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Fluid systems in inverted rifted margins are challenging to interpret because fractures formed before compression were often reactivated acting as fluid pathways as new ones formed. Deciphering the fracture and fluid flow history in such complex settings has key implications for the prediction of the distribution of mineral resources. As an example, we reconstruct the fluid flow evolution of a portion of the inverted Pyrenean rift, the Upper Pedraforca thrust sheet, from the Mesozoic extension to the Alpine orogeny. We combine structural analysis and petrographic, geochemical and geochronological data obtained from 87 samples of fracture-filling carbonate cements. During the Late Jurassic-Early Cretaceous, low-temperature seawater produced dolomitization of Jurassic and Lower Cretaceous limestones in an extensional setting. During the Early Cretaceous salt-related extension, formation waters, probably evolved seawater or fluids that interacted with Triassic evaporites, at temperatures from 125 to 149°C migrated through fractures. The formation of breccias within post-salt rocks in primary weld zones facilitated the upward migration of formation waters that interacted with pre-salt rocks with high 87Sr/86Sr ratios. Formation waters at temperatures of 80°C migrated during the emplacement of the Upper Pedraforca thrust sheet in the Late Cretaceous-Palaeocene. These fluids interacted with Upper Cretaceous Carbonates and/or Triassic evaporites. In contrast, the influence of meteoric fluids increased in shallower positions due to the exhumation of the SE Pyrenees during the Eocene-Oligocene. Coevally, hot dolomitizing fluids migrated along diapir walls during the formation of secondary welds. Supergene ores documented in diapiric areas worldwide related to meteoric fluids, and the similar meteoric percolation occurred in the Upper Pedraforca thrust sheet, suggest that supergene mineralization could be found in the Pyrenees. Brecciation of rocks in primary weld zones and evaporite detachments, where mineralization accumulate in fractures from basement-derived fluids, also suggests that similar ores could be found in the Pyrenees., This research was performed within the framework of DGICYT Spanish Project PGC2018-093903-B-C22 Ministerio de Ciencia, Innovación y Universidades/Agencia Estatal de Investigación/Fondo Europeo de Desarrollo Regional, Unión Europea, SUBTETIS (PIE-CSIC-201830E039), ALORBE (PIE-CSIC-202030E310) and Grup Consolidat de Recerca ”Geologia Sedimentària” (2017SGR-824) and Generalitat de Catalunya, Grant/Award Number AGAUR 2017SGR-847. The isotopic analyses were carried out at “Centres Científics i Tecnològics” of the Universitat de Barcelona. Strontium analyses were done at the “CAI de Geocronología y Geoquímica Isotópica” of the Universidad Complutense de Madrid. The high resolution inductively coupled plasma-mass spectrometry analyses were carried out at labGEOTOP of the GEO3BCN-CSIC, a cofounded structure by FEDER-UE (Ref. CSIC08-4E-001). The clumped isotopes analyses were performed in the Qatar Stable Isotope Laboratory of Imperial College of London. E.G.R. acknowledges the Spanish Ministry of Science, Innovation and Universities for the “Ramón y Cajal” fellowship RYC2018-026335-I.

International audience; We describe a singular structure in Upper Cretaceous rocks of the Eaux-Chaudes massif of the western Pyrenees, consisting of a kilometre-scale fold nappe with a sheared overturned limb. High ductile strain attests a deformation style rarely reported for the alpine Pyrenees, and peak temperature in Upper Cretaceous carbonates is estimated by Raman spectroscopy of carbonaceous material palaeothermometry in the lower greenschist facies (>300°C). The normal fold limb retains the original sedimentary textures, while the overturned limb shows calcite crystal-plastic deformation and dynamic recrystallization, with crystallographic preferred orientation. The observed ductility and metamorphic temperature bear similarities with the lower Helvetic nappes of the Alps, suggesting deep burial and/or possibly high geothermal gradient in this part of the Pyrenees.

[The Greater Caucasus may constitute a natural example of early continental collision. New detrital zircon U‐Pb geochronology data, together with published Cenozoic stratigraphy and structural data from the Greater Caucasus, suggests collision began in the Late Miocene to Pliocene, leading to diachronous changes in deformation and sedimentation in the orogen and associated basins. , Abstract The Greater Caucasus orogen on the southern margin of Eurasia is hypothesized to be a young collisional system and may present an opportunity to probe the structural, sedimentary and geodynamic effects of continental collision. We present detrital zircon U‐Pb age data from the Caucasus region that constrain changes in sediment routing and source exposure during the late Cenozoic convergence and collision between the Greater Caucasus orogen and the Lesser Caucasus, an arc terrane on the lower plate of the system. During Oligocene to Middle Miocene time, following the initiation of deformation within the Greater Caucasus, marine sandstones and shales were deposited between the Greater and Lesser Caucasus, and detrital zircon age data suggest no mixing of Greater Caucasus and Lesser Caucasus detritus. During Middle to Late Miocene time, Greater Caucasus detritus was deposited onto the Lesser Caucasus basin margin, and terrestrial, largely conglomeratic, sedimentation began between the Greater and Lesser Caucasus. Around 5.3 Ma, upper plate exhumation rates increased and shortening migrated to pro‐ and retro‐wedge fold‐thrust belts, coinciding with the initiation of foreland basin erosion. Sediment composition, provenance and structural data from the orogen together suggest the existence of a wide (230–280 km) marine basin that was progressively closed during Oligocene to Late Miocene time, probably by subduction/lithospheric underthrusting beneath the Greater Caucasus, followed by initiation of collision between the Lesser Caucasus arc terrane and the Greater Caucasus in Late Miocene to Pliocene time. The pace of the transition from hypothesized subduction to collision in the Caucasus is consistent with predictions from numerical modeling for a system with moderate convergence rates (

[A new tectonic and depositional model is presented for the Lower Old Red Sandstone of the northern Midland Valley Basin—consolidating new and existing sedimentological data—reconstructing a large foreland basin DFS that records the time‐period between the late phases of the Caledonian Orogeny and the onset of post‐orogenic collapse in the mid‐Devonian , Abstract Reconstruction of the geological history of orogenic events can be challenging where basins have limited and/or fragmentary preservation. Here, we apply understanding gained from modern analogues to the sedimentological analysis of the succession of Upper Silurian to Lower Devonian Lower Old Red Sandstone (LORS), northern Midland Valley, Scotland, in order to reconstruct the foreland to the Caledonian orogeny. A new depositional model is presented which differs significantly from current understanding. Using facies analysis, grain size distribution and palaeocurrent data a large distributive fluvial system is reconstructed. Three lithofacies and nine sublithofacies are identified, forming fluvial channel and floodplain facies associations. The system was derived from an emerging mountain range in the Caledonian foreland undergoing constant tectonic rejuvenation to produce 9 km of coarse‐grained sediment, exhibiting an overall decrease in thickness towards the west and a large‐scale downstream reduction in grain size. Conglomerate sublithofacies dominate proximal areas in the east where amalgamated fluvial channel facies association is abundant, with a downstream increase in the dominance of floodplain facies. Additionally, observed grain size cyclicity is attributed to a pulsatory tectonic influence. The LORS records the time‐period between the late phases of the Caledonian Orogeny and the onset of post‐orogenic collapse in the mid‐Devonian and the presented model allows improved understanding of the north‐Atlantic Caledonian foreland.]

Controversy over the plate tectonic affinity and evolution of the Saxon granulites in a two- or multi-plate setting during inter- or intracontinental collision makes the Saxon Granulite Massif a key area for the understanding of the Palaeozoic Variscan orogeny. The massif is a large dome structure in which tectonic slivers of metapelite and metaophiolite units occur along a shear zone separating a diapir-like body of high-Pgranulite below from low-Pmetasedimentary rocks above. Each of the upper structural units records a different metamorphic evolution until its assembly with the exhuming granulite body. New age and petrologic data suggest that the metaophiolites developed from early Cambrian protoliths during high-Pamphibolite facies metamorphism in the mid- to late-Devonian and thermal overprinting by the exhuming hot granulite body in the early Carboniferous. A correlation of new Ar-Ar biotite ages with publishedP-T-tdata for the granulites implies that exhumation and cooling of the granulite body occurred at average rates of similar to 8 mm/year and similar to 80 degrees C/Ma, with a drop in exhumation rate from similar to 20 to similar to 2.5 mm/year and a slight rise in cooling rate between early and late stages of exhumation. A time lag ofc. 2 Ma between cooling through the closure temperatures for argon diffusion in hornblende and biotite indicates a cooling rate of 90 degrees C/Ma when all units had assembled into the massif. A two-plate model of the Variscan orogeny in which the above evolution is related to a short-lived intra-Gondwana subduction zone conflicts with the oceanic affinity of the metaophiolites and the timescale ofc. 50 Ma for the metamorphism. Alternative models focusing on the internal Variscan belt assume distinctly different material paths through the lower or upper crust for strikingly similar granulite massifs. An earlier proposed model of bilateral subduction below the internal Variscan belt may solve this problem., Zweitver��ffentlichungen der Universit��t Potsdam : Mathematisch-Naturwissenschaftliche Reihe; 1227

[A tectonic model for the evolution of the Zagros Orogenic Belt based on the different types of melanges in the Neyriz region. , Abstract Melanges are formed by sedimentary, tectonic and diapiric processes and are generally found in collisional belts. The Zagros Orogeny provides an intriguing geological laboratory for the study of melange‐forming processes during the progressive tectonic evolution of the Neotethys Ocean. Different types of tectonic and sedimentary melanges occur in specific structural positions within the Zagros orogenic belt in the Neyriz Region (Iran). Based on their block‐in‐matrix fabrics, and tectonostratigraphic positions, we differentiated 14 different melange types, which mark different episodes of the tectonic evolution of the Neyriz Region from the Cretaceous subduction to the Miocene collision. The Cretaceous subduction stage is recorded by volcanic‐sedimentary melanges (Mv). Sedimentary melanges characterized by megabreccia from the Cretaceous limestone (Ms1) and Eocene polymictic megabreccia (Ms2) represent epi‐nappe melanges formed during the Palaeocene–Eocene in wedge‐top basins. The ophiolite emplacement in the Oligocene resulted in local extensional tectonics in the upper part of the ophiolitic nappe, and deposition of a polymictic megabreccia (Ms3, Ms4). As the final production of the Neotethys Ocean closure and the Eurasian‐Arabian collision, the sedimentary melanges characterized by different types of chaotic rock units (Ms5, Ms6, Ms7 and Ms8 facies) were developed in front of the Cretaceous–Eocene nappes due to growth of the orogenic wedge in the Miocene. Our findings indicate that the recognition and distinction of different types of melange may provide additional constraints for a better understanding of the tectono‐sedimentary evolution of the Neotethyan region.]

The Hailar Basin is located in the northern portion of NE China and preserves relatively complete Middle Jurassic to Cretaceous volcanic and clastic successions. The understanding of the basin's Mesozoic stratigraphic development can help reveal Mesozoic tectonic complexity in NE China. This study focuses on Mesozoic sequences of the Hailar Basin based mainly on interpretations of seismic profiles and logging data. Three tectono-stratigraphic sequences are dividable, the pre-Mesozoic, the Middle Jurassic to Lower Cretaceous, and the Upper Cretaceous successions, respectively. Two angular unconformities separate the three sequences, with one below the Middle Jurassic and the other atop the Lower Cretaceous. Noticeable is the absence of the two angular unconformities in the Jurassic to Lower Cretaceous sequence, which are usually observed in the northern North China Block. Instead, a disconformity occurs between the Jurassic and Lower Cretaceous. The absence of angular unconformities in the Hailar Basin implies that this region had not been affected by crustal shortening or the Yanshanian Orogeny that had strongly influenced the northern North China Block in the late Mesozoic. It is concluded that the closure of the Mongol-Okhotsk Ocean exerted little impact on the continent on the south, and flat subducting of the Palaeo-Pacific Plate might have been responsible for the occurrence of the Yanshan Orogeny.

The Colorado Rockies were initially raised during the Laramide Orogeny ca. 70-45 Ma. But consensus exists that the range experienced a second, post-Laramide episode of surface uplift; the timing an...

International audience; Since the discovery of shatter cones (SCs) near the village of Agoudal (Morocco, Central High Atlas Mountains) in 2013, the absence of one or several associated circular structures led to speculation about the age of the impact event, the number, and the size of the impact crater or craters. Additional constraints on the crater size, age, and erosion rates are obtained here from geological, structural, and geophysical mapping and from cosmogenic nuclide data. Our geological maps of the Agoudal impact site at the scales of 1:30,000 (6 km(2)) and 1:15,000 (2.25 km(2)) include all known occurrences of SCs in target rocks, breccias, and vertical to overturned strata. Considering that strata surrounding the impact site are subhorizontal, we argue that disturbed strata are related to the impact event. Three types of breccias have been observed. Two of them (br1-2 and br2) could be produced by erosion-sedimentation-consolidation processes, with no evidence for impact breccias, while breccia (br1) might be impact related. The most probable center of the structure is estimated at 31 degrees 59 ' 13.73"N, 5 degrees 30 ' 55.14"W using the concentric deviation method applied to the orientation of strata over the disturbed area. Despite the absence of a morphological expression, the ground magnetic and electromagnetic surveys reveal anomalies spatially associated with disturbed strata and SC occurrences. The geophysical data, the structural observations, and the area of occurrence of SCs in target rocks are all consistent with an original size of 1.4-4.2 km in diameter. Cosmogenic nuclide data (Cl-36) constrain the local erosion rates between 220 +/- 22 m Ma(-1) and 430 +/- 43 m Ma(-1). These erosion rates may remove the topographic expression of such a crater and its ejecta in a time period of about 0.3-1.9 Ma. This age is older than the Agoudal iron meteorite age (105 +/- 40 kyr). This new age constraint excludes the possibility of a genetic relationship between the Agoudal iron meteorite fall and the formation of the Agoudal impact site. A chronolgy chart including the Atlas orogeny, the alternation of sedimentation and erosion periods, and the meteoritic impacts is presented based on all obtained and combined data.

Platform carbonates diagenesis in salt basins could be complex due to potential alterations of fluids related and non-related to diapirism. This paper presents the diagenetic history of the Hettangian to Pliensbachian platform carbonates from the Tazoult salt wall area (central High Atlas, Morocco). Low structural relief and outcrop conditions allowed to define the entire diagenetic evolution occurred in the High Atlas diapiric basins since early stages of the diapiric activity up to their tectonic inversion. Precipitation of dolomite and calcite from both warmed marine-derived and meteoric fluids characterised diagenetic stages during Pliensbachian, when the carbonate platforms were exposed and karstified. Burial diagenesis occurred from Toarcian to Middle Jurassic, due to changes of salt-induced dynamic related to increase in siliciclastic input, fast diapir rise and rapid burial of Pliensbachian platforms. During this stage, the diapir acted as a physical barrier for fluid circulation between the core and the flanking sediments. In the carbonates and breccias flanking the structures, dolomite and calcite precipitated from basinal brines, whereas carbonate slivers located in the core of the structure, were affected by the circulation of Mn-rich fluids. The final diagenetic event is characterised by the income of meteoric fluids into the system during uplift caused by Alpine orogeny. These results highlight the relevant influence of diapirism on the diagenetic modifications in salt-related basins in terms of diagenetic events and involved fluids. © 2019 The Authors. Basin Research © 2019 John Wiley & Sons Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists, This study is funded by Equinor Research Centre, Bergen (Norway), by the Spanish Ministry of Education and Science (MEC) through the process Intramural Especial (CSIC 201330E030), Alpimed (PIE‐CSIC‐201530E082), CSIC‐FSE 2007‐2013 JAE‐Doc postdoctoral research contract (E.S.), as well as the Group of Sedimentary research of the University of Barcelona (UB) (CGL 2015‐66335‐C2‐1‐R and SGR2017‐824).

The biota of New Caledonia is one of the most unusual in the world. It displays high diversity and endemism, many peculiar absences, and far-flung biogeographic affinities. For example, New Caledonia is the only place on Earth with both main clades of flowering plants - the endemic Amborella and 'all the rest', and it also has the highest concentration of diversity in conifers. The discovery of Amborella's phylogenetic position led to a surge of interest in New Caledonian biogeography, and new studies are appearing at a rapid rate. This paper reviews work on the topic (mainly molecular studies) published since 2013. One current debate is focused on whether any biota survived the marine transgressions of the Paleocene and Eocene. Total submersion would imply that the entire fauna was derived by long-distance dispersal from continental areas since the Eocene, but only if no other islands (now submerged) were emergent. A review of the literature suggests there is little actual evidence in geology for complete submersion. An alternative explanation for New Caledonia's diversity is that the archipelago acted as a refugium, and that the biota avoided the extinctions that occurred in Australia. However, this is contradicted by the many groups that are anomalously absent or depauperate in New Caledonia, although represented there by a sister group. The anomalous absences, together with the unusual levels of endemism, can both be explained by vicariance at breaks in and around New Caledonia. New Caledonia has always been situated at or near a plate boundary, and its complex geological history includes the addition of new terranes (by accretion), orogeny, and rifting. New Caledonia comprises 'basement' terranes that were part of Gondwana, as well as island arc and forearc terranes that accreted to the basement after it separated from Gondwana. The regional tectonic history helps explain the regional biogeography, as well as distribution patterns within New Caledonia. These include endemics on the basement terranes (for example, the basal angiosperm, Amborella), disjunctions at the West Caledonian fault zone, and great biotic differences between Grande Terre and the Loyalty Islands.

Slovakia is located within the Central Western Carpathians (CWC), one of many connected curved mountain belts prominent throughout the Mediterranean area and Europe. It is divided into tectonic dom...

An unconventional porous silicified carbonate reservoir was unveiled in the Middle Ordovician fractured limestone within a strike-slip fault zone in the Tarim Basin, NW China. The silicified carbonates are mainly composed of fine- to medium-crystalline fascicular quartz matrix and coarse crystalline bladed to columnar quartz cement. Fluid inclusion leachate-residue paired Rb-Sr isotopic dating of the quartz cement yields an isochron age of 167 +/- 15 Ma, attesting to a causal link to the Jurassic (Yanshanian) orogeny. Pervasive replacement of matrix quartz and subsequent precipitation of cement quartz through nonisothermal effervescence probably induced by episodic influxes of the hot silica- and Sr-87-rich basinal brines from the neighbouring deeper Manjiaer depression. This study thus signifies the usefulness of using Rb-Sr isotope dating method in constraining the timing of carbonate alteration, enabling to establish the deterministic relationship of basinal fluid evolution with the major tectonic activity.

The Palaeogene Isparta Basin of southwestern Anatolia formed between two convergent arms of the Isparta Bend orocline of the Tauride orogen. The origin of this tightening orocline is hypothetically explained in plate-tectonic terms. Basin sedimentation commenced on a down-warped Mesozoic carbonate platform of a crustal block accreted at the end of Cretaceous to the southern margin of the Anatolian plate. The basin earliest deposits are Palaeocene reddish mudstones with a fossil-barren condensed basal part and increasingly interspersed with thin calcarenitic turbidites towards the top. The supply of turbiditic sediment to the basin plain subsequently increased, as the upper-bathyal basin plain became surrounded from both sides by a narrow littoral shelf with an advancing turbiditic slope ramp. A major forced regression occurred at the end of Bartonian, causing incision of subaerial to submarine valleys up 600 m deep, filled in with gravelly to sandy turbidites and debrisflow deposits during the subsequent rise of relative sea level. The half-filled valleys were re-incised due to a Rupelian forced regression and were fully filled with fluvio-deltaic bayhead deposits during a final marine transgression that re-established the basin-margin biocalcarenitic shelf. The littoral environment then expanded across the shallowing basin, as the basin axial zone was up-domed and eroded to bedrock level at the end of Oligocene and the basin was tectonically inverted in Miocene. The pattern of intra-orocline foreland sedimentation documented by this case study provides tentative criteria for the recognition of synorogenic oroclines and for their distinction from post-orogenic oroclines. © 2017 The Authors. Basin Research © 2017 John Wiley & Sons Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists

The evolution of the Tethys Ocean is a significant geological event in global evolution history. However, although the hinterland of China has Tethyan sedimentary formations, the original extent of the Neo-Tethyan Ocean remains vague and controversial. It has been confirmed that the Triassic strata in the Qinling Orogen is bounded by regional faults in the north and the south with an east–west-trending distribution, as well as a scissor-like linked to Paleo-Tethyan flysch to the Bayakala area. The Qinling Orogen is characterized by great thickness and unique sedimentary formations, including deep-water gravity flows, colluvial deposits, and olistostromes. Moreover, the Triassic strata have plastic rheology and buckling folds that are stronger than those of the adjacent pre-Triassic strata in an aulacogen sedimentary setting. The original Yangtze-type platform facies deposition in the Qinling rapidly switched into the Tethyan-type aulacogen deposition after the Ladinian marine regression during the Middle Triassic. The Qinling Ocean was separated from the original and coeval Yangtze Ocean to the east and then connected with the Tethys Ocean to the west, and the orogeny started after the “emergency” closure of the basin during the late Middle Triassic to early Late Triassic. This unusual sedimentation and evolution highlight the uniqueness and complexity of the Qinling Tethyan-type deposition. The Qinling Tethyan-type Triassic formation is remarkably different from that of the Yangtze-type platform facies Triassic formation in China recording the opening and closing of the Tethys Ocean within the mainland of China in the Triassic. The discovery and confirmation of the Triassic Tethyan-type aulacogen sedimentation in the hinterland of China provide important evidence for further study of identification of the distribution and configuration of ocean and continent, and refinement and modification of the Tethyan Ocean of the global Triassic plate tectonic evolution.

Strain localization within shear zones may partially erase the rock fabric and the metamorphic assemblage(s) that had developed before the mylonitic event. In poly-deformed basements, the loss of information on pre-kinematic phases of mylonites hinders large-scale correlations based on tectono-metamorphic data. In this study, devoted to a relict unit of Variscan basement reworked within the nappe stack of the Northern Apennines (Italy), we investigate the possibility to reconstruct a complete pressure (P) – temperature (T) – deformation (D) path of mylonitic micaschist and amphibolite by integrating microstructural analysis, mineral chemistry and thermodynamic modelling. The micaschist is characterized by a mylonitic fabric with fine-grained K-white mica and chlorite enveloping mica-fishes, quartz, and garnet pseudomorphs. Potassic white mica shows Mg-rich cores and Mg-poor rims. The amphibolite contains green amphibole+ plagioclase+garnet+quartz+ilmenite defining S1 with a superposed mylonitic fabric localized in decimetre- to centimetre-scale shear zones. Garnet is surrounded by an amphibole+plagioclase corona. Phase diagram calculations provide P-T constraints that are linked to the reconstructed metamorphic-deformational stages. For the first time an early high-pressure stage at > 11 kbar and 510 °C was constrained, followed by a temperature peak at 550-590 °C and 9-10 kbar and a retrograde stage (< 475 °C, < 7 kbar), during which ductile shear zones developed. The inferred clockwise P-T-D path was most likely related to crustal thickening by continent-continent collision during the Variscan orogeny. A comparison of this P-T-D path with those of other Variscan basement occurrences in the Northern Apennines revealed significant differences. Conversely, a correlation between the tectono-metamorphic evolution of the Variscan basement at Cerreto pass, NE Sardinia and Ligurian Alps was established. This article is protected by copyright. All rights reserved.

Although eclogites in the Belomorian Province have been regarded as Archean in age and among the oldest in the world, there are also multiple studies that have proposed a Paleoproterozoic age. Here we present new data for the Gridino-type eclogites, which occur as boudins and metamorphosed dykes within tonalite–trondhjemite–granodiorite (TTG) gneisses. Zircon from these eclogites has core and rim structures. The cores display high Th/U ratios (0.18–0.45), negative Eu anomalies and strong enrichment in HREE, and have Neoarchean U–Pb ages of c. 2.70 Ga; they are interpreted to be magmatic in origin. Zircon cores have δ18O of 5.64–6.07 ‰ suggesting the possibility of crystallization from evolved mantle-derived magmas. By contrast, the rims, which include the eclogite facies minerals omphacite and garnet, are characterized by low Th/U ratios ( 18 kbar for the Gridino-type eclogites suggests an apparent thermal gradient of < 39–42 °C/kbar for the Lapland–Kola collisional orogeny. This article is protected by copyright. All rights reserved.

Tectonic forcing of delta progradation is increasingly being invoked to explain stratal stacking patterns in foreland basins. Nonetheless, the recognition of different types of tectonic forcing and their consequences for the spatial and temporal distribution of accommodation often rely on incomplete datasets and indirect sequence stratigraphic criteria. Previous work has concluded that the Cenomanian-Turonian Frontier Formation of northern Utah, north-west Colorado, and south-west Wyoming (‘Vernal Delta’) owes its origin largely to tectonic overprinting of depositional patterns, although the lack of a comprehensive sequence stratigraphic framework for the unit has hampered evaluation of this claim. The present study provides detailed facies and sequence stratigraphic analyses based on outcrop sections and wireline log suites from the Uinta, Piceance and Green River basins. Four genetically-related intervals were defined and mapped by using regionally traceable stratigraphic horizons (flooding surfaces and sequence boundaries). Internally, intervals are composed of distal and proximal delta front lithologies, and coastal plain facies. Overall, Intervals 1 to 4 form a major basinward projection of coarse clastic strata generated in response to four separate, high-frequency regressions. Furthermore, a change through time from southward projection of elongate lobes (Intervals 1 and 2) to eastward dispersal and development of a broad, arcuate planform (Intervals 3 and 4) can be explained in terms of changes in prevailing tectonic forcing mechanisms. North–south trending Sevier Orogeny forebulge structures controlled Intervals 1 and 2. West–east progradation (Intervals 3 and 4) was probably controlled by Proterozoic basement lineament reactivation due to Laramide foreland uplifts. Therefore, this study provides direct geological evidence for the initiation of local Laramide deformation as early as 90 Ma. These findings contribute to a more complete understanding of tectonic forcing of coastal to shallow marine successions in foreland basins and the tectonic evolution of the western USA. This article is protected by copyright. All rights reserved.

The sedimentary features of the Cixerri Formation (Eocene–Oligocene) and its evolution in space and time are described through mapping, investigation of all the significant outcrops, and also by analysing the depositional architecture of well-exposed and laterally extensive outcrops. The Cixerri Formation marks the middle Eocene Pyrenean unconformity and blankets a former structural ridge-and-swale morphology. This started by covering the flanks of the ridges with small alluvial fans and ultimately filled the swales with fluvial deposits in braided to meandering stream environments. In this latter sedimentation phase, the depositional environment of the formation evolved both upwards, and from west to east, to gradually lower energy environments, suggesting a transgressive-type evolution. The Eocene–Oligocene Cixerri Formation was deposited by a fluvial network with a regular flow regime under a humid–warm climate: This network was formed by a main W-E-directed trunk and a NW-SE-directed minor branch that ultimately joined together. The Cixerri Formation, which was fed by the erosion of a sector of the Pyrenean Chain, passes upwards to coarser deposits that indicate the transition from a quiet tectonic environment to an active transtensional tectonic phase (Apennine phase). A comparison with similar coeval formations in Northern Sardinia, Corsica, and the Western Mediterranean area (Balearic Islands, France) is attempted, before the significance of the formation in the Pyrenean orogeny is then discussed.

The Proterozoic belts that occur along the margins of the West Australian Craton, as well as those in intraplate settings, generally share similar geological histories that suggest a common plate-margin driver for orogeny. However, the thermal drivers for intraplate orogenesis are more poorly understood. The Mutherbukin Tectonic Event records a protracted period of Mesoproterozoic reworking of the Capricorn Orogen and offers significant insight into both the tectonic drivers and heat sources of long-lived intraplate orogens. Mineral assemblages and tectonic fabrics related to this event occur within a 50 km-wide fault-bound corridor in the central part of the Gascoyne Province in Western Australia. This zone preserves a crustal profile, with greenschist facies rocks in the north grading to upper amphibolite facies rocks in the south. The P–T–t evolution of 13 samples from 10 localities across the Mutherbukin Zone is investigated using phase equilibria modelling integrated with in situ U–Pb monazite and zircon geochronology. Garnet chemistry from selected samples is used to further refine the P–T history and shows that the dominant events recorded in this zone are prolonged D1 transpression between c. 1,320 and 1,270 Ma, followed by D2 transtension from c. 1,210 to 1,170 Ma. Peak metamorphic conditions in the mid-crust reached >650°C and 4.4–7 kbar at c. 1,210–1,200 Ma. Most samples record a single clockwise P–T evolution during this event, although some samples might have experienced multiple perturbations. The heat source for metamorphism was primarily conductive heating of radiogenic mid- and upper crust, derived from earlier crustal differentiation events. This crust was thickened during D1 transpression, although the thermal effects persisted longer than the deformation event. Peak metamorphism was terminated by D2 transtension at c. 1,210 Ma, with subsequent cooling driven by thinning of the radiogenic crust. The coincidence of a sedimentary basin acting as a thermal lid and a highly radiogenic mid-crustal batholith restricted to the Mutherbukin Zone accounts for reworking being confined to a discrete crustal corridor. Our results show that radiogenic regions in the shallow to mid crust can elevate the thermal gradient and localize deformation, causing the crust to be more responsive to far-field stresses. The Mutherbukin Tectonic Event in the Capricorn Orogen was synchronous with numerous Mesoproterozoic events around the West Australian Craton, suggesting that thick cratonic roots play an important role in propagating stresses generated at distant plate boundaries.

In the transitional period between the Middle and the Late Triassic, the Indochina orogeny caused two tectonic events in South China: (1) the formation and uplift of the Qinling-Dabie orogenic belt along the northern margin of the South China Plate, due to its collision with the North China Plate; and 2) the development of a 1300-km-wide intra-continental orogen in the southeastern part of the South China Plate, which led to a northwestward movement of the foreland thrust-fold zone. These tectonic events resulted in the ending of the Yangtze Platform, and were a stable paleogeographic factor from the Eidacaran to the end of the Middle Triassic. This platform was characterized by the widespread development of shallow-water carbonates. After the end of the Yangtze Platform, the upper Yangtze foreland basin (or Sichuan foreland basin) was formed during the Late Triassic and became a accumulation site of fluvial deposits that are composed of related strata of the Xujiahe Formation. In western Sichuan Province, the Xujiahe Formation overlies the Maantang Formation shallow-water carbonate rocks of the Xiaotangzi Formation siliciclastic rocks (from shelf shales to littoral facies). The sequence-stratigraphic framework of the Upper Triassic in the upper Yangtze foreland basin indicates a particular alluvial architecture, characterized by sequences composed of (1) successions of low-energy fluvial deposits of high-accommodation phases, including coal seams, and (2) high-energy fluvial deposits of low-accommodation phases, including amalgamated river-channel sandstones. The spatial distribution of these fluvial deposits belonging to the Xujiahe Formation and its relative strata is characterized by gradual thinning-out, overlapping, and pinching-out toward both the east and south. This sedimentary record therefore expresses a particular sequence-stratigraphic succession of fluvial deposits within the filling succession of the foreland basin. The sequence-stratigraphic framework for the Upper Triassic in the Upper Yangtze region provides a record of the end of the Yangtze Platform and the formation of the upper Yangtze foreland basin.

Analysis of current temperature data in the Canadian Arctic Archipelago results in the recognition of two major thermal regimes. High temperature regions are observed where salt diapirs and salt cored anticlines are present. Low temperature fields are observed along the western and southern basin margins and around Cornwall-Amund Ringnes islands, where regional Mesozoic aquifers are exposed to surface, connected to basin boundary faults, or regional unconformities. Meteoric and Holocene sub-glacial water recharge are inferred to be responsible for the low geothermal regime and low formation water salinity. Neither exhumation associated with the Eocene “Eurekan” orogeny nor volcanic intrusion associated with opening of Amerasia Basin in late Jurassic-early Cretaceous have been interpreted to be a significant influence on the present day temperature field, although thermal indicators show evidence of elevated thermal alteration of organic matter pointing to earlier, but now dissipated, thermal anomalies.

Dolomites occur extensively in Cambrian to Lower Ordovician carbonates in the Tienshan orogen of the Quruqtagh area, north-east Tarim Basin, where thick (up to 1 km), dark grey lenticular limestones of semi-pelagic to pelagic origin are prominent. The dolomites generally occur as beige, anastomosed geobodies that cross-cut well-stratified limestones. Based on detailed field investigations and petrographic examination, three types of matrix dolomite are identified: fine crystalline planar-e (Md1); fine to coarse crystalline planar-s (e) (Md2); fine to coarse crystalline non-planar-a (Md3) dolomites. One type of cement dolomite, the non-planar saddle dolomite (Cd), is also common. The preferential occurrence of Md1 along low-amplitude stylolites points to a causal link to pressure dissolution by which minor Mg ions were probably released for replacive dolomitization during shallow burial compaction. Type Md2, Md3 and Cd dolomites, commonly co-occurring within the fractured zones, have large overlaps in isotopic composition with that of host limestone, implying that dolomitizing fluids inherited their composition from remnant pore fluids or were buffered by the formation water of host limestones through water–rock interaction. However, the lower δ18O and higher 87Sr/86Sr ratios of these dolomites also suggest more intense fluid–rock interaction at elevated temperature and inputs of Mg and radiogenic Sr from the host limestones with more argillaceous matter and possibly underlying Neoproterozoic siliciclastic strata. Secondary tensional faults and fractures within a compressional tectonic regime were probably important conduits through which higher-temperature Mg-rich fluids that had been expelled from depth were driven by enhanced tectonic compression and heating during block overthrusting, forming irregular networks of dolomitized bodies enclosed within the host limestones. This scenario probably took place during the Late Hercynian orogeny, as the Tarim block collided with Tienshan island arc system to the north and north-east. Subsequent downward recharges of meteoric fluids into the dolomitizing aquifer probably terminated dolomitization as a result of final closure of the South Tienshan Ocean (or Palaeo-asian Ocean) and significant tectonic uplift of the Tienshan orogen. This study demonstrates the constructive role of notably tensional (or transtentional) faulting/fracturing in channelling fluids upward as a result of intense tectonic compression and heating along overthrust planes on the convergent plate margin; however a relatively short-lived, low fluid flux may have limited the dolomitization exclusively within the fractured/faulted limestones in the overthrust sheets. This article is protected by copyright. All rights reserved.

The determination of the thermal (temperature–time) histories of high-P metamorphic terranes has been commonly based on the concepts of slow cooling and closure temperatures. In this paper, we find that this approach cannot reconcile a geochronological data set obtained from the amphibolite-facies allochthonous Leknes Group of the Lofoten islands, Norway, which reveals an extremely complex thermal history. Using detailed results from several different geochronometers such as 40Ar/39Ar, Rb–Sr and U–Pb, we show that a model invoking multiple, short-lived thermal pulses related to hot-fluid infiltration channelized by shear zones can reconcile this complicated data set. This model suggests that hot fluids infiltrated throughout basement shear zones and affected the overlying cold allochthon, partially resetting U/Pb rutile and titanite ages, crystallizing new zircon and produced identical 40Ar/39Ar and Rb/Sr ages in muscovite, biotite and amphibole in various rocks throughout the region. This paper shows the enormous potential of coupling laser Ar-spot data with thermal modelling to identify and constrain the duration of short-lived events. An optimal P–T–t history has been derived by modelling the age data from a previously dated large muscovite crystal (Hames & Andresen, 1996, Geology, 24:1005) and using Zr-in-rutile thermometry which is consistent with all geochronological data and geological constraints from the basement zones and allochthon cover. This tectonothermal model history suggests that there have been three episodic hot-fluid and 40Ar-free infiltration events, resulting in the total resetting of Ar ages during the Scandian (425 Ma) for 1 Ma at 650°C and two reheating events at 415 Ma for 400 ka at 650°C and at 365 Ma for 50 ka at 600°C, which are modelled as thermal spikes above an ambient temperature of 300°C. Independent confirmation of these parameters was provided by Pb-diffusion modelling in rutile and titanite. The model suggests that the amphibolite facies rocks of the Leknes Group probably remained cold before being exhumed for at least 60 Ma (425–365 Ma) and successfully explains the presence of different minerals that crystallized or were totally/partially reset in the allochthon and in the basement. The migration of hot fluids for short periods of times within conduits extending through the basement and allochthon rock units is likely associated with episodic seismic activity during the Caledonian orogeny.

A comprehensive dataset for discrete groundwater inflows to mines in the Poehla-Tellerhaeuser Ore Field and the mining scale fault zones has been compiled from unpublished data recorded by eastern German and Soviet hydrogeologists at the Soviet-German stock company (SDAG) Wismut. This dataset has been analyzed to provide novel insights into the 3D distribution of preferential groundwater pathways and the impacts of faulting on the distribution of hydraulic parameters in crystalline rocks at site scale. The sampled 1030 discrete inflows include flow rates ranging from 1.7E-8 to 3.7E-2 m3 sec−1, which were transformed into mesoscale fracture transmissivity values ranging between 3E-13 and 2E-4 m2 sec−1. These mesoscale fracture transmissivities were spatially correlated with fault zones exhibiting trace lengths between 0.3 and 30 km, which were mainly formed during and reactivated several times since Variscan orogeny. The statistical correlations are based on a 3D geological model composed of 14 litho-stratigraphic units and 131 mining scale faults, separated into five main strike directions. These fault zones strongly overlap and cover about 90% of the investigated rock mass volume with a decreasing percentage of overlap in the investigated depth range (0–900 mbgs). 97% of all inflows are located within fault damage zones, and most of the flow occurs within the overlap of multiple fault damage zones. A dimensionless hydraulic model for the distribution of flow Q as a function of the position x within mining scale fault zones has been derived as Q = 1.1e−4.5x (where x decreases from the fault core to the protolith and the exponent varies as a function of fault orientation). 75–95% of the flow occurs within the inner 50% of the damage zone, and mainly NW-SE and NE-SW striking mining scale faults are transmissive. The orientations of conductive mesoscale fractures within these damage zones show a larger variability than the corresponding mining scale faults.

New petrographic and microstructural observations, mineral equilibria modelling and U/Pb (monazite) geochronological studies were carried out to investigate relationship between deformation and metamorphism across the Rehamna massif (Moroccan Variscan belt). In this area, typical Barrovian (muscovite to staurolite) zones developed in Cambrian to Carboniferous metasedimentary rocks that are distributed around a dome-like structure. First assemblages are characterized by the presence of locally preserved andalusite, followed by prograde evolution culminating at 6 kbar and 620 °C in the structurally deepest staurolite zone rocks. This Barrovian sequence was subsequently uplifted to supracrustal levels, heterogeneously reworked at greenschist facies conditions, which was followed locally by static growth of andalusite, indicating heating to 2.5−4 kbar and 530−570 °C. The 206Pb/238U monazite age of 298.3 ± 4.1 Ma is interpreted as minimum age of peak metamorphic conditions whereas the ages of 275.8 ± 1.7 Ma and 277.0 ± 1.1 Ma date decompression and heating at low pressure, in agreement with previous dating of Permian granitoids intruding the Rehamna massif. The prograde metamorphism occurred during thickening and associated horizontal flow in the deeper crust (S1 horizontal schistosity). The horizontally disposed metamorphic zones were subsequently uplifted by a regional scale antiform during ongoing N-S compression. The re-heating of the massif follows late massive E-W shortening, refolding and retrograde shearing of all previous fabrics coevally with regionally important intrusions of Permian granitoids. We argue that metamorphic evolution of the Rehamna massif occurred several hundred kilometres from the convergent plate boundaries in the interior of continental Gondwanan plate. The tectonometamorphic history of the Rehamna massif is put into Palaeozoic plate tectonic perspective and Late Carboniferous reactivation of (Devonian)-Early Carboniferous basins formed during stretching of the north Gondwana margin and formation of the Palaeotethys Ocean. The inherited heat budget of these magma-rich basins plays a role in the preferential location of this intracontinental orogen. It is shown that rapid transition from lithospheric stretching to compression is characterized by specific HT type of Barrovian metamorphism, which markedly differs from similar Barrovian sequences along Palaeozoic plate boundaries reported from Variscan Europe. This article is protected by copyright. All rights reserved.

The Tinjar-West Baram Line is a NW-trending trans-lithospheric fault in northern Kalimantan; its northwestern extension into the South China Sea (SCS) is the West Baram Line. In this paper, we propose that the geodynamic processes of the proto-South China Sea (PSCS) played a key role in the formation and evolution of the Tinjar-West Baram Line, based on previous studies of the strata, crustal thicknesses, gravity anomalies and other characteristics of the blocks adjacent to the Tinjar-West Baram Line and the palaeomagnetic-based plate reconstructions of the PSCS. The Tinjar-West Baram Line has a close link to the subduction of the PSCS. Structural restoration reveals that (1) before 35 Ma, the Tinjar-West Baram Line was a NE-trending transform fault, which is consistent with the NE-trending strike-slip faults widely distributed in the East Asian Continental Margin, in the PSCS. (2) From the perspective of tectonic evolution, the extinction of the PSCS and the spreading of the SCS drove the Luconia Block in the northern SCS to accrete to the western side of the Tinjar-West Baram Line. This process resulted in a contrast of crustal rocks adjacent to the Tinjar-West Baram Line; to the east of this line, the Nansha Trough is oceanic crust, whereas to the west of this line the Luconia Block has an affinity with continental crust. The velocity and thickness of the crust show great differences on either side of the Tinjar-West Baram Line. (3) The kinematic analysis of the Tinjar-West Baram Line reveals that the collisional orogeny between the Luconia and Kalimantan blocks happened at 45–37 Ma on the west of the Tinjar-West Baram Line; on its eastern side, the Nansha Trough was subducting south towards Kalimantan Island. During the interval 35–10 Ma, the kinematics of the Tinjar-West Baram Line shows a feature of dextral strike-slip faulting. (4) The earlier published palaeomagnetic data show that the Kalimantan Block experienced a counterclockwise rotation of about 50° during the period from 25 to 10 Ma. In addition, the exert counterclockwise rotation of about 20° of the Tinjar-West Baram Line happened due to the resistance of the Luconia Block. Therefore, the Tinjar-West Baram Line changed from an early NE-trending to late NW-trending structure which results in its present day tectonic framework. Thus, we suggest that the Tinjar-West Baram Line was originally a NE-trending transform fault of the PSCS extending to the continental crust. Subsequently, the Tinjar-West Baram Line became the western border of the PSCS, accompanying the collisional orogeny between the Luconia and Kalimantan blocks. Copyright © 2016 John Wiley & Sons, Ltd.

The aims of this study were to synthesize data on the orogeny of the Tibetan Plateau (TP), with a focus on its elevation since the collision of the Eurasian and Indian plates, and to review the arguments in 100 phylogeny-cum-biogeography papers that have linked young inferred divergence times to recent TP uplift phases. I surveyed the literature on the geological history of the TP, focusing on different types of data used to infer its past height. I also tabulated the supposed TP history (and supporting references) in papers since 1998. Since the early 1990s, evidence from tectonics, isotopes, fossils and climate simulations increasingly indicates that the TP has been 4–5 km high since the mid-Eocene. The data also indicate that the Indian summer monsoon, South-east Asian summer monsoon, and Central Asian winter monsoon arose at different times and are unrelated to Tibetan uplift. A growing number of studies by biologists, however, are linking node ages between 0.5 and 15 Ma to specific (author-dependent) uplift phases of the TP citing geological papers that are outdated or miscited. Biogeography of the TP thus currently appears to be in a self-created bubble that encloses hundreds of authors and referees. Our understanding of the biogeography of Tibet requires up-to-date interpretation of its geological history and more fieldwork on local ecological habitat diversity, the plateau's history during the Pleistocene and the distribution of possible refugia.

The Ross orogen of Antarctica is an extensive (>3000 km-long) belt of deformed and metamorphosed sedimentary rocks and granitoid batholiths, which formed during convergence and subduction of palaeo-Pacific lithosphere beneath East Gondwana in the Neoproterozoic–early Palaeozoic. Despite its prominent role in Gondwanan convergent tectonics, and a well-established magmatic record, relatively little is known about the metamorphic rocks in the Ross orogen. A combination of garnet Lu–Hf and monazite U–Pb (measured by laser-ablation split-stream ICP-MS) geochronology reveals a protracted metamorphic history of metapelites and garnet amphibolites from a major segment of the orogen. Additionally, direct dating of a common rock-forming mineral (garnet) and accessory mineral (monazite) allows us to test assumptions that are commonly used when linking accessory mineral geochronology to rock-forming mineral reactions. Petrography, mineral zoning, thermobarometry and pseudosection modelling reveal a Barrovian-style prograde path, reaching temperatures of ~610–680 °C. Despite near-complete diffusional resetting of garnet major element zoning, the garnet retains strong rare earth element zoning and preserves Lu–Hf dates that range from c. 616–572 Ma. Conversely, monazite in the rocks was extensively recrystallized, with concordant dates that span from c. 610–500 Ma, and retain only vestigial cores. Monazite cores yield dates that overlap with the garnet Lu–Hf dates and typically have low-Y and heavy rare earth element (HREE) concentrations, corroborating interpretations of low-Y and low-HREE monazite domains as records of synchronous garnet growth. However, ratios of REE concentrations in garnet and monazite do not consistently match previously reported partition coefficients for the REE between these two minerals. High-Y monazite inclusions within pristine, crack-free garnet yield U–Pb dates significantly younger than the Lu–Hf dates for the same samples, indicating recrystallization of monazite within garnet. The recrystallization of high-Y and high-HREE monazite domains over >50 Ma likely records either punctuated thermal pulses or prolonged residence at relatively high temperatures (up to ~610–680 °C) driving monazite recrystallization. One c. 616 Ma garnet Lu–Hf date and several c. 610–600 Ma monazite U–Pb dates are tentatively interpreted as records of the onset of tectonism metamorphism in the Ross orogeny, with a more robust constraint from the other Lu–Hf dates (c. 588–572 Ma) and numerous c. 590–570 Ma monazite U–Pb dates. The data are consistent with a tectonic model that involves shortening and thickening prior to widespread magmatism in the vicinity of the study area. The early tectonic history of the Ross orogen, recorded in metamorphic rocks, was broadly synchronous with Gondwana-wide collisional Pan-African orogenies.

Foliation inflexion/intersection axes (FIAs) preserved within porphyroblasts that grew throughout Isan orogenesis reveal significant anticlockwise changes in the direction of bulk horizontal shortening between 1670 and 1500 Ma from NE–SW, N–S, E–W to NW–SE. This implies an anticlockwise shift in relative plate motion with time during the Isan orogeny. Dating monazite grains amongst the axial planar foliations defining three of the four FIAs enabled an age for the periods of relative plate motion that produced these structures to be determined. Averaging the ages from monazite grains defining each FIA set revealed 1649±12 Ma for NE–SW shortening, 1645±7 Ma for N–S shortening, and 1591±10 Ma for that directed E-W. Inclusion trail asymmetries indicate shear senses of top to the SW for NW–SE FIAs and dominantly top to the N for E–W FIAs, reflecting thrusting towards the SW and N. No evidence for tectonism related to early NE–SW bulk horizontal shortening has previously been detected in the Mount Isa Inlier. Amalgamation of the Broken Hill and possibly the Gawler provinces with the Mount Isa province may have taken place during these periods of NE–SW and N–S-directed thrusting as the ages of tectonism are similar. Overlapping dates, tectonic, metamorphic, and metallogenic similarities between eastern Australia (Mount Isa and Broken Hill terranes) and the southwest part of Laurentia imply a most probable connection between both continental masses. Putting Australia in such position with respect to North America during the Late-Paleo-to-Mesoproterozoic time is consistent with the AUSWUS model of the Rodinia supercontinent.