close to the northwestern end of the Boiano Basin extensional Fault System. The average slip rate calculated for part of the Holocene for one of the recognised faults ranges from 0.75 to 1.00 mm/year. The identification of the active CLP Basins Fault System partially fills the gap of data at the boundary between the Central and Southern Apennines. From a more general point of view, we hypothesise that this boundary might be regarded as a ‘‘persistent segment boundary’’, forming a long-term barrier to the propagation of rupture of active fault systems. Under this perspective, a redefinition of the seismic zonation of Italy for the study area is suggested. D 2002 Elsevier Science B.V. All rights reserved.

The Monte Alpi area of the Southern Apennines represents the only sector of the thrust belt where the reservoir rocks (i.e. Apulian Platform carbonates) for major hydrocarbon accumulations in southern Italy are interpreted to crop out. Tectonic evolution and exhumation of this area were analysed by integrating stratigraphic and structural data with different organic and inorganic parameters which record the burial and thermal evolution of the sediments (vitrinite reflectance, fluid inclusions, and I/S mixed layers in clayey sediments). Our analyses suggest that the presently exposed Monte Alpi structure suffered a loading of ca. 4000 m, owing to the emplacement of allochthonous units in Early Pliocene times. Available geological data indicate that erosion of the tectonic load occurred since the Late Pliocene, when the area first emerged. This implies an average exhumation rate in excess of 1 mm/year. A model can be constructed which matches the maturity indices and also takes into account intermediate stages of the evolution, resulting from combined structural and fluid inclusion data. By this model, a first stage of exhumation would have taken place at an average rate of about 0.36 mm/year. This was controlled by uplift and erosion associated with both: (i) thrusting at depth within the Apulian carbonates (Late Pliocene), and (ii) strike-slip faulting (Early Pleistocene). A second exhumation stage would have occurred in the last 700 ky at a much faster rate (ca. 4 mm/year) as a result of extensional tectonics. © 2002 Éditions scientifiques et médicales Elsevier SAS. All rights reserved.

The geological structure of the Central Apennines along a section line across the Lazio-Abruzzi carbonate plat- form has traditionally been interpreted using a thin-skinned thrust tectonic model, in which the sedimentary cover has been detached from an undeformed basement below. Such models have been used to predict that very large amounts of crustal shortening (e.g. 172 km over a section 173 km long) have occurred. Alternatively, in this paper we reinterpret the surface geology and well data along the same section line us- ing a thick-skinned thrust tectonic model. Restoration of this section shows that the amount of shortening (37 km over a section 158 km long) is considerably lower than previously predicted; this is accomplished by open buckling of the car- bonate platform, tighter folding of the basin scarp stratig- raphy, and reactivation of pre-existing extensional faults. Age bracketing on thrust fault movement allows shortening rates for the two different models to be calculated; these are < 6 mm yr 1 for the new interpretation, but over 24 mm yr 1 for the equivalent thin-skinned model. This latter value is significantly greater than shortening rates reported for most other thrust belts, suggesting that thick-skinned tectonics is a more satisfactory explanation for the structure of this area. The two most important implications of this are that sub- thrust hydrocarbon plays are largely absent in the area, and Neogene contractional deformation in this part of the Apen- nines resulted in much less crustal shortening than previously predicted.

The Abruzzi–Molise sector in the Central Apennines is a part of a fold and thrust belt that has been deforming since the Late Cretaceous as a result of collision tectonics between the European and Adriatic plates. The superposition of different deformational styles highly reworked the originally complex palaeogeography of this portion of the southern Tethyan margin. Analogue modelling has been performed on thrusting mechanisms in the Abruzzi–Molise area in order to (1) reduce the number of admissible hypotheses regarding palaeogeographic setting, and (2) define thrusting mechanics. Both of these goals are crucial for hydrocarbon exploration purposes. The sandbox apparatus used to simulate the undeformed passive margin consisted of a thin compartment juxtaposed against a thick one along a linear boundary having variable geometries and mechanical stratigraphy; a rigid but mobile backstop was used to deform the stratigraphy in a Coulomb thrust wedge. Results from six experiments show that the geometric relationships between different structural units depend on the distribution of palaeogeographic domains. These domains are defined by mechanical and/or geometrical parameters, such as the orientation between the maximum compression direction and the palaeogeographic boundary, the mechanical stratigraphy and the thickness of the successions reproduced in the models. The present-day tectonic styles and Meso–Cenozoic palaeogeography of the Abruzzi–Molise area are discussed in terms of the mechanisms and structures analysed through the models.

The Abruzzo-Molise-Sannio region is part of the Central Apennines foreland fold and thrust belt, a structure that formed during the Neogene as a result of the continental collision between the European and Adria plates. Certain areas of this crust experienced anomalously high temperatures due to deep burial, while others did not. This burial has been investigated using optical indicators of organic matter (OM) maturity and clay mineralogy. The maximum depths of burial of Tertiary surface sequences have been established based on the vitrinite reflectance (Ro) and thermal alteration index (TAI) of OM dispersed in synorogenic sediments and from clay mineralogy of pre-thrusting clayey deposits. The synorogenic deposits show low levels of organic maturity having Ro values less than 0.6% indicating early mature to mid-mature hydrocarbon generation. The pre-thrusting deposits are shales characterised by a very high percentage of clay minerals with lesser amounts of quartz, K-feldspar, plagioclase and calcite. The dominant minerals are highly smectitic interstratified illite/smectite (RIS). Both Ro and I/S ratios were used to calibrate burial and thermal evolution of this chain sector by numerical modelling. The results indicate that the structural units which outcrop in the study area (particularly the Molise Unit) were never overthrust by significant thicknesses of rocks during mountain building, at least before Pliocene times; the hypothesis that more internal units overthrust the presently exposed units also seems to be unlikely.

This work is part of a project aimed to the development and application of hydrogeological, hydrogeochemical and geological methodologies for the study of the geothermal system of Rosario de La Frontera (NW Argentina).The surface thermal manifestations of this area, whose temperatures range from 22.6 to 92.6°C, are mainly located in the northern sector of Sierra de la Candelaria anticline. This regional structure crops out between the provinces of Salta and Tucuman (NW Argentina), at the foothills of the central Andean retro-wedge.The present investigation focuses on hydrogeological and structural data, and isotopic compositions (18O, D and 3H) of thermal springs.Preliminary results allowed to define: i) the meteoric origin of spring water and their long (more than 50 years) residence time at depth, ii) a positive water balance, ranging between 2 and 4 millions of m3/yr, and iii) a conservative geothermal reservoir volume of about 39km3, iv) a geothermal potential with Er=5.6*1018J and Ef=0.8*1018J. © 2014 Elsevier Ltd. Fil: Invernizzi, Chiara. Università Degli Studi Di Camerino; Italia Fil: Pierantoni, Pietro Paolo. Universtà Degli Studi Di Camerino; Italia Fil: Chiodi, Agostina Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones en Energia No Convencional. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Física. Instituto de Investigaciones en Energia No Convencional; Argentina Fil: Maffucci, Roberta. Università Degli Studi "Roma Tre"; Italia Fil: Corrado, Sveva. Università Degli Studi "Roma Tre"; Italia Fil: Baez, Walter Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones en Energia No Convencional. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Física. Instituto de Investigaciones en Energia No Convencional; Argentina Fil: Tassi, Franco. Universita Degli Studi Di Firenze; Italia Fil: Giordano, Guido. Università Degli Studi "Roma Tre"; Italia Fil: Viramonte, Jose German. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones en Energia No Convencional. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Física. Instituto de Investigaciones en Energia No Convencional; Argentina

An extensive dataset of vitrinite reflectance, FTIR parameters on organic matter, illite content in mixed layers illite-smectite, apatite fission tracks and U-Th/He dating has been used to reconstruct the stepwise propagation of the Eastern Sicily fold-and-thrust belt during Late Palaeogene and Neogene times. The results indicate that the fold-and-thrust belt is divisible into two levels of thermal maturity. These levels consist of a less evolved level of thermal maturity that records limited sedimentary burial and minor heating, and a more evolved level of thermal maturity that indicates tectonic burial and exhumation at different times. Deformation and exhumation of shallowly buried units are linked to wedge forward propagation by low-angle thrusts, whereas the evolution of deeply buried units is associated with tectonic imbrications by duplex formation and steep thrusts. The two tectonic styles alternate during evolution of the fold-and-thrust belt under low erosion rates. © 2014 John Wiley & Sons Ltd.

We performed XRD investigations on the sedimentary cap rock of the geothermal system developed in the area of Vico volcano (Northern Latium) to assess its effectiveness and degree of interaction with fluids. The system consists of a positive thermal anomaly, a permeable carbonate reservoir at shallow depths and a low permeability siliciclastic cap rock. Unfractured cap rock shows maximum paleo-temperatures

Determining the deposit temperature of pyroclastic density currents (PDCs) is a first order priority in the assessment of volcanic hazard. For past eruptions, in which no direct measurements are possible, PDC deposit temperatures have been calculated mainly using magnetic proxies. A more recent and innovative approach consists of the determination of the degree of charring of preserved wood fragments by optical analysis. In this study, we perform optical analyses on wooden beams belonging to the Villa dei Papiri at the archeological site of Herculaneum, which was destroyed by PDCs during the 79 AD eruption of Vesuvius. The new temperature data from this study range between 240 °C and 370 °C, and are in good agreement with literature data for this eruption. The large T variation measured can be interpreted as due to the interaction of the PDCs with the local environment, i.e. the impacted buildings of the villa and the sea shoreline. The study of in situ charred wood allows to constrain the charring kinetics and to evaluate the sensitivity of the reflectance proxy in recording PDC depositional features. We demonstrate that the charcoal reflectance is an excellent proxy for the determination of the PDC deposit temperatures even at a local scale, and it can be used in conjunction with, or in alternative to other more traditional methodologies, especially in case of pre-heating effects which may alter the T determinations by thermoremanent magnetization.

Orientation and distribution of fractures in the Oligocene–Early Miocene Asmari Formation (a major reservoir rock of the Zagros petroleum system) were investigated in two anticlines of the Zagros fold-and-thrust belt. The Sim and Kuh-e-Asmari anticlines developed in the areas of the Zagros characterized by the occurrence and absence of Cambrian evaporites at the bottom of the stratigraphic pile, respectively. The aim was to outline major differences in terms of fracture spacing and saturation. Organic matter maturity and clay minerals-based geothermometers suggest that the depth of deformation for the top of the Asmari Formation in the Kuh-e-Asmari anticline was in the range of 1.5–2.7 km assuming a geothermal gradient of 22.5 °C/km. The Asmari Formation in the Sim anticline probably experienced a slightly deeper sedimentary burial (maximum 3 km) with a geothermal gradient of 20 °C/km. The spacing of fractures is generally 2–3 times larger (i.e., strain accommodated by fracturing is smaller) in the Sim anticline than in the Kuh-e-Asmari anticline. This is consistent with regional geological studies, analogue, and numerical models that suggest that thrust faults geometry and related folds are markedly different in the absence or presence of a weak decollement (evaporites). The larger spacing in the Sim anticline is also consistent with higher temperature predicted for the Asmari Formation in this area. By contrast, the orientation of fractures with respect to the fold axes is the same in both anticlines. The fracture systems are rather immature in both anticlines. The amount and density of fractures in the twofolds are controlled by regional (occurrence/absence of salt and probably different burial), rather than local features (fold geometry).

Organic and inorganic thermal indicators throughout the Late Paleozoic sedimentary fill of the Aragón-Béarn Basin in the western Pyrenees, integrated with stratigraphic and structural data, point to a two-stage tectonic evolution: (i) High heat flow values and widespread magmatic intrusions driven by deeply rooted strike-slip faults characterized the first stage. This regime accompanied the rapid and localized deposition of the lower sedimentary succession and ended with uplift and erosion. (ii) The second stage was characterized by lower heat flow values, shallower strike-slip faults active during the deposition of an upper transgressive sedimentary succession and minor magmatic intrusions. The lower portion of the succession (Unidad Gris, Unidad de Transito and Unidad Roja Inferior, mainly Stephanian-Early Permian in age) records maximum temperatures between 170°C and 220°C as shown by clay mineral-based geothermometers (KI between 0.40 and 0.52°D2q, conversion of mixed layer illite-smectite to discrete illite), vitrinite reflectance (about 2.5%), and total homogenization temperatures from host-rock quartz cements between 160 and 180°C. The upper portion of the succession (Unidad Roja Superior, mainly Upper Permian in age) records maximum temperatures between 100-110° and 150°C as indicated by KI values between 0.57 and 0.94°D2q, illite content in mixed layer illite-smectite of 85-92%, and fluid inclusions in host-rock quartz-calcite cements. Local thermal maturity anomalies affected selected portions of the Late Paleozoic sedimentary succession with organic matter and clay minerals reaching respectively Ro%: 4.2-4.7% and KI up to 0.32°D2q in the lower sequence, and Ro% 2.9% in the upper sequence. These localized anomalies with respect to the basin thermal signature are the result of contact metamorphism related to the emplacement of magmatic intrusions across the sedimentary fill during two different magmatic events.

Levels of organic maturity of Mesozoic and Tertiary sequences outcropping in the Central Apennines have been established, using vitrinite reflectance techniques, the Thermal Alteration Index and fluorescence colours of organic matter dispersed in sediments. These results provide new constraints throughout the Meso-Cenozoic evolution of this crustal sector. In exploration geology, vitrinite reflectance provides data on hydrocarbon maturation by constraining organic matter maturity. In sedimentary basin modelling, it is adopted to define the palaeothermal regime. Vitrinite reflectance (Ro) also provides information on the burial history of sedimentary basins and may be employed to estimate tectonic uplift and erosion rates. Thermal Alteration Index (TAI) and fluorescence colour values can be correlated with Ro and may be used to estimate the degree of maturation when vitrinite is absent. Samples derived from the Sabini and Tiburtini Mts, in slope facies between the Latium–Abruzzi carbonate Platform and the Umbria–Marche pelagic Basin; from the Simbruini and Ernici Mts, in carbonate Platform facies, and from upper Miocene turbiditic deposits outcropping between the Olevano–Antrodoco Une, towards the West, and the Marsica slope facies, towards the East. Both the pre-terrigenous Meso-Cenozoic sequences show a low grade of organic maturity: the Sabini and Tiburtini Mts show Ro values that are less than 0.4%, and the Simbruini–Ernici Range show Ro values that range between 0.5% and 0.65%. Field analysis indicates that the cause of these low maturity levels is that thick sequences of turbidites were never deposited during the Neogene evolution of the Apennine thrust belt. Moreover, Upper Miocene turbiditic deposits also show low maturity levels, with Ro values that are less than 0.5%, indicating that these deposits were never overthrusted by huge volumes of rocks, during the chain building. The slight increase in the maturity level recorded in the Marsica area may be related to local heating along shear zones in areas of strike-slip tectonics.

The characteristics of a shallow-level shear zone that is representative of the deformation in the external sectors of the Northern Apennine fold-and-thrust belt are described. The characterization involved an integrated approach using microstructural analysis of deformation fabrics, vitrinite reflectance measurements, XRD analysis on clay minerals and carbon and oxygen stable isotopes analyses. This data set provides the evidence that the thrust was active at very shallow depths (ca. less than 3 km), with maximum paleotemperatures ranging from 60 degrees to 100-110 degrees C. The regime during fault activity evolved through cycles of compaction and dilation linked to transient build up of fluid overpressure and injection. The alternating cycles of fluids supply generated a fault-fracture mesh with a complex network of blocky and striped veins that formed at temperatures ranging from 150 degrees to 200 degrees C, not compatible with the conditions in the host rocks. This evidence implies that the shear zone was flooded by hot fluids coming upward from diagenetic and low-grade metamorphic dehydration of clay minerals active at deeper structural levels. The fluids were thus highly channelled and focused where deformation also focused, producing a local pronounced isotopic difference between fluids and host rock. (C) 2012 Elsevier Ltd. All rights reserved.

The western Lucretili Mts. in the central Apennines (Latium, Italy) have been recently re-mapped in great detail and are the subject of combined stratigraphic, sedimentological and structural investigations. In this paper, we present a new stratigraphic interpretation of the Jurassic paleogeography of western Lucretili Mts., where a rift-derived intrabasinal paleo-high of the Alpine Tethys has been identified for the first time by means of facies analysis and biostratigraphic dating. Recognised facies associations, combined with dated stratigraphic sections, allow to define the morphology of the structural paleo-high and to identify the associated gravity-driven deposits (olistoliths) accumulated in the surrounding basin. Furthermore, we investigated the modes of interaction between Jurassic extensional structures and the subsequent contractional patterns developed during the Tertiary mountain building. In detail, the role played during Apennines tectonics by the paleo-escarpments bounding the paleo-high and by the surrounding olistoliths has been analysed. The paleo-escarpments either acted as focussing features for ENE-directed frontal thrust ramp localisation and were offset with small shortening amounts or reactivated as NNE striking high angle transpressional faults or preserved the original geometries as a result of variable orientation of paleo-escarpments with respect to the Neogene compressive stress field (with ENE oriented sigma1). Newly formed ENE striking tear faults connect these either inherited or neo-formed discontinuities. This complex stratigraphic and structural pattern is substantially different from the previous interpretations of this portion of the central Apennines based on a hypothesised layer-cake stratigraphy deformed by neo-formed Neogene thrusts. This contribution strengthens the importance of integrating facies analyses and structural investigations to detect the influence of pre-orogenic structures on compressive structural patterns, in an area where commercial seismic lines are not available and cannot help in reconstructing the subsurface geometries. © 2011 Springer-Verlag.

We integrated X-ray diffraction (XRD) data concerning the illite content in mixed-layer illite–smectite with data derived from Fourier Transform Infrared spectroscopy (FTIR) on H-rich organic matter to constrain the burial-exhumation path of the Mt. Judica sedimentary succession cropping out in tectonic window in Eastern Sicily. Thermal structural model constrained by organic and inorganic thermal parameters showed that the Mt. Judica succession experienced paleo-temperatures in the range of 100–130 °C in deep diagenetic conditions and early mature stage of hydrocarbon generation. Specifically, the illite content in mixed-layer I–S ranges from 50 to 76% and FTIR-derived indexes suggest a thermal maturity equivalent to VRo values of at least 0.5–0.7%. As a whole, the Mt. Judica succession experienced maximum tectonic burial (ranging between 2.4 and 3.2 km) during the Middle Miocene as a result of the emplacement of the allochthonous units atop it. The subsequent breaching phase characterized by up-thrust geometries, and erosion during Pliocene times ruled out the Mt. Judica exhumation. This last tectonic phase did not overprint thermal maturity because the extent of overthrusting was negligible when compared with the magnitude of vertical movements. Restoration of balanced cross sections revealed an increase of shortening from the salient to the Mt. Judica recess with values from 12.3 to 23.9 km, consistent with the increase of tectonic thickening of the fold-and-thrust belt. Integration of maximum burial and shortening values along the curvature of the Sicilian fold-and-thrust belt allowed us to reconstruct the wedge paleo-geometry in the Mt. Judica recess area, to investigate the along-strike variations of the tectonic overburden, and to discuss the geodynamic causes of these changes. These results were compared with theoretical models of wedge dynamics.

Structural Scheme of the Umbria-Sabina fold-and-thrust belt (Central Italy) derived from the geological mapping of 366 Palombara Sabina and 375 Tivoli sheets (CARG Project).The geological mapping of the sheets 366 Palombara Sabina and 375 Tivoli (1: 50.000 scale; CARG Project; in preparation) allowed the revision of the structural setting of the westernmost portion of this part of the Neogene fold-and-thrust belt of the Central Apennines.The area comprises the Cornicolani, Lucretili, eastern Sabini, Tiburtini, Ruffi and Prenestini Mts (Latium region). Most of the area (Cornicolani, Lucretili and Tiburtini Mts) is made of the pre-orogenic deposits (Upper Triassic-Serravallian) referred to the calcareous-marly-siliceous Sabina Succession, that were accumulated in the southern part of the Umbria-Marche-Sabina Pelagic Basin (Sabina Domain), proximal to the Latium-Abruzzi Carbonate Platform. In general, in the eastern areas, more proximal to the platform, coarser lithofacies crop out. Moreover, in the Cornicolani and western Lucretili Mts (Castelvecchio Mt) areally restricted outcrops of condensed pelagic carbonates (Bugarone Group and calcari dolomitici di S. Angelo Romano) document the occurrence of Jurassic intrabasinal structural highs evolved into Pelagic Carbonate Platforms. These structural highs were generated after the Early Jurassic rifting, that broke-up the pre-existing carbonate platform (Calcare Massiccio).In the mapped area, the Latium - Abruzzi Platform is represented in the hangingwall of the Olevano-Antrodoco line only in the southern Prenestini Mts (Rocca di Cave), by upper Cretaceous shelf carbonates. Whereas in the footwall of the Olevano-Antrodoco line it crops out along the Aniene River valley. Both Sabina and Latium - Abruzzi successions are overlain by upper Tortonian - lower Messinian marls and siliciclastic syn-orogenic deposits, best observed in the easternmost areas and inbetween the Ruffi and Prenestini Mts.In their turn, the syn-orogenic deposits are unconformably overlain by post-orogenic Plio-Pleistocene marine clastic deposits and Quaternary volcanic and alluvial sediments. From a structural point of view, the Sabina Domain is arranged into several thrust sheets verging toward the east, developed in middle-late Miocene-early Pliocene times. The early Pliocene Olevano-Antrodoco out-of-sequence thrust marks the eastern tectonic boundary of this structural domain where the pelagic and slope sediments overthrust the Latium - Abruzzi Carbonate Platform and its associated syn-orogenic deposits. In late Miocene-early Pliocene extensional tectonics down-threw the western border of this imbricated structure enhancing the marine ingression along the peri-Tyrrhenian margin. The western border of the region was also reactivated by N-S right-lateral strike-slip fault dissecting the earlier structures in Pleistocene times.From top of the orogenic edifice three main tectonic units have been identified:- Unit 1 (Morra Mt) made up of Upper Triassic to Lower Jurassic dolomite limestones (Dolomia Principale) and Calcare Massiccio, overthrust onto unit 2.- Unit 2 (comprising Cornicolani Mts, western Lucretili Mts) made up of Dolomia Principale, Calcare Massiccio, Corniola detritica and, in the Cornicolani and western Lucretili Mts, Bugarone Group. Long wavelength upright folds mainly characterize this unit and faults with high angle cuts-offs prevail, and Jurassic structural highs occur (Cornicolani Mts, Castelvecchio Mt).- Unit 3 (comprising Elci Mt, eastern Lucretili Mts and Tiburtini Mts) made up of most of the Sabina basin stratigraphic succession - from Corniola detritica Fm. to the Guadagnolo Member (marly lithofacies); the unit is characterized by NW to NE verging overturned to recumbent folds.- Unit 4 (comprising Prenestini Mts, Ruffi Mts and eastern Sabini Mts) made up of the upper portion of the basin succession between the Marne a Fucoidi and Upper Miocene siliciclastics and the Rocca di Cave carbonate platform succession.This unit is made up by two sub-units, based on the deformation-style and stratigraphy: the sub-unit 4A (Granaro Mt, Colle Serviano and Arzillo Mt in the western Prenestini Mts), is mainly characterized by east-verging packed asymmetrical folds with sub-vertical axial-planes, and N-S striking dextral-transpressive faults. The sub-unit 4B (Castel Madama area, eastern and central Prenestini Mts, Ruffi Mts and eastern Sabini Mts) is characterized by a wide symmetrical anticline in the western portion, and by folds with very steep axial planes, and N-S to NNW-striking dextral transpressional faults.The units are separated by low-angle thrusts or by high-angle transpressive faults: the stratigraphic successions characterizing each unit rejuvenate eastward. The innermost unit 1 and unit 2, where massive or poorly stratified deposits are exposed, are mainly deformed by high angle faults. Whereas the more external unit 3 and unit 4 are composed by alternating carbonate, marls and siliciclastics, and are mostly characterized by east-verging slightly to strongly asymmetrical and overturned folds.A new geometric and kinematic scenario for the Neogene evolution of the units preserved in the hangingwall of the Olevano-Antrodoco thrust is here outlined.The revision of the stratigraphy and structural data put in evidence the presence of paleo-structures of the Tethyan passive margin not evidenced in the past cartography, their influence on Neogene compressive structures and the coexistence of non-coaxial structural trends in areas of limited extension.

We used vitrinite reflectance and mixed layered clay minerals to investigate levels of diagenesis of the Oligocene-Miocene basin developed on the nappes of the Alpine orogen in the Peloritani Mts. (NE Sicily). Paleothermal indicators were integrated with stratigraphic-structural analyses and apatite fission-track and (U-Th-Sm)/He ages to define the late evolutionary stages of the Peloritani Mts. The reconstruction of the paleogeothermal gradient in Oligocene-Miocene times was performed to constrain the burial-thermal evolution. In the southern area, thermal parameters increase with depth suggesting that their evolution is ruled by sedimentary burial. They recorded a decrease in paleogeothermal gradients which marked the evolution of the basin from a fore-arc to a thrust-top setting during convergence-collision. In the northern edge of the basin, higher vitrinite reflectance values indicate that thermal evolution was controlled by tectonic burial related to late Langhian-early Serravallian out-of-sequence thrusting. This overburden was removed by extensional tectonics and/or erosion since late Miocene. The short time span at maximum temperature (

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.

The results of the combined application of a series of analytical methods (clay mineralogy, vitrinite reflectance, Raman microspectroscopy) placed tight constraints on the thermal evolution of the Karakaya Complex of northern Anatolia, a mostly Permo-Triassic subduction-accretion complex resulting from the progressive closure of the Palaeotethys. The thermal evolution of the Karakaya Complex is the result of Permian-Triassic subduction-accretion processes, and was not significantly affected by later Alpine-age tectonism, as shown by Liassic shallow-water siliciclastic and carbonate deposits overlying unconformably the Karakaya Complex which did not undergo any significant burial. The Lower Karakaya Complex, comprising metabasite and subordinate marble and phyllite, experienced maximum temperatures ranging from 340 to 497 degrees C, in agreement with independently determined thermobarometric reconstructions. The entire Upper Karakaya Complex, previously considered unmetamorphosed or slightly metamorphosed, was affected by zeolite to lower greenschist facies metamorphism (120-376 degrees C). The coherent results of this study show that Raman thermometry has great potential for palaeotemperature determination at low temperature ranges (200-350 degrees C).

A multi-method investigation (structural analysis, organic matter thermal maturity and clay mineralogy) was carried out on highly deformed foredeep successions in the Northern Apennine with special regard to shear zones in the Lago Trasimeno area (Rentella Unit) to unravel the main structural mechanisms and the thermal condition of the Miocene accretionary processes of the Northern Apennines belt. The Rentella Unit consists of a foredeep succession deposited in a paleogeographic domain between the Tuscan and the Umbria-Marche Domains. Meso- and microstructural data indicate shear planes compatible with C-planes (N160°, 45°SW). C-planes veins show dilational jogs and a staircase shape coherent to a top-to-the-NE sense of shear. Type II calcite twins in the shear zone associated veins suggest temperatures of 150-200°C. Temperature-dependent clay minerals and vitrinite reflectance indicate lower maximum paleo-temperatures (

New constraints on the thermobaric evolution of the Liguride complex of the Southern Apennines are provided by inorganic and organic thermal indicators. In detail, quantitative data on the thermobaric signature of the medium-to low-metamorphic Frido Unit and non-metamorphic North-Calabrian Unit have been derived using different methodologies such as clay mineralogy, fluid inclusion microthermometry, fission tracks analyses, and organic matter maturity. A good convergence among data from different, indipendent methods was obtained. The Frido Unit underwent temperatures in the range of anchizone (250-300 degrees C) according to data derived from both clay mineralogy and fluid inclusion microthermometry. Pressure estimates by white mica b(0) parameter are typical of accretionary wedges and in the range of 6-8 kbar. In the non metamorphosed North Calabrian Unit, clay mineralogy, organic matter maturity and fluid inclusion microthermometry record thermal conditions from diagenesis (similar to 130 degrees C) to the late diagenesis - anchizone boundary (similar to 200 degrees C) for the Crete Nere Fm., and diagenetic conditions (temperatures around 100-110 degrees C) for the Saraceno Fm. In a regional framework, these data help to better constraint the thermal evolution of the units belonging to the Liguride complex with respect to the timing of final exhumation at 5-6 My, as suggested by apatite fission tracks data.

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.

Illite crystals in siliciclastic sediments are heterogeneous assemblages of detrital material coming from various source rocks and, at paleotemperatures >70°C, of superimposed diagenetic modification in the parent sediment. Only diagenetic rather than detrital phases should be used to estimate paleo-temperatures and to constrain the burial history of sedimentary successions that range in alteration intensity from diagenesis to low-grade metamorphism. The relative proportions of 2M1 detrital illite and diagenetic 1Md 1M illite were distinguished by a combined analysis of crystal-size distribution and illite polytype quantification. It was found that the proportions of 1Md 1M and 2M1 illite could be determined from crystallite thickness measurements by unmixing measured crystallite thickness distributions using theoretical and calculated lognormal and/or asymptotic distributions. In addition, quantitative polytype analysis was carried out using RockJock software for comparison. The two techniques gave comparable results which indicate that the unmixing method permits one to calculate the proportion of illite polytypes and, therefore, the proportion of 2M1 detrital illite, from crystallite thickness measurements that should not be used for paleotemperature evaluation.

Vitrinite reflectance data and clay mineral assemblages were used to investigate levels of diagenesis from the Messinian Laga Basin (Central Apennines) developed at the footwall of the Sibillini Mts. and the Gran Sasso Massif. Data derive from stratigraphic units forming the siliciclastic basin fill up to Middle Messinian gypsum-arenites and its pre-orogenic substratum. Highest Ro% values and percentages of illite layers in I/S are found in the basin depocentre and at the footwall of the carbonate thrust sheets. Lower Ro% values and percentage of illite layers in I/S characterize less subsided sectors. I/S records the maximum paleo-temperature the Laga Fm. experienced related to its burial history whereas KI data suggest higher temperatures related to detrital K-micas inherited from the uplift of the Alpine-Apennines chain. A calculation of paleo-temperatures from selected data of organic and inorganic parameters is proposed and compared with recent stratigraphic and structural data. This allowed proposing that the Laga basin fill never experienced temperatures > 100-110°C, due to variable sedimentary loading, while localised anomalous heating is due to the effect of the tectonic emplacement and subsequent local erosion of the Sibillini and Gran Sasso thrust sheets.

Temperature-dependent clay mineral assemblages and vitrinite reflectance data have been used to investigate levels of diagenesis from the Apenninic-Maghrebian fold-and-thrust belt in eastern Sicily at the footwall of the Peloritani-Calabride Arc. Data are from units sampled along a regional transect between the Nebrodi Mountains to the north and Mount Judica to the south. These units developed in very different tectonic settings from those of oceanic to passive continental margin domains deformed during the Cenozoic mountain building and related active margin deposits. The integration of organic and inorganic thermal indicators allowed us to distinguish among different tectonic settings, with thermal maturity generally decreasing from hinterland to foreland as a result of progressively less severe thermal evolution and/or tectonic loading during the mountain building. Specifically, the highest vitrinite reflectance (VR0%) values (ca. 0.60%-0.75%) and percentages of illite layers in illite-smectite (I-S; 60%-80%) are found in trench-involved and accreted passive margin units. Lower VR0% values (0.20%-0.47%) and percentages of illite layers in IS (30%-60%) are found in thrust-top and foredeep basin deposits and far-traveled Sicilide units that have escaped involvement in trench evolution. Furthermore, either sedimentary or long-lived tectonic burial (at least more than 5 m.yr.) seem to have affected levels of diagenesis of the studied successions. The correlation between organic and inorganic thermal indicators is satisfactory for most of the samples derived from hemipelagic and siliciclastic deposits, whereas it is poor for some proximal siliciclastics. A tentative calculation of paleotemperatures is also proposed for the studied tectonostratigraphic units.

Temperature-dependent clay mineral assemblages and vitrinite reflectance data have been used to investigate levels of diagenesis from the Messinian Laga Basin in the Central Apennines developed at the footwall of the Sibillini Mts. and the Gran Sasso Massif. Data are from stratigraphic units forming the main siliciclastic basin fill up to Middle Messinian gypsum-arenites and its pre-orogenic substratum. Specifically, the largest Rom% values and percentages of illite layers in illite-smectie (I-S) are found in the basin depocenter and at the footwall of the main carbonate thrust sheets. Smaller Rom% values, and percentage of illite layers in I-S characterize less subsided sectors surrounding the depocenter. The X-ray diffraction data were treated using decomposition methods and the peaks identified were rationalized in terms of discrete and/or mixed-layer phases. Complex clay mineral assemblages were found in the Laga Fm. including three sub-populations of illitic material corresponding to authigenic and detrital components. I-S mixed layers record the maximum paleotemperature the Laga Fm. experienced, which is directly related to its burial history. Kubler index (KI) data, however, suggest higher temperatures related to detrital K-micas inherited from the uplift of the Alpine-Apennines chain. A tentative calculation of paleotemperatures from selected data of organic and inorganic parameters is also proposed and compared with recent sedimentological, stratigraphic and structural data. We conclude that the Laga Basin fill never experienced temperatures of >100–110°C, generally due to variable sedimentary loading, whereas localized anomalous heating is due to the effect of the tectonic emplacement and subsequent local erosion of the Sibillini and Gran Sasso thrust sheets.

Monte Alpi represents the only area of the southern Apennines where Apulian carbonates, elsewhere buried beneath a several-km thick allochthon, are exposed at the surface. These rocks also represent the reservoir interval in southern Italy's major oil fields. The tectonic evolution of this substantially exhumed area of the fold-and-thrust belt, derived from conventional structural and stratigraphic considerations via integration into the regional framework, has been tested and detailed by the analysis of vitrinite reflectance, clay mineralogy, apatite fission track, and fluid inclusion data. The Apulian carbonates of Monte Alpi underwent significant tectonic burial as a result of thin-skinned thrusting in early Pliocene times. Simplified burial and thermal modeling suggests that the thickness of allochthonous material emplaced on top of Monte Alpi was probably in excess of 5 km. Exhumation is envisaged to have started in the late Pliocene, when the area emerged and the tectonic load started to be eroded off Monte Alpi. A significant stage of exhumation is inferred to have taken place in uppermost Pliocene-early Pleistocene times as a result of thick-skinned reverse faulting at depth and coeval thin-skinned extension within the overlying allochthon. After shortening ceased throughout the whole southern Apennines, middle Pleistocene-Holocene tectonic exhumation of Monte Alpi was essentially controlled by thickskinned extensional tectonics. This process is still active and controls the present-day seismicity of the study area.

The inception and growth of the active Carpino-Le Piane Basin Fault System (CLPBFS; central-southern Apennines, Italy) was analysed with respect to the neighbouring Isernia and Surrounding (ISFS) and Boiano Basin (BBFS) extensional Fault Systems. Ar-39-Ar-40 dating showed that the BBFS was already active 649 +/- 21 ka bp and that the ISFS was active at least 476 +/-10 ka bp, whereas the activity of the CLPBFS started certainly later than 253 +/- 22 ka bp, and very probably as recently as

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.