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Oblique-slip along transform fault boundaries is often partitioned between a strike-slip system and thrust faults that accommodate contraction. However, topography along the Yakutat-North American transform (Fairweather fault), is asymmetric with low-terrain above active thrusts on the western, Yakutat side of the transform and high topography on the continental side with peaks >4500 m (Mount Fairweather: 4671 m) to the west of the Border Ranges fault, limited recorded earthquakes >M4, and no apparent reverse faults to generate the highest terrain. In this study we compile, for the first time, published U-Pb zircon, 40Ar/39Ar and K-Ar (hornblende, muscovite, and biotite) and U-Th/He and fission-track (zircon and apatite) bedrock ages (109) from 75 samples to investigate the exhumation history of the Fairweather Range region, complemented by a published detrital sample (ZFT and AFT) and 13 new 40Ar/39Ar (hornblende, biotite, and K-feldspar) ages on 9 bedrock samples from both sides of the Fairweather fault. Additionally, we examined published seismicity and geodetic data of the Fairweather region and assessed if plate paleo-vectors correlate with the cooling history of the Fairweather Range. Cooling age, seismic, and block-motion patterns indicate the Fairweather Range has been vertically extruded between the Fairweather and the Border Ranges faults as a coherent block since ca. 25 Ma. The pre-6 Ma Pacific plate motion (N30°W) aligns with the N33°W strike of the Fairweather Fault whereas a hypothetical pre-6 Ma Yakutat microplate paleo-vector of (N39°W) does not: indicating a post-6 Ma timing for Yakutat microplate counter-clockwise rotation (9°). We infer that rotation and impingement of the Yakutat microplate along the Fairweather fault at ca. 3 Ma led to the development of the Fairweather restraining bend and increased cooling rates. The resultant thickened Fairweather welt and the ∼30 km thick southeast end of the Yakutat microplate compounded double-indenter tectonics into Alaska's southeast convergent corner • The Fairweather Transform has been active since at least ca. 30 Ma. • The Fairweather transform has experienced ∼1300 kms of horizontal slip at a minimum. • The Fairweather Range block has been undergoing vertical extrusion since ca. 25 Ma. • Double-indenter tectonics likely led to a ca. 3 Ma Yakutat microplate rotation. • The Fairweather fault restraining bend may have formed at ca. 3 Ma. [ABSTRACT FROM AUTHOR]

We deployed a linear seismic array consisting of 50 broadband stations in the southern part of the Great Xing'an orogenic belt to investigate seismic anisotropy in the Songliao Basin, the orogenic belt and the Erlian Basin by making SKS wave splitting measurements. Different features of anisotropy are revealed on the two sides of the north-south gravity lineament. The anisotropy on the east side of the gravity lineament primarily results from mantle flows in the big mantle wedge above the flat Pacific slab in the mantle transition zone, and the SKS fast polarization direction is generally NW-SE, being consistent with the subduction direction of the western Pacific plate. On the west side of the gravity lineament, the SKS splitting is attributed to freezing anisotropy in the stable lithosphere under the Erlian Basin. The SKS splitting delay times show some changes with azimuths of the teleseismic events, but the fast polarization directions are generally the same, indicating that the anisotropies below these seismic stations have the same origin in the continental lithosphere and active flows in the big mantle wedge. • Different features of anisotropy are revealed on two sides of the north-south gravity lineament. • The main cause of anisotropy in the southern Songliao Basin is flows in the big mantle wedge. • SKS splitting in the Erlian basin area originates from freezing anisotropy in the stable lower lithosphere. [ABSTRACT FROM AUTHOR]

The Munsiari and Vaikrita thrusts are crucial to understanding the geodynamic evolution of the Himalayas. However, the structural architecture and kinematic evolution of these thrusts and associated deformation zones are still poorly understood. Furthermore, the existing criteria for field identification of the Vaikrita Thrust are varied and ambiguous. We address these issues through extensive large-scale mapping and structural analysis across the Alaknanda, Dhauliganga, and Bhagirathi valleys in the Garhwal Himalayas. Our results demonstrate that the Munsiari and Vaikrita thrust zones are the tectonic mosaics of high-strain cores and low- to moderate-strain damage zones. The large-scale mapping also brings out the tectonic interleaving of different group rocks in both thrust zones. New structural observations point to a shared history of progressive ductile shearing during which successive folds and mylonite foliation were developed and transposed in both thrust zones. The Munsiari Thrust consistently appears as a distinct litho-tectonic boundary across the valley sections. In contrast, the Vaikrita Thrust presents varied surface expressions. While manifesting as a ductile shear zone in the Bhagirathi Valley, it is exposed as a brittle-fault zone in the Dhauliganga Valley. The Vaikrita Thrust lacks distinct surface expression in the Alaknanda Valley. In such regions, it is routinely marked by the 'kyanite-in isograd´ criterion, i.e., the first appearance of Barrovian kyanite in the Greater Himalayan Sequence. Our discovery of Barrovian kyanite occurrences in the Lesser Himalayan rocks challenges the tenability of the 'kyanite-in isograd´ criterion for delineating the Vaikrita Thrust. Instead, we propose that identifying a high-strain anomaly within the strain profile from the footwall to the hanging wall represents the most reliable criterion for mapping the Vaikrita Thrust in such terrains. The shear zone framework approach is potentially useful for unraveling the geometry and kinematic evolution of an orogen. • First study of the Munsiari and Vaikrita thrust zones in a shear zone framework. • Delineates the cores and damage zones in the two thrust zones. • Vulnerability of the 'kyanite-in isograd´ criterion for identifying the Vaikrita Thrust. • Identification of the Vaikrita Thrust on the basis of high-strain anomaly. • Schematic representation of the structural anatomy of the two thrust zones. [ABSTRACT FROM AUTHOR]

The Cenozoic Qaidam Basin on the northern Tibetan Plateau is bounded by the foreland thrust belts of the East Kunlun Mountains to the south and Qilian Mountains to the north. In this basin, the maximum thickness of the accumulated sedimentary strata is ∼17 km near the geographic center of the basin. Such a basin architecture challenges the classic foreland-basin deformation model, wherein substantial sediments should be localized near the basin margins owing to thrust loads on a bending plate. Based on the available geological and geophysical constraints, we built a two-dimensional viscoelastoplastic finite element model to investigate whether the unique pattern of the Qaidam Basin was mechanically related to the rheological structure of the crust and frictional strength of the basin-bounding thrust fault. By testing reasonable bounds on the viscosity of the ductile crust and effective frictional coefficient of the thrust faults, we modeled a basin framework that fits well with that of Qaidam Basin. The model parameters include a layered rheological structure, with the viscosity of the ductile crust of the basin being two orders of magnitude greater than that of the adjacent mountain belts and an effective frictional coefficient of >0.2. Furthermore, the initial width of the basin significantly affected its deformation style. Therefore, the layered rheological structure of the crust and frictional strength of the basin-bounding thrust faults played important roles in the formation of the Qaidam Basin. Our findings suggest that the inelastic behavior of the crust affects foreland deformation, highlighting that the classic foreland basin model must be revised for some tectonic settings. • A new mechanical model is proposed to explain the Qaidam Basin. • Crustal rheology and fault strength strongly influence the basin architecture. • Pre-Cenozoic tectonics is a main factor in forming the Qaidam Basin. [ABSTRACT FROM AUTHOR]

This paper sheds light on the structural architecture and tectonic evolution of the Campania-Lucania segment of the Southern Apennines orogen through an integrated analysis of mostly unpublished and partly published (CROP-04 line) seismic reflection profiles, exploratory well logs and geologic-structural relations among the lithostratigraphic units of this region. The pre-orogenic Mesozoic-Neogene carbonate platform, margin-slope and basinal units that compose the upper orogenic level (Apennines fold and thrust belt) were detached from their basement during Miocene thrusting and form a heterogenous multilayer that was thrust above the Apulian foreland platform. The Apulian Platform itself was involved in Pliocene thick-skinned thrusting that controlled the style and localization of Quaternary transtension and extension. The velocity data from sonic logs, the well stratigraphy, and the seismic reflection facies were integrated through an accurate well-to-seismic tie, allowing the building of a specific velocity model for the time-to-depth conversion. We identified different seismic units with distinctive reflections attributes, which were assigned to the lithostratigraphic units logged in the wells. Our analysis documents the stratigraphic-structural arrangement of the thin-skinned thrusts sheets (Liguride Basin, Apennine Platform and Lagonegro-Molise Basin units) that form the Apennines fold and thrust belt. These units show strong lateral thickness changes because of both the original depositional environments and the non-coaxial deformation stages. In contrast, the underlying Apulian Platform is characterized by a regional anticlinorium (∼30–50 km wavelength) that, based on our new reconstruction, extends further west than hitherto known. The anticlinorium exhibits shorter-wavelength (<10 km) anticlines limited by N- to NE-verging thrust ramps, whose high dip (∼45°) suggests they root in the crystalline basement. Our work provides a sound link between surface and subsurface structural setting and an improvement of the geometry of the Apulian Platform, with important implications for structural and seismotectonic models of the region. • Seismic reflection profiles unravel the deep structure of the Southern Apennines. • Integrated use of seismic profiles, well data and geological maps. • Evolution from thin- to thick-skinned shortening. • Orogenic structure controlled by Meso-Cenozoic mechanical stratigraphy. [ABSTRACT FROM AUTHOR]

Interpretation of 2014–2015 deep crustal seismic reflection and magnetotelluric data has revised the architecture and geodynamic framework of western Queensland, with implications for the assembly and dispersal of the supercontinents Nuna, Rodinia and Gondwana. In the Mount Isa Province, crustal-scale boundaries of the Leichhardt River Domain, Kalkadoon-Leichhardt Domain and Eastern Subprovince are mapped in the third dimension. The Leichhardt River and Kalkadoon-Leichhardt domains have similar Nd isotopic T 2DM model ages to provinces to the west, indicating they were part of ancestral North Australian Craton (NAC); the Eastern Subprovince is a separate terrane, with the Pilgrim Fault a collisional suture. The Gidyea Suture Zone separates the Mount Isa Province from the subsurface Numil Seismic Province. To the east, the west-dipping Yappar Fault separates east-dipping structures in the west from west-dipping structures in the east, forming a classic doubly vergent orogen within the upper plate of a convergent margin. The northwestern boundary of the Bernfels Seismic Province, the Kynuna Fault, truncates the Gidyea Suture Zone, implying this seismic province was welded to the NAC prior to initial deposition of the Etheridge Province. The Cork Fault truncates the north-south grain of the Mount Isa Province; the easternmost part of the NAC has been excised, presumably during breakup of Nuna. The subsurface Brighton Downs Seismic Province, formerly part of the northern Thomson Orogen, is a discrete seismic province, located between the NAC and the Thomson Orogen, and welded to the NAC during the accretion of Rodinia. Basement to the Thomson Orogen is a collage of microplates, accreted to the Brighton Downs Seismic Province during the assembly of Gondwana. By 530 Ma, eastern Australia faced an open Pacific Ocean, with the Thomson Orogen in a backarc setting. Thus, northeastern Australia contains a record of repeated continental accretion and breakup over at least three supercontinent cycles. • Interpretation of 2014–2015 deep crustal seismic reflection data in western Queensland. • Two new discrete seismic provinces discovered in the subsurface. • At least four Paleoproterozoic terranes recognised in easternmost North Australian Craton. • Part of North Australian Craton excised at Cork Fault during breakup of Nuna. • Northeast Australia records continental assembly and breakup over three supercontinent cycles. [ABSTRACT FROM AUTHOR]

The southeastern Brazilian onshore-offshore margin and underlying lithosphere are investigated by three-dimensional magnetotelluric imaging using 202 high-quality broadband and long-period amphibious MT-dataset, orthogonally traversing the regional surface deformation hills of Serra da Mantiqueira and Serra do Mar, as well as the coast-parallel onshore-offshore lineaments. Three-dimensional conductivity model reveals an electrically heterogeneous crust (up to 40 km) in the onshore Brasília and Ribeira Orogenic Belts, and ∼ 2–10 km thick-conductive-sedimentary-wedge beneath the offshore Santos Basin laying on top of a stretched and thinner resistive crust. Regionally, the lithosphere is found ∼130 km thick beneath the most northwestern part of the Brasília Orogenic Belt which is thinning out towards the deep-water Santos Basin (∼70 km). This thinning coincides with the lithosphere-asthenosphere boundary in recent seismic tomography results, reflecting the current state of the uplifted asthenosphere post-West Gondwana break-up. A major steeply dipping sub-lithospheric conductor, in conjunction with a confined asthenosphere upwelling (or lithospheric thinning), has been observed underneath Embu-Paraíba do Sul domain (Ribeira belt), which may be somehow associated with the continental scale rifting, surface uplift and the Cretaceous São Paulo-Rio de Janeiro dykes swarm. Our findings provide valuable insights into the formation of southeast Brazilian highlands and its association with mantle plume-induced lithospheric delamination (or removal) and the occurrence of alkaline magmatism, after reactivation of some pre-existing weak zones. • The crust is thick and electrically heterogeneous in the Brasília and Ribeira belts and becomes relatively thin and uniform in the offshore margin. • The opening of the South Atlantic Ocean raised the lithosphere towards the offshore Santos basin. • Mantle-plume-driven lithospheric delamination has been observed underneath the highlands of southeastern Brazil. [ABSTRACT FROM AUTHOR]

The collision of the North China and Yangtze blocks, along with multiple orogenic movements, has caused complex tectonic deformation of the lithosphere in Hubei Province. In order to reveal the stress distribution features and tectonic deformation mechanisms of the regional lithosphere, we inverted an azimuthal anisotropic structural model of the Hubei lithosphere from anisotropic Rayleigh wave tomography with data obtained from 48 broadband seismometers deployed in and around the province. Our model revealed strong lateral variations of azimuthal anisotropy in the crust and upper mantle, providing new seismological evidence for the lithospheric modification of the Yangtze block and the layered deformation of the lithosphere east of the North-South Gravity Lineament. We speculate that the primary dynamic factor causing lithospheric modification in the Yangtze block is related to the rifting events associated with the super-mantle plume, triggered by the deep subduction of the Pacific and Philippine plates. Meanwhile, the rifting event is also the main cause of the lithospheric structural layered deformation east of the North-South Gravity Lineament. The inverted anisotropic model, together with the results of previous geodetic and seismologic studies, revealed the causes and tectonic deformation mechanisms of anisotropy generation in the crust and upper mantle in Hubei Province. Crustal deformation in the Hubei region may be related to the eastward expansion of materials from the Tibetan Plateau and the ultra-high pressure metamorphic zone formed by the subduction and collision of the Yangtze and North China blocks, while upper mantle deformation is associated with subduction and collision of Yangtze and North China blocks, preserved fossil anisotropy from previous orogenic movements, and rifting events tied to the super-mantle plume induced by the deep subduction of the Pacific and Philippine plates. Moreover, we analyzed the regional crust-mantle coupling mechanism and concluded that the crust-mantle in the Dabie orogenic belt is coupled, whereas it is decoupled in other regions. • An azimuthal anisotropic model is built for the crust and upper mantle of Hubei Province. • Anisotropic model provides new seismic evidence for lithospheric modification of the YZB. • We observed the layered deformation of the lithosphere east of the NSGL. • Anisotropic causes and tectonic deformation mechanisms of the Hubei lithosphere are revealed. [ABSTRACT FROM AUTHOR]

Inherited zircons from Early Cretaceous dykes across the Jiaodong Peninsula provide a means of exploring magmatic episodes. Negative Eu anomalies, high Th and U contents, and high U/Yb ratios confirmed a zircon source of ancient continental crust. Differences in mineralogy, chronology, geochemistry, and Hf isotopes showed that these inherited zircons were not brought in by the Triassic Yangtze Craton collision. Zircons within 2938–2800 Ma confirmed that the ancient crust in the Jiaobei Terrane originated from the Mesoarchean crustal growth. This crustal growth continued until the Early Paleoproterozoic and was accompanied by crustal transformation activities in the later period. After the collision of the Jiao–Liao–Ji Belt, the Jiaodong Peninsula entered a typical craton period until it was reactivated at the end of the Neoproterozoic, which was characterised by the Archean crustal transformation. During the Palaeozoic, smooth crustal thickness change with limited addition of oceanic crust material indicated the Qinling–Dabie–Sulu Orogenic Belt as a distal island arc system that slowed the impact of Paleo-Tethys subduction. There was no record of positive-ε Hf (t) zircons in the Jiaodong Peninsula during the Mesozoic, but the crust thickened rapidly. This confirmed that the Paleo-Pacific Plate may have directly subducted beneath the lithospheric mantle and had little contact with the lower crust. This subduction pattern released little hydrous fluid but much heat, which prompted the remodelling of the lower crust in the Mesozoic. Furthermore, the large-scale lithospheric thinning event around 120 Ma was identified as a result of the delamination of the lithospheric mantle together with lower crust. [Display omitted] • Ancient zircon records confirmed the Mesoarchean juvenile crust in the Jiaodong. • Differences of zircons indicate a Neoproterozoic crust reactivation of Jiaodong. • Negative ε Hf (t) values confirmed few additions of subduction material to the Mesozoic crust. [ABSTRACT FROM AUTHOR]

Widespread fold and thrust belt and magmatism that occurred in the Mesozoic South China Block (SCB) have generated much debate on their dynamic mechanism related to the western Pacific Plate. Unlike a delayed Andean orogen, the SCB contains large areas of magmatic rocks coinciding with the absence of Upper Jurassic strata, which is not consistent with a flat-slab subduction geometry, and no consensus model has been suggested. To obtain more general insight into the effects of paleo-Pacific Plate subduction on the SCB, thermal-fluid-solid simulations of the subduction process are conducted. The models involved varied subduction rates and lithospheric viscosities to investigate their effect on the subduction style, mantle flow and overriding plate deformation. Low-rate subduction easily forms a subduction geometry with a higher angle, while high-rate subduction causes the slab to break off and drip downward. Fast subduction produces a quasi-horizontal mantle flow and a poloidal flow at the front of the mantle wedge, whereas slow subduction produces two poloidal flows developed on both sides of the subducting slab. The strain tensor of the overriding plate coincides well with the gradient of the horizontal mantle flow rate. A high subduction rate and low lithospheric viscosity promote the deformation of the overriding plate and are further attributed to mantle flow. Combining these results with global plate reconstructions, we find that accelerated subduction of the paleo-Pacific Plate resulted in the Late Jurassic uplift of the SCB. The low viscosity of the overriding plate caused by multiphase orogenic deformation promoted the thinning of the lithosphere due to induced mantle flow, which was associated with the intrusion of magmas and foundering of the subducted slab in a compressional regime. At the end of the Late Jurassic, subduction-induced mantle flow transformed from westward to eastward. Concurrently, the subducted slab began to steepen, and widespread Cretaceous magmatism occurred. • Fast subduction gives rise to a quasi-horizontal mantle flow and slab dripping style. • Fast subduction and low lithospheric viscosity promote a fast mantle flow. • Accelerated subduction rates of the paleo-Pacific Plate promoted the Late Jurassic uplift of the SCB. [ABSTRACT FROM AUTHOR]

The study of crustal structure plays a crucial role in understanding the tectonic development and seismicity of orogens. In this contribution, we analyzed the gravitational responses caused by the subsurface structure of the Tian Shan orogen using global EIGEN-6C4 gravity field data. The quality of the EIGEN-6C4 gravity data in the eastern Tian Shan area was evaluated, and we employed the wavelet multi-scale analysis method in combination with an existing P-wave velocity model to reveal the structures at different scales. The gravity Moho of the study area that best fits the seismological Moho was obtained from the filtered third-order wavelet approach component after several tests using different reference depths and density contrasts. The results reveal significant lateral discontinuities in the lower crust and upper mantle structures across the eastern and western Tian Shan orogens. The Moho beneath the western Tian Shan is about 9 km deeper compared to the eastern Tian Shan. Towards the Tarim and Junggar basins, the Moho decreases to about 45 km in depth. The analysis of the isostatic anomaly suggests that the eastern and western Tian Shan possess varying capabilities for isostatic adjustment. Furthermore, it indicates a gradual weakening of mantle upwelling in the Tian Shan orogen from west to east, implying that different stages of mantle dynamics may have occurred in the western and eastern Tian Shan. The north Tarim fault, Nikolaev-North Nalati fault, and Kazakh fault serve as channels that control magma upwelling in the Tian Shan orogen. The distribution of earthquakes differs between the eastern and western Tian Shan, with the western Tian Shan exhibiting greater gravitational potential energy. These variations between the eastern and western Tian Shan may be attributed to the clockwise rotation of the Tarim craton. • Decomposing gravity anomaly of the Tian Shan region using wavelet multi-scale method. • Gravity inversion constrained by seismic data providing an optimal Moho depth. • The Tian Shan orogen experienced different stages of mantle dynamic revealed by gravity and Vp anomalies. [ABSTRACT FROM AUTHOR]

The Dinggye region, in the central part of the Himalayan orogenic belt, includes the southern part of the Xainza-Dinggye rift and the Mabja Gneiss Dome with leucogranite cores. Previous studies of gneiss domes in this region report the existence of channel flow processes or tectonic exhumation, in addition to partial melting of orogenic mid-crust. However, the relationship between the crustal migration of materials and the north-south-trending normal rifts remains largely unexplored. In this work, we generate a new 3-D electrical resistivity model from an array of magnetotelluric data in the Dinggye region and examine it in addition to other electrical resistivity models to the north and east from previous works. By comparing the geophysical models with available geological and geochemical evidence, we find a clear relationship between the electrical resistivity structure, the presence of gneiss domes, north-south-trending normal rifting, and deep plunging subduction which is related to the source of Helium isotopes (crustal or mantle origin). Overall, the results suggest that the southern migration of lithospheric materials likely contributed to the evolution of the rifts in the Tethys-Himalaya terrane, which also may have been influenced by uplifting and cooling of gneiss domes. The models are consistent with tearing of the Indian lithosphere beneath the Xainza-Dinggye rift and other adjacent rifts. Additionally, the difference in the electrical structure related to the Indian crust along the east-west direction likely results from the exhumation of the continental slab, metamorphism in the Tethys-Himalaya terrane, and southern extrusion of materials in the Lhasa terrane. [Display omitted] • A conductive layer is interrupted by the Mabja Gneiss Dome, below which is resistive. • Clear relation between electrical resistivity, presence of rifts, and gneiss domes. • Viscous flow in crustal channels influenced the evolution of rifts in the region. • Crustal conductivity variations observed along strike of the subducting Indian plate. • Electrical structure consistent with proposed locations of tearing of Indian Plate. [ABSTRACT FROM AUTHOR]

The debated mechanism and timing of formation of the Pamir orogenic salient provides an ideal case to combine paleomagnetic and metamorphic analyses. Opposing views argue for either oroclinal bending of the Pamir since the India-Asia collision or for an originally arcuate shape, which can be tested using paleomagnetism to estimate vertical-axis rotations. Furthermore, Pamir deformation can be dated and characterized by the analysis of a well-expressed regional metamorphism. However, paleomagnetism is seldom applied to metamorphic rocks such that the significance of their rock magnetic signal with respect to deformation remains poorly understood. We studied a > 2 km thick sequence of slightly metamorphosed Cretaceous-Paleogene volcanic and volcaniclastic rocks from the western Central Pamir Mountains using metamorphic petrology, geochronology, and paleomagnetic analyses. These rocks present a medium-grade metamorphism and have undergone fine grained recrystallisation of biotite due to NW-SE compression. 40Ar/39Ar and Rb/Sr ages (∼17 to 15 Ma) on whole rock and biotite, confirm that the greenschist facies metamorphism is related to the coeval exhumation of Pamir gneiss domes during the Middle Miocene. The rocks generally show homogenous magnetic properties. High field magnetic properties and SEM/EDS data show that the main magnetic remanent carrier is titano-hematite. Thermal demagnetizations yield complex characteristic remanent magnetization with site-mean directions obtained for only 14 of the 44 studied sites but scattered mainly within the foliation plane defined by the anisotropy of magnetic susceptibility (AMS). These rocks have also unusual magnetic characteristics where strong-field isothermal remanent magnetizations induce an AMS fabric, likely related to the specific composition and structure of the metamorphic titano-hematite but independent of the original anisotropy fabrics. Combined paleomagnetic and geochronological data from the Bartang volcaniclastics rocks enable us to identify a ∼ 17–15 Ma compressive deformation event contemporaneous with the emplacement of the gneiss domes and suggest no oroclinal bending since that event. • The Bartang volcanic rocks underwent greenschist facies metamorphism at 17–15 Ma. • Ti-poor titano-hematite is the main magnetic carrier in the rocks. • The metamorphic event occurred under local NW-SE compressive deformation. • No oroclinal bending is recorded in the Pamir orogen since 17 Ma. [ABSTRACT FROM AUTHOR]

Constraining the tectono-geomorphological evolution of the Pyrenees is still a major challenge, especially in the Eastern Pyrenees where late Neogene exhumation history and topographic evolution appear contrasted and have been debated. In this study, we performed thermo-kinematic (Pecube) modeling using a relatively dense spatial compilation of previously-published low-temperature thermochronological data for the Eastern Pyrenees, and quantified the late-Neogene exhumation history based on different topographic evolution models reconstructed from literature constraints. Our modeling outcomes suggest a major decrease in the regional exhumation rate between 37 and 35 Ma, associated to an early-end contractional tectonics for the Eastern Pyrenees. Two main periods of the Têt fault normal activity have been characterized, with the existence of pluri-kilometric (2–3 km) post- Oligocene-Miocene displacement along the western segment of the Têt fault. The different topographic evolution models show relatively similar results for the regional exhumation since ca. 35 Ma and for the most recent (mid to late-Miocene) tectonic event recorded along the Têt fault. Conversely, inversion results obtained for pre-35 Ma regional exhumation rates, and more importantly for the Oligocene-Miocene activity of the Têt fault appear contrasted between the investigated topographic scenarios. Overall, this study confirmed a mid to late Miocene significant extensional tectonic event for the Eastern Pyrenees, which may have had a non-negligible role in late-stage relief evolution for this part of the orogen. However, deciphering the long-term evolution of topographic relief through thermo-kinematic modeling appears still challenging for slowly-exhuming mountain ranges given the limited resolution of low-temperature thermochronological data to topographic changes. • Major mid to late Miocene normal faulting in the Eastern part of the Pyrenees. • Cenozoic tectono-geomorphological evolution of the eastern Pyrenees. • Exhumation/fault slip thermo-kinematic inversion using topographic evolution models. • Comparison of inversion approaches for low-temperature thermochronology data. [ABSTRACT FROM AUTHOR]

The Mesozoic-Cenozoic exhumation and deformation of the northeastern Qinghai–Tibetan Plateau generated extensive regional rugged mountains. We aimed to explore the prolonged kinematic evolutionary history since the Mesozoic. We collected Mesozoic magmatic rock samples from the Chaqiabeishan-Shaliuquan lithium‑beryllium ore district in the Northern Qaidam tectonic belt (NQTB) to constrain the cooling exhumation history using apatite fission track (AFT) thermochronology. Twenty samples yielded AFT ages from 111 to 11 Ma, including four age groups:111–103, 89–75, 71–47, and 30–11 Ma, with mean track lengths of 12.5–11.2 μm. Four thermal history phases of 120–90, 90–50, 50–20, and 20–0 Ma were established based on the inverse thermal model and isostatic adjustment of the lithosphere. Additionally, the average cooling rates of the four phases were 1.67 ± 0.17, 1.25 ± 0.13, 0.33, and 1.75 ± 0.5 °C/Myr, with a corresponding exhumation amount of 1.15 ± 0.07 km, 0.98 ± 0.06 km, 0.86 ± 0.05 km, and 1.09 ± 0.06 km respectively, and the maximum exhumation was 6.021–6.787 km since 120 Ma. In the first phase, the far-field effects of Mid-Tethys Ocean subduction and closure drove the rapid exhumation of the research area. The closure of the Neo-Tethys Oceans and the continuing collision of the India-Asia plate disturbed the northeastern plateau, inducing regional backlash fault events in the NQTB, demonstrated in the second phase of thermal history. The third phase of the stable tectonic setting is consistent with previous research results, suggesting a similar cooling history for the NQTB and Qilian Mountains, evidenced by the widespread absence of Eocene to Miocene cooling signals. The rapid exhumation and reactivation of the NQTB and Qilian thrust fault system since 20 Ma represents the final stage of growth and expansion of the northeastern Qinghai–Tibet Plateau. The multi-phased tectonic events and cooling uplift history of the North Qaidam Tectonic Belt (NQTB) since the Late Mesozoic are revealed by apatite fission track data from the Chaqiabeishan-Shaliuquan Li Be ore district. In addition, thermochronological ages of multi-stage tectono-thermal events are recorded extensively on the northeastern Qinghai-Tibet Plateau. The regionally extensive Early Cretaceous thermochronological signal of the NQTB and the Qilian Mountains are recorded later than the Eastern Kunlun Orogenic Belt, which implies progressive propagation of tectonic stress from plateau collision frontier to the northeastern margin in the Early Cretaceous. The Cenozoic India-Asia plate convergent collisional transmitted stresses produced significant regional tectonic deformation in northeastern Tibet, and the extensive Cenozoic thermochronological signal in northern Tibet emphasizes the similar cooling history of the NQTB and Qilian Mountains. The cooling break and weak age record from the Middle Eocene to Oligocene probably suggest the tectonic reorganization of the northeastern plateau to accommodate out-of-sequence tectonic deformation and crustal shortening. [Display omitted] • Research yielded four stage-pulse exhumation happened during Cretaceous. • Quantitatively recovered the cooling and exhumation history. • The northeastern Plateau experienced sustained deformation since the Late Cretaceous. • Rapid cooling event in the Miocene record final activity of the Chaqiabeishan fault. [ABSTRACT FROM AUTHOR]

The Lianhuashan fault zone (LHSFZ), which divides the Cathaysia Block (CB) into the coastal volcanic and Cathaysian fold belts, is an important intraplate lineament in the CB. Its fine structure is crucial to understand the Late Mesozoic tectonic evolution of South China. Herein, the fine S-velocity structure of the LHSFZ above 6.0 km and its depth extent were studied by ambient noise tomography and teleseismic relative travel-time residual analysis using a dense (∼1 km station spacing) seismic array spanning 123 km at the southern end of the LHSFZ. Our results indicate that the area within 70 km of the coast has a higher S-wave velocity, which extends to the southeast below 6 km. We propose that the high velocity anomaly is a result of magma intrusion caused by the subduction of the Paleo-Pacific plate in the Late Mesozoic, and the magma upwelling trajectory occurs from the coast to the inland. In addition, a low-velocity anomaly is found beneath the core area of the LHSFZ at a depth of 3–6 km, which is more evident in the S-wave than in the P-wave and corresponds well with the presence of hot springs and earthquakes. We hypothesize that the low-velocity anomaly represents the existing fault system of the Late Mesozoic volcanoes, which now provides channels for fluid migration and facilitates seismicity. Our model suggests that the LHSFZ plays a key role in the evolution of the coastal areas of South China. • We obtained the upper crust structure of the Lianhuashan Fault Zone. • Late Mesozoic magmatism in the Lianhuashan Fault Zone tilts southeast as depth rises. • Upper-crustal fluid migrations facilitate hot springs in the Lianhuashan Fault Zone. [ABSTRACT FROM AUTHOR]

Gondwana (Tauride/Kırşehir blocks) and Eurasia (Pontides) derived continental blocks delimit the Haymana basin, central Turkey, to the south and the north, respectively. The boundaries of these blocks define the Izmir-Ankara-Erzincan and Intra-Tauride Suture zones which are straddled by a number of Late Cretaceous to Oligocene marine to continental basins. The Haymana Basin is located at the junction of the IAESZ and ITSZ and comprises Upper Cretaceous to Middle Eocene basin infill deposited in response to the interaction of these blocks. The basin provides a unique opportunity to unravel spatio-temporal relationships related to the timing of late stage subduction history of Neo-Tethys Ocean and subsequent collision of the intervening continental blocks. We have conducted a multidisciplinary study in the region that includes mapping of major structures combined with fault kinematic analyses. E-W striking folds dominate the basin, cross-section balancing of these structures indicates around 25% roughly N-S shortening in the region. Paleostress studies indicate that the basin was initially subjected to N-S to NNE-SSW extension until the middle Paleocene (phase 1) and then N-S directed syn -depositional compression and coeval E-W directed extension until the middle Miocene (phase 2) implying strike-slip deformation and pure shear shortening in the basin. These different deformation phases are attributed to first fore-arc (subduction) basin development then foreland (collision) stages of the basin. Apatite (U-Th)/He dating of 5 samples indicate that exhumation of the SE segment of the basin started in early Oligocene, whereas the NW segment of the basin exhumed in the early Miocene. The differential uplift is possibly related to progressive north-westwards movement of Dereköy basin bounding fault at the north. We propose that the Haymana basin evolved from extensional forearc basin during the late Cretaceous to early Paleocene and foreland basin after the terminal subduction and subsequent collision of Tauride and Pontide blocks. • The Haymana basin evolved from extensional forearc basin to foreland basin during late Cretaceous-middle Eocene. • Oligocene – Miocene AHe uplift ages mark the continental collision of Tauride and Pontides in the Central Anatolia. • Pure shear shortening is the main factor for the development of fold and thrust belt in the Haymana Basin. [ABSTRACT FROM AUTHOR]

We present a new three-dimensional density model of the Central Andes characterizing the structure and composition of the lithosphere together with a geodynamic simulation subjected to continental intraplate shortening. The principal aim of this study is to assess the link between heterogeneities in the lithosphere and different deformation patterns and styles along the orogen-foreland system of the Central Andes. First, we performed a 3D integration of new geological and geophysical data with previous models through forward modelling of Bouguer anomalies. Subsequently, a geodynamic model was set-up and parametrized from the previously obtained 3D structure and composition. We do not find a unambigous correlation between the resulting density configuration and terrane boundaries proposed by other authors. Our models reproduce the observed Bouguer anomaly and deformation patterns in the foreland. We find that thin-skinned deformation in the Subandean fold-and thrust belt is controlled by a thick sedimentary layer and coeval underthrusting of thin crust of the foreland beneath the thick crust of the Andean Plateau. In the adjacent thick-skinned deformation province of the inverted Cretaceous extensional Santa Barbara System sedimentary strata are much thinner and crustal thickness transitions from greater values in the Andean to a more reduced thickness in the foreland. Our results show that deformation processes occur where the highest gradients of lithospheric strength are present between the orogen and the foreland, thus suggesting a spatial correlation between deformation and lithospheric strength. • Density heterogeneities correlate with different tectonic evolution and processes. • The lithosphere is weak in the orogen and strong in the foreland and forearc. • Deformation localizes in the transition between weak and strong lithosphere. [ABSTRACT FROM AUTHOR]

In contractional (subduction/collisional) settings, convergence is accommodated by the formation of thin- and thick-skinned thrust and fold belts. The transmission of such deformation over larger distances into orogenic foreland areas is influenced by the inherited rheological characteristics of continental lithosphere. Lateral rheological variations parallel to the strike of continental foreland areas creates contrasting geometries and sequences of deformation that interact during orogenic build-up. We investigate the far-field transmission of strain within a continental lithosphere characterized by a laterally variable rheology through physical analogue modelling. Rheological weak crustal zones were introduced at distance from an advancing backstop to study the progressive along strike linkage and interference of structures during contraction. The results reveal that rheologically weak crustal zones localise far-field contractional deformation. When the size of weak zones, by means of their horizontal extend to depth ratio, is large, deformation localises at the boundaries of the weak zone where they lead to the formation of large-offset faults. Subsequently the faults migrate along-strike into areas that are rheologically stronger. When the size of the weak zone is reduced, a large-scale contractional step-over forms in orogenic forelands, where rheologically contrasting domains transmit out-of-sequence deformation by a gradual migration of thrust offsets and fold amplitudes along their strike. These results show that crustal scale orogenic step-overs do not always reflect variations in the geometry of the plate boundary (indenter) or along-strike gradients in shortening rates. Such features may also form in response to variations in rheology, as the ones created by inherited extensional basins situated at large distances from plate boundaries in the orogenic foreland. • Crustal weak zone(−s) localise strain at far distance from the indenter. • Contractional step over might reveal the presence of crustal weak zone. • Crustal deformation at weak zone will be associated with lithospheric folding. • The symmetry of lithosphere fold can reveal the lithosphere strength. [ABSTRACT FROM AUTHOR]

The Atlas and Tell domains constitute a major segment of the Circum-Mediterranean Alpine fold and thrust belts in the Maghreban part of North Africa. South of the Tell, the Atlas results from a progressive Late Cretaceous to present foreland inversion of former Jurassic to Cretaceous extensional tectonic features inherited from the opening of the Tethys along the northern African margin. In contrast, the Tell is made up of allochthonous Cretaceous to Neogene basinal units detached along a tectonic sole made up of remobilized Triassic salt and tectonic mélanges. Since the last decade, the major tectonic steps accounting for the development of the eastern Maghreb structures are becoming more precisely constrained by seismic data and associated structural analyses. However their overall configuration at depth, as well as the deep architecture of the underlying basement remain poorly understood because only few wells yet penetrated deeper than the Triassic series in the Atlas and adjacent foreland basin. Therefore, this paper is intended to give an overview on the deep structural features affecting the Pan-African basement in the eastern Maghreb by means of tentative regional cross-sections. Our purpose is to stimulate exploration of deep hydrocarbon plays and give some insights to help both the industry, universities and other public research institutes to undertake jointly a major research program on the deep crustal configuration in the eastern Maghreb with particular focus on the pre-Triassic series beneath the Tellian allochthon in the north, the parautochthonous inverted Atlasic structures in the center, and in the adjacent autochthonous foreland domain extending southeastward in the offshore. • A review of the deep crustal architecture, major structures and tectonic calendar are presented in the Eastern Maghreban Domain of North Africa. • Structural regional transects are presented inferring the geometry and configuration of the basins and crust. • Discussion of the Paleozoic pre-salt oil and gas traps potential beneath the Atlas and its foreland basins. • Discussion on the importance to undertake an international deep seismic sounding program to unlock the pres-salt traps which have important potentialities. • The presented long structural transect can be considered as a starting point to record a long seismic section along the Maghreban margin. [ABSTRACT FROM AUTHOR]

An extensive early Carboniferous foreland basin (the Moravosilesian Culm Basin, MSCB) delineates the northeastern margin of the Bohemian Massif (Variscan orogenic belt). The basin overlays a complex suture between the outer Brunovistulia microplate, forming a promontory previously accreted to Laurussia, and inner Gondwana-derived units that form the remainder of the Bohemian Massif. Our structural, paleomagnetic and magnetic anisotropy data from the eastern portion of the MSCB indicate that its depositional architecture, internal fabric, and deformation by folding and faulting record a major switch from orthogonal convergence to orogen-oblique strike-slip shearing. First, the Brunovistulia microcontinent was subducted frontally towards W during ~346–335 Ma, followed by a shift of the subduction vector towards ~SSW at around 335–330 Ma. From ~330 Ma onwards, the underthrusting had ceased and the ~WNW–ESE dextral Elbe shear zone, related to the westward movement of Gondwana with respect to Laurussia, controlled deformation of this region. Displacement of the northerly Eastern Sudetes 'block' towards ~ESE produced regional ~WNW–ESE pure-shear shortening against the Brunovistulia indentor and resulted in an overall doubly-vergent structure of the MSCB. Simultaneously, the southerly Moldanubian unit was translated towards ~WNW, away from the Brunovistulian microplate, and likely contributed to an extensional regime related to orogenic collapse progressing outward from the internal domains of the Bohemian Massif. On a larger scale, we suggest that the MSCB is an illustrative example of a polykinematic foreland basin, where deposition, syn- to post-sedimentary deformation, and thus geodynamic processes changed significantly during basin evolution, starting off with microplate impingement into a continental margin reentrant and terminated by strike-slip shearing. Our data also do not support previous models for the tectonic development of the northeastern termination of the Variscan Belt, which suggested either a large-magnitude, vertical-axis oroclinal rotation of the foreland or its translation along an orogen-perpendicular strike-slip fault. • Structural, magnetic anisotropy and paleomagnetic study of a foreland basin • Late-orogenic Moravosilesian Culm Basin, northeastern Variscan belt • The deformational architecture developed in two stages • Basin records switch from frontal convergence to dextral strike-slip shearing • Shearing driven by westward movement of Gondwana with respect to Laurussia [ABSTRACT FROM AUTHOR]

The Araçuaí-Ribeira belt formed during the amalgamation of West Gondwana in the late Neoproterozoic. Its evolution included a main tectonometamorphic peak at 600–580 Ma and a minor peak associated with the final collision with the Western Congo at 540–530 Ma. This belt has the characteristics of a hot orogen, including a high thermal gradient (>30 °C/km), pervasive partial melting of the middle crust, emplacement of large volumes of magmas resulting from partial melting of the lower crust and underlying mantle, and slow cooling after the peak temperature. We report 21 new amphibole, biotite and muscovite 40Ar/39Ar ages that complement previously published data. These data suggest slow cooling (3–5 °C/Myr) over several tens of million years after the peak temperature (~800 °C at ~600 Ma) followed by faster cooling (>10 °C/Myr) after the final amalgamation of West Gondwana. We estimate that ~30 Myr was required to heat the middle crust to the peak temperature and that anatectic and plutonic bodies remained in the magmatic state for ≥40 Myr. This protracted thermal evolution likely had major effects on the rheology of the middle crust and on the tectonic evolution of this orogen. For example, the correlation of U-Pb zircon crystallization ages and 40Ar/39Ar biotite cooling ages in the anatectic core of the orogen denotes a diachronic thermal evolution likely related to 3D deformation involving successive upwelling of anatectic components within a thrust unit crosscutting the pre-existing fabric ("channel flow-like"). This study also highlights that classical structural analysis techniques relying on changes in pressure or temperature conditions to identify the succession of deformation phases are not efficient at deciphering the tectonic evolution of hot, slowly cooling orogenic belts, where the temperature varies slowly over tens of million years, allowing diachronic episodes of deformation to occur under nearly similar pressure and temperature conditions. • The Neoproterozoic Araçuaí belt reached a temperature of ≥800 °C at a depth of ~25 km by ~600 Ma. • The postorogenic peak cooling rate of the Araçuaí middle crust was ~3–5 °C/Myr. • The middle crust remained partially molten for 40–45 Myr. • Slow cooling from high temperatures results in low strength, favoring 3D deformation. • Nearly stable HT conditions over long periods of time may prevent the identification of successive tectonic phases. [ABSTRACT FROM AUTHOR]

The Triassic-Jurassic transition marks an important change in the basin configuration of the Greater Barents Sea. A contiguous basin with km-thick sedimentary successions changed into a partitioned basin with uplift in the west and foreland basins in the east with significant implication for the basin infill history. Our study employs a range of different high-resolution datasets from a distal part of the basin which unravels the complex pattern of differential uplift and erosion in the basin during this period. We record for the first time distinct angular unconformities between Upper Triassic strata and overlying Lower Jurassic strata within the basin, showing that large parts of it formed topographic highs. Our study links these angular unconformities to compression induced by the Novaya Zemlya Fold and Thrust Belt. A heterolithic basement below a thick sedimentary succession where the fold belt developed created a complex uplift pattern in the basin, at the same time similar to but different from typical forebulge areas. Compression caused inversion of older basement rooted faults defining platforms and graben systems throughout western parts of the Barents Sea basin, in addition to salt remobilization that resulted in differential uplift and erosion. These local zones of uplift controlled the sediment distribution pattern to the basin at a time when the most important reservoir units in the basin were deposited. This new understanding of the basin development explains hitherto enigmatic sequence boundaries that has inspired complex paleogeographic models in the past. • Compression-induced uplift of sedimentary basin • Tectonic control on distribution of reservoir rocks • Impact of Novaya Zemlya Fold and Thrust Belt • Northward continuation and late stage evolution of the Uralide orogeny • Remobilization of salt [ABSTRACT FROM AUTHOR]

The Southern Patagonian Andes (SPA) between 47°–48°S are characterized by relatively high elevations (1500–4000 m) and a 200-km-wide, largely exhumed, basement domain along the backbone of the Cordillera, bounded by a narrow 30-km-wide fold and thrust-belt to the east. The tectonic evolution of the SPA includes widespread Jurassic extension during the opening of the Austral-Magallanes basin and the Rocas Verdes back-arc oceanic basin (RVB), followed by Cretaceous to Cenozoic shortening. Although the main phases of deformation that affected this Andean segment have been the focus of previous studies, its finite geometry and step by step structural and kinematic evolution have not been quantitatively determined. In this work, we present kinematically restored cross sections, showing the variable geometry, trough time, of the eastern basement domain and the fold and thrust-belt. A regional westward-dipping listric decollement, interpreted as formed during the Jurassic extensional event, was reactivated during the Andean deformation constituting the main detachment surface of basement structures and the fold and thrust belt. West verging faults systems are considered a consequence of inversion of north-south trending extensional features as passive roof high-angle west-vergent faults. Using regional data such as field relations, unconformities, and existing ages to differentiate deformational stages, three main phases of contractional deformation are proposed for the area, starting with an Aptian - Cenomanian? phase related to inversion of the extensional depocenter in inmediate response to the closure of northernmost RVB. A second, Miocene phase responsible for most of the shortening occurred between 18 Ma and 10 Ma. Finally, the onset of glaciations and glacial erosion might have triggered out-of-sequence thrusting in the interior of the orogen after 7 Ma. • We conducted detailed geological mapping that led to the generation of two geological maps and three cross-sections of the Southern Patagonian Andes. • Kinematic retrodeformation of the cross-sections demonstrated that geometries and sequence of contractional deformation proposed are plausible. • Extensional stage Austral/Magallanes basin structures were inverted during Andean deformation. • Deformation may have started as early as the Aptian-Cenomanian prior to the complete inversion of Rocas Verdes Basin to the south. • Major contraction seems to have taken place between 18 and 10 Ma with duplex generation. After 7 Ma, onset of glaciations could have triggered out-of-sequence thrusting towards the interior of the orogen. [ABSTRACT FROM AUTHOR]

Joint analysis of high-penetration multi-channel and high-resolution single-channel seismic reflection profiles, calibrated by deep well boreholes, allowed a detailed reconstruction of the Late Miocene to Recent tectonic history of the Capo Granitola and Sciacca fault systems offshore southwestern Sicily. These two fault arrays are part of a regional system of transcurrent faults that dissect the foreland block in front of the Neogene Sicilian fold and thrust belt. The Capo Granitola and Sciacca faults are thought to reactivate inherited Mesozoic to Miocene normal faults developed on the northern continental margin of Africa. During Latest Miocene-Pliocene, the two ~NNE-SSW striking faults were active in left transpression, which inverted Late Miocene extensional half-grabens and created push-up ridges along both systems. Tectonic activity decreased during the Pleistocene, but transpressional folds deform Middle-Late Pleistocene sediments as well, suggesting that the two fault systems are active. The ~40 km long longitudinal amplitude profile of 1st order folds (Capo Granitola and Sciacca anticlines) shows ~15–20 km bell-shaped undulations that represents 2nd order folds. The length of these undulations together with the map pattern of faults allowed to divide the CGFS and SFS into two segments, northern and southern, respectively. Total uplift of the Sciacca Anticline is twice than the uplift of the Capo Granitola Anticline. Incremental fold growth rates decreased during time from 0.22 mm/yr (Capo Granitola Anticline) and 0.44 mm/yr (Sciacca Anticline) in the Pliocene, to 0.07 and 0.22 mm/yr, respectively, during the last ~1.8 Ma. • Seismic reflection profiles evidence tectonic inversion and active strike-slip faults offshore SW Sicily foreland • Pliocene-Quaternary transpressional inversion of Late Miocene extensional basins • Transpressional fold growth rates were high in Latest Miocene-Pliocene and decreased during Quaternary [ABSTRACT FROM AUTHOR]

In this paper, we combined new field geological, structural, paleo-temperature and subsurface data together with deep geophysical data to build a new 210 km-long crustal-scale balanced and sequentially restored cross-section in the Central Pyrenean belt (Nestes-Cinca transect). The present-day surficial thrust system geometry of the belt consists of bi-vergent basement-cover thrust sheets with inverted extensional basins and halokinetic structures. Its crustal geometry consists of a thrust wedge geometry of the European lithosphere between the Axial Zone imbricate system of the Iberian upper crust and the north-directed subduction of the Iberian lower crust. Along the study transect, the contractional belt corresponds to the inversion of the Mesozoic Pyrenean Rift system, which consisted in a hyper-extended relay zone of two metamorphic zones with exhumation of lithospheric mantle, the Montillet and Baronnies zones, separated by the Barousse upper crustal boudin. Surface and subsurface data show that the European and Iberian crusts include major inherited structures of the Variscan belt and Permian Rift. These old crustal features controlled the location and geometry of the Mesozoic Pyrenean Rift system. During the upper Cretaceous-lower Miocene contraction, both Paleozoic and Mesozoic inherited features controlled the thrust kinematics and the structural architecture of the Pyrenean orogen. Palinspastic restorations show that the orogenic shortening recorded in the Central Pyrenean belt reaches 127 km (39%) including the closure of the hyper-extended Pyrenean Rift system that initially archived 56 km of extension. This study emphasizes the long-term influence of Paleozoic-Mesozoic structural and thermal inheritances for the evolution of orogenic belts. • New crustal-scale balanced and restored cross-section along the Nestes and Cinca valleys of the Central Pyrenean belt. • Pyrenean orogenic shortening is 127 km including the closure of the Pyrenean Rift system that initially archived 56 km of extension. • The evolution of the belt has been controlled by the Mesozoic Pyrenean Rift system, Permian Rift, and Variscan thrust belt. [ABSTRACT FROM AUTHOR]

This paper investigates the characteristics of the electrical structure and key geological issues of the Alxa and Ordos blocks using a lithospheric resistivity model obtained from a west-east trending magnetotelluric sounding profile. The electrical model shows that the lithosphere of the Alxa Block is high resistivity, except for two crustal low-resistivity bodies. The crust of the Helanshan Orogenic Belt is characterized by medium to high resistivity surrounded by two low-resistivity bodies on both sides. The upper crust of the Ordos Block exhibits discontinuous high resistivity. Still, the lower crust and upper mantle show distinctly low resistivity, which connects with the shallow low-resistivity body above it. The lithosphere of the Lüliang Uplift and the Shanxi Graben is generally characterized by high resistivity, with only localized low-resistivity anomaly found near Moho and in the shallow part of the Shanxi Graben. We propose that the Alxa Block has a stable cratonic lithosphere and that the crustal low-resistivity body within it is a remnant of the southward subducted oceanic crust of the Paleo-Asian Ocean. The low-resistivity body in the lower crust of the Trans-North China Orogen is also interpreted as a remnant of oceanic crust; the upper mantle low-resistivity body is proposed to be a partial melt resulting from the upwelling of asthenosphere caused by the combination of westward subduction of the Paleo-Pacific Plate and northeastward growth of the Tibetan Plateau. This low-resistivity anomaly spreads to the shallow crust, with its lateral distribution to the east and west being blocked by the Lüliang Orogenic Belt and the Alxa Block, respectively, then consequently upwelling along the Yinchuan Graben during the Mesozoic and Cenozoic. We propose that the Alxa Block has been subducted to the Ordos Block along the Helan Mountain in the Early-Middle Paleozoic, which may have formed an ancient suture zone. This ancient suture zone was reactivated in the Mesozoic and Cenozoic by the Paleo-Pacific Ocean subduction and northeastward growth of the Tibetan Plateau, becoming a material upwelling channel and ablating the roots of the Helan Mountain. • The Alxa and Ordos blocks were probably merged during the Early-Middle Paleozoic. • The subduction zone was reactivated by the Paleo-Pacific Plate subduction and the Tibetan Plateau's northeastward growth. • The western North China Craton was also destructed by mantle upwelling beneath the northern Ordos Block. [ABSTRACT FROM AUTHOR]

The kinematic history of the Philippine Sea Plate (PSP) is crucial for interpreting its geological record related to subduction initiation processes and the paleogeography of the junction between the Paleo-Pacific and Tethyan oceanic realms. However, reconstructing PSP's kinematic history is difficult because the plate has been surrounded by subduction zones for most of its history. In absence of marine magnetic anomalies to constrain PSP's motion relative to its neighboring plates, paleomagnetic data may be used as quantitative constraints on its motion. Previous paleomagnetic studies interpreted easterly deflected declinations to infer clockwise rotations of up to 90° since the Eocene. However, rotations inferred from these datasets may also reflect local block rotations related to plate margin deformation. We here re-evaluate to what extent paleomagnetic data from the PSP unequivocally demonstrate plate motion rather than local rotation. To this end, we provide new data from Guam, in the Mariana forearc, and reassess published paleomagnetic data. Our new data from Guam come from two localities in the Eocene, two in the Oligocene, and two in the Miocene. Our compilation assesses data quality against recently defined criteria. Our new results demonstrate that in Guam, declination differences of up to 35° exist in rocks of Eocene age, indicating local rotations. Our compilation identifies both clockwise and counterclockwise rotations from the plate margins, with little confidence which of these would reflect plate-wide rotation. We compiled paleolatitude data from igneous rocks, which we correct for microplate rotation constrained by intra-PSP marine magnetic anomalies and show a northward drift of the PSP of ∼15° since the Eocene, but without a paleomagnetic necessity for major vertical axis rotation. Hence, with the currently available data, rotations of the PSP may be permitted, but are not required. Plate motion is currently better reconstructed from geological constraints contained in circum-PSP orogenic belts. • New paleomagnetic data from Eocene, Oligocene, and Miocene locations in Guam • Reassessment of published paleomagnetic data using recent quality criteria • Paleomagnetic data do not unequivocally demonstrate whole-plate vertical-axis rotation • Northward motion of the Philippine Sea Plate since the mid-Eocene was about 15° [ABSTRACT FROM AUTHOR]

The Central Andean Forearc (26°S) structure has been debated for decades. Extension, contraction, and strike-slip deformation are commonly proposed mechanisms to explain the main tectonic elements exposed in the Domeyko Cordillera, Salar de Pedernales Basin, and others partially exposed in the Coastal Cordillera and Central Depression. Although pre-Andean tectonic inheritance seems to have influenced the style and mechanisms of mountain uplift in this region, its current architecture and the way it controlled the shortening distribution during orogen evolution are highly speculative, mainly because some of the tectonic provinces in this segment consist of covered areas (e.g., the Central Depression). To address this question, we present the first balanced cross-section and pre-shortening restoration of the Andean forearc at 26°S. We integrated new field data from the Coastal and Domeyko cordilleras with well data and re-interpreted 2D seismic profiles from the Salar de Pedernales Basin to construct a regional-scale cross-section of 210 km length from the Coastal Cordillera to the current Volcanic Arc, thus showing a two-dimensional (2D tectonic model to help understand the tectonic evolution of the western Central Andes. The results indicate a pre-shortening architecture dominated by Late Permian–Jurassic half-graben structures related to continental rifting. West- and east-dipping basement-rooted normal faults controlled rift-related basins, along which kilometric-scale marine and continental syn -rift sequences accumulated. During early Andean orogenesis, the normal faults were partially inverted, and large anticlines developed at the hanging wall faults, which Upper Cretaceous progressively covered to Paleocene synorogenic units. This suggests that the initial topographic relief in the region resulted from a basin inversion. During the more advanced stages of orogenesis (mid-Cenozoic), new reverse and thrust faults (or shortcut faults) were created, which connected upward with incompetent stratigraphic units and facilitated the propagation of localized fold-and-thrust belts in the eastern Domeyko Cordillera and Salar de Pedernales basins. A minimum of 16.3 km of W-E shortening was reported; however, nearly 11 km was accommodated by the newly created thrusts, indicating that these were most relevant to mountain building. • The 2D tectonic model of the Central Andes forearc at 26°S shows present-day and pre-orogenic architectures of the western Central Andes. • The structures consisted of thick-skinned and doubly verging structures. • 16.3 km of W-E shortening was accommodated by the propagation of shortcut faults connecting the basement-involved to the thin-skinned structures. [ABSTRACT FROM AUTHOR]

The continental lithosphere of the Arabian Plate has evolved through a long and complex tectonic history and comprises major geological features such as an ophiolite complex, Cenozoic basalt extrusion, and Proterozoic basement outcrops. In eastern Arabia, an NW-SE to N-S oriented orogenic belt is present in Oman and the United Arab Emirates (UAE). The mountain belt formed due to the Late Cretaceous obduction of the Semail ophiolite, where a thick slab of oceanic crust and upper mantle was emplaced on the rifted Arabian continental margin. However, the mechanical strength of the lithosphere over the entire region is poorly known. In this study, we employ Bouguer gravity anomaly and topographic data, along with data on crustal properties obtained from teleseismic analyses, to assess the spatial variations in the effective elastic thickness (T e) of the eastern Arabian Plate. The joint inversion of coherence and admittance yielded T e values ranging from 10 to 50 km and an initial subsurface-to-surface load ratio (F) of 0.1 to 0.8. T e values in the southern part of eastern Arabia are low (< 20 km), while the northeastern regions of Saudi Arabia, the UAE, and Qatar exhibit intermediate to high T e values ranging from 30 to 45 km. The Oman-UAE mountain belt is associated with an intermediate T e of 30 km in the northern segment and a low T e of 20 km in the southern segment. The reduction in T e observed along the strike of the mountain belt suggests weakening of the lithosphere during the obduction of the Semail ophiolite. T e correlates well with both the seismic thickness of the lithosphere (T s) and the decrease in shear-wave velocity at a depth of 150 km. The seismogenic thickness in eastern Arabia, however, is about 15 km, which is significantly less than T e and shows that both the crust and upper mantle contribute to the strength of the continental lithosphere. The T s / T e ratio ranges from 1 to 9, with a maximum peak at 3–5, which is similar to the results observed for the oceanic lithosphere. • T e is <20 km in southeastern Arabia, and >30 km in northeastern regions. • Oman-UAE mountain belt has T e values of 30 km and 20 km in the northern and southern segments. • Reduction in T e suggests weakening of the lithosphere during the obduction of the Semail ophiolite. • T e correlates both the lithosphere thickness and the decrease in shear-wave velocity. • Both the crust and upper mantle contribute to the strength of the lithosphere. [ABSTRACT FROM AUTHOR]

In order to find insights of plate origin, intraplate deformation and plate driving force, we propose the characteristics and genetic model of microplates which are the residuals of large plates by summarizing previous studies. Subduction-derived Oceanic Microplates (SOMs) are formed in the footwall of the subduction system and generally bounded by spreading ridges, trenches and transform faults when the mid-ocean ridge and subduction zone move towards each other. The identified SOMs are remnants of the Farallon Plate and Phoenix Plate. Large SOMs may fragment further due to the buoyancy of young oceanic crust and subduction velocity difference in response to the interaction between large tectonic plates. Subduction-derived Continental Microplates (SCM) are a type of tectonic feature that originate from the intra-oceanic plate with continental lithosphere. These microplates are typically found in the orogenic belt, which is bounded by suture zones. When the adjacent oceanic crust subduction is entirely consumed through subduction, the plate collides with the hanging wall to form an orogenic belt. The plate is then subject to continuous compression, resulting in crustal shortening and the formation of a strip-shape SCM parallel to the orogenic belt. In the case of the SOMs offshore North America, oceanic crusts with ages below 3–4 Myr can significantly impede subduction, leading to the segmenting of the ridges. By analyzing the spatiotemporal variation of footwall mid-ocean ridge activity, we suggest that the presence of subduction zones is conducive to the seafloor spreading near continental margins. • We put forward the evolution model of microplates which are the residuals of large plates. • The existence of ocean-continent subduction zone enhances the activity of the footwall mid-ocean ridge. • For the Farallon series microplates, 3–4 Myr could be the crust age threshold for whether it is favorable for subduction. [ABSTRACT FROM AUTHOR]

The Songliao Basin in Northeast China is located within the eastern part of the Central Asian Orogenic Belt and to the north of the accretionary belt of the North China Craton. The lithosphere beneath the basin and the surrounding region has undergone a series of complex deformation processes due to sequential interactions among different tectonic plates since the Palaeozoic. Here we construct a three-dimensional lithospheric shear-wave (S -wave) velocity model for the region via surface-wave tomography to better understand the deep dynamic processes that shaped the Songliao Basin. The S -wave velocity model highlights strong linkages between the surface geology and mantle lithospheric structures. The Baicheng–Changchun uplift (or Song-Liao watershed), which divides the basin into two river systems, is underlain by a dome-like area of uplifted crust. The central Songliao basin is underlain by a weak, thin lithosphere that is ∼80 km thick, whereas the eastern Great Xinggan Range to the northwest is underlain by a normal crust and lithosphere that is ∼100 km thick. The northern North China Craton and southern Songliao Basin are also underlain by normal crust and a lithosphere that is up to ∼150 km thick, with a low-velocity zone penetrating the high-velocity mantle lithosphere at ∼80–100 km depth. Such structural features imply that the far-field effect of Pacific Plate subduction since the Cenozoic varies across Northeast China and is dependent on the lithospheric structures that existed prior to subduction. [Display omitted] • Surface-wave tomography is implemented targeting on the Songliao Basin. • 3-D lithospheric S-velocity of the Songliao Basin (SLB) is presented. • Lithosphere of central SLB is thin, implying bottom destruction before 40 Ma. • Two-layer mantle lithosphere exists in the southern SLB. [ABSTRACT FROM AUTHOR]

The deformation of the Timor Trough is controlled by the combined dynamics of Australian Plate subduction and the arc–continent collision between Australian continent and Banda arc, and its development remains controversial. Based on the seismic, earthquake, and well datasets, we focus on these controversial problems and analyzed the deformation features and mechanism of the Timor Trough, and we established a tectonic model to discuss the arc–continent collision evolution and plate coupling. Our results and model suggest that the subsidence of the Timor Trough and uplift of the Timor Island begin at ∼3.3 Ma and marked the deformation of the Australian northwestern continental margin. We propose that the arc–continent collision underwent two phases and transformed the subduction zone into collision zone. The earliest phase uplifted and closed the forearc basin since ∼6 Ma, and the second phase of regional deformations at ∼3.3 Ma is represented by the development of backarc thrust, the cessation of volcanism, the uplift of Banda arc, and the subsidence of Timor Trough. The tearing oceanic crust provides a window for the development of backarc thrust to the southeastward. The outer and inner Banda arcs may have become a cohesive block after the collision; consequently, it is possible for them to move northward as a whole along the backarc thrust. • The deformation of the Timor Trough started during the late Pliocene at 3.3 Ma. • Arc–continent collision can be divided into two phases: 6–4 Ma and after 3.3 Ma. • The initial distal part collision interrupted the volcanism. • The subsequent collision caused the deformation of the Banda arc and the trough. • The Banda arc has the potential to move northward along the backarc thrust. [ABSTRACT FROM AUTHOR]

As an important component of the Central Asian Orogenic Belt (CAOB), the West Junggar represents a natural laboratory to explore intracontinental deformation in a complex terrane. Although some low-temperature thermochronological studies have been conducted in this range, the number of exhumation stages and the corresponding driving forces behind exhumation remain highly debated. In particular, the exhumation history of the northern West Junggar remains poorly studied owing to a lack of data. Here, we present a study that integrates apatite fission track (AFT) and (U Th)/ He (AHe) dating from the igneous rock in the Sawur Mountains in northern West Junggar to further constrain the exhumation history of the region. AFT dating of the samples dominantly yields Late Triassic ages (200–227 Ma) with mean track lengths (MTLs) varying between 13.33 and 14.98 μm, while AHe dating produced widely dispersed Late Triassic to Late Cretaceous single grain ages (73–215 Ma), with sample mean ages between 100 and 195 Ma. Inverse thermal history modeling of our results and analysis of age-elevation relationships reveal that the Sawur Mountains experienced an extended period of rapid cooling related to local exhumation during the Middle–Late Triassic. A gradual reduction in surface relief following rapid erosion is related to peneplanation processes. The timing and patterns of this exhumation indicate it was caused by reverse oblique-lip reactivation of older strike-slip faults, and it can be explained as the response to the far-field effects of the final closure of the Paleo-Asian Ocean. • Middle to Late Triassic rapid cooling is preserved throughout the West Junggar. • The reactivation of strike-slip faults with limited vertical motion controlled the rapid exhumation in the Triassic. • The deformation's most likely trigger is the Paleo-Asian Ocean's final closure. [ABSTRACT FROM AUTHOR]

The Cambay rift basin (CRB) evolution has been associated with separation of the Indian continent from the African continent and subsequent interaction with the Réunion mantle plume, which resulted in significant alternations in the regional lithospheric structure of western India, more prominently in the CRB due to its proximity to the plume track. In our continued effort to delineate the lithospheric structure of the CRB and adjoining regions, we acquired magnetotelluric (MT) data at 31 sites along a profile across the CRB and analyzed these. The 2D geoelectric model derived from this dataset reveals a collage of conductive and resistive formations. The resistive blocks indicate the Archaean lithosphere on the west, the uplifted crust within the CRB, and various structural units of the Precambrian Era on the east providing evidence for continuation of the Aravalli-Delhi Fold Belt trend beneath the CRB into Saurashtra. The conductive anomalies beneath the CRB infer the magmatic underplating associated with thermal influx derived from the upper mantle as a result of the Réunion plume interaction. Integration of previous geophysical and present results infers a spatially heterogeneous lithosphere possibly representing an assemblage the Archaean and Proterozoic lithospheres beneath the CRB. The Proterozoic lithosphere is more vulnerable to the impact of the Réunion plume due to its weak nature in comparison to the Archaean lithosphere. The Archaean lithosphere on the western side of CRB indicates initial stage of rifting, whereas Proterozoic lithosphere infers second stage coeval with the Deccan volcanic eruption. The heterogeneity in sedimentary thickness within the CRB spatially correlates with the contact of Archaean and Proterozoic lithospheres, which might have played a role in the formation of the basin structure, and sediment deposition. • MT study along a 200-km-long profile across the Cambay rift basin (CRB) and Adjoining Aravalli-Delhi Fold Belt (ADFB). • Extension of the ADFB beneath the CRB into the Saurashtra. • Spatially heterogeneous lithosphere beneath the CRB. • Variation in basin thickness across the CRB might be associated to the deep structure. [ABSTRACT FROM AUTHOR]

The Taiwan orogenic belt has high precipitation and high exhumation rates (3–6 km/Myr), making it a natural laboratory for understanding how erosion, tectonics, and climate interact. Understanding how rock exhumation rates have evolved since the late Miocene is key to unraveling climate–tectonic interactions. In this study, we present 8 new zircon fission track (ZFT) and (U Th)/He (ZHe) cooling ages (including 2 unreset ages) from 5 samples from 1700 to over 3300 m elevation around the highly incised Dajia River in the core of the Hsuehshan Range (termed the mid-HR in this study) in central Taiwan. Two of the ZFT and ZHe ages (5.3 Ma and 2.6 Ma) are the oldest ages recorded in this region. These ages suggest that the cooling rate of the mid-HR is lower than that of the Backbone Range and Yushan. With these and previously published cooling ages, we modeled the exhumation and cooling history using a 2-D thermal diffusion equation with time-varying erosion. The ZFT and ZHe ages are best explained by a steadily increasing exhumation rate up to 3.4 + 0.5/−0.3 km/Myr from 7 to 1 Ma. The exhumation rate in the last million years is not as well constrained but appears to have increased at a slower rate. Our findings differ from those of previous studies that propose that the exhumation rate increased rapidly in the last 1–2 Myr. We propose that the steady increase in the exhumation rate in the mid-HR indicates increasing topographic relief, which is likely caused by progressive crustal thickening. • The ZFT and ZHe ages (5.3 Ma and 2.6 Ma) are the oldest ages recorded in the middle Hsuehshan Range (mid-HR) in Taiwan. • The exhumation rate in the mid-HR steadily increases from 0 to 3.4 km/Myr from 7 to 1 Ma and then increases at a slower rate. • Steady increase in the exhumation rate indicates increasing topographic relief, likely due to progressive crustal thickening. [ABSTRACT FROM AUTHOR]

The Changshan islands are scattered among the Yellow Sea east of the Liaodong Peninsula, west of North Korea and north of the Sulu Orogenic Belt. They consist of three lithotectonic units: i) Archean gneiss, ii) Paleoproterozoic marble and micaschists, and iii) Neoproterozoic weakly metamorphic sedimentary rocks. Three stages of deformation (D 1 -D 3) documented in this study indicate that Changshan islands are a key region to decipher the Mesozoic tectonic evolution of eastern China. The earliest deformation D 1 corresponds to a ductile deformation with NE-SW trending mineral and stretching lineations and top-to-the-NE sense of shear. The deformation D 2 , observed in the micaschists and sedimentary rocks, is characterized by the SW-verging folds with NE-dipping axial planar cleavage S 2 and SW-directed thrusting. D 2 could be considered as the back-folding and back-thrusting of the D 1. D 3 is expressed by the NE-SW trending low-angle brittle and ductile detachment faults representing a NW-SE extensional event. To the east of Guanglu and Guapi islands, two samples from a granite pluton that only record D 3 fabrics yield SIMS zircon ages of 165.4 ± 1.6 Ma and 164.7 ± 1.5 Ma, which indicate that D 1 and D 2 occurred earlier than 165 Ma, while D 3 is younger than this age. Similar geometric and kinematic features with those of the South Liaodong Peninsula suggest that D 1 and D 2 occurred in the Middle-Late Triassic as the structural response of overriding plate to the continental subduction of the South China Block (SCB) beneath the North China Craton (NCC), while the D 3 occurred in the Early Cretaceous during the development of the Liaonan Metamorphic Core Complex (MCC). The ductile shear zone and brittle normal faults of the Changshan islands represent the early extensional structures of the Liaonan MCC. They may develop further southeastward and controlled the early development of the North Yellow Sea Basin. • The Changshan islands experienced three stages of deformation in the Mesozoic. • The D 1 and D 2 responded to the Middle-Late Triassic continental subduction of the SCB beneath the NCC. • The structures of D 3 resulted from the Early Cretaceous NW-SE extension throughout the whole eastern Eurasian continent. [ABSTRACT FROM AUTHOR]

Carbonate formations from many locations reveal magnetizations that are secondary. Attaching a numerical age to these remagnetizations would provide information on orogenic processes. To contribute to the effort of assigning an age to remagnetization events, Lower Cretaceous formations from the Monterrey Salient in northeast Mexico were sampled. Individual fold tests reveal eight site-pair synfolding remagnetizations (set A) of Eocene age. The remanence is a chemical remanent magnetization (CRM) carried by magnetite. The magnetization of set B is possibly due to an early carbonate alteration that produced a remanence significantly older than folding. A complexity of set B is that the site pairs reveal k-versus-unfolding percentage diagrams with maximum unfolding peaks at 100 to 125%. An explanation of multiple deformation phases with an earlier horizontal folding phase around a non-plunging horizontal axis and a later vertical axis rotation is suggested for the past 100% peaks of the B sites. The latter deformation, rotation about a vertical axes, is revealed by a declination-strike test in set A sites and site means of the full collection that deviate counterclockwise from the reference declination. By combining synfolding results with published 40Ar/39Ar illite ages of folding (Fitz-Diaz et al., 2016), remagnetization ages in set A sites of 48–52 Ma are obtained. The magnetization in set B sites is likely older, though not well constrained. Interestingly, prior results from the central Sierra Madre Oriental, to the south, show two remagnetization events, Late Cretaceous and Early Eocene in age, in a succession from W to E (Nemkin et al., 2015). The age of folding and remagnetization acquisition in set A sites along the Monterrey Salient are concurrent with the frontal, remagnetized folds in the central Sierra Madre Oriental. Thus, the timing of major remagnetization in the Monterrey Salient occurred in the Eocene. [ABSTRACT FROM AUTHOR]

Abstract Kinematic restorations in fold and thrust belts, which are a valuable tool for studying the deformational history of fold and thrust belts, have been poorly used to understand erosion rates. In this contribution, we estimated the amount of eroded material in thrust-belts via kinematic reconstructions. We combined kinematic restitutions with the classic critically-tapered Coulomb wedge model, following the assumption that at times when thrusting is triggered, the surface slope was less than the angle required to reach self-similar growth, i.e. critical. Following conservative geometrical considerations, we were able to compute a time-varying Coulomb wedge. Such unsteady wedge is used to calculate first-order, time dependent erosion rates, which are compared to denudation and provenance results derived from other techniques. We applied our model to the Argentine Precordillera at the Jáchal river section, whose extensively studied outcrop data have let establish a well-constrained episodic deformation of the thrust-belt; even though no kinematic model of the area had been presented so far. Our results show two contrasting erosion rates, one prior to the movement along the last-in-sequence fault (Niquivil) and one after, 0.1 and 1.34 Km/Myr, respectively. Our findings indicate that the amount of eroded material might not always be directly proportional to cumulative slip in the thrust system, as slip along Niquivil thrust is only 22% of the total horizontal displacement, though it produced most of the uplift and erosion. Our results are in striking accordance to long-term erosion estimation proxies, like U-Th/He, 10Be and sedimentological studies, which highlights the validity of the economical methodology herein proposed. Furthermore, our kinematic model of the evolution of the Argentine Precordillera allows us to perform 2D flexural numerical modeling, which suggests that tectonic loading seems to not be enough to reproduce basin geometry and that additional mechanisms, such as dynamic subsidence or lithospheric mantle thickening (among others), would be required. Highlights • We pose an economical methodology for estimating the amount of eroded material in fold and thrust belts. • The first-to-date kinematic structural modeling of the Argentine Precordillera is proposed. • Amount of eroded material may not always be directly proportional to cumulative slip in the thrust system. [ABSTRACT FROM AUTHOR]

Abstract Two distinct styles of continental collision are observed in nature, i.e. lithospheric-scale subduction versus crustal-scale underthrusting. The former refers to a collision scenario where the lower plate subducts below the lithospheric mantle of the overriding plate, whereas the latter is characterized by the underthrusting of the subducting plate beneath the crust of the overriding plate. Systematic numerical models were constructed to study the dynamics of these two different collision modes. The model results indicate that low convergence rate and cold overriding plate contribute to the lithospheric-scale subduction, which incorporates limited shortening of the overriding lithosphere during collision. In contrast, the crustal-scale underthrusting requires relatively high convergence rate and hot/weak overriding plate, in which the thickened lithospheric mantle of the overriding plate is progressively delaminated from the overlying crust and is replaced by the sub-horizontally underthrusted plate. The model results were systematically compared with four ongoing collisional orogens along the Alpine–Himalayan belt, i.e. the central-western Alps, the East Anatolian plateau, the Zagros–Iranian plateau, and the southern Tibetan plateau. It indicates that the lithospheric-scale subduction is widely observed and generally consistent with the natural orogens, for example, the Alps, Anatolia, and Zagros. On the other hand, the crustal-scale underthrusting is reconciled with the India–Asia collision zone, with respect to the geodynamic conditions, crustal-lithospheric structure, as well as the uplift history. Highlights • Continental lithospheric-scale subduction versus crustal-scale underthrusting • Density and thermo-rheological properties of the upper plate control mode selection • Plate convergence rate also affects the continental collision mode. • Models applied to four ongoing collisional orogens along the Alpine–Himalayan belt. [ABSTRACT FROM AUTHOR]

Abstract A series of numerical experiments based on the discrete element method were performed to simulate the formation of fold belts, with varied décollement layer thickness and cover rock cohesion, to investigate their controls on structural styles of fold belts. Each model consists of a weak, unbonded basal décollement layer with a relatively low to high thickness, and a bonded cover with a relatively low to high cohesive strength. Horizontal shortening of the particle assemblage was achieved by horizontal motion of a vertical boundary wall, resulting in deformations in the system. The results show that shortening was mainly accommodated by detachment folds (sinusoidal and box folds), fault-related folds and opening-mode fractures in the models. The combination of a lower cohesion and a thinner décollement resulted in more distributed strain and a larger number of folds, whilst the combination of a higher cohesion and a thicker décollement led to more pronounced strain localisations in fewer folds. Surface uplift and fold amplitude (diapir height) are mainly positively affected by the décollement thickness, i.e. the thicker the décollement is, the greater the surface uplift and fold amplitude are. The propagation rate of deformation is predominately controlled by the cover rock cohesion. A lower cohesion led to a higher propagation rate of deformation. The model with a relatively low cohesion and décollement thickness produced regularly-spaced box folds, which are comparable to those in the southern Zagros Fold-and-Thrust Belt. The models presented demonstrate that the combined effect of décollement layer thickness and cover rock cohesion can play a critical role in the structural styles and kinematic evolution of fold belts. Graphical abstract Unlabelled Image Highlights • Discrete element models were constructed to simulate fold belts with varied structural styles. • The cover rock cohesion can significantly control the propagation rate of deformation. • A thicker décollement and a higher cohesion could result in a greater surface uplift. • A high rock cohesion favours strain localizations and generation of fault-related folds. • A thin décollement and a low cover rock cohesion could preferentially produce regularly-spaced box folds. [ABSTRACT FROM AUTHOR]

Abstract The Cuu Long Basin is situated off the southeastern coast of Vietnam. This study utilizes all available seismic data in the Cuu Long Basin, Vinh Chau Basin and coastal Mekong Delta to constrain the tectonic history of the area. The linkage between the Mae Ping Fault Zone and deformation in the Cuu Long Basin is also examined in detail. Two major deformational events are observed: a transtensional rifting event from the mid Eocene to mid-Early Oligocene (40–31 Ma) followed by transpression from mid-Early Oligocene to mid-Late Oligocene (31–25 Ma). The data strongly suggest that all the very straight major tributaries of the Mekong River Delta follow northwest trending faults that link into to the southwestern end of the Cuu Long Basin fault system and that the basin opened between where the Mekong Delta faults enter and a point of zero extension at the NE termination of the basin. The Mekong Delta Fault Zone exhibited left-lateral displacement during extension in the Cuu Long Basin and right-lateral displacement during younger transpression. The orientation, age and sense of displacement of the Mekong Delta Fault Zone are consistent with slip on the Mae Ping Fault Zone in Thailand and Cambodia, and hence are considered to be part of the same regional fault system. Based on a Chainat Duplex analogue and other data, the Mekong Delta and Mae Ping fault zones appear to be linked by a NNW-striking step-over zone, referred to here as the Mekong-Ton Le Sap step-over zone. This zone follows the eastern boundary of the Paleocene to Early Eocene Kampot Fold Belt. Based on structural and stratigraphic similarities, it appears the adjacent Vinh Chau Basin shares a common tectonic history with the Cuu Long Basin, but the linkage to the Mekong Delta Fault Zone is less clear. Highlights • Documenting the 3D architecture and deformational history of the Cuu Long Basin • Identifying the impact of preexisting structures on subsequent deformation • Establishing a link between the Mekong Delta and Mae Ping fault zones • Identifying the Chainat Duplex as an analogue for the Mekong-Ton Le Sap step-over • Describing the impact of the Kampot Fold Belt on the Mekong Delta Fault Zone [ABSTRACT FROM AUTHOR]

Abstract Unravelling the orogenic structure of the Sierra Grande de San Luis (Argentina) is essential to understand the geological evolution of the Famatinian orogen and the western margin of Gondwana. However, its structural organization is still poorly known and widely debated. In this contribution, a new interpretation of the complex geological structures in the southern sector of the Sierra Grande de San Luis is presented. This work is based on a litho-constrained joint inversion of gravity and magnetic datasets combining lithological, structural and rock properties information. Results are consistent with a large-scale doubly-vergent structure caused by a compressional tectonic setting as a consequence of the collision between an allochthonous terrane (Cuyania/Precordillera) and the proto margin of Western Gondwana. A convex morphology of the indenter is proposed to be responsible for producing a significant clockwise rotation of the horizontal deviatoric stresses. This stress field caused a small sinistral component of movement and gave rise to the doubly-vergent transpressive mega-structure. [ABSTRACT FROM AUTHOR]

Abstract Lower crustal flow zones occur in large and hot orogens and rifts, where they occur in association with large areas possessing high gravitational potential energy (GPE) and low lower crust viscosity. Lower crustal flow zones are also known from regions where neither the rheological nor GPE conditions are sufficiently well developed for widespread flow to occur. For these examples, the conditions required to form crustal flow zones are less well defined. One such case occurs within the ca. 600–530 Ma Petermann Orogeny in central Australia. This work investigates the conditions under which this flow zone developed, considering differences with the adjacent regions where flow is not observed. A transect of crustal structure in the central Petermann Orogen is developed that takes into account geological and geophysical data, including time-constrained pressure and temperature estimates for the Petermann Orogeny. The deformation of this region is reconstructed, showing that lower crustal flow was driven by high amplitude crustal-scale folding. The folding extruded the lower crust towards the foreland, causing crustal thickening and buoyant uplift of the orogenic core. Channelized lower crustal flow is not known from either the eastern or western parts of the orogen, and a comparison with these regions suggests three main conditions are required: Firstly, the lower crust must be sufficiently hot and volatile-rich to allow melt-weakening. Secondly, crustal rheology must allow ductile deformation of the mid to lower crust without high-strength layers. Finally, a high degree of lateral confinement is required to form pressure-gradients capable of driving flow. These three conditions were met only in the central Petermann Orogen, and not in the east or the west. This example of a lower crustal flow zone illustrates the combined influence of thermal, rheological and kinematic threshold conditions on the initiation and development of channelized lower crustal flow in orogens. Highlights • Boundary conditions are examined for an example of channelized lower crustal flow. • Thermal and rheological conditions are near the threshold for flow to occur. • Crustal-scale folding of a warm crust (T moho ≈ 800 °C) is the driver of flow. • Kinematic conditions must also be met for channelized flow to occur. [ABSTRACT FROM AUTHOR]

Abstract Late Cenozoic orogen-derived sediments recorded in the pro- and retro-foreland basins on both sides of the Taiwan orogenic wedge provide important constraints on sediment provenance evolution, and further outline the exhumation and erosion histories of the orogenic belt. We present 172 sandstone petrographic data from seven representative regions on the pro- and retro-foreland basins, which we coupled with previous thermochronological data from the pro-wedge of the Hsuehshan Range and the retro-wedge of the Backbone Range to elucidate the source-sink relationships between a source orogenic wedge and its associated foreland basin. Our data analysis and estimation provide evidence that the initial depositional age of orogen-derived sediments in pro- and retro-foreland basins is consistent with the exhumation and erosion histories of the adjacent orogen, indicating that the Backbone and Hsuehshan Ranges started to build up at ~12 and 5–6 Ma, respectively. The diachronous onset of orogenic sediment deposition and orogenic uplift also suggest a tendency for progressively southward and westward migration of the foreland basin, and asymmetric exhumation and erosion of the orogenic wedge over time due to oblique collision. The timing of the onset of the Taiwan orogeny formed the retro-wedge of the Backbone Range at ~12 Ma, which is much older than the previously determined onset age of Taiwan mountain building of ~6 Ma. We divide the Taiwan orogenic evolution into two stages: the first stage comprises the extrusion and exhumation of the subduction wedge formed as the Yuli Belt of the Backbone Range prior to the collision during the middle Miocene. The second stage comprises the arc-continent collision, producing doubly vergent orogenic wedge extrusion, leading to a diachronous uplift history of the Hsuehshan and Backbone Ranges since late Miocene. Highlights • Geochronological and petrographic data constrain the exhumation history of orogeny. • The onset age of the Taiwan mountain building occurred at ca. 12 Ma. • Stage 1: exhumation in a subduction wedge since middle Miocene • Stage 2: collision produced by doubly vergent wedge extrusion since late Miocene [ABSTRACT FROM AUTHOR]

Abstract In this paper, we present a review about stratigraphy, petrology, deformation and metamorphism of the oceanic, sedimentary, magmatic and metamorphic successions exposed from northern Calabria to the Campania region (southern Italy), referred to the paleogeographic Southern Ligurian Domain. These successions experienced different tectonic episodes, with those located in the westernmost sector of the Southern Ligurian Domain firstly subducted, reaching high pressure/low temperature metamorphic conditions (Eocene) and subsequently exhumed and exposed (Tortonian). On the contrary, the deep-basin successions located in the easternmost sector (close to the continental Adria margin) were obducted and frontally accreted (Aquitanian-Burdigalian). The tectonic transport for the obducted successions was dominantly to SE (in the present geographic coordinates), whereas new data about tectonic transport directions and vergences of the subducted ophiolites, exposed in northern Calabria, indicate a mean eastward-directed transport during the tectonic exhumation. The petrochemical comparison between the mafic rocks of the Southern Ligurian Domain successions with the corresponding rocks exposed in the Alps, Corsica and northern Apennines, representing the northern sector of the Ligurian Domain, suggests an ocean-continental transition paleotectonic setting for the entire Ligurian Domain. The early orogenic stages of the southern Apennines-northern Calabria system, defined by the subduction of Ligurian lithosphere, were characterised by a complex kinematic evolution of the subduction system, including the migration of the basal and roof decollements upward, downward and toward the foreland within the subduction channel. Highlights • We present a review about geology of oceanic successions of Southern Ligurian Domain. • Tectonic vergences of the HP/LT ophiolites indicate a E/NE transport. • Petrological data suggests an OCT setting for the entire Ligurian Domain. • We model the subduction channel kinematic evolution. [ABSTRACT FROM AUTHOR]

Abstract Neoproterozoic-early Paleozoic Pan-African mobile belts that formed during the amalgamation of Gondwana, such as the Zambezi Belt, are inherently weak zones that are susceptible to reactivation by later tectonism. With the exception of Karoo rifting, however, the post-Pan-African morphotectonic history of the Zambezi Belt is poorly constrained. Here, we use multiple low-temperature thermochronometers on samples collected across major structures in northern Zimbabwe to reveal the temporal and spatial pattern of tectonism and denudation in this portion of the Zambezi Belt. Thermal history modelling suggests that a large crustal block encompassing part of the Zambezi Belt and northern margin of the Zimbabwe Craton experienced differential denudation during three main Phanerozoic episodes. This denudation of the Archean-Proterozoic basement was associated with reactivation of the Zambezi Escarpment Fault, which demarcates the southern margin of the Karoo Cabora Bassa Basin. In contrast, other major structures within the region remained relatively stable. The results highlight the value of using a multi-thermochronometer approach, where essentially zircon (U-Th)/He data preserve evidence of late Carboniferous Karoo rifting, apatite fission track data record the thermal effects of Jurassic tectonism associated with Gondwana breakup, and the apatite (U-Th-Sm)/He data reveal Paleogene reactivation of the basin-bounding fault. Thermal history modelling also suggests that the Cabora Bassa Basin experienced Gondwana breakup-related denudation, potentially associated with a proposed concurrent major regional drainage reversal. Since the Cretaceous, the basin has experienced limited sedimentation and erosion. Highlights • First apatite and zircon (U-Th)/He data for the Zambezi Belt • Multi-thermochronometer data constrain morphotectonic history from mid-Paleozoic. • Reactivation of Zambezi Escarpment Fault in Carboniferous, Jurassic and Paleogene • Reactivation caused denudation of large Zambezi Belt-Zimbabwe Craton crustal block. • Karoo Cabora Bassa Basin experienced Triassic-Cretaceous breakup-related unroofing. [ABSTRACT FROM AUTHOR]

Abstract The goal of this paper is to use the structural, metamorphic and geochronological record from the migmatitic core of the Naxos dome (Greece) and its associated subdomes to address the internal dynamics of a partially molten orogenic root. U-Pb ages from ca. 24 to 16 Ma and textures of zircon in the migmatites suggest successive dissolution and precipitation cycles with a period of 1 to 2 Ma , interpreted as the timescale of convective instabilities in a ca. 20 km thick partially molten layer. Dimensional analysis indicates that convection of this root requires a viscosity lower than 1018 Pa·s, consistent with viscosity values expected for partially molten felsic rocks. Structural analysis and U-Pb geochronology of deformed granitic dikes rooting in the migmatites record the subsequent development of the Naxos dome by diapirism from ca. 16 to 13 Ma. The size of the first order migmatite dome on Naxos (5 × 12 km) requires that the unstable layer at the onset of diapirism was 5 to 10 km thick and presented a moderate viscosity contrast with its envelope. From this analysis we propose that the Naxos migmatite dome documents a two stage dynamic evolution for the partially molten root of the Aegean belt characterized by (1) crustal scale convection for at least 8 Ma and (2) diapirism for about 3 Ma during progressive thinning of the collapsing orogenic crust. Graphical abstract Unlabelled Image Highlights • Naxos migmatite domes and subdomes denote a gravitationally unstable orogenic root. • U-Pb zircon ages are consistent with dissolution-precipitation cycles of 1 to 2 Ma. • U-Pb ages of dikes indicate that dome development occurred in about 3 Ma. • Convection of a 20 km thick molten crust requires a viscosity lower than 1018 Pa·s. • Diapirism involves a 5–10 km unstable layer and occurred during orogenic collapse. [ABSTRACT FROM AUTHOR]

Abstract Although the upper crust is the most accessible among other crustal units, so far little attention was paid about its role on the continental collision style and on exhumation processes of metamorphic rocks. With this respect, several 2D thermo-mechanical numerical experiments of post-subduction continental collision were performed, which allowed investigating the interplay between surface processes, thermal history and rheology of the upper crust units. The viscous strength of upper and lower plate upper crust (U.U.C. and L.U.C.) was systematically changed, obtaining a reference set of experiments to which subsequently we applied enhanced erosion patterns and variable radiogenic heat productivity of the sediments. We obtained three classes of collisional style: 1) decoupled asymmetric; 2) coupled asymmetric; 3) coupled symmetric. In general, for high-rates of radiogenic heating, a strong U.U.C. leads to one-sided, asymmetric and coupled hot orogen, which shifts to two-sided symmetric for weaker U.U.C. Lower radiogenic heat productivities yield colder orogens, promoting more asymmetric orogens and eventually the decoupling between upper and lower plates. The enhanced erosion leads to narrower and colder orogens, affecting the collisional style only for a relatively strong L.U.C. rheology. Exhumation of high-grade metamorphic rocks mainly depends on the L.U.C. strength: a weak viscous rheology promotes pure shear thickening of the incoming crust in the orogenic front, which inhibits both burial and exhumation processes. Higher viscous strengths promote deeper subduction of the L.U.C., with subsequent heating, delamination, partial melting and exhumation of high-grade rocks via channel flow. Enhanced erosion, although not a necessary condition, favours the extrusion of the partially melted mid-crustal channel. Overall, the numerical experiments reproduce the first order structural and/or metamorphic patterns of several natural cases (Himalayas, Boehmian Massif, Eastern-Central Alps, Apennines) and further suggest that the upper crust rheology is one of the key parameters controlling the collisional style and exhumation processes. Highlights • We present 2D numerical experiments of post-subduction collision. • The rheology of the upper crust is systematically investigated. • The effects of surface processes and radiogenic heating rates were also explored. • Crust rheology and heat sources affect exhumation patterns and the collisional style. • Results are compared with natural examples of collisional systems (i.e. Himalaya). [ABSTRACT FROM AUTHOR]

Abstract The model of an orogenic wedge has been applied to explain the tectonic evolution of many orogens worldwide. Orogenic wedges are characterized by (1) a first-order shear zone which underthrusts the mantle lithosphere and lower crust beneath the adjacent mantle lithosphere and (2) a sequence of second-order upper crustal shear zones which form tectonic nappes. Shear zone formation in the lithosphere is, however, incompletely understood. We perform two dimensional thermo-mechanical numerical simulations of lithospheric shortening to study shear zone formation, propagation and associated wedge formation. The only perturbation in the model lithosphere is a different temperature at the left (1300 ° C) and right (1400 ° C) half of the model bottom. Despite this smooth and weak perturbation, simulations show self-consistent and spontaneous formation of first- and second-order shear zones generating an orogenic wedge. The shear zones are caused by thermal softening and temperature-dependent rock viscosity. Lateral spacing of upper crustal shear zones spans between 30 and 50 km and is controlled by the depth of the boundary between upper and lower crust which acts as mechanical detachment level. Modelled upper crustal shear zones are active for ∼1 to ∼4 My. Surface processes such as sedimentation and erosion influence shear zone orientation, spacing and duration but do not impact fundamental processes of shear zone formation and propagation. Simulations produce both singly-vergent and doubly-vergent wedges. Topographic uplift rates are controlled by the applied bulk shortening rate. The modelled surface uplift and subsidence associated with crustal shear zones could explain major consecutive thrusting events and related sedimentation within flexural basins during the formation of the Helvetic nappe system in Western Switzerland. Furthermore, results for shear zone propagation along a mid-crustal detachment and associated uplift of crustal basement could potentially explain foreland basement-cored uplifts in natural orogens such as the Laramide orogen, Taiwan or the Shillong Plateau. Highlights • Thermal softening causes spontaneous ductile shear zone formation and propagation. • Thermally-activated shear zones form orogenic wedge during lithospheric shortening. • Surface processes influence shear zone propagation but not their formation. • Applications of orogenic wedge model to natural examples are discussed. [ABSTRACT FROM AUTHOR]