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The Central and South‐Central Andes form a "two‐sided" mountain belt bounded by distinct zones of convergence in the forearc and backarc flanks. Previous geodetic interseismic deformation studies found that the forearc to backarc velocity field is better explained when elastic models allow reverse aseismic slip on the Andes eastern‐flank décollement faults. Here, we extend the earlier interpretation of interseismic motion and argue that normal aseismic creep of the Precordillera décollement is required to explain backarc Global Navigation Satellite System displacements during the co‐ and early postseismic phases of the 2015 Illapel, Chile, earthquake. This model significantly reduces the previously reported overlap between coseismic slip and afterslip on the megathrust of this earthquake, consistent with the expectation that these slip modes are spatially partitioned. These findings have direct implications for estimating recurrence interval and slip rate, and for probabilistic seismic hazard analysis on both sides of the orogen. Plain Language Summary: Between consecutive earthquakes in the Central and South‐Central Andes, during what is known as the interseismic phase, the traditional Nazca‐South America two‐plate model underpredicts the surface Global Navigation Satellite System (GNSS) velocities on the east side of the mountain belt. Previous studies show that adding an "Andean microplate," thus forming a three‐plate model, kinematically explains the observed velocity field on both sides of the Andes. We analyzed the GNSS coseismic displacements caused by the Mw 8.3 2015 Illapel, Chile, earthquake, and found that the traditional two‐plate model also underpredicts GNSS observations in the eastern side of the Andes. We show that adding the Andean microplate to the model, in the same manner as for the interseismic phase, and allowing aseismic slip on the detachment interface beneath it significantly reduces the observed surface displacements misfit. We also show that this holds for the displacements observed 50 days after the main shock, evidencing that the detachment geometry slips before, during, and after a large magnitude earthquake. Using the three‐plate model produces fault slip distributions that decrease overlap between local maxima in coseismic and aseismic slip, consistent with expectations from rate‐ and state‐dependent friction laws. Key Points: Revised co‐ and postseismic slip models account for forearc‐backarc coupling by allowing slip on the Argentine Precordillera décollementObserved continuous and survey Global Navigation Satellite System displacements on both sides of the Andes are better explained by models with a décollementAdding a décollement significantly reduces megathrust coseismic slip and afterslip overlap, compatible with rate and state friction law [ABSTRACT FROM AUTHOR]

The Adyrtor multiphase pluton is situated in the easternmost part of the 'Main Structural Line of Tien Shan', or the 'Nikolaev Line', and intrudes the Paleoproterozoic metamorphic sequence representing the oldest (1.8–2.5 Ga) continental basement fragment in the Tien Shan orogenic belt. The intrusions comprise mafic to intermediate (monzodiorite, monzonite, quartz syenite) and silicic (quartz monzonite, monzogranite, and leucogranite-alaskite) rocks. Geochemical signatures of the igneous rocks correspond to high-K calc-alkaline to shoshonitic series intrusions, with a strong A-type granite affinity, emplaced in post-collisional setting. Based on the isotopic U-Pb data, quartz syenite from the Adyrtor intrusions crystallized at 330.7 ± 4.3 Ma, and quartz monzonite – at 329.5 ± 5.8 Ma. Although the ages identified correspond to those of the subduction-related magmatism in the western part of the Middle Tien Shan, geochemical characteristics of the rocks support rather post-collisional setting of the plutons, principally due to a 'scissor-like' closure of the Turkestan paleoocean, starting from the east. Magmatic evolution included a generation of shoshonitic magma by low-degree partial melting of the metasomatically-enriched upper mantle, followed by amphibole fractionation in a deep (lower crustal ?) magma chamber. Then, under the influence of mantle-supplied fluids and heat, granitic magmas in the crustal protolith could have been generated, with further mixing/mingling of the mantle-derived mafic (shoshonitic) magma and mantle-induced crustal granitic magma, followed by the magma fractionation and emplacement at shallower crustal levels. Assimilation of an old continental crust is also envisioned, consistent with the presence of the xenocrystic zircons dated at ca. 1.6 Ga to 2.5 Ga and the A-type granitoid affinity of the igneous rocks. The associated skarn-porphyry W-Mo(-Cu-Au) mineralization is consistent with post-collisional setting of the productive intrusions. This mineralization complements the group of similar deposits and occurrences associated with high-K calc-alkaline to shoshonitic series intrusions in the Middle Tien Shan and globally. The high endowment in W and Mo can be explained by the fertilization of subduction-modified subcontinental lithospheric mantle in these metals, with its further involvement in the magma generation in post-collisional setting. Also, a stronger W-Mo mineralization can reflect a greater role of a crustal protolith in the magma generation, as revealed by the distinct A-type affinity of the igneous rocks. [ABSTRACT FROM AUTHOR]

The Eastern Pontide Orogenic Belt (EPOB), a well-preserved palaeo-magmatic arc, exists south of the Black Sea, from Bulgaria to Georgia. The region, which forms an essential part of the Alpine-Himalayan belt, contains volcanic rocks formed in the Late Cretaceous. This paper aims to investigate the petrogenesis of the Late Cretaceous volcanic rocks using both new and previously existing geochemical and geochronological data. Based on the geochemical features, the studied volcanics are divided into Group I (dacite/rhyolite) and Group II (basalt/basaltic andesite). According to LA-ICP-MS zircon U–Pb data, the crystallization age of Group I is 83.43 ± 0.87 Ma. The εNd(t) values of Group I are −1.4 and + 4.5, and the εNd(t) value of Group II is +3.0. The Lu–Hf isotope data from zircon shows that Group I have positive εHf(t) values (+14.20 - +12.15), and their crustal model age is 240–339 Ma. The εHf(t) values indicate that the Group I rocks are derived from the melting of a depleted mantle source. Whole-rock geochemistry data show that Group II samples were formed by partial melting of metasomatised spinel-bearing lherzolites at shallow depths. It is thought that the Late Cretaceous volcanic rocks are the products of arc magmatism associated with the northward subduction of the Neotethys oceanic lithosphere under the Eurasian plate, and the EPOB was an active continental margin arc during the Late Cretaceous. [ABSTRACT FROM AUTHOR]

Seismic velocity models provide important constraints on Greenland's deep structure, which, in turn, has profound implications for our understanding of the tectonic history of this region. However, the resolution of seismic models has been limited by a sparse network, particularly in northern and central Greenland. We address these limitations by generating new high-resolution Rayleigh-wave phase velocity maps encompassing Greenland and northeastern Canada by processing over three decades of teleseismic earthquake records and incorporating recently added stations in Greenland and Arctic Canada. These phase velocity maps are sensitive to structure from the lower crust down to the sub-lithospheric mantle (25–185 s period). We find significant heterogeneity and a strong correlation between isotropic and anisotropic seismic velocities with inferred geological structure. High seismic velocities associated with cratonic lithosphere are broadly divided into two regions, with a belt of reduced velocity spanning central Greenland, which we interpret as lithospheric erosion resulting from interaction between the Greenland continental keel and the Iceland plume. Within each region, we identify tectonic subdivisions that suggest fundamental differences between the blocks that make up Precambrian Greenland. In the south, the North Atlantic craton (NAC) has a high-velocity keel exhibiting anisotropic stratification. Between the NAC and the cratonic lithosphere further north, the Proterozoic Nagssugtoqidian orogenic belt shows a distinct signature of reduced seismic velocity to |$\sim$| 75 s period, but then appears to pinch out at depth. The northern Greenland lithosphere exhibits significant isotropic heterogeneity, with a distinct core of high velocities in the northwest (⁠|$\sim$| 55–75 s period) giving way to a set of distinct east-west trending high-velocity belts at longer periods. At all periods sensitive to the lithospheric mantle in this region, anisotropic fast orientations are E–W, consistent with a north–south Precambrian assembly of the Greenland shield. In contrast to the NAC, there is no evidence of anisotropic stratification in the northern part of the cratonic keel. Based on both isotropic and anisotropic phase-velocity anomalies, we suggest that the Phanerozoic Caledonian and Ellesmerian-Franklinian fold belts are relatively thin-skinned features onshore Greenland, though the Caledonian belt may have a stronger signature off the east coast. At the longest periods, a prominent low-velocity anomaly initially centred on Iceland migrates northwards and spreads beneath central-eastern Greenland. Coupled with NW–SE trending anisotropy, this feature is interpreted as the effect of mantle flow radiating outward from the Iceland plume and interacting with the eroded Greenland lithosphere. [ABSTRACT FROM AUTHOR]

The tectonic regime is an important factor controlling the formation of ore deposits, and magmatic rocks generated in different tectonic regimes are characterized by contrasting ore affinities and mineralization styles. A series of early Carboniferous volcanogenic massive sulphide (VMS) deposits occur in the western segment of the Dananhu Arc in the Central Asian Orogenic Belt. In contrast, coeval magmatic rocks in the middle segment are devoid of VMS copper mineralization but host porphyry copper deposits. However, the relationship between tectonic setting and mineralization still needs to be clarified. Herein, we synthesize the new and existing geochemical data of the Carboniferous arc rocks of the Dananhu Arc, showing diverse arc magmatism and contrasting Cu mineralization styles in the western and middle segments. Magmatic rocks in the western segment are consistent with normal island arc origin. In contrast, magmatic rocks in the middle segment of the Dananhu Arc have adakite-like affinities. The magmatic rocks in the western segment were derived from the partial melting of the juvenile lower crust triggered by slab rollback in an extension setting. In contrast, the rocks in the middle segment originated from partial melting of the subducted slab that was triggered by flat subduction. The extension setting coupled with high temperature magmatic activity induced the circulation of the hydrothermal fluids, which were critical to the development of the Xiaorequanzi VMS deposit. Copper would become progressively enriched in the fractionating melt under the high–fO2 condition, and the compressional regime caused by flat subduction reduces the 'leakage' of hydrothermal fluids, which are favourable for the formation of the porphyry mineralization in the middle segment. It is, therefore, evident that variations in the tectono-magmatic setting across the Dananhu Arc played an important role in generating the diversity of Cu deposit types and variable ore affinities throughout the Eastern Tianshan. [ABSTRACT FROM AUTHOR]

In this paper, we study the tectonic stress around the South Caspian Basin (SCB), which includes the Kopeh Dagh, Alborz, Talesh, eastern Greater Caucasus mountain belts, the Apsheron sill, and the Balkhan-Ashkabad fault zone. We apply the stress inversion to focal mechanisms of 410 mainshocks that have occurred over the last 69 years. These mechanisms indicate that the surrounding fault zones of the SCB exhibit diverse types of faulting, ranging from thrust to strike-slip, normal, and their combinations. The results of the stress inversion align with the kinematics of the major fault zones bounding the SCB and emphasize the spatial heterogeneity of the stress field in this region. The region is predominantly under compression, but transpressive and strike-slip regimes are also present. This highlights the role of obliquely oriented basement faults with respect to the maximum horizontal compressive stress (SHmax) in accommodating deformation through convergent zones. The orientation of the SHmax is in the NE to NNE direction in the Kopeh Dagh, Alborz, Talesh, and Ashkabad-Balkhan fault zones, being rotated to NNE-N in the Greater Caucasus. The orientation of the SHmax relative to the convergence direction of the Arabian and Eurasian plates indicates that the Arabian-Eurasian oblique convergence-derived tectonic stress is the primary contributor to the total stress and deformation in this region. [ABSTRACT FROM AUTHOR]

We present the latest magnetotelluric models on profiles in the northeastern part of Slovakia and the southeastern part of Poland. These models are focused on deciphering the tectonic structures at the contact of the Inner Carpathians with the European Platform in this area. For the Inner Carpathian block, we propose the term Carpathia. Profile SA-01 shows shallower structures and the parallel MT-05 profile shows deeper structures. These models are also correlated with the seismic profile CEL-05. All results are compatible and show an original subduction-collisional structure, which was later replaced by a transpressive-transtensional one. The most striking structures are thick highly conductive subhorizontal zones in the middle crust and a tectonically controlled deep vertical conductive structure—the Carpathian conductive zone. Other significant structures, which also appear in the seismic section, are back thrusting of Flysch Belt and the Klippen Belt basement (Penninic crust) uplift. [ABSTRACT FROM AUTHOR]

ABSTRACT To reconstruct the detailed location of proto‐Japan around northeastern Gondwana during the early Palaeozoic, this article presents detrital zircon U–Pb age spectra for lower Palaeozoic metamorphic complexes and Silurian–Devonian strata from the western margin of the South Kitakami belt in northeast Japan. Psammitic and siliceous schists have youngest age peaks ranging from the Ordovician (479–458 Ma) to early Silurian (ca. 439 Ma). Sandstones have youngest age peaks varying from the early Silurian (ca. 435 Ma) to Late Devonian (370–360 Ma). The U–Pb age spectra exhibit major peaks at 510–500, 480–470, and 450–440 Ma. Excluding the Upper Devonian sandstones, significant age peaks occur at 650–550 and 1300–900 Ma. These data can be interpreted as a Pacific Gondwana signature, indicating a tectonic association with the Terra Australis Orogen that developed along the northeastern Gondwanan margin and Paleo‐Pacific Ocean, extending from eastern Australia (i.e., the Thomson, Lachlan, and Delamerian orogens) to Antarctica (i.e., the Ross Orogen). In northeast Asia, the Pacific Gondwana detrital zircons and 480–470 Ma zircons occur in the Bainaimiao arc belt along the northern margin of the North China Craton and in the Jiangyu continental arc in the Jilin area. The magmatic arcs of proto‐Japan and these regions were part of the Terra Australis Orogen during the Ordovician–early Silurian. A decrease in the proportion of Pacific Gondwana detrital zircons in Upper Devonian strata may be due to multistage trench retreat, such as that recognized in the Tasmanides in eastern Australia, which corresponds to the northern Terra Australis Orogen. [ABSTRACT FROM AUTHOR]

Research on the geological process of the Xing'an -- Mongolia Orogenic Belt has attracted the attention of scholars both domestically and internationally. Its genesis and tectonic location may help revealing the geological processes asscoaited with the evolution of the Xing'an -- Mongolia Orogenic Belt. This study focuses on the development of the Permian granitic complex in Jielin Ranch, and we conduct systematic geological, petrographic, zircon U-Pb chronology, Hf isotope, and geochemical tracing of rock elements for evidence. The results show that the granitic complex is mainly composed of monzogranite and syenogranite, which obtained zircon U-Pb ages of 291.1 ± 1.1 Ma and 260.8 ± 1.1 Ma, respectively. The monzogranite and syenogranite are all acidic and aluminum rich rocks, and the monzogranite is a potassium rich, high potassium calcium alkaline rock series with relatively low REE content, high degree of fractionation, and insignificant europium anomalies, enriched with LILE (Rb, Th, U, K), deficient elements such as Ba, Sr, Nb, Ti, and P, εHf(t) values are from +4.1 to +7.0 (TDM2=1130-920 Ma). Geochemistry shows that the monzogranite belongs to high fractionation of I-type granite, which formed in a subduction-compressional or extension tectonic environment, and Middle Neoproterozoic lower crust rocks as the major source material of magma. The syenogranite is a potassium high potassium transitional rock series with a high rare earth content (214 x 10-6~325 x 10-6), low LREE/HREE (2.54-6.41), δEu (0.04-0.15) and the typical "four component effect" fractionation mode is enriched in large ion lithophilic elements such as Rb, Th, K, and strongly depleted in elements such as Ba, Sr, Nb, Ta, Ti, P, εHf(t) values are from +4.2 to +8.6 (TDM2=738-1228 Ma), suggesting the characteristics of an "A2 type" granite. The magma originated from partial melting of the lower crust of the Middle and Neoproterozoic with the participation of mantle derived melts, and was formed in a back-arc extensional environment. This suggests that the study area experienced a subduction-compressional or extension tectonic environment during the early Permian and a brief backarc extension process in the late Permian. [ABSTRACT FROM AUTHOR]

In order to distinguish terrestrial material sources in the Okinawa Trough (OT), this study analyzed four surface sediment samples from the northern, middle, and southern parts of the OT using detrital zircon U-Pb age analysis. The detrital zircon age distributions in the northern Okinawa Trough (N-OT) predominantly fall into 1,000-2,300 Ma and 100-600 Ma age groups. In contrast, in the middle Okinawa Trough (M-OT) and southern Okinawa Trough (S-OT), the detrital zircon age groups of 100-600 Ma and 600-1,000 Ma increase significantly, while the age groups of 1,000-2,300 Ma and >2,300 Ma decrease. Detrital zircons from the N-OT primarily originate from the Yellow River and mixed with the Old Yellow River, while those from the M-OT come mainly from the Yellow River, Yangtze Rivers, and East China Sea. And Zhuoshui River maybe a potential source for the M-OT. The detrital zircons from the S-OT are mainly influenced by the Yangtze River, with some effects from the Lanyang River. This study utilizes detrital zircon U-Pb age analysis to gain a better understanding of the terrestrial material sources in various regions of the OT. Most of the zircon grain are coarse, with grain sizes of 40-150 µm long and 30-100 µm wide in the N-OT, smaller in the M-OT and S-OT in this study, which are probably not modern deposits, but the products in the low sea level period of last glaciation mixed with modern sediments. The transport and sedimentation processes reflect the comprehensive influence of sea level change, Kuroshio Current, river input, East Asian monsoon and other factors from last glaciation to present. [ABSTRACT FROM AUTHOR]

The Tianshan Orogenic Belt underwent a series of complex tectonic changes from the Late Palaeozoic to the Cenozoic, providing key insights into the evolution of the Central Asian Orogenic Belt (CAOB). The continuous Permo-Triassic sedimentary records of the Turpan Basin are among the best archives of the tectonic evolution of the Tianshan Orogenic Belt. However, the evolution of the Turpan Basin during this period is poorly understood. Using detrital zircon U-Pb chronology and geochemistry, we reconstructed the source-to-sink system changes and the basinal tectonic evolution in the Permo-Triassic, thus providing new evidence of its tectonic evolution. Our results show that the Early-Middle Permian source-to-sink systems of the Turpan Basin were mainly proximal and constrained by horst and graben landforms due to internal extension formed in the back-arc setting during accretionary orogenesis in Central Asia. In the Late Permian-Early Triassic, exotic sources, including the North Tianshan and Yili Block-Central Tianshan, dominated the source-to-sink system, which suggests that rifts were infilled and expanded across the entire thermal sag basin. In the Middle-Late Triassic, the sediment sources diversified, with external and internal provenances revealing that a foreland basin formed with thrusting at the southern margin, and the intraplate-associated Bogda forebulge experienced initial uplift, signifying that the CAOB gradually changed from an accretionary to an extrusive orogeny. The three evolutionary episodes of the Turpan Basin implicated the long-lasting effect of the orogenic process from the final closure of Palaeo-Asian Ocean to the following build-up of the CAOB. [ABSTRACT FROM AUTHOR]

Earth owes much of its dynamic surface to its bimodal hypsometry, manifested by high-riding continents and low-riding ocean basins. The thickness of the crust in the lithosphere exerts the dominant control on the long-wavelength elevations of continents. However, there is a limit to how high elevations can rise by crustal thickening. With continuous crustal thickening, the mafic lower crust eventually undergoes a densifying phase transition, arresting further elevation gain--an effect clearly observed in modern orogenic belts. On early Earth, lower crust densification should also limit how high a thickening crust can rise, regardless of the thickening mechanisms. We suggest that lower crust densification combined with a thicker oceanic crust in the Archean may have limited the whole-Earth topographic relief to 3 to 5 kilometers at most--half that of the present day. Unless the oceans were far less voluminous, limited relief would inevitably lead to a water world on early Earth. [ABSTRACT FROM AUTHOR]

The global demand for lithium is steadily increasing, driving an increased focus on exploration efforts worldwide. Lithium, a crucial metal for lithium-ion batteries (LIBs) used in renewable energy technologies, is vital in the global drive to reduce carbon emissions. India’s ambitions to become a manufacturing hub for LIBs and achieve 100% electric vehicle (EV) sales by 2030 require significant quantities of lithium. However, challenges due to limited domestic reserves within the country, prompting efforts to define new exploration targets and develop existing lithium occurrences. Recent discoveries in northern Jammu and Kashmir and southern Karnataka highlight promising lithium deposits. This study focuses on India’s lithium exploration within pegmatite belts across various cratonic blocks, identifying significant potential for lithium exploration and mining. Notably, spodumene-rich pegmatites are found in Karnataka’s Dharwar Craton, while lepidolite-rich pegmatites exist in Rajasthan’s Aravalli-Delhi Fold Belt and the Madhya Pradesh-Chhattisgarh region. Regions like Bihar-Jharkhand, Maharashtra, Odisha, and Assam-Meghalaya also exhibit promise for lithium exploration. These findings emphasize the diverse lithological settings where lithium exploration can be strategically pursued in India. This study recommends adopting modern exploration techniques and developing cost-effective extraction technologies to advance India’s lithium exploration efforts. These initiatives are crucial in meeting the escalating demand for lithium and advancing India’s clean energy objectives in the transition to renewable energy sources. [ABSTRACT FROM AUTHOR]

The Qilian orogenic belt (QOB) located in the northeast margin of the Tibetan Plateau is featured by remarkable crustal thrusting and shortening, providing a key natural example to understand the lithospheric deformation of the Tibetan Plateau. Two types of continental collision are observed in the QOB: lithosphere subduction beneath Southern Qilian and crust underthrusting of Alxa terrain along the North Border Thrust (NBT). Deep seismic reflection profiles reveal complex stress field evolution, including compressional deformation in the lower crust, extensional deformation in the upper crust, and detachment deformation in the middle crust. In this study, we use 2D numerical modeling to investigate the dynamics of these two different collision types and the evolution of Qilian uplift. Model results suggest three patterns of continental collision, i.e., crust underthrusting follows lithosphere subduction, lithosphere subduction and the failed underthrusting/subduction. The key factors that may influence model evolution, including crustal rheology, convergence direction and rate, are systematically investigated. Our model results are further compared to observations, suggesting that lower convergence rate and crust underthrusting along NBT likely control the uplift and crust stress stratification of the QOB. [ABSTRACT FROM AUTHOR]

The East Kunlun Orogenic Belt is an essential part of the Qin-Qikun composite orogenic system, the most crucial orogenic belt in Qinghai Province, and an important gold ore-producing area in China. The Gouli gold field in its eastern section is one of the most important gold fields discovered in the belt in recent years. The Mailong mining area is an important gold mining area in the Gouli ore-concentrated area. The area has experienced frequent and intense magmatic activity, with intrusive rock bodies extensively exposed and intersected by a complex network of fault structures, providing excellent geological conditions for the formation of gold deposits. However, it is difficult to explore due to high altitude, poor transportation, and shallow coverage. This study used an audio magnetotelluric sounding method to track the deep direction and inclination of known mineral belts in the Mailong mining area, and identified mineral exploration targets, providing a basis for mineral exploration. Subsequently, a gold ore body was discovered through drilling verification, achieving a breakthrough in deep mineral exploration. The electromagnetic exploration method works well for exploring structurally altered rock-type gold deposits in plateau desert areas, and combined with the results of this electromagnetic exploration, a metallogenic geological model and genesis process of the Mailong mining area has been constructed. [ABSTRACT FROM AUTHOR]

The Great Xing'an Range (GXR) is a significant belt of polymetallic deposits located in the eastern segment of the Central Asian Orogenic Belt. The recently found Huoluotai porphyry Cu (Mo) deposit is situated in the northern GXR region in northeastern (NE) China. The deposit has been studied extensively using field geology and geochronological methods, which have identified two distinct mineralization events. These events include an early occurrence of porphyry-type Cu (Mo) mineralization and a later occurrence of vein-type Cu mineralization. Prior geochronology investigations have determined an approximate age of 147 Ma for the early porphyry-type Cu (Mo) mineralization. 40Ar/39Ar dating of K-feldspar of the altered Cu-mineralized quartz diorite porphyry veins for the overprinting vein-type Cu mineralization provides plateau ages of 123.1 ± 1.5 Ma, 122.3 ± 2.8 Ma, and 122.2 ± 0.4 Ma. Sulfide S-Pb isotope compositions of the two mineralization events suggest that both have a magmatic source. The origin of ore-forming metals displays the features of a crust–mantle mixing origin. The regional extensional tectonic setting in NE China during the Early Cretaceous was caused by large-scale lithosphere delamination and upwelling of the asthenospheric mantle. These processes were triggered by the rollback of the Paleo-Pacific Plate. The tectonic event in question resulted in the lithospheric thinning, significant magmatic activity, and mineralization in NE China. [ABSTRACT FROM AUTHOR]

The Qilian Orogenic belt is one of the typical orogenic belts globally and a natural laboratory for studying plate tectonics. Many researchers have studied the ophiolite and high pressure and ultra-high pressure metamorphic rocks in the Qilian orogen and obtained valuable achievements. However, a hot debate exists on the basement property, the distribution of ophiolite, and the boundaries of tectonic units. Large-scale high-precision aeromagnetic surveys have recently been conducted in the Qilian Orogenic belt and adjacent areas. In this study, we are trying to analysis the tectonic framework of the Qilian Orogen using 1:500, 000 aeromagnetic data. The results provide geophysical perspectives for studying the structural framework and deformation of this area. According to the aeromagnetic ΔT anomaly map, the central and Southern Qilian have the same magnetic anomaly feature that noticeably differs from the North Qilian Orogenic belt and the Qaidam Block. This result indicates that the central and Southern Qilian have a unified magnetic basement and differ from the North Qilian orogenic belt and Qaidam Block. The map shows the distribution of ophiolite in the North Qilian orogenic belt. Linear magnetic anomalies represent the ophiolites because the mafic–ultramafic rocks usually have high magnetic susceptibility. The ophiolite belts are continuously distributed in the western part of North Qilian orogenic belt and have a large scale. However, the scale of the ophiolite belt and the outcropping of mafic–ultramafic rocks reduces when they pass through Qilian County to the east. The results indicate differences in the evolution process between the eastern and western parts of North Qilian, with Qilian County as the transition zone. This study also systematically defines the geophysical boundaries of the Qaidam Block, Qilian Block, North Qilian Orogenic belt, and Alxa block. It is proposed that the sinistral displacement of the Altun Fault is adjusted and absorbed by the series of NE-trending faults in the Qilian orogen and merge into the Longshoushan–Gushi Fault. The extension of the North Qilian Orogenic belt is strengthened by the neotectonics movement along the shearing direction, which separated the North Qilian Orogenic belt into several segments and formed a series of northeast-trending faults. [ABSTRACT FROM AUTHOR]

The Canadian Cordillera marks a transition region from the current plate boundary through the Phanerozoic Cordilleran orogen to the Precambrian cratons. Knowledge of the subsurface structure of western Canada has been greatly advanced by seismological investigations during the past two decades, pioneered by the Lithoprobe project and, more recently, by regional passive seismic arrays. In this study, we construct a new model (WCANM22) of crustal thickness and P‐ to S‐wave velocity ratio, or Vp/Vs, by compiling receiver function data from 473 stations and existing constraints from over 2,600‐km long active source experiments. Our model covers a broad swath (about 1/4) of the land area of North America (105°–140°W, 48°–72°N) and shows an overall flat Moho beneath the Cordillera with an average depth of ∼36 km and a standard deviation of 3 km across orogenic belts. This study provides a comprehensive catalog of Vp/Vs in western Canada and reveals a moderate correlation between Poisson's ratio and the age of crustal domains. The average Vp/Vs values are 1.72, 1.79, and 1.82 for the Phanerozoic Cordillera, Proterozoic Cratons, and Archean‐aged Medicine Hat Block, respectively, suggesting continued modifications to crustal composition through episodic tectonothermal events. This distinct trend in western Canada sheds new light on the debated role of secular changes in the composition of continental crust. Plain Language Summary: The crust of western Canada consists of complex tectonic domains that collided during a protracted geological history dating back to 4 billion years ago. To uncover crustal structures and the associated tectonic processes, we systematically determine the depth to the base of the crust (Moho depth) and compressional‐to‐shear seismic wave speed ratio (Vp/Vs) beneath 473 seismic stations integrated with the results from existing active source experiments. Along a northwest‐southeast profile, Vp/Vs ratios exhibit a gradually increasing trend with the age of the crust. This variation in Vp/Vs may be caused by modifications to the crustal composition during the geological evolution of western Canada. Key Points: We construct a new model of crustal thickness and Vp/Vs of western Canada from integrated active and passive seismic constraintsWe propose that increased Vp/Vs with the age of tectonic domains may reflect a secular change in crustal compositionWe highlight key tectonic boundaries at crustal depth formed during the collision and assembly of cratons [ABSTRACT FROM AUTHOR]

Curved mountain belts are spectacular natural features that contain crucial 3D information about the tectonic evolution of orogenic systems in the absence of other kinematic markers. The Mesozoic units exposed in the Mexican Fold and Thrust Belt in northeastern Mexico show a striking curvature, whose kinematic history has not been studied. The existing tectonic models of the region simply assumed the shape of the tectonic units as an inherent feature to the orogen. We investigated the kinematic history of this curvature through paleomagnetism and rock magnetism analyses, coupled with an exhaustive review of available published literature. The studied data sets indicate a protracted history of (re)magnetizations that occurred during the Late Jurassic‐Paleocene times at least during the Late Jurassic, Cretaceous and early Eocene. More significantly, they show significant counterclockwise rotations in the northern flank of the curvature and moderate clockwise vertical axis rotations along its southern flank. This data set suggests that the Sierra Madre Oriental was a linear belt that experienced oroclinal bending or buckling during the Cretaceous to early Eocene period (120–50 Ma). Plain Language Summary: The geological history of the American Cordillera is complex due to its extensive geological history. We have investigated a section of this Pacific‐Panthalassa region: the remarkable curved sector of the Mexican Fold and Thrust Belt in northeastern Mexico. This winding area, known as the Sierra Madre Oriental, potentially holds important clues about the evolution of the North American crust. To contribute to a better understanding of this area and to complement the scarce geophysical and geological studies, we used the magnetic properties of rocks and reviewed existing published research to investigate. We've uncovered a complex history of rock magnetizations with at least two main events dating back to the Late Jurassic and Cretaceous periods. Our findings also reveal that these mountain ranges were rotated from their original position on vertical axes, suggesting they were originally linear and were bent or buckled during the period from approximately 120 to 50 million years ago. Key Points: With Paleomagnetism we explore the nature of the striking curvature of the Northeastern section of the Mexican Fold‐and‐Thrust BeltOur study shows evidence of Orocline bending or Buckling during the major horizontal crustal shortening event of the Mesozoic in Mexico [ABSTRACT FROM AUTHOR]

Sedimentary basins record crustal-scale tectonic processes related to the construction and demise of orogenic belts, making them an invaluable archive for the reconstruction of the evolution of the North American Cordillera. In southwest Montana, USA, the Renova Formation, considered to locally represent the earliest accumulation following Mesozoic–Cenozoic compressional deformation, is widespread but remains poorly dated, and its origin is debated. Herein, we employed detrital zircon U-Pb and (U-Th)/ He double dating and sanidine 40Ar/39Ar geochronology in the context of decimeterscale measured stratigraphic sections in the Renova Formation of the Muddy Creek Basin to determine basin evolution and sediment provenance and place the basin-scale record within a regional context to illuminate the lithospheric processes driving extension and subsidence. The Muddy Creek Basin is an extensional half graben in southwest Montana that is ∼22 km long and ∼7 km wide, with a >800-m-thick sedimentary package. Basin deposition began ca. 49 Ma, as marked by multiple ignimbrites sourced from the Challis volcanic field, which are overlain by a tuffaceous fluvial section. Fluvial strata are capped by a 46.8 Ma Challis ignimbrite constrained by sanidine 40Ar/39Ar dating. An overlying fossiliferous limestone records the first instance of basinal ponding, which was coeval with the cessation of delivery of Challis volcanics–derived sediment into the Green River Basin. We attribute initial ponding to regional drainage reorganization and damning of the paleo–Idaho River due to uplift and doming of the southern Absaroka volcanic province, resulting in its diversion away from the Green River Basin and backfilling of the Lemhi Pass paleovalley. Detrital zircon maximum depositional ages and sanidine 40Ar/39Ar ages show alternating fluvial sandstone and lacustrine mudstone deposition from 46 Ma to 40 Ma in the Muddy Creek Basin. Sediment provenance was dominated by regionally sourced, Challis volcanics–aged and Idaho Batholith– aged grains, while detrital zircon (U-Th)/He (ZHe) data are dominated by Eocene cooling ages. Basin deposition became fully lacustrine by ca. 40 Ma, based on an increasing frequency of organic-rich mudstone with rare interbedded sandstone. Coarse-grained lithofacies became prominent again starting ca. 37 Ma, coeval with a major shift in sediment provenance due to extension and local footwall unroofing. Detrital zircon U-Pb and corresponding ZHe ages from the upper part of the section are predominantly Paleozoic in age, sourced from the Paleozoic sedimentary strata exposed in the eastern footwall of the Muddy Creek detachment fault. Paleocurrents shift from south- to west-directed trends, supporting the shift to local sources, consistent with initiation of the Muddy Creek detachment fault. Detrital zircon maximum depositional ages from the youngest strata in the basin suggest deposition continuing until at least 36 Ma. These data show that extension in the Muddy Creek Basin, which we attribute to continued lithospheric thermal weakening, initiated ∼10 m.y. later than in the Anaconda and Bitterroot metamorphic core complexes. This points to potentially different drivers of extension in western Montana and fits previously proposed models of a regional southward sweep of extension related to Farallon slab removal. [ABSTRACT FROM AUTHOR]

The Tian Shan is a typical active intracontinental orogenic belt that is driven by the ongoing indentation of India into Eurasia. However, the geological features of Quaternary deformation, especially in the easternmost sector near Harlik Mountain, remain elusive. Field observations, topographic analysis, and Electron Spin Resonance (ESR) dating were employed to comprehensively assess the deformation features and evaluate the deformation pattern for this region during the Quaternary period. The results disclose evidence of deformation in the northern and southern foreland basins of Harlik Mountain. In the Barkol Basin to the north, crustal shortening results in the formation of surface scarps and folds, indicating north-directed thrusting, with a shortening rate of ~0.15 mm/yr. In the Hami Basin, the north-directed thrust elevates the granites, which offset the alluvial fans, with a shortening rate of ~0.18 mm/yr. Together with the shortening along the boundary fault, the aggregated north–south shortening rate is approximately 0.69 mm/yr in the easternmost Tian Shan, corresponding with the differential motion rate between the north and south Harlik Mountain revealed by the GPS velocity. These findings imply that, distal to the collision zone, tectonic strain in the eastern Tian Shan is primarily accommodated through the reactivation of pre-existing strike–slip faults, with crustal shortening concentrated at the overlapping position of parallel northeast-trending left-lateral strike–slip faults. [ABSTRACT FROM AUTHOR]

In the study of the Khanmeikhoi Formation of the central zone of the Kharbei amphibolite–gneiss complex, it was shown that the amphibolites, schists, and plagiogneisses common here form two primary igneous series: low-alumina tholeiitic metabasalts of normal alkalinity and a differentiated series of high-alumina rocks from metatrachybasalts to metarhyolites with high alkalinity. According to the zoning of garnets, progressive and regressive branches of metamorphism are recorded, the peak conditions of which, according to calculations using the winTWQ program, correspond to the high-temperature stage of the amphibolite facies at high pressures (T = 690–750°C, P = 8.1–9.4 kbar). For the first time, metamorphic zircon from Grt-Bi plagiogneiss with low Th/U ratios of 0.01–0.04 and weakly expressed positive cerium (Ce/Ce* = 1.4–1.7) and negative europium (Eu/Eu* = 0.7–0.9) has been identified in the anomalies, the age of which, according to the results of the U–Pb LA-ICP-MS isotope method, is estimated to be Early Carboniferous (359–341 Ma). This time apparently characterizes the transition from the peak of metamorphism to the regressive stage associated with the exhumation of rocks. The results obtained indicate the formation of the Kharbei amphibolite–gneiss complex during the formation of the Ural orogen and allow us to consider it as an indicator of Paleozoic collision processes. [ABSTRACT FROM AUTHOR]

New U–Th–Pb (SIMS)–geochronological, petro-geochemical, and Sr–Nd isotopic data for granitoids of three plutonic complexes (Sakhani, Omchikanda, and Arga–Emneken), located in the joint area of the two large batholih belts of the Verkhoyan–Kolyma fold area, Glavnyi and Severnyi, are presented. The Valanginian–Hauterivian age of the granitoids of all three complexes is established. The similarity of the granites and leucogranites of the Omchikanda and Sakhani complexes to the I–S-type granites and the similarity of the Arga–Emneken granitoids to the I-type granites are shown. The petro-geochemical peculiarities of the granitoid composition indicate a metasedimentary source for the granites and leucogranites of the Omchikanda and Sakhani complexes and a metamagmatic (amphibolitic) source for granitoids of the Arga–Emneken Complex. Sr–Nd isotopic data show that the granitoids were melted from different crustal sources, in which there are various proportions of mature material of the continental crust. The totality of geological and newly obtained geochronological, petro-geochemical, and isotopic data allow us to suppose a collisional setting of their formation in the terminal Valanginian–Hauterivian stage of collision between the Kolyma–Omolon microcontinent and the Siberian continent. [ABSTRACT FROM AUTHOR]

In the Altai Accretionary Wedge, several periods of Barrovian‐ and Buchan‐type metamorphic cycles were dated from Ordovician to Permian. However, the timing and link between these cycles are not clear, and their causes are debated. In order to contribute to the understanding of Barrovian‐ to Buchan‐type evolution of the accretionary wedges, we studied an area composed of three parallel belts in the easternmost extremity of the Hovd domain located in Mongolian Altai Zone: garnet gneiss in the north, garnet–staurolite–kyanite schist overprinted by ±sillimanite±cordierite±andalusite‐bearing assemblages in the centre and garnet–sillimanite gneiss in the south. Petrography, garnet zoning and thermodynamic modelling indicate that the garnet gneiss from the northern belt records burial from ~510°C and ~3–4 kbar to ~600°C and ~5 kbar, followed by heating to ~660°C and decompression to ~4.5 kbar. The garnet–staurolite–kyanite schist from the central belt records burial from ~550°C and ~3–4.5 kbar to ~640–680°C and ~7 kbar, followed by decompression to the sillimanite stability field at ~650°C and ~6 kbar. Crystallization of cordierite, andalusite, late muscovite and chlorite in some samples indicates cooling on decompression to ~540°C and ~3.5 kbar. In the southern gneiss belt, the garnet–sillimanite gneiss with almost unzoned garnet suggests re‐equilibration at ~6 kbar and ~710°C. In situ U–Pb monazite and xenotime dating carried out inclusions in porphyroblasts and matrix grains revealed Carboniferous and Permian ages. The monazite and xenotime from gneisses of the northern and southern belts record Carboniferous and Permian ages, which are interpreted as Carboniferous crystallization at c. 347 Ma associated with metamorphic peak, followed by Permian (re)crystallization at c. 300 and 283 Ma. In the central belt, rare Carboniferous xenotime grains in a garnet–staurolite–kyanite–andalusite–muscovite schist indicate a possible Carboniferous age of the prograde metamorphism. Predominant ages between c. 280 and 260 Ma recorded by monazite are interpreted as a result of complete recrystallization during an LP metamorphic overprint. The Carboniferous ages from the gneisses can be interpreted as constraining the timing of the exhumation of deep crustal rocks to shallow crustal levels. This event corresponds to the formation of crustal‐scale migmatite‐magmatite domes in the Mongolian Altai Zone. The prograde Barrovian assemblages in the central schist belt are interpreted as having formed contemporaneously during burial in a synform between the migmatite‐magmatite domes. The Permian ages reflect LP–HT metamorphism, best recorded by the Buchan‐type assemblages in the central schist belt, and are related to massive heat flux from tectonically mobile deep partially molten crust. Correlation with similar Barrovian‐ and Buchan‐type episodes from the Chinese Altai Zone indicates multiple compressional and extensional events in the upper plate accretionary wedge, probably related to retreating and advancing modes of the subduction zone. [ABSTRACT FROM AUTHOR]

Using data from the regional broadband dense temporary array deployed by the ChinArray project, we applied the three-dimensional (3D) Kirchhoff migration method of the teleseismic P-wave receiver function to investigate discontinuity structures of the mantle transition zone (MTZ) in the central and western parts of the North China Craton (NCC) using a high-resolution 3D velocity model of the East Asian region. The results show that the 410-km discontinuity beneath the Datong Volcano is depressed by ∼10 km, indicating the presence of a high-temperature anomaly near the depth of 410 km, which is likely related to small-scale mantle upwelling caused by the dehydration of the stagnant Pacific Plate in the MTZ. The upwelling of hot material provides a heat source for surface magmatic activity. Beneath the Bohai Bay Basin, significant subsidence of the 660-km discontinuity is observed, and the transition zone here is extensively thickened. It's suggested that the anomalies in this region are related to the stagnation of the Pacific slab in the MTZ. Although the thickness of the transition zone west of the North-South Gravity Lineament appears normal, we propose that the subducting front of the Pacific slab did not cross the gravity lineament in the NCC. In comparison, the small-scale subsidence of the 660-km discontinuity and the thickening of the MTZ observed north of the Hannuoba Volcano likely indicate that the slab crossed the gravity lineament at its turning point and remained in the MTZ. Furthermore, a local thickening of the MTZ is observed in the Dabie orogenic belt of the Qinling Mountains. This is believed to be a combined effect of lithospheric delamination into the transition zone in the lower Yangtze region and the stagnation of the Pacific Plate. [ABSTRACT FROM AUTHOR]

The Paleoproterozoic Jahaj–Govindpura Formation of the Raialo Group of Delhi supergroup, India exposes volcanic and volcaniclastics rock at multiple stratigraphic levels and hence, provides a unique scope for the study of volcaniclastics of varying rheology and their bearing on the tectono-magmatic setting of the basin. From a detailed field study in three spatially disparate sections, associated sedimentary facies types and textural evidences such as clast annealing, deformation in pumice fragments, eutaxitic foliation and shattered crystals, the volcaniclastics are documented as pyroclastic flow (VLC 1), welded tuff (VLC 2), clast-/matrix-supported boulder pyroclastic conglomerate (VLC 3), and pyroclastic fall deposits (VLC 4). Whereas, VLC 1 and VLC 2 are identified as subaqueous, VLC 3 and VLC 4 are grouped under subaerial categories. The facies distribution of volcaniclastics and eastward paleocurrent motif from associated sedimentary facies is indicative of proximal-distal relationship varying between subaerial to sub-marine depositional settings. From collation and comparison of available geochemical data (major, trace element, and REE) of volcanic rock and new geochemical data generated from volcaniclastics under the present study, it is inferred that the source magma was more basic (low SiO2 and high MgO) resembling tholeiitic to calc-alkaline island-arc source composition while a more intermediate to felsic composition is posited for the volcaniclastics. Considering the ca-1876 Ma time frame of the basin and a subduction-related magmatic character for the volcaniclastics, a possible Orosirian subduction margin, related to the 'Columbia' supercontinent, in the vicinity of the Bayana sub-basin in North Delhi fold belt is suggested. Highlights: Primary subaerial to subaquous volcaniclastics described from Paleoproterozoic Bayana sub-basin, North Delhi Fold Belt, India. Unequivocal petrological features allowed subaerial and subaquous emplacement of volcaniclastics. Depending on associated sedimentary facies and paleocurrent motif a proximal-distal relationship established between different volcaniclastic facies. Whereas volcanics register tholeiitic to calc-alkaline composition, a more intermediate to felsic composition is inferred for the volcaniclastics. From geochemical signature, an overall compressional tectonic set-up is suggested with riftogenic Bayana basin a part of it. It is argued that in terms of tectonic and depositional setting, the Bayana basin shares a common geological history with contemporary basins in North China Craton. [ABSTRACT FROM AUTHOR]

The folded flank of the Bengal Basin (i.e., Chittagong–Tripura Fold Belt, CTFB) is the westward prolongation of the Indo-Burman Ranges (IBR), which developed as accretionary wedge due to the oblique subduction of the Indian Plate beneath the Burmese Plate. The tectonic evolution of this area and its control on the paleo-depositional environment has been archived in the Neogene outer IBR. Within the outer IBR (i.e., CTFB), the deformation intensity and ages of the tectonic deformation, in general, decrease from east to west. However, there is still some disagreement regarding the tectonostratigraphic evolution of this area, especially during the Pliocene and onward. The present study attempts to synthesize geomorphic, structural, lithofacies, and deformation kinematics of the area to infer the tectonostratigraphic evolution of the Bandarban Anticline and its adjacent areas. Based on geomorphic attributes and fault-related deformation structures, two sets of faults, longitudinal (NNW–SSE) and transverse (E–W), have been identified. The longitudinal faults are thrust faults running through the flanks of the structure; the fault on the western flank is the main thrust, while the fault on the eastern flank is the back thrust of the main thrust. The transverse faults are strike-slip faults that partially control the course of the antecedent Sangu River. Three major facies associations: shelf/shallow marine (FA-1; Lower Boka Bil/Upper Bhuban Formation), tide dominating delta (FA-2; Boka Bil Formation), and fluvial (FA-3; Tipam and Dupi Tila formations) have been revealed from the exposed rock formations suggest that the study area experienced different depositional settings temporally and spatially. During post-Boka Bil deposition in Pliocene–Pleistocene, the continued tectonics and/or sea level fall, the area emerged/uplifted significantly and the Tipam and the Dupi Tila formations deposited under fluvial settings. This late-stage tectonics is still going on and shaping the geomorphology of the area. [ABSTRACT FROM AUTHOR]

The East Kunlun Orogenic Belt (E-KOB) in the northern Tibet Plateau has undergone a long multi-stage history of drifting, accretion, and collision of the Proto- and Palaeo-Tethyan oceans. It has been addressed a trench-arc-back-arc basin system of the Proto-Tethys in the E-KOB, and the tectonic history of this major ocean has been well constrained by previous studies. However, the evolution of the back-arc basin still remains unclear. In this study, the Yugusayi monzodiorite, quartz-bearing syenite, and gradually contacted skarn rocks characterized by garnet megacrysts, in the North Qimantagh Belt were investigated. To reveal the tectonic setting and skarnization mechanism, geochemical and geochronological studies were conducted on the intrusions and garnet skarn, and the elemental compositions of the garnet megacrysts were also analysed. These monzodioritic rocks have high MgO (6.87–8.31 wt.%), Sr and La contents, low Y and Yb contents, and relatively high La/Yb (31–55) and Sr/Y (41–51) ratios, resembling to high-Mg adakites. They display right-sloping chondrite-normalized REE patterns, enriched in LILEs, and depleted in Ti with significant Nb-Ta troughs, which are similar to those of continental arc rocks. Zircons from monzodiorite and skarn samples have contemporaneous U-Pb ages of 459 ± 3 Ma and 454 ± 4 Ma with εHf(t) values of − 8.53 to − 4.64 and − 7.7 to + 12.8, respectively. In addition, the chemical zoning garnet megacrysts are composed mainly of grossular and andraditic grossular, and are characterized by spoon-shaped REE patterns. Based on our new data and the regional geology, it can be concluded that the Yugusayi intrusive rocks formed in a subduction-related tectonic setting and resulted in the skarnization. These data not only provide key constraints on the initial subduction of the Qimantagh back-arc basin's oceanic crust, but also offer a unique opportunity to explore the Caledonian skarnization in the Qimantagh Belt. [ABSTRACT FROM AUTHOR]

The East Kunlun Orogenic Belt, an important part of the Central Orogenic Belt in China, preserved wealthy geological information for the tectonic evolution of the Proto- and Paleo-Tethys Ocean. Several Permian mafic-ultramafic rocks were identified in the Qimantagh area, EKOB, and zircon U-Pb dating, zircon Hf isotope, geochemistry and whole-rock Sr-Nd isotopes were studied in this paper. The results suggest that the formation age of the Xiyingzhaogou intrusion is 280 ± 4 Ma. The rocks show the characteristics of continental-arc calc-alkaline basalt. The whole-rock εNd(t) value of gabbro in Xiyingzhaogou intrusion is −4.2~-2.6 and the εHf(t) value of zircon is 2.77 ~ 5.82, indicating the characteristics of enriched or weakly depleted mantle; The formation age of Yingzhaogou intrusion is 263 ± 4 Ma. The geochemical characteristics of the Yinzhaogou rocks are consistent with those of continental-arc tholeiite. The whole-rock εNd(t) value of gabbro in Yingzhaogou intrusion is 0.73 ~ 0.92, and the εHf(t) value of zircon is 8.33 ~ 13.50, indicating the characteristics of depleted mantle. We believe that the Xiyingzhaogou intrusion was formed in the Early Permian and originated from the mantle wedge metasomatized by subduction fluid. The Yingzhaogou intrusion was formed in an extensional continental-arc environment caused by the retreat of the subduction plate. Asthenospheric mantle and fluid metasomatic lithospheric mantle were jointly involved in the mantle source. This study confirmed that the subduction of the Paleo-Tethys oceanic slab should had started before the Early Permian and a wide magma arc formed due to flat subduction. The retreat of the subduction plate led to the extension of the East Kunlun region, resulting in the significant enhancement of magmatism in the Middle Permian. [ABSTRACT FROM AUTHOR]

Using new and published data, we synthesize the tectonic evolution of the Ottawa River Gneiss Complex (ORGC), the metamorphic core and detachment zone of a large mid- to late-Ottawan metamorphic core complex in the western Grenville Province. Field and petrologic data indicative of retrogression and exhumation, combined with maps and schematic crustal-scale sections, are used to document spatial and temporal relationships of multi-scale structures developed during its formation, of which the largest, termed mega-cross-folds and megaboudins, occur within and define the detachment zone. Mega-cross-folds, orogen-normal structures up to 70 km in length with coaxial constrictional fabrics in their hinge-lines, formed in a single phase of deformation during retrogression and exhumation. A cluster of asymmetric megaboudins, individually from 10–50 km long with granulite-facies cores and high-strain amphibolite-facies rims, similarly formed during syntectonic retrogression and exhumation of granulite-facies precursors. We argue the mega-cross-folds developed in a regime of regional transtension, whereas the megaboudin cluster formed by extensional inversion of an anastomosing early-Ottawan thrust system, with the strain patterns of both suggesting the detachment zone was the site of intense ductile flow between the stronger metamorphic core and cover. Comparison of these results with generic numerical models of extensional collapse of overthickened continental crust suggests the first-order tectonometamorphic features of the ORGC developed during necking of the upper crust and associated large-scale extensional flow of the mid and lower crust into the domiform necked region during collapse of the early-Ottawan thrust stack. [ABSTRACT FROM AUTHOR]

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Copyright of Arid Zone Research / Ganhanqu Yanjiu is the property of Arid Zone Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article discusses N.K. Jemisin's Broken Earth trilogy and its exploration of the Anthropocene, a proposed geological epoch characterized by human impact on the Earth. The trilogy challenges the dominant narrative of the Anthropocene by emphasizing the role of colonialism and power structures in shaping the environmental crisis. It also highlights the importance of diverse and marginalized voices in discussions about the Anthropocene and the need for systemic change. The novels critique the naturalization of climate change and the dehumanization of certain groups, suggesting that a reimagining of the Anthropocene narrative is necessary to address the current crisis and promote justice. [Extracted from the article]

This paper presents an integrated approach involving geophysical and remote sensing datasets in the identification of regions that have undergone hydrothermal alteration in the gold-hosted site of the Ife–Ilesa schist belt. Geophysical methods employed include the aeromagnetic and aeroradiometric data, while the remote sensing involved Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data. Derivatives such as analytic signal, total horizontal derivative, tilt derivative of the total horizontal derivative, and 3-D Euler deconvolution were applied on the aeromagnetic data for the mapping and delineation of structures guiding migration of hydrothermal and mineralizing fluids in the study area. Radiometric analyses involving K/eTh, Ideal K anomalies deviation (Kd), and F-parameter, including principal component analyses on ASTER to isolate Potassic, Argillic, Propylitic, and Phyllic alteration zones were performed to delineate hydrothermally altered zones. The lineament map showed that the study area is geodynamically active as evident by the presence of deep-seated intersecting structures with depths ranging from 189 to 899 m, principally trending NE–SW, which is an impression of the Pan–African orogeny. The fuzzy gamma operator 0.9 was thereafter used in the integration of aeroradiometric and ASTER data for the hydrothermal alteration map production. Subsequently, five classes ranging from background to very high alteration anomalies were derived using the concentration–area (C–A) fractal model from the hydrothermal alteration map. These classes reveal the pervasive styles of alteration in the study area. The study further revealed the close association of structures, granitoids, hydrothermal alteration, and orogenic gold deposits. Also, the flurry of mining activities in the southern flank of the study coincides with most of the hydrothermally mapped areas with the Prediction–area (P–A) plot showing 78% occurrence of orogenic gold deposits in 22% of the total area explored. This translates to high potential of orogenic gold mineralization in the study area. The study therefore concluded based on the validation result that hydrothermal alteration mapping is important in the mapping of orogenic gold deposit. Hence, unexplored areas particularly in the western and eastern flank of the study area where there are strong indications of hydrothermal alteration have good prospect for gold mineralization. [ABSTRACT FROM AUTHOR]

The Central Asian Orogenic Belt (CAOB) was formed by the aggregation and collage of numerous Paleozoic subduction‐accretion assemblages and Precambrian microcontinental blocks. However, the tectonic nature of the southeastern CAOB remains controversial, which complicates the reconstruction of the Paleo‐Asian Ocean. To address this issue, a deep seismic reflection survey was initiated across the southeastern CAOB and reveals broad gentle sub‐horizontal reflectors in the middle‐lower crust and a relatively transparent zone in the upper crust. Combining with the Precambrian geological outcrops and other geophysical features, we support a microcontinental block, the Xilinhot Block, existed in the Paleo‐Asian domain. Thus, the Paleo‐Asian Ocean was separated into two branches that underwent north‐dipping and double‐dipping oceanic plate subduction, respectively, to form the Hegenshan‐Heihe and Solonker sutures. Multiple relics beneath Hegenshan‐Heihe Suture indicate that multiple sets of unidirectional oceanic subduction‐accretion and magmatism were important mechanisms of continental growth. Plain Language Summary: During the consumption of the Paleo‐Asian Ocean, a great number of Paleozoic subduction‐related accretionary complexes were developed and combined with pre‐existing Precambrian continental fragments to form the Central Asian Orogenic Belt (CAOB). However, research on the tectonic evolution of this area has been limited, and the tectonic nature of the southeastern CAOB remains controversial. A deep seismic reflection survey along the southeastern CAOB shows the crustal architecture in detail. The broad gentle sub‐horizontal reflectors and a relatively transparent zone in the profile reveal a Precambrian continental fragment existed in the North Orogenic Belt of CAOB. The Paleo‐Asian Ocean was further separated into two parts, the fossil subduction zones of which show northward and bidirectional dipping characteristics beneath the Hegenshan‐Heihe and Solonker sutures, respectively. Several relics of the unidirectional subduction beneath the Hegenshan‐Heihe Suture indicate that multiple sets of unidirectional oceanic subduction‐accretion and magmatism were important mechanisms of continental growth. Key Points: A preserved microcontinental block has been revealed in the North Orogenic Belt of Central Asian Orogenic BeltThe Paleo‐Asian Ocean was separated into two branches, which were closed respectively by north‐dipping and double‐dipping subductionMultiple unidirectional subduction‐accretion and oceanic magmatism may contribute to continental growth [ABSTRACT FROM AUTHOR]

Structural, metamorphic, and geochronological study of the Delhi Supergroup rocks near the western margin of the Aravalli-Delhi Mobile Belt (ADMB) elucidate the Neoproterozoic tectonics of the South Delhi Fold Belt (SDFB) and its implication for the evolution of the Greater Indian Landmass (GIL). In this study, we establish three deformational events in the SDFB. While the D1 event produced isoclinal, reclined F1 folds synchronous with prograde amphibolite facies metamorphism (~5 kbar, 650°C), D2 formed outcrop to map-scale upright F2 folds. D3 comprised ‘partitioned transpression’ along two subvertical shear zones. Oblique dextral-reverse movement (D3a) along one shear zone formed an outcrop-scale positive flower structure, while sinistral-reverse movement along the other rotated and steepened the hinges of the F2 folds (D3b). U-Pb zircon dating of post-tectonic (post-D2, but pre-D3) and syntectonic (syn-D3) granite intrusives suggests >844 Ma age for D2 and ca. 820 Ma for D3. An older magmatic event (ca. 990 Ma) is recorded from sheared pink granites (pre- to syn-D1 intrusion). We suggest that the amalgamation of the ADMB and the Marwar Craton was initiated by the Grenville-age (ca. 1000 Ma) subduction-collision, while the younger events (ca. 844 Ma and 820 Ma) mark the final stitching of the ADMB – Marwar Craton along the Phulad-Ranakpur palaeo-suture zone to form the GIL. The distribution of early (ca. 1000–900 Ma) and late (ca. 800–700 Ma) Tonian magmatic and metamorphic ages in the SDFB suggest that the final growth of the GIL took place through multiple stages of oblique collision in a pulsating orogenesis through the Early Neoproterozoic. [ABSTRACT FROM AUTHOR]

The Triassic tectonic evolution and affinity among the Yangtze Block, Qinling Orogenic Belt and Songpan-Ganzi Terrane remain subjects of ongoing scientific debate. In this context, the sedimentary rocks of Xujiahe Formation (second segment) (T3x2) represent an ideal case for addressing this issue. In this study, new stratigraphic, geochemical and detrital zircon analyses have been conducted on two sections of the T3x2. The stratigraphic assemblage and features suggests a braided delta as the depositional setting. Whole-rock geochemical results indicate that the sandstones from the T3x2 exhibit moderate palaeo-weathering and primarily originate from upper crustal felsic rocks, mostly S-type granites. The detrital zircons within these sandstones display distinctive age peaks at intervals of 200-300 Ma, 700-900 Ma, and 1800-2000 Ma, similar to those from the Qinling Orogenic Belt. Both the clastic particle composition and whole-rock geochemistry indicates that the T3x2 sections were deposited in a tectonic environment transitioning from a passive to an active continental margin, highlighted by a braided delta influenced by rivers flowing from the northeast to the southwest. [ABSTRACT FROM AUTHOR]

The Lesser Xing'an—Zhangguangcai Range of northeast China is located in the eastern segment of the Central Asian Orogenic Belt (CAOB), which records intense magmatism during the Mesozoic. The petrogenesis and geodynamic setting of the Early Jurassic intrusive rocks in this region are unclear. In this paper, we present new zircon U–Pb age and whole-rock geochemical data for these intrusive rocks to investigate their origins and tectonic setting. Zircon U–Pb dating suggests these intrusive rocks were emplaced during the Early Jurassic (197–187 Ma). The granites are enriched in silica and alkali, and depleted in MgO and CaO. They are metaluminous to weakly peraluminous, and have high A/CNK values and low zircon saturation temperatures (TZr ~ 779°C), suggesting they are highly fractionated I-type granites derived by partial melting of lower crustal materials. The granites exhibit negative Nb, Ta, P, Eu, and Ti anomalies due to fractional crystallization. The diorites and gabbros have low SiO2 contents and high Mg# values, and are enriched in light rare earth and large-ion lithophile (Ba, K, and Sr) elements, and depleted in heavy rare earth and high field strength (Nb, Ta, and Ti) elements. The geochemical characteristics show that the mafic magmas were derived by partial melting of mantle that had been metasomatized by subduction-related fluids. Based on the geochemical characteristics of coeval intrusive rocks and the regional geological setting, we suggest the Early Jurassic intrusive rocks in the Lesser Xing'an—Zhangguangcai Range were formed along an active continental margin, possibly as a result of bidirectional subduction of the Mudanjiang Oceanic plate between the Jiamusi and Songnen—Zhangguangcai Range massifs. [ABSTRACT FROM AUTHOR]

The Qinling Orogenic Belt (QOB) is a multi‐stage orogenic belt recording subduction and collision processes. The ductile shearing deformation with different properties and ages is developed on the boundary of the different litho‐tectonic units, which can be used to decipher the tectonic evolution of the QOB. Previous studies mainly concentrated on the pre‐Late Mesozoic shearing deformation, while the Late Mesozoic shearing deformation received less attention. It restricts the understanding of the Late Mesozoic tectonic evolution of the QOB. Hence, we conducted detailed field structural analysis and laboratory analysis of the Shagou shear zone (SGSZ) in the middle part of the Shangdan suture zone (SDSZ). The SGSZ, developed in the southern margin of the Baliping pluton, is an S–SSW‐dipping sinistral strike‐slip ductile shear zone with a top‐to‐the‐ESE shear sense. The mylonite protoliths are voluminous Late Triassic granites (200–215 Ma) and a small amount of Neoproterozoic granites (759 Ma) and Early Cretaceous granites (145 Ma). Microstructures and geothermobarometer results suggest that the ductile shearing deformation occurred under high greenschist–low amphibolite‐facies conditions (400–650°C) at middle crustal depths (13–21 km). Zircon U–Pb and amphibole‐biotite 40Ar/39Ar dating results constrain the timing of shearing deformation to 135–145 Ma and the rapid exhumation of the SGSZ to 115–135 Ma. Combining with the regional data, we consider that the sinistral strike‐slip shearing deformation in the SGSZ controls and accommodates the south‐eastward extrusion of the East SQB under the intracontinental compression. Subsequently, the intracontinental extension led to the rapid exhumation of the SGSZ. [ABSTRACT FROM AUTHOR]

Interpretation and inversion of P-T (Pressure-Temperature) paths of high-pressure (HP) and ultrahigh-pressure (UHP) metamorphic rocks are critical to understanding the subduction and exhumation histories of an orogen. The Sulu orogen constitutes the eastern part of the Dabie-Sulu orogen, in which, HP metamorphic rocks are relatively poorly as studied compared to the well-documented UHP metamorphic rocks. This study presents the P-T paths of HP eclogites constructed by petrography, mineral chemistry, and pseudosection modelling by using the GeoPS software within the MnNCFMASKHTO (Mn-CaO-FeO-MgO-Al2O3-SiO2-K2O-H2O-TiO2-O2) system. Sample 19LR70–1 mainly consists of omphacite, garnet, quartz, minor rutile, ilmenite, and amphibole. Sample 19LR71–1 is mainly composed of omphacite, garnet, kyanite, and accessory minerals of rutile and amphibole. These two eclogite samples recorded clockwise P-T paths with peak P-T conditions of P ≥ 21.3 kbar, T ≥ 755°C and P ≥ 23.0 kbar, T ≥ 871°C, respectively. Well-correlated U-Pb ages and trace element data show that the protoliths of eclogites were 655–699 Ma and 676–754 Ma, the metamorphic ages were 212–232 Ma, and the time of partial melting were 221–225 Ma. Combined with regional geological data, we conjectured that before 240 Ma, the South China plate was subducted to the North China craton; subsequently, at 240–220 Ma, HP eclogite facies metamorphism occurred at a depth of 60–70 km. This was followed by the exhumation of these HP metamorphic rocks, coupled with concurrent partial melting, around 220–200 Ma. [ABSTRACT FROM AUTHOR]

The West Kunlun orogenic belt located in the northwestern margin of the Qinghai-Tibet Plateau is an important record of the formation and northward extension of the plateau, but the current research mainly focuses on the tectonic activities of the Cenozoic era, and there is still considerable controversy regarding the formation and evolutionary history of pre-Cenozoic orogenic belts. This study focuses on Cretaceous sandstone samples from the Kedong region in the piedmont belt of the West Kunlun orogenic belt. U-Pb geochronological analysis was performed on 200 detrital zircon grains from the core samples. Combined with stratigraphic data and previous research, the main provenance direction was investigated to constrain the tectonic evolutionary history of the orogenic belt's peripheral regions. The results show that the detrital zircons are aged from 290 to 208 Ma, 520-310 Ma, 810-580 Ma, 1,400-880 Ma and 2,548-1,730 Ma, reflecting the complexity of provenance in this area. Based on a comprehensive analysis of the characteristics of igneous rocks, zircon age composition and stratigraphic conditions in potential source areas, it is concluded that the primary source regions include the East Kunlun orogenic belt and the North and South Kunlun terranes, with a low likelihood of contributions from within the Tarim Basin. The evolution of the West Kunlun orogenic belt can generally be divided into two opening and two closing phases. The detrital zircon ages predominantly exhibit two peak values at 259 Ma and 459 Ma, respectively representing the ages of transition from oceanic crust subduction to continentcontinent collision for the Paleo-Tethys Ocean and the Proto-Tethys Ocean. Additionally, there is a temporal gap between the evolution of the Proto-Tethys Ocean and the Paleo-Tethys Ocean. The Triassic period marks a transitional phase in tectonic evolution, shifting into an intracontinental evolutionary stage. This study provides new geochronological evidence for the early developmental history of the West Kunlun orogenic belt. [ABSTRACT FROM AUTHOR]

The Nagaland-Manipur ophiolites (NMO), part of the Phanerozoic (538.8–0 Ma) Tethyan ophiolites, occur in the NNE-SSW trending Indo-Myanmar Orogenic Belt (IMOB), northeast India. The NMO hosts both high-Al (0.46 < Cr# < 0.53) and high-Cr chromitites (0.71 < Cr# < 0.79). These chromitite bodies are hosted in lherzolite, harzburgite, and dunite and show various textures, including massive, disseminated, nodular, and granular. The high-Al chromitite compositions in conjunction with the calculated Al2O3[melt] (15.66–16.39 wt.%), TiO2[melt] (0.65–0.94 wt.%), and FeO/MgO[melt] (0.65–0.83 wt.%) values indicate that they were derived from the tholeiitic melt that formed at the mid-ocean ridge centre through low-degree partial melting. In contrast, the high-Cr chromitites, coupled with the Al2O3[melt] (11.24–12.99 wt.%), TiO2[melt] (0.21–0.33 wt.%), and FeO/MgO[melt] (0.58–1.54) values show similar geochemical affinities to those derived from boninitic melts produced by partial melting of already depleted mantle due to the subduction of oceanic plate in a supra-subduction zone environment. The total platinum group element (PGE) contents (60–190 ppb) of high-Al chromitites are lower than the total PGE contents (118–2341 ppb) in high-Cr chromitites. Chondrite-normalized PGE patterns in high-Al chromitites are flat from Os to Rh and negatively sloping from Rh to Pd, whereas high-Cr chromitites show strongly fractionated chondrite-normalized PGE patterns. Total PGE contents and low Pd/Ir ratios (0.02–0.64) of chromitites are consistent with typical ophiolitic chromitites. Mineral chemistry and PGE systematics suggest that NMO chromitites were generated in two separate tectonic settings. Thus, we argue that the upper mantle of the NMO of the IMOB has been modified by a substantial amount of supra-subduction zone components after initially being formed in a mid-ocean ridge tectonic environment. [ABSTRACT FROM AUTHOR]

The development of geothermal energy has received extensive attention because of global energy scarcity and environmental pollution. The Tangquan area is in the north of the Yangtze fold belt, and the lack of magmatic rock development has resulted in a low-temperature type of geothermal reservoir. There are sporadic hot springs and cold springs exposed in the study area, but the uncertain deep geological structure, unknown geothermal reservoir formation mechanism, and lack of detailed exploration data seriously restrict the exploration and development of geothermal resources in the area. Filling underground faults with water can significantly reduce electrical resistivity, while traps filled with warm water can cause a decrease in S-wave velocity. Thus, a new integrated geophysical method, including the controlled source audio-frequency magnetotelluric (CSAMT) and microtremor methods, is applied for geothermal exploration in the region. The combination of CSAMT and microtremor methods can determine thermal-controlled and water-conducting structures more effectively and locate geothermal storage more accurately. The source, channel, storage, and cover of regional geothermal reservoir formation are analyzed using geophysical and geological data. That is, the regional NE- and NW-trending faults are explained as thermal-controlled and water-conducted structures, respectively. The deep Sinian Dengying Formation supplies a heatand water-bearing space. The tectonic intersection area, especially the tensional fault zone, is found to be closely related to the existence of geothermal reservoirs, which is well verified by later drilling results. Finally, a geothermal reservoir model is established to comprehensively understand the distribution of geothermal energy in the region. [ABSTRACT FROM AUTHOR]

The scientific question of precisely determining the northern boundary of the Qinling Orogenic Belt (QOB) with regard to the southern segment of the North China Craton (S-NCC) has been controversial and unresolved, as it is heavily covered by loess and lacks some geological evidence. In order to identify the concrete northern boundary of the QOB, this paper first reports the metabasalt discovered in the Qianhe River Basin in Northwestern China, on the foundation of petrography, mineralogy, geochronology and geochemistry analyses. Detailed regional geological survey presents that the Qianhe metabasalt (QMB) is in unconformable contact with the Mesoproterozoic Gaoshanhe Group. Moreover, there is the new laser ablation (LA) inductively coupled plasma mass spectrometry (ICP-MS) U-Pb dating for magmatic zircons that yielded a weighted mean age of 450 ± 9 Ma, revealing that the QMB occurred in the Late Ordovician rather than that in the Mesoproterozoic period as previously considered. Both major and trace elements show that the samples are characterized by the back-arc basin (BAB) basalt affinity. In addition, combined with the regional geology analysis, it stands to reason that the QMB is very similar to those of Ordovician Caotangou Group along the northern QOB (N-QOB). Accordingly, it is illuminated that the QMB belonging to the N-QOB, is more likely originated from the back-arc basin setting, and truly defines the QOB's northern boundary in this segment, which has prominent geoscientific significance for determining the tectonic boundary in the heavily loess-covered regions. [ABSTRACT FROM AUTHOR]

The Jiao-Liao-Ji Belt (JLJB) is one of the Paleoproterozoic orogenic belts within the North China Craton (NCC), whose tectonic evolution is still controversial due to multiple magmatic/metamorphic events after its formation. To tackle this controversy, we conducted petrological, geochronological, geochemical and zircon Hf isotopic studies for the meta-mafic rocks from the North Liaohe Group (NLG) in the central JLJB. 207Pb/206Pb weighted average ages of 1849 ± 36 Ma and 1853 ± 13 Ma indicate that the protoliths of the amphibolites in the Shisixian area formed at ca. 1.85 Ga. Geochemically, the amphibolites belong to tholeiitic series; while the meta-gabbros can be divided into the low-Ti and high-Ti types: the former belongs to calc-alkaline series, whereas the latter belongs to tholeiitic series. The high-Ti rocks are enriched in light rare earth elements (LREEs) and large-ion lithophile elements (LILEs; e.g., Ba, K and Pb), and depleted in heavy rare earth elements (HREEs) and high field strength elements (HFSEs; e.g., Nb, Ta, P and Ti). These rocks display slightly positive εHf(t) values (+1.40 to +2.02). The low-Ti meta-gabbros were most likely derived from the partial melting of the enriched lithospheric mantle in the spinel stability field, which was metasomatized by subduction-related fluids and/or melts with significant contamination of crustal material, while the amphibolites and high-Ti meta-gabbros were derived from partial melting of depleted asthenospheric mantle in the spinel stability field, which was metasomatized by limited subduction-related fluids and/or melts, coupled with fractional crystallization. The lithological and geochemical characteristics show that the low-Ti meta-gabbros formed in a magmatic arc environment, the high-Ti rocks formed in the later stage of a back-arc basin; while the amphibolites formed in a post-collisional extensional environment. Combined with literature data, we suggest that the JLJB experienced a process from subduction, collision, to extension: At ca. 2.2–2.1 Ga back-arc basin opened via southward subduction of an oceanic plate followed by northward subduction at ca. 2.1–1.91 Ga, and subsequently closed to form the JLJB at ca. 1.91 Ga, which led to the Longgang-Nangrim continental collision, and post-collision extension occurred at ca. 1.85 Ga along with the collapse of the collisional orogen. [ABSTRACT FROM AUTHOR]

This article presents the results of U–Pb (ID-TIMS) geochronological, geochemical, and Sm–Nd isotopic-geochemical studies of metavolcanic rocks of the Djagdagle Formation, which belong to the key elements of the Bureya continental massif. It was established that the age of metavolcanic rocks of the Djagdagle Formation is 217 ± 7 Ma and corresponds to the Late Triassic. This fact contradicts the traditional ideas, according to which the Djagdagle formation is the Early Precambrian in age. The results of Sm–Nd isotope studies of the metavolcanic rocks indicate the melting of rocks of continental crust with Paleoproterozoic model ages during the formation of initial melts. The new geochronological data and previously published data allow us to distinguish at least two stages of magmatic activity in the Triassic within the northwestern part of the Bureya massif: ~243 and 219–201 Ma. On the basis of synchronous of Neoproterozoic, Early Paleozoic, Late Paleozoic, and Early Mesozoic magmatic events in the geologic history of the Bureya and Songnen–Zhangguangcai Range massifs, an assumption about their common geological history at least since the Late Neoproterozoic has been proposed. The close spatial position of metavolcanic rocks of the Djagdagle Formation and the Mongol–Okhotsk Orogenic Belt, their Late Triassic age (217 ± 7 Ma), and geochemical features allow us to link the formation of initial melts of metavolcanic rocks of this formation with within-plate magmatism in the rear part of subduction zone of the Mongol–Okhotsk Ocean beneath the northern (in modern coordinates) margin of the Bureya continental massif. [ABSTRACT FROM AUTHOR]

An editorial focuses on the discovery and significance of layered chromite mineralization within mafic-ultramafic rocks in the Gayahe area of the East Kunlun Orogenic Belt, Northwestern China. It highlights the identification of chromitite layers with high ore grades, marking a significant find in an area previously lacking economically valuable chromite deposits.

An editorial focuses on the newly discovered Jinshui tin deposit located in the middle section of the East Kunlun Orogenic Belt in northwestern China. It highlights the mineralization age of the deposit, determined through U-Pb dating of zircon and cassiterite, and discusses its implications for exploration in this region. It reports that the Jinshui deposit represents a significant addition to the known tin deposits in the area, with the ages of mineralization and magmatic activity.

The West Qinling Orogen (WQO) is located in the western part of the Qinling Orogen and in the transition zone of Qilian Orogen, Songpan-Garze Orogen and Yangtze Block, and also the key position of Triassic collision orogenic event. The study of the Early Triassic strata in the WQO is contributed to analyze the closure process of the paleo-Tethys. We conducted LA-ICP-MS U-Pb dating studies on detrital zircons to determine the provenance, depositional age, and tectonic setting of the Early Triassic Longwuhe Formation in the Lintan area of the WQO. The results show that the majority of the detrital zircons in the Longwuhe Formation are mainly magmatic origin and have characteristic of crust source zircon. The lowest limit of sedimentation of the Longwuhe Formation is constrained to the Early Triassic, with the youngest detrital zircon age of 253 ± 3 Ma. The ages can be divided into five age groups: 3 346–1 636 Ma, with two peak ages of ca. 2 495 and ca. 1 885 Ma; 1 585–1 010 Ma, with a peak age at ca. 1 084 Ma; 992–554 Ma, with a peak age at ca. 939 Ma; 521–421 Ma, with a peak age at ca. 445 Ma; 418–253 Ma, with a peak age at ca. 280 Ma. Apparently, the sources of the Longwuhe Formation include the northern margin of the WQO, the Qilian Orogen (QLO) and the basement of the southern margin of the North China Block (NCB), of which the ancient basement of the southern margin of the NCB is the main source area of the Longwuhe Formation. Combined with previous studies, we propose that the Longwuhe Formation was formed in a fore-arc basin, which is related to the closure of the A'nyemaqen-Mianlüe Ocean from the Early Permian to Early–Middle Triassic due to the northward subduction-collision of the Yangtze Block (YZB). This also indicates that the A'nyemaqen-Mianlüe Ocean has flat subduction characteristics. [ABSTRACT FROM AUTHOR]

The Cenozoic topographic development of the Himalaya‐Tibet orogen (HTO) substantially affected the paleoenvironment and biodiversity patterns of High Asia. However, concepts on the evolution and paleoenvironmental history of the HTO differ massively in timing, elevational increase and sequence of surface uplift of the different elements of the orogen. Using target enrichment of a large set of transcriptome‐derived markers, ancestral range estimation and paleoclimatic niche modelling, we assess a recently proposed concept of a warm temperate paleo‐Tibet in Asian spiny frogs of the tribe Paini and reconstruct their historical biogeography. That concept was previously developed in invertebrates. Because of their early evolutionary origin, low dispersal capacity, high degree of local endemism, and strict dependence on temperature and humidity, the cladogenesis of spiny frogs may echo the evolution of the HTO paleoenvironment. We show that diversification of main lineages occurred during the early to Mid‐Miocene, while the evolution of alpine taxa started during the late Miocene/early Pliocene. Our distribution and niche modelling results indicate range shifts and niche stability that may explain the modern disjunct distributions of spiny frogs. They probably maintained their (sub)tropical or (warm)temperate preferences and moved out of the ancestral paleo‐Tibetan area into the Himalaya as the climate shifted, as opposed to adapting in situ. Based on ancestral range estimation, we assume the existence of low‐elevation, climatically suitable corridors across paleo‐Tibet during the Miocene along the Kunlun, Qiangtang and/or Gangdese Shan. Our results contribute to a deeper understanding of the mechanisms and processes of faunal evolution in the HTO. [ABSTRACT FROM AUTHOR]