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The structural analysis of large intracontinental wrench faults is fundamental for deciphering the long-term evolution of continental crust in complex areas in terms of their geodynamic evolution and large-scale crustal block displacements. In this contribution, we demonstrate a pre-Miocene dextral activity of the present-day left-lateral Great Kavir - Doruneh Fault System (GKDFS, Central Iran), one of the major intracontinental active strike-slip faults extending from the Afghan border to the Nain region between Central Iran and the Sanandaj-Sirjan Zone. We document important dextral shearing recorded along a segment of the GKDFS, the Arusan Fault System (AFS), located east of Jandaq, close to the present-day active trace of the GKDFS. The AFS include several ENE-WSW striking strands exposed for a length of more than 50km, which couple pre-Cretaceous ophiolites and metamorphic basement units with the Cretaceous succession of the Khur basin. The fault shows transpressional structures consistent with a dextral shear including thrusts and en échelon folds affecting the Cretaceous carbonate units. Paleostress reconstruction based on mesoscopic fault analysis and related folds geometry allowed to establish vorticity parameters indicating that deformation occurred close to a total simple shear regime with a calculated Wk between 0.9 and 1. The enormous Meso-Cenozoic dextral displacements occurred along the AFS and along the entire GKDFS are attested by the up to several hundreds of kilometers offset of the Paleotethys suture zone, from NE Iran to the western border of Central Iran.

New age estimates obtained via Strontium Isotope (87Sr/86Sr) Stratigraphy and new paleoclimatic data are here presented for the Miocene Chilcatay and Pisco formations exposed in the East Pisco Basin, an Andean forearc basin of southern Peru, which is renowned worldwide for its exceptional content of fossil marine vertebrates. Mollusk and barnacle shells, carbonate nodules, and shark teeth were collected along three stratigraphic sections for applying Strontium Isotope Stratigraphy on both carbonates and phosphates. To avoid diagenetic biases, mollusk and barnacle shells were analyzed in detail by means of optical and scanning electron microscopy, cathodoluminescence, and inductively coupled plasma-optical emission spectrometry, whereas only the enameloid from the best-preserved shark teeth was sampled. The obtained 87Sr/86Sr ages confirm a late early Miocene (Burdigalian) age for the Chilcatay strata, and reveal middle Miocene (Langhian to Serravallian) ages for the lower Pisco unit (i.e., the P0 sequence) – a result that matches the relatively archaic aspect of its cetacean fossil assemblage. New and literature data about the fossil assemblage of the lower Pisco beds highlight the presence of several thermophilic invertebrates and vertebrates, thus suggesting a warm-water, tropical paleoenvironment for this middle Miocene sequence. Such a paleoenvironmental scenario recalls the warm conditions associated with the Chilcatay Formation, rather than the cooler setting inferred for the remainder of the Pisco Formation (i.e., the P1 and P2 sequences). This pattern likely reflects the late Miocene trend of global cooling, as well as a middle to early late Miocene strengthening of the Humboldt Current.

Fault inversion may lead to significant obliteration of earlier tectonic structures, thus preventing the straightforward interpretation of the complete kinematics and deformation history of faults. We adopt a multidisciplinary approach to: (1) reconstruct the tectonic evolution through space and in time of the extensionally-inverted Mt. Tancia Thrust (Central Apennines, Italy); (2) understand the deformation mechanisms and the transition and reactivation of compressional structures during negative tectonic inversion; and (3) constrain the origin of fluids involved during tectonic processes. To this end, we combined: (1) detailed geological mapping and multiscale structural analysis; (2) illite-smectite paleothermal indicators; (3) C, O, and clumped isotopes on calcite mineralizations and (4) K–Ar dating of authigenic and/or syn-kinematic illite from the Mt. Tancia Thrust fault rocks. We show that shortening occurred between ~9 and ~7 Ma, during possibly multiple events of fluid overpressure and shear rupturing involving fluids entrapped over long term within the host rocks. Post-compressive tectonic inversion occurred at ~3 Ma under fluid pressure fluctuations during shear events with an input of meteoric-derived fluids. Tectonic inversion is spatially confined within the first few metres below the thrust surface in a volume dominated by the partial overprinting, folding, transposition, and re-utilization of the earlier compressional fabric.

Stratigraphic and sedimentologic studies of the norian succession outcropping in rhe Lombardy Basin allowed the reconstruction of the paleogeographic and strucural evolution oi this area, 1) restricted lagoon and tidal flat are the most common deposits ar the Carnian-Norian boundary (Lower Member of the Dolomia Principale); 2) these are overlain by a thick inner platform succession organized in shallowing upwards cycles (lower Dolomia Principale), with the exception of Idro Lake area where intraplatform basin already generated; 3) the overlying middle-upper Dolomia Principale is dissected by synsedimentary faults with subsequent widespread development of intraplatform basin, margin, and slope facies with marked asymmetric distribution; the inner platform was locally emerged; 4) in the uppermost Dolomia Principale buildup margins become more abundant and the platform partially prograded on the basins; 5) at last the platform drowns and terrigenous sedimentation becomes prevalent (Riva di Solto Shales). The drowning of the platform is favoured by the lack of carbonate production, due to clay pollution and climatic changes in an area with high subsidence rates. The observed asymmetric distribution of buildup margins and fault-scarp related breccias, which outcrop on the western side of the basins west of Iseo Lake and bounding the eastern side of the basins east of Iseo Lake, allows us to propose a model of norian ensialic asymmetric rifting for the Lombardy Basin. This asymmetric rifting could be explained by interpreting the Lombardy Basin as a pull-apart basin, linked to transtension with E-W trending faults., Rivista Italiana di Paleontologia e Stratigrafia (Research In Paleontology and Stratigraphy), V. 98, N. 1

The successions exposed in the Pin and Spiti valleys, a classical area for the Tethyan Triassic, provides an extraordinarily complete sedimentary and paleontologic record and is thus well-suited to check the validity of global eustatic charts and applicability of sequence stratigraphic concepts. New detailed stratigraphic data allowed us to present a revised lithostratigraphic scheme - largely based on previous works by Hayden (1904) and Srikantia (1981) - which can be directly compared with successions exposed all along the Tethys Himalaya from Zanskar to Tibet. The Permian/Triassic boundary represents a major break in sedimentation, with time gaps of up to several Ma testified in the upper Pin valley. In the Induan to Anisian, the Tamba Kurkur Fm. mainly documents global eustatic changes, with transgressive stages characterized by sedimentation of condensed nodular Lmestones on the outemost shelf/uppermost slope (e.g., Griesbachian/Early Dienerian, Spathian) and regressive stages marked by mudrock deposition on the continental shelf (e.g., Late Dienerian/Smithian). A glauconitic condensed horizon occurs at the Anisian/Ladinian boundary, and the top of the formation reaches the Early Ladinian in more complete proximal sections. Greater clay supply characterizes the late Early Ladinian, but accumulation rates remain low in the lower part of the Hanse Group(Kaga and Chomule Fms.), to increase sharply in the late Early to early Late Carnian ("Grey beds"), reaching 100 m/Ma in the latest Carnian (Nimaloksa Fm.). At least nine, third- to fourth-order transgressive,/regressive sequences can be recognized in the Nimaloksa Fm. and Alaror Group, where facies distribution pattems indicate that the Spiti continental margin deepened towards the north. The Nimaloksa Fm. documents progradation of a carbonate ramp in the latest Carnian(Lower Member), followed in the Early Norian by subtidal mixed carbonate/terrigenous sedimentation (Middle Member) and by platform carbonate deposits (Upper Member). Next, the major disconformity at the base of the Alaror Group testifies to an extensional tectonic event, followed by rapid increase in quanzo-feldspathic detritus in the late Early Norian. Siliciclastic supply is reduced only during flooding stages, marked by oolitic ironstone or phosphatic condensed horizons ("Juvavites beds", "Monotis shale'); cleaner waters foster local development of knoll reefs round the Early/Middle Norian boundary ("Coral limestone'). Accumulation rates gradually begin to decrease before the close of the Triassic, when the "Quartzite series" records a sharp regressive event, followed by renewed transgression at the base of the Kioto Group., Rivista Italiana di Paleontologia e Stratigrafia (Research In Paleontology and Stratigraphy), V. 101, N. 3

Quantitative analysis of depositional systems using numerical models can provide insights into the interaction of sedimentological and diagenetic processes, difficult to interpret from observation of the geological products alone. Numerical models can highlight the interactions between controlling parameters, and generate best estimate simulations of case studies from the geological record. Different data sources (e.g., outcrop data, uniformitarian constraints, paleogeography) need to be considered in the process of defining the parameters required to produce models that honour individual case studies. We present a best-estimate forward model of a high-relief Triassic carbonate platform (Southern Alps, Italy) generated using CARB3D+, a 3D process-based forward modelling package able to simulate sedimentary facies, geometries and early diagenesis of isolated carbonate platforms. The parameters used for the presented forward model have been deduced by the study of architectural, sedimentological and diagenetic features of the platform, and by data from modern and ancient analogues. Sensitivity analysis is used to tune values of the parameters within ranges defined from field, laboratory and uniformitarian constraints. Critical evaluation of the model allowed 1) verification of the validity of the used parameters; 2) evaluation of the interaction between controlling parameters; 3) development of a numerical model that can be used for quantitative elaborations. Furthermore, the process of generating the numerical model required a detailed interpretation of field and laboratory data, crucial to define the required input parameters. Modelling the studied carbonate platform also enabled evaluation of the effects of the interaction between productivity, environmental energy and creation of accommodation space, promoting the understanding of their role on the architecture of carbonate systems. Forward modelling also allows the integration of data from conventional data sets with data from present-day observations and seismic geometries, promoting a transition from a qualitative to a semi-quantitative/quantitative sedimentological approach. Forward models can further be used to parameterise petrophysical properties of complex geobodies, with potential application for the management of georesources.

The occurrence in Iran of several ophiolite belts dating between Late Palaeozoic to Triassic poses several questions on the possible existence of various sutures marking the closure of the Palaeotethys ocean between Eurasia and this Gondwana-derived microplate. In this scenario, the Anarak region in Central Iran still represents a conundrum. Contrasting geochronological, paleontological, paleomagnetic data and reported field evidence suggest different origins for the Anarak Metamorphic Complex (AMC). The AMC is either interpreted, as: (1) relict of an accretionary wedge developed at the Eurasia margin during the Palaeotethys subduction as part of the Cimmerian suture zone of NE Iran, displaced to Central Iran by a large counter-clockwise rotation of the central Iranian blocks; (2) autochthonous unit forming a secondary branch of the main suture zone. Our structural, petrographic and geochemical data indicate that the AMC consists of several metamorphic units also including dismembered “ophiolites” which display different tectono-metamorphic evolutions. Three main ductile deformational events can be distinguished in the AMC. The Morghab and Chah Gorbeh complexes preserve a different M 1 metamorphism, characterized by blueschist relics in the S 1 foliation of the former unit, and greenschist assemblages in the latter. They share a subsequent similar D 2 deformational and M 2 metamorphic history, showing a prograde metamorphism with syn- to post-deformation growth of blueschist facies mineral assemblages on pre-existing greenschist facies associations. High pressure, low temperature (HP/LT) metamorphism responsible for the growth of sodic amphibole has been recognized also within marble lenses at the contact between the Chah Gorbeh Complex and serpentinites. Evidence of HP/LT metamorphism also occurs in glaucophane-bearing meta-pillow lavas and serpentinites, which contain antigorite and form most of the “ophiolites” within the AMC. Structural relationships show that the Chah Gorbeh and Morghab units and the “ophiolites” were tectonically coupled within an accretionary wedge before the D 2 folding stage. The other units of the AMC lack evidence of HP metamorphism in the area around Anarak, especially the Lakh Marble, a large thrust sheet that occupies the uppermost structural position in the AMC. Available radiometric ages of trondhjemite dikes and stocks that intruded the accretionary wedge, as well as our new data, constrain the subduction event at the end of the Carboniferous, before 290 Ma. These data suggest that the AMC is part of an allochthonous crustal fragment belonging to the Variscan belt developed along the southern Eurasian margin before the Cimmerian collision of Iran. Subsequent deformational events that occurred during the Mesozoic and the Cenozoic, up to the Miocene and possibly later, resulted in folding, thrusting and faulting that dismembered the original structure of the wedge accompanying its displacement to the present day position.

The lateral continuity of the E–W trending thrust sheets developed within the Lower to Middle Triassic cover of the central Southern Alps (Orobic belt) is disturbed by the occurrence of several N–S trending transverse zones, such as the poorly known Grem–Vedra Transverse Zone (GVTZ). The GVTZ developed during the emplacement of the up to six S-verging thrust sheets consisting of Lower to Middle Triassic units, occurring immediately south of the Orobic Anticlines. The transverse zone, active during thrust emplacement related to the early Alpine compressions which pre-date the Adamello intrusion, includes three major vertical shear zones, the Grem, Pezzel and Zuccone faults. The major structure of the transverse zone is the dextral Grem fault, forming a deep lateral ramp between thrust sheets 3 and 5. A similar evolution also occurred along the Zuccone and Pezzel faults, which show a left-lateral displacement of syn-thrust folds. The Grem fault was later reactivated as an oblique tear fault during the emplacement of the Orobic Anticlines, due to back-thrusting along out-of-sequence thrust surfaces (Clusone fault). Transpressional deformations along the fault zone are recorded by the rotation of major syn-thrust folds, which also suggest a horizontal offset close to 0.5 km. Records of the first stage of evolution of the Grem fault are better preserved along its northern segment, and structural relationships suggest that it propagated southward and downward in the growing thrust stack. The study of the meso and megascopic structures developed along the GVTZ constrains the evolution of the transverse zone, illustrating the complex deformational phenomena occurring in a transpressional regime. The GVTZ probably reflects the existence of pre-existing tectonic lineaments with a similar orientation. Evidence of pre-existing structures are not preserved in the exposed units, nevertheless the N–S extensional fault systems that characterize the Norian to Jurassic rifting history of the Lombardian basin are valid candidates.

The Triassic succession of the central Southern Alps (Italy) is stacked into several units bounded by south-verging low-angle thrust faults, which are related to two successive steps of crustal shortening. The thrust surfaces are cut by high-angle extensional and strike-slip faults, which controlled the emplacement of hypabissal magmatic intrusions that post-date thrusts motions. Intrusion ages based on SHRIMP U-Pb zircon dating span between 42 ± 1 and 39 ± 1 Ma, suggesting close time relationships with the earliest Adamello intrusion stages and, more in general, with the widespread calc-alkaline magmatism described in the Southern Alps. Fission-track ages of magmatic apatites are indistinguishable from U-Pb crystallization ages of zircons, suggesting that the intrusion occurred in country rocks already exhumed above the partial annealing zone of apatite (depth < 2-4 km). These data indicate that the central Southern Alps were already structured and largely exhumed in the Middle Eocene. Although we describe minor faults affecting magmatic bodies and local reactivations of older structures, no major internal deformations have occurred in the area after the Bartonian. Neogene deformations were instead concentrated farther south, along the frontal part of the belt. © 2010 Springer-Verlag

An important, 2.4 km-thick Triassic succession is exposed at Nakhlak (central Iran). This succession was deformed during the Cimmerian orogeny and truncated by an angular unconformity with undeformed Upper Cretaceous sediments. This integrated stratigraphic study of the Triassic included bed-by-bed sampling for ammonoids, conodonts and bivalves, as well as limestone and sandstone petrographic analyses. The Nakhlak Group succession consists of three formations: Alam (Olenekian–Anisian), Bāqoroq (?Upper Anisian–Ladinian) and Ashin (Upper Ladinian). The Alam Formation records several shifts from carbonate to siliciclastic deposition, the Bāqoroq Formation consists of continental conglomerates and the Ashin Formation documents the transition to deep-sea turbiditic sedimentation. Petrographic composition has been studied for sandstones and conglomerates. Provenance analysis for Alam and most of the Ashin samples suggests a volcanic arc setting, whereas the samples from the Bāqoroq Formation are related to exhumation of a metamorphic basement. The provenance data, together with the great thickness, the sudden change of facies, the abundance of volcaniclastic supply, the relatively common occurrence of tuffitic layers and the orogenic calc-alkaline affinity of the volcanism, point to sedimentation along an active margin in a forearc setting. A comparison between the Triassic of Nakhlak and the Triassic succession exposed in the erosional window of Aghdarband (Koppeh Dag, NE Iran) indicates that both were deposited along active margins. However, they do not show the same type of evolution. Nakhlak and Aghdarband have quite different ammonoid faunal affinities during the Early Triassic, but similar faunal composition from the Bithynian to Late Ladinian. These results argue against the location of Nakhlak close to Aghdarband. Central Iran is geologically a very complex area, characterized by a tremendous variety of rock types ranging from Precambrian to Miocene sedimentary rocks, Palaeozoic–Cenozoic ultramafic–acid igneous rocks and Palaeozoic–Mesozoic metamorphic rocks. Such an astonishing geological diversity is related to a very long history that started with the assembly of Gondwana in early Palaeozoic times and continued to the present-day collision of the Arabian Plate with Eurasia. The unravelling of this long and complex history is challenging. The understanding of the Cimmerian system (Sengor 1984) is especially difficult as the Carboniferous–Jurassic rocks were often deformed, eroded, covered and/or metamorphosed during more recent collisional events, and their boundaries were sometimes reactivated by more recent faults and thrusts. Despite many published contributions to the geology of Central Iran, no shared interpretation has emerged at the microplate and local scales. For instance, there is no consensus on the proposal by Davoudzadeh et al. (1981) and Soffel et al. (1996) that the present-day Central Iran microplate has rotated by 1358 counterclockwise since the Triassic. This model has usually been accepted (Davoudzadeh & Weber-Diefenbach 1987; Ruttner 1993; Alavi et al. 1997; Seyed-Emami 2003), but a From: BRUNET, M.-F., WILMSEN, M. & GRANATH, J. W. (eds) South Caspian to Central Iran Basins. The Geological Society, London, Special Publications, 312, 287–321. DOI: 10.1144/SP312.14 0305-8719/09/$15.00 # The Geological Society of London 2009. test carried out by Wendt et al. (2005) on the basis of the palaeogeographical distribution of Palaeozoic facies actually failed to confirm the model. At the local scale there are often different interpretations of the stratigraphic v. tectonic relationships of several sedimentary and metasedimentary units. For instance, in the key areas of Nakhlak and Anarak, very different pictures were provided not only for the complexly metamorphic Anarak Range (e.g. Sharkovski et al. 1984; Bagheri 2007; Bagheri & Stampfli 2008), but also for the nearby unmetamorphosed Nakhlak Range (e.g. Sharkovski et al. 1984; Alavi et al. 1997). In order to clarify the general setting of Central Iran and its related Cimmerian history we selected the Nakhlak–Anarak area, which has been known since the 1970s (Davoudzadeh & Seyed-Emami 1972) for the contrast of its peculiar 2.4 km-thick mixed siliciclastic, volcaniclastic and carbonatic succession with the surrounding Triassic successions (i.e. Shotori Range, Tabas: Stocklin et al. 1965; see Seyed-Emami 2003 for a comprehensive summary). Based on lithological similarity, several authors suggested a correlation between the Nakhlak Triassic and an almost coeval succession exposed at Aghdarband (Koppeh Dag, NE Iran). Moreover, this correlation was used to support the 1358 counterclockwise rotation of Central Iran since the Triassic (Davoudzadeh et al. 1981). Despite its great significance it is worth noting that the geology and stratigraphy of the Nakhlak–Anarak area are not known in detail, as demonstrated by the rather different descriptions available in the literature (Davoudzadeh & Seyed Emami 1972; Sharkovski et al. 1984; Alavi et al. 1997; Vaziri 2001). The area was visited by a team of stratigraphers, structural geologists, palaeontologists and palaeomagnetists in 2003 and 2004. Most of the stratigraphic data are presented here, while the geological, structural and the palaeomagnetic analyses are described in separate contributions (Muttoni et al. 2009; Zanchi et al. 2009). The geology of the Nakhlak area: open

The Eo-Cimmerian orogen results from the Late Triassic collision of Iran, a microplate of Gondwanan affinity, with the southern margin of Eurasia. The orogen is discontinuously exposed along the northern side of the Alborz Mountains of North Iran below the siliciclastic deposits of the Shemshak Group (Late Triassic–Jurassic). A preserved section of the external part of the belt crops out in the Neka Valley (eastern Alborz) south of Gorgan. Here the Mesozoic successions (Shemshak Group–Upper Cretaceous limestones) overlay a pre-Jurassic Eo-Cimmerian thrust stack with a sharp unconformity. The stack includes the Gorgan Schists, an Upper Ordovician–Lower Silurian low-grade metamorphic complex, overthrusted southward above a strongly deformed Late Palaeozoic–Middle Triassic succession belonging to north Iran. In the Talesh Mountains (western Alborz), the Shanderman Complex, previously interpreted as an ophiolitic remnant isolated along the Eo-Cimmerian suture, is considered an allochthonous nappe of deeply subducted continental crust. The new evidence for this is the occurrence of previously unknown eclogites dating to the Carboniferous, and probably related to the Variscan history of Transcaucasia. South of the Shanderman Complex, Upper Palaeozoic slates and carbonates occurring below the Lower Jurassic Shemshak Group also record the occurrence of an Eo-Cimmerian metamorphic event. Based on our new data, the Eo-Cimmerian structures exposed in the Alborz appear to be remnants of a collisional orogen consisting mainly of deformed continental crust where no ophiolites are preserved.

During the late Sakmarian (Early Permian), the Haushi limestone was deposited in a shallow embayment of the Neotethys Ocean covering what is now north Oman and parts of southeast Saudi Arabia. The sea persisted through the late Sakmarian, but by the time of the deposition of the ?Artinskian Middle Gharif Member, limestone deposition had ceased and generally arid fluvial and minor lacustrine palaeonvironments in a low accommodation space setting had become established. Analysis of three subsurface cored boreholes and other surface sections of the Haushi limestone shows an upward change in microfacies from bryonoderm to molechfor associations reflecting the passage from heterozoan to photozoan communities. The biotic turnover indicates cooler climate and eutrophy in the lower parts of the unit and an upward trend towards warmer climate and more oligotrophic conditions in the upper part. Common autochthonous algal palynomorphs and high δ13Corg in the lower part suggest that high nutrient levels were due to greater fluvial runoff, while allochthonous pollen assemblages indicate that the climate of the hinterland became more arid through the deposition of the unit, causing upward increasing seawater trends in δ18Ocarb. Several extraneous factors are likely to have contributed to this palaeoenvironmental change, which was more abrupt than in other parts of post glacial Early Permian Gondwana. First, the Haushi sea, being an embayment partially isolated by Hawasina rift shoulder uplift, was more vulnerable to changes in rainfall and runoff than an open sea. Second, continued post glacial global warming and small northward movement of Gondwana may have contributed to temperature increase. Aridity may have been caused by the onset of monsoons and the influence of rift shoulders to the northeast and southeast.

In the Neka Valley (Eastern Alborz, Iran), glaucony-bearing marine sediments of early-middle Santonian age directly overlie Palaeozoic to Triassic units deformed during the Eo-cimmerian orogenic event (Late Triassic). The Upper Cretaceous open marine sediments were deposited on a flat surface lacking any evidence of pedogenesis. The geochemical and morphological features of glaucony grains, which characterize the base (1 to 1.5 m) of the Upper Cretaceous succession, indicate an autochthonous origin of the highly-evolved glaucony, denoting a long-lasting period of low sedimentation rate. The development of glaucony in the observed stratigraphic position is indicative of a rapid drowning of the former Cimmerian relief that cannot be explained by a eustatic rise alone: the palaeo-depth needed for the development of glaucony and for the presence of the observed bathyal foraminifera assemblages is greater than the maximum eustatic excursion documented in the Cretaceous. The occurrence of glaucony in this stratigraphic position reflects thus an important episode of increased subsidence rates, related to a geodynamic event framed in a time-interval of major plate reorganization in the complex puzzle of the Iranian plates: the subsidence event that caused the development of the glauconitic horizon in the Neka Valley could likely represent the effect of a Santonian stage of the complex and long-lasting story of the opening of the Caspian Sea.

Structural analyses carried out in the southern-central Alborz (Iran) have shown that the evolution of this belt has been strongly conditioned by the inversion of pre-existent extensional faults. Inversion tectonics has been identified especially in the southern part of the belt, and it is related to the reactivation of grabens formed in the foreland of the Late Triassic Eo-Cimmerian orogen, resulting from the accretion of the Iranian block to Eurasia. Three main associations of structures—active during the late Cenozoic—have been distinguished: (1) E–W thrust faults and folds followed by the activation of (2) E–W right-lateral strike-slip faults associated to large ENE–WSW trending en echelon folds, and finally (3) ESE–WNW to SE–NW thrust faults and left-lateral strike-slip faults inverting in some cases previous E–W right-lateral faults. Central Alborz is strongly controlled by the geometry of pre-existing tectonic discontinuities, which are responsible for strain partitioning between strike-slip and reverse faults during convergence. These results provide new insights on the style and evolution of this complex intracontinental belt, which can be considered a significant example of transpressive tectonics.

In the Central Lombardy Basin (Southern Alps) Anisian carbonate platform marginal facies yielding the first documented occurrence of coral colonies in this area of the Western Tethys has been recognized. These marginal facies identify the east-west transition between two sectors with a different Anisian evolution. West of the recognized marginal facies the Anisian succession is characterised by subtidal bioturbated limestones passing upward to peritidal dolostones, whereas toward the east a thicker succession of subtidal facies persist until the end of the Anisian. The margin belt develops at the passage between a more subsiding eastern portion and a less subsiding one toward the west. The different facies and thickness of the Anisian succession east and west of the marginal facies is indicative of syndepositional tectonics. The transition from subtidal to peritidal facies in the western sector is ascribed to a sea-level fall that favoured the onsetting of peritidal facies on the less subsiding block and of marginal facies on its border. The occurrence of a N-S trending syndepositional Anisian fault system could also explain the scarce progradational evolution of the margin facies, prevented both by the paleobathymetric setting and by the scarce productivity of the Anisian marginal communities. The presence, in the Anisian marginal facies, of crinoids and corals (together with the occurrence of one of the oldest specimen of coralline red algae) outlines the return to normal marine conditions and documents the recovery of the carbonate platform marginal faunal association after the Permo-Triassic crisis in the Western Southern Alps.

A shallowing-upward carbonate sequence was studied from the outcrop at Gyulakeszi, Tapolca Basin (western Hungary), and it is interpreted as a Middle Triassic (Curionii or younger) platform progradation. Two lithostratigraphic units are distinguished. Microfacies analysis and micropaleontological investigation conducted on the red nodular, cherty limestone (Vászoly and Buchenstein formations) suggest that the lower unit was deposited during the Reitzi and the Secedensis ammonoid zones. The overlying white platform limestone (upper unit) is typical of a prograding platform and includes gravity-driven deposits at the base followed by periplatform facies deposited in shallow marine warm waters around the fair-weather wave base. The section at Gyulakeszi was unaffected by fabric-destructive dolomitization, which is uncharacteristic of similar platform facies in the Balaton Highland. Isopachous and radiaxial fibrous calcite cement found in the grainstone and boundstone facies are indicative of early lithification and diagenesis in the marine phreatic zone. “Evinospongiae”-type cement is described for the first time from the Balaton Highland and it is similar to the outer platform cements published previously from the Alps (Italy and Austria). The progradation could have advanced over the pelagic limestones as early as the Curionii zone, which is an undocumented event in the Veszprém Plateau. Similar event, however, is well known from the Western Dolomites, where aggradation was followed by intense progradation during the Gredleri and Archelaus ammonoid zones. The length of this progradation event at Gyulakeszi, however, is ambiguous since proven Ladinian (Longobardian) rocks are not exposed in the study area and were not penetrated by boreholes in the Tapolca Basin., Rivista italiana di Paleontologia e Stratigrafia, Vol 120, No 2