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The position of structures of Mongolia during Rodinia break‐up and Paleo‐Asian Ocean opening is debatable, and reconstructions between them are poorly known. In this paper, we apply an integrated approach to the not widely known yet distinctive structure (ribbon‐like) of the Lake and Mongolian Altay zones in western Mongolia, relating these with the surrounding Tuva–Mongolian and central Mongolian microcontinents (CMMs) development within the Central Asian Orogenic Belt (CAOB) and Paleo‐Asian Ocean evolution. We present a summary of the Neoproterozoic–early Palaeozoic tectonic development of western Mongolia and the CAOB and suggest a new comprehensive model for its evolution. The Lake zone of Mongolia is a major zone of ophiolite and arc complexes within the CAOB. The main sections of ophiolites are located along the west margin, bordering with Precambrian crystalline basement of the CMM. The ophiolites are distributed from north to south and have been dated to have similar ages. A classic oceanic plate stratigraphy section is preserved in the Lake zone. Serpentinite mélange and other volcanogenic‐terrigenous assemblages from the Lake zone are characterized by a system of nappe sheets thrust over the Dzavkhan block of the CMM. The ribbon‐like structure that the southern part of the Altay–Lake zone preserves at present provides an explanation for the development between the Gondwana‐derived microcontinent and Paleo‐Asian Ocean. During the pre‐Neoproterozoic, convergence accretion between Siberia and the CMM formed the Tuva–Mongolian belt, which later converted to the Altay–Lake collision zone associated with the thrusting of its eastern margin. All well‐known ophiolites of western Mongolia (Agardag, Khantayshir, and Dariv) as well as ophiolites of the Erdene Uul area mostly correspond to an "open‐ocean" phase with drifting microcontinents between 655 and 540 Ma or Neoproterozoic. In the early Neoproterozoic, the Altay peninsula‐like ribbon microcontinent after rifting of East Gondwana gradually drifted to Siberia. In this time, the east margin of the Paleo‐Asian Ocean was developed as a passive margin with the Dzavkhan Block. The Paleo‐Asian ocean plate simultaneously drifted to the CMM, whereas the Altay microcontinent moved into Siberia‐CMM. In middle‐upper Neoproterozoic times, the eastern part of the Paleo‐Asian ocean plate was thrusted over the CMM, obducting ophiolites (e.g., Tas Khairkhan), in the early Cambrian time, an oceanic spreading centre (?) of the Paleo‐Asian Ocean reached the CMM and stopped obduction. In the Neoproterozoic, the west margin of the Paleo‐Asian Ocean was developed as an active continental margin, with subduction under the Gondwana‐derived microcontinent. In the early Cambrian, there was significant subduction rollback and accretion of seamounts (Turgen). Later, in middle Cambrian–early Ordovician times, a large turbidite sequence was deposited in Altay. During the Devonian to Carboniferous, the Paleo‐Asian Ocean was preserved as a remnant ocean or big sea (Lake zone), accumulating marine deposits after collision of Siberia and the Altay microcontinent by late Cambrian. [ABSTRACT FROM AUTHOR]

The Tianshan Belt, which lies in the southwest part of Central Asian Orogenic Belt (CAOB), is characterized by abundant ophiolites or ophiolitic mélanges, which are indicators of the existence of oceanic basin can be used for tracking the tectonic evolutionary history of the orogen. The Bindaban (BD) ophiolitic mélange is located in the Central Tianshan Belt, northwest China, which comprises mainly gabbros, diabases, basalts, basaltic lavas (greenschist), and cherts. This paper presents new zircon geochronology, whole‐rock major and trace elements, and Sr, Nd isotope data for mafic rocks in the BD ophiolitic mélanges. In the eastern part of BD ophiolitic mélanges, one normal (N)‐MORB‐type basalt has a U–Pb zircon age of 265.2 ± 1.8 Ma, and one enriched‐MORB‐type dolorite in the western part of BD ophiolitic mélanges has an age of 425.4 ± 3.9 Ma, respectively, indicating either an existing ocean basin from continental rifting to normal oceanic spreading with a long time span from late Silurian to Permain, or two separate ocean basins that formed in late Permian and late Silurian during the Paleo‐Tianshan Ocean evolution. In particular, the 265.2 ± 1.8 Ma age of N‐MORB‐type basalt from BD ophiolitic mélange suggests the youngest oceanic basin (late Permian) existed in southwest CAOB, which reveals that Paleo‐Asian Ocean might last to late Permian, therefore finally closed in or after the late Permian in the North Tianshan area. [ABSTRACT FROM AUTHOR]

Mafic‐ultramafic intrusions occur sporadically but are pivotal to constrain the tectonic evolution of the Chinese Altay, a key part of the Central Asian Orogenic Belt. The tectonic setting of the Early‐Middle Devonian is well documented, but that of the Late Devonian remains a matter of ongoing debate. The Kayinde gabbro occurs in the Ashele Basin of the South Altay. This paper reports petrologic, zircon U‐Pb geochronological, geochemical, and Sr‐Nd isotopic data of the Kayinde gabbro, with the aims to investigate its formation time, petrogenesis, and geodynamic significance. Zircons separated from the gabbro yield a cluster of concordant data points and a weighted mean age of 373.1 ± 4.1 Ma, representing a Late Devonian emplacement. Geochemically, the Kayinde gabbro is subalkaline, tholeiitic, and characterized by high Mg# values (68–73), enrichment in large‐ion lithophile elements (including Ba, Sr, Rb, and U), depletion in high‐field‐strength elements (including Nb, Ta, Zr, and Hf), fairly flat REE patterns, low (87Sr/86Sr)i (0.70366–0.70440) and positive εNd(t) (3.4–5.4) values. The geochemical characteristics collectively suggest that the Kayinde gabbro was derived from a spinel‐stable lithospheric mantle source, which was depleted by previous magma extraction and metasomatized by later slab‐derived fluids or melts in an island arc setting. The geochemical similarities between the Kayinde gabbro and other contemporary mafic‐ultramafic intrusions reveal that the subduction continued during the Late Devonian in the Chinese Altay. In combination with the published research, we favour a two‐unit arc system composed of a continental arc and an island arc, spanning across the Early to Late Devonian. The Ashele Basin can be considered to be an oceanward setting in this model. [ABSTRACT FROM AUTHOR]

As one of the largest Phanerozoic orogens in the world, the Central Asian Orogenic Belt (CAOB) is a natural laboratory for studies of continental dynamics and metallogenesis. This paper summarizes the research progresses of the accretionary processes and metallogenesis of the CAOB since the People's Republic of China was founded, and puts forward the prospect for future research. During the early period (1950s–1970s), several geological theories were applied to explain the geological evolution of Central Asia. In the early period of China's reform and opening-up, the plate tectonics theory was applied to explain the evolution of the northern Xinjiang and Xingmeng regions, and the opinion of subduction-collision between Siberian, Kazakhstan, and China-North Korea-Tarim plates was proposed. The idea of the Solonker-Yanbian suture zone was established. In the 1990s, the study of the CAOB entered a period of rapid development. One school of scholars including geologists from the former Soviet Union proposed a multi-block collision model for the assemblage of the CAOB. In contrast, another school of scholars, led by a Turkish geologist, Celal Şengör, proposed that the Altaids was formed through the growth and strike-slip duplicates of a single island arc, and pointed out that the Altaids is a special type of collisional orogen. During this period, Chinese geologists carried out a lot of pioneering researches on ophiolites and high-pressure metamorphic rocks in northern China, and confirmed the main suture zones accordingly. In 1999, the concept of "Central Asian metallogenic domain" was proposed, and it became one of the three major metallogenic domains in the world. Since the 21st century, given the importance for understanding continental accretion and metallogenic mechanism, the CAOB has become the international academic forefront. China has laid out a series of scientific research projects in Central Asia. A large number of important scientific research achievements have been spawned, including the tectonic attribution of micro-continents, timing and tectonic settings of ophiolites, magmatic arcs, identification and anatomy of accretionary wedges, regional metamorphism-deformation, (ultra)high-pressure metamorphism, ridge subduction, plume-plate interaction, archipelagic paleogeography and spatio-temporal framework of multiple accretionary orogeny, continental growth, accretionary metallogenesis, structural superposition and transformation, etc. These achievements have made important international influences. There still exist the following aspects that need further study: (1) Early evolution history and subduction initiation of the Paleo-Asian Ocean; (2) The accretionary mechanism of the extroversion Paleo-Asian Ocean; (3) The properties of the mantle of the Paleo-Asian Ocean and their spatiotemporal distribution; (4) The interaction between the Paleo-Asian Ocean and the Tethys Ocean; (5) Phanerozoic continental growth mechanism and its global comparison; (6) Accretionary metallogenic mechanism of the Central Asian metallogenic domain; and (7) Continental transformation mechanism. [ABSTRACT FROM AUTHOR]

This paper considers the distribution of technogenic 137Cs and naturally occurring radionuclides: 238U, 232Th and 40К concentrations in soils and 137Cs in atmospheric dry depositions by altitudinal belts of the Aragats mountain massif, Republic of Armenia. Undisturbed soil samples were collected at altitudes from 1000 to 3200 m. For the determination of geochemical variability, two soil sampling campaigns were undertaken. Atmospheric dry depositions were sampled from five stations at 1100–3200 m collected onto organic fiber filters between June and December 2016. 137Cs activity was measured using a high-purity Germanium detector coupled to a multichannel analyzer (Canberra). Results indicated that specific activity of 137Cs in soils at 1000 m is 495–528 Bq m−2, and at 3200 m is 10,500–11,470 Bq m−2. No correlation observed for 137Cs versus naturally occurring radionuclides, which varies in distribution by altitude. Specific activities of 137Cs in dry atmospheric depositions varies from 1.06 at 846 m to 2.37 Bq m−2 per quarter at 3200 m and increases as the altitude increases. Activities of 137Cs in soil and dry atmospheric deposition correlated significantly, and 137Cs activity in soils and atmospheric dry depositions decrease as the absolute altitude decreases. The 50-year effective dose from exposure to 137Cs fallout varies with altitude from 0.007 to 1.42 mSv. [ABSTRACT FROM AUTHOR]

Felsite inclusions (FIs) in granulite garnets from continental collision orogens are supercooled felsic melt inclusions. Not only do these represent non‐equilibrium textures, such as dendritic and spherulitic crystals of quartz and other minerals, but the porphyritic texture is that of hypabyssal and volcanic rocks. This paper presents representative zoned quartz phenocryst‐bearing FIs in various granulites from the Highland Complex in central Sri Lanka, the Lützow‐Holm Complex in East Antarctica, the Grenville Province in southeastern Canada, and the Kerala Khondalite Belt in southern India. Quartz phenocrysts show simple and definite cathodoluminescence (CL) zoning with euhedral bright cores and dark rims and overgrowths. Euhedral quartz never develops in subsolidus metamorphic rocks except for vein quartz, and is characteristic of growth in a melt phase. Groundmass quartz surrounding quartz phenocrysts within the FIs is always dark in CL, whereas matrix quartz outside garnet and single‐grain inclusion quartz in garnet are usually brighter than the cores of quartz phenocrysts. The close relationship between violet CL emission intensity and Ti content of quartz indicates different growth temperatures in harmony with the inferred crystallization sequence. The preservation of CL growth zoning in quartz phenocrysts and fine non‐equilibrium textures imply that the cooling rates of some granulites are 1 to 2 orders of magnitude faster than so far presumed. [ABSTRACT FROM AUTHOR]

The lithospheric "de‐rooting" of the Sulu‐Dabie Orogen (SDO) is an important tectonic mechanism for post‐orogenic tectono‐magmatism, which influenced the sedimentation, evolution, and development of oil–gas accumulation in the Hefei Basin (HB). Combined with seismic, geological, and sedimentary data of the HB and the SDO, this paper studies the coupling of the HB and the SDO since the Late Mesozoic. While the North China Block (NCB) indented south‐eastwards under the Greater South China Block (GSCB) since the Mesozoic, the SDO underwent three intense tectonic stages, i.e., subduction, exhumation, and uplift. The upwelling of deep mantle material causes the exhumation of the ultrahigh‐pressure metamorphic (UHPM) rocks to the upper crust or surface, forming the UHPM. Influenced by the indentation of the NCB, the "de‐rooting" of the SDO lithosphere, caused the delamination and thinning of the lithosphere, accompanied by the continuous flexural subsidence in the HB. The basin underwent at least four stages of tectonic evolution, involving sequentially: the flexural basin, the foreland basin, the strike‐slip‐related basin, and the faulted graben development periods. The tectonic evolution of the HB was closely coupled with the SDO orogeny. The "de‐rooting" of the SDO lithosphere resulted in a strong uplift and erosion of the orogen, providing abundant source of material for the HB and causing the successively northwards migration of basin depocenters at its early stage. Finally, influenced by the subduction retreat of the (Palaeo‐) Pacific Plate and the strike‐slip movement of the Tanlu Fault, the depocenters migrated to the east. [ABSTRACT FROM AUTHOR]

The Carboniferous tectonic history of the northern West Junggar of NW China is of key importance for understanding the tectonics of the Altaids. This paper presents a systematic study of the emplacement of the E'min ophiolite, the ages of turbidites, and a stitching granite dike in order to constrain the late Carboniferous oceanic evolution of northern West Junggar. Our field investigation reveals that the Tarbagatay subduction–accretion complex formed by imbrication of turbidites and ophiolitic slices in the Western Tarbagatay Mountain, which is considered as the forearc of the Saur arc in northern West Junggar. Field relationships and zircon geochronology suggest that the emplacement of the E'min ophiolite was later than the minimum time of deposition of hanging wall turbidites, which have a zircon age of 324 Ma, and must be earlier than the crystallization time of a 311‐Ma stitching granite dike that intruded the younger turbidites. The turbidites become younger from north to south, with minimum deposition ages varying from 324 to 309 Ma. The 311‐Ma dike has an adakitic affinity suggesting that it may have formed by magma melted from a subduction slab wedge and from accreted material at ~310 Ma. Therefore, we propose an accretionary arc setting for the Saur arc, with southward migration of the trench and magma front. The 311‐Ma dike has a high Al enrichment and arc‐related geochemical signature suggesting that it was generated by melting of accreted trench sediments. This may indicate that subduction of the Saur arc may have lasted to at least the late Carboniferous. The development of such arc accretion suggests that the formation of the southern Altaids was fundamentally similar to that of accretionary orogens in the western Pacific. [ABSTRACT FROM AUTHOR]

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With the improvement of regional geological research surrounding the Junggar Basin, whether Junggar terrane has a Precambrian basement is becoming one of the most popular topics of study. The Alashankou area, situated in the west of the Laba unit, is a westernmost trailing-shaped part of the Junggar terrane in the Central Asian Orogenic Belt. Precise petrological, geochronological and geochemical constraints of the metamorphic igneous rocks in the Alashankou area provide a better understanding of the tectonic evolution of the Laba unit, and combining these constraints with the previously geochronological and geophysical results is crucial to reevaluate the nature of the basement of the Junggar terrane. In this paper, our diagnostic results reveal that (1) the two-mica plagioclase schist, biotite amphibole plagioclase schist and granitic mylonite were formed in 447.6 Ma, 443.7 Ma and 428.8 Ma, and their protoliths are possible acidic tuff, andesite, and granite (porphyry), respectively; (2) these rocks have geochemical signatures that originated from typical continental arcs, including intermediate-acid calc-alkaline series rocks; the enrichment of enriched in large ion lithophile elements (LILE), Zr, and Hf; the depletion of Ta, Nb, P and Ti; (3) the granitic mylonite has 0.90 Ga–2.58 Ga inherited zircons, low εHf(t) to 8.11 and old TDM2 (Hf) age to 2.91 Ga, suggesting the existence of a Precambrian crust or similar materials as their sources. Based on these parameters, we suggest that (1) the metamorphic igneous rocks were formed in an Early Paleozoic continental arc along the west margin of the Junggar terrane, and (2) the Southern and Eastern Junggar Basin possibly has Precambrian basements, whereas the Northern Junggar Basin consists of accretionary complexes. Southward subduction of the Junggar oceanic plate beneath the Laba unit occurred in the Late Ordovician to Middle Silurian, and the regional continental accretion and metamorphism of the Laba unit happened in the Early Devonian. [ABSTRACT FROM AUTHOR]

Provenance analysis of sediments provides important constraints on basin formation and orogenic processes. With the aim to define the sedimentary provenance and tectonic evolution of the southern margin of the North China Craton, this paper presents new detrital zircon U-Pb data from Early Triassic sediments in the Yiyang area. The results showed major peaks at 1848, 458, 425, and 268 Ma and subordinate peaks at ca. 2500, 872, and 957 Ma on age spectra from the Liujiagou Formation. The Heshanggou Formation exhibited a major age peak at 445 Ma and subordinate peaks at 755 and 947 Ma. Integrated with the analysis of sandstone detrital compositions, we suggest that the sources of the Liujiagou Formation were mainly a mixture of the southern margin of the North China Craton and the North Qinling Orogenic Belt, whereas the Heshanggou Formation was derived primarily from the North Qinling Orogenic Belt. Age comparisons of detrital zircon geochronology collected from different basins in the North China Craton indicated that the paleogeography of the North China Craton during the Early Triassic was strongly asymmetric, wherein the uplifted highland along the southern margin of the North China Craton was relatively lower than the northern margin. Meanwhile, the marked shift in source region from the Liujiagou to the Heshanggou formations provides a constraint regarding the conversion from denuded zone to deposited zone along the southern margin of the North China Craton in the Early Triassic, which controlled the evolution of the provenance and sedimentary system. [ABSTRACT FROM AUTHOR]

This paper presents new LA-ICP-MS zircon U-Pb geochronology, whole-rock major and trace element geochemistry, and Sr-Nd isotopes systematically on porphyritic granitic and K-feldspar granitic intrusions from the Dananhu belt, eastern Tianshan orogenic belt (ETOB). Zircon U-Pb dating indicates that the porphyritic granitic and K-feldspar granitic plutons were formed at 357±3 and 311±3 Ma, respectively. The porphyritic granites show geochemical and isotopic characteristics (high SiO2, low MgO and Mg#, depleted Sr-Nd isotopic values (about 0.703 4 and 6.13, respectively), with Nb/Ta (13.3–14.7) and Zr/Hf (31.0–33.9) ratios) similar to those of the crustal-derived magmas. The above characteristics suggest they were probably originated from juvenile lower crustal materials. The K-feldspar granites also have high SiO2, low MgO and Mg#, depleted Sr-Nd isotopic values (0.703 3–0.704 6 and 4.41–5.67, respectively). But some trace elements contents vary widely, with variable Nb/Ta (12.7–22.7), Zr/Hf (21.3–36.1) and Nb/La (0.38–1.07) ratios, indicating that the K-feldspar granites were formed by partial melting of juvenile lower crustal materials with old crustal materials. Combined with previous data on Carboniferous granitoids in the Dananhu belt, we infer that all the Carboniferous granitic plutons in the Dananhu belt were most likely emplaced in an island arc environment (Dananhu arc). Subsequently, a tectonic transition from oceanic subduction to post-collisional extension probably occurred in the ETOB. [ABSTRACT FROM AUTHOR]

In their paper: U–Pb geochronology of intrusive rocks of northwestern Mesa Central province and Sector Transversal of Sierra Madre Oriental, Mexico: Time and space distribution of inland Cretaceous-Paleogene magmatism during the Mexican orogeny, Díaz-Bravo et al. (2022) present a database of geochronological ages reported in literature and seven generated by themselves, with which they adapt a model of flat-slab subduction to explain the geographical distribution of the Cretaceous-Paleogene magmatism in north-central Mexico. In our opinion, the paper contains limited bibliographic documentation, since it omits previously published zircon U–Pb ages, whose relationship with the Mexican orogeny has been discussed in several previously published papers. Furthermore, an important approach on the distribution of plutons is that the effects of contractional deformation during pluton emplacement and younger extensional tectonics in the studied area were not evaluated. We propose that the syntectonic relationships with the Mexican Orogeny for some of the plutons imply that the magmas were emplaced in rocks undergoing shortening and eastward-NE translation during the development of the Mexican fold and thrust belt. Therefore, they are not in their original position and must be carefully studied to establish the magmatic model presented in this work. • The Cretaceous plutons in the Mesa Central and Sector Transversal of the Sierra Madre Oriental are syntectonic to the development of the Mexican Fold and Thrust Belt. • The Cretaceous syntectonic plutons are allochthonous, so they do not represent a fixed position to model the subduction angle of the Farallon plate. • Pico de Teyra and El Peñuelo plutons show evidence of mylonitic recrystallization, S-C structures, and cleavage, congruent with northeastward tectonic transport of the Mexican Fold and Thrust Belt. [ABSTRACT FROM AUTHOR]

In this paper we intend to reveal the architecture and structural styles in the outer unit of the Nankai accretionary prism, using a 672 km² seismic survey that was acquired by the Japanese Government in 2006 in order to infer the origins of some major tsunamigenic earthquakes. Understanding deformation mechanisms and the distribution and morphology of the thrust sheets and faults is essential for the oil and gas industry and for academic study as well, as scientists intend to prevent the impact of devastating hazards that appear often in active tectonic settings, such as subduction zones. [ABSTRACT FROM AUTHOR]

Widespread anatexis was a regional response to the evolution of the Himalayan-Tibetan Orogen that occurred some 30 Ma after collision between Asia and India. This paper reviews the nature, timing, duration and conditions of anatexis and leucogranite formation in the Greater Himalayan Sequence ( GHS), and compares them to contemporaneous granites in the Karakoram mountains. Himalayan leucogranites and associated migmatites generally share a number of features along the length of the mountain front, such as similar timing and duration of magmatism, common source rocks and clockwise P-T paths. Despite commonalities, most papers emphasize deviations from this general pattern, indicating a fine-tuned local response to the dominant evolution. There are significant differences in P-T- [ABSTRACT FROM AUTHOR]

Defining the structural style of fold–thrust belts and understanding the controlling factors are necessary steps towards prediction of their long-term and short-term dynamics, including seismic hazard, and to assess their potential in terms of hydrocarbon exploration. While the thin-skinned structural style has long been a fashionable view for outer parts of orogens worldwide, a wealth of new geological and geophysical studies has pointed out that a description in terms of thick-skinned deformation is, in many cases, more appropriate. This paper aims at providing a review of what we know about basement-involved shortening in foreland fold–thrust belts on the basis of the examination of selected Cenozoic orogens. After describing how structural interpretations of fold–thrust belts have evolved through time, this paper addresses how and the extent to which basement tectonics influence their geometry and their kinematics, and emphasizes the key control exerted by lithosphere rheology, including structural and thermal inheritance, and local/regional boundary conditions on the occurrence of thick-skinned tectonics in the outer parts of orogens. [ABSTRACT FROM PUBLISHER]

The multi-stage geological evolution and extensive continental deformations during the course of its history make the Central Asian metallogenic region (CAMR) a unique and complicated large-scale metal domain. New geological observations and precise age-data allow an improved reconstruction of the geological evolution of the CAMR. This paper summarizes the Paleozoic orogenic evolution and related ore formation in the core part of the CAMR based on the geological data published both during the Soviet period and the last decades. Four ore-formation provinces (Altay, Balkhash-Junggar, Chu-Yili-Tianshan, and Southwest Tianshan) could be classified. The Balkhash-Junggar and Chu-Yili-Tianshan provinces are the major topics of this paper. The Balkhash-Junggar province consists of 4 huge ore-forming belts (Zharma-Saur, Tarbahtay-Xiemistay, Aktogay-Baerluke, Balkhashwestern Junggar) with 11 large ore-college areas. The Chu-Yili-Tianshan province consists of 4 huge ore-forming belts (Alatau-Sairimu, Chu-Yili-Bolehuole, Issyk-Awulale, Kazharman-Nalaty) with 22 large ore-college areas. Formation of large ore-college area corresponds to a specific stage of continental crust growth. Comparison of geology and ore deposits in the CAMR provides rich information for future exploration and understanding of ore-forming processes. The Paleo-Junggar Ocean closed at Early Devonian in the Balkhash-western Junggar ore-forming belt. Afterwards, widespread volcanicsedimentary rocks formed at extensional stage due to delamination of the thick lower crust formed during previous accretionary processes. Felsic magma intrusion caused formation of porphyry Cu-Au deposit at ∼310 Ma and related hydrothermal gold deposits about 10 Ma later. For example, in the Hatu-Baobei-Sartohay Au-Cr ore-college area in the Balkhash-western Junggar ore-forming belt, small granitic to diorite plutons and various dykes (312-277 Ma) and large granite bodies (∼300 Ma) intruded into the Devonian to Early Carboniferous volcano-sedimentary basin. These magmatic activities and fault systems mainly controlled ore-forming processes. [ABSTRACT FROM AUTHOR]

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Permian mafic-ultramafic intrusions in or besides the Central Asian Orogenic Belt (CAOB) have been the focus of several recent studies, mainly located in Altay, East Tianshan, and Beishan Rift from north to south. Some of them host economic magmatic sulfide deposits. Among those, Poyi is a large magmatic Cu-Ni sulfide deposit related to ultramafic rock in Beishan Rift. Poyi does not have massive ore, but only disseminated ore in hornblende-peridotite, so Poyi is not as rich as the Karatongk Cu-Ni deposit in the Altay area or the Huangshandong and Tulargen Cu-Ni sulfide deposits in Eastern Tianshan. To address these questions, this paper contrasts the feature of PGE (Platinum Group Element) and olivine composition in magmatic Cu-Ni deposits between three regions (Altay, East Tianshan, and Beishan Rift) to provide a view of the metallogenic process of the Poyi magmatic Cu-Ni deposit. The degree of sulfide segregation (DSS) of Poyi is around 0.01%; the value of R (the ratio of the mass of silicate magma to the mass of sulfide that reached equilibrium together) is 500-5000, and is 2333 on average; the R value of Cu-Ni sulfide deposits in East Tianshan is in the range of 100-500, and the degree of sulfide segregation is about 0.013%; Poyi Cu-Ni deposit is not as rich as the magmatic Cu-Ni deposits in East Tianshan, probably because the degree of sulfide segregation of the former (0.01%) is lower than that of the latter (0.013%). From Beishan area to East Tianshan and then to Altay Region, the R value changed from 2333 to 100-500 and then to 100 according to the theory of Naldrett (2011). Poyi does not have the potential to be a PGE deposit. The olivine of Poyi has higher contents of MgO and SiO and lower contents of FeO and CaO, which reach sulfur saturation more easily, but due to the lack of sulfur, it is still very difficult to reach sulfur saturation, and therefore the olivine of Poyi has the highest Ni content among the Permian magmatic Cu-Ni deposits in Xinjiang. [ABSTRACT FROM AUTHOR]

In a pre-Mesozoic drift reconstitution, the Borborema Province in northeastern Brazil connects with the Central African Fold belt to the East and with the Nigerian and Tuareg shields to the North. Therefore, the Borborema Province is an important component to consider in the context of the amalgamation of western Gondwana. The tectonic setting of the Borborema Province has been debated, with some workers advocating for the accretion of allochthonous terranes and others arguing for the decratonization of a large continental landmass followed by the re-accretion of the fragments, either involving or not involving formation of large oceanic domains between them. Resolving the tectonic setting of the Borborema Province has implications for correlations with other Brasiliano-Pan-African belts and supercontinent reconstructions. This paper discusses proposed evidence for oceanic subduction, arc magmatism, and oceanic basin closure based on a comprehensive literature review. This information is integrated with data from the African counterparts of the Borborema Province to provide a geodynamic model for the Neoproterozoic evolution of this portion of western Gondwana. The main evidence for subduction is provided by ultra-high-pressure rocks and c. 660–640 Ma-old intermediate metaigneous rocks with relatively young (1.4–1.0 Ga) whole-rock Sm Nd and zircon Hf model ages in the northwestern part of the Borborema Province. However, a key aspect of the Brasiliano Orogeny in most of the Borborema Province is its synchronous nature. Deposition of predominantly siliciclastic sediments throughout the province ended slightly before or partly coeval with c. 640–610 Ma tectonothermal activity and early orogenic magmatism. Plutons and batholiths emplaced during this age interval comprise predominantly alkali-calcic monzogranites and syenogranites with a large contribution of Paleoproterozoic sources. Together with the absence of juvenile oceanic crust remnants and calc-alkaline metavolcanic rocks, it is thus concluded that (i) widespread crustal extension was almost immediately followed by contractional deformation and regional metamorphism, and (ii) crustal reworking was the dominant process, with limited formation and consumption of oceanic lithosphere. A similar conclusion applies to the Nigerian Shield and the central and southern parts of the Central African Fold Belt. In contrast, large volumes of juvenile crust are found in the Tuareg Shield and in the northern part of the Central African Fold Belt. The model envisions that no large oceanic domain separated the São Francisco/Congo Craton from the Amazonian/West Africa Craton in the middle Neoproterozoic, which were part of the Atlantica paleocontinent since c. 2.0 Ga. Extensional conditions in the Borborema Province and its African counterparts are attributed to far-field stresses transmitted to the interior of Atlantica by an outwardly, N-dipping subduction system. The onset of the contractional phase resulted from the accretion of the different components of the Tuareg Shield to the northern part of Atlantica (whose E -W suture zone is now hidden by the Saharan Desert), and the combined SE-directed and SW-direct indentation of the West African and Saharan cratons, respectively. • A geodynamic model is presented for the Borborema Province during the Brasiliano Orogeny. • 750–650 Ma extension resulted in fragmentation of the Atlantica paleocontinent. • Reamalgamation of the fragments involved limited consumption of oceanic lithosphere. • 640–610 Ma early tectonothermal events were synchronous throughout most of the province. • Early orogenic plutons comprise alkali-calcic granites, not calc-alkaline tonalites. [ABSTRACT FROM AUTHOR]

The Gharebagh area consists of a suite of mafic to acidic rocks located in northwestern Iran, in the Sanandaj-Sirjan zone (SSz), which is part of the Zagros orogenic belt. In this paper, we present a detailed petrological, geochronological, and isotopic study of representative rocks of Late Paleozoic igneous activity in NW Iran. LA-ICP-MS dating of zircons shows that the Gharebagh intrusive body (GIB) was formed in a tight time frame of 300 Ma. Geochemical analyses as well as isotopic studies of Lu Hf on zircon and Sm Nd on whole-rock were used to determine the petrogenesis of these rocks and develop a tectonic model. Crustal-model ages (Hf-t NC) of 0.57 to 1.02 Ga indicate the contribution of older Neoproterozoic crust to the formation of these rocks. The partially melted lower crust was one part of the magma together with a mafic melt formed by differentiation of the depleted mantle. The GIB suite was presumably formed by an anorogenic magmatic event (continental rift) that included extensive mantle upwelling and partial melting of the lower crust. So the gabbroid and granitoid rocks are coeval with the 300 Ma but not co-magmatic origin. • A bimodal magmatism event took place at around 300 Ma in the NW of SSz. • Gabbros were likely derived from a depleted mantle with partial crustal contamination. • A-type granite, were likely formed by crustal partial melting. • Intermediate rocks resulted from mixing of crust and mantle derived magma. • Bimodal magmatism suites were generated at a anorogenic (crustal rifting) setting. [ABSTRACT FROM AUTHOR]

Adakites formed at the oceanic subduction zones are sodic, whereas adakitic rocks in continental collision zones are generally potassic. Many orogenic belts also contain sodic adakitic rocks which formed during continental collision. The source and petrogenesis of these sodic adakitic rocks are debated. In this paper, we present whole-rock geochemical and Sr Nd isotope, and zircon U–Pb–Hf–O isotope and trace element data for the newly identified Early Devonian granitic pluton from the Balong area in the East Kunlun Orogen (EKO), China. The Balong granites are characterized by low K 2 O/Na 2 O (0.40–0.84), high Sr/Y (33–53), and variable (La/Yb) N (6–40) ratios coupled with low Yb (0.71–1.05 ppm) and Y (7.80–12.8 ppm) concentrations. They display low MgO contents (0.60–1.23 wt%) and Mg# values (38–45), as well as low Cr (2.57–5.08 ppm) and Ni (1.10–1.90 ppm) concentrations. They have whole-rock (87Sr/86Sr) i = 0.7101–0.7123 and ε Nd (t = 418 Ma) = −6.8 to −5.8. Autocrystic zircon rims yield U Pb ages of 420–417 Ma, whereas relict zircon cores have Neoproterozoic ages of 918–909 Ma. The zircon rims have low P contents, variable ε Hf (t = 418 Ma) values of −6.4 to +2.2, and δ18O values of 5.4‰–7.5‰, whereas the zircon cores have elevated P contents, variable ε Hf (t) values of −5.5 to +5.3, and relatively high δ18O values of 8.2‰–9.8‰. These whole-rock and zircon geochemical characteristics suggest a genetic link with the Neoproterozoic S-type orthogneisses and MORB-like (mid-ocean ridge basalt) eclogites in the EKO. Two end-member mixing calculations show that the whole-rock Sr Nd and autocrystic zircon Hf isotopic compositions of the Balong granites can be produced by mixing 60–50 wt% orthogneiss-derived melt and 40–50 wt% eclogite-derived melt. Given that the P–T paths of the exhumed continental eclogites did not intersect the wet solidus of mafic rocks, we suggest the Balong granites formed by partial melting of ultrahigh-pressure metamorphic rocks of the subducted plate trapped beneath the lower crust of the overlying plate. These results, combined with existing data from adjacent regions, suggest the partial melting of ultrahigh-pressure metamorphic terranes was related to slab breakoff at the terminal stage of continental collision. This study provides a novel model for the origin of sodic adakitic rocks in the continental collision zones. [ABSTRACT FROM AUTHOR]

The Nanping geothermal field in Hainan is situated within the Wuzhi Mountain fold belt of the South China fold system based on its geotectonic units. Although there is abundant surface heat detected and widespread distribution of Late Mesozoic granite in the area, the geological background of geothermal resources remains unclear. In this article, we collected core samples from boreholes within the Nanping geothermal field to conduct testing and analysis on rock thermal conductivity and heat-production rate. By combining these results with temperature logging data, we discuss a method for diterming the heat flow background of convective geothermal system. Furthermore, the study analyzed the geothermal flux and deep thermal structure of the research area. The results demonstrate that the average radioactive heat production rate of the Baocheng rock mass in the study area is 3.16 μW/m³, primarily attributed to the decay heat of Th and U, while the heat contribution of K is negligible. The thermal conductivity values of the rocks are relatively high, ranging from 2.29 to 3.75 W/(mK), slightly exceeding the average thermal conductivity of the upper crust. The study area represents a typical convective geothermal field influenced by groundwater convection, exhibiting a high geothermal temperature gradient. Using the groundwater-correction method, the geothermal flux in the study area is calculated to be 89–108.27 mW/m², of which the thermal conduction component is 73.17 mW/m² and the convective component is 15.83–35.1 mW/m². Among these components, heat generated from radioactive decay of crustal radioactive elements contributes 35.44 mW/m² to thermal conduction, while deep mantle conduction accounts for a heat flux is 37.73 mW/m², with a ratio of 1:1.07 between them. The difference between crustal and mantle heat fluxes is minimal in this region, indicating an approximation towards a "crust-mantle heat source balance zone". Furthermore, the thickness of the "hot" lithosphere in the study area ranges from 42 to 46 km, indicating significant characteristics of extension-thinning. [ABSTRACT FROM AUTHOR]

The Qinling‐Dabie‐Sulu orogen is the eastern part of the Central China Orogenic Belt. Looking back on previous studies of the sedimentary record we systematically compiled the dataset of detrital zircon U–Pb ages and Hf isotopes for this orogenic belt. The dataset incorporates a comprehensive compilation of 32,449 detrital zircon U–Pb ages and 979 Hf isotopes. The findings demonstrate that distinct tectonic units within the orogenic belt exhibit unique tectonic evolution histories during various geological epochs. This dataset can be used to constrain the tectonic framework and orogenic evolution including ocean subduction, continental collision and orogen exhumation. It can be integrated with other geological datasets to improve our understanding of the Central Orogenic Belt in China, and possibly plate tectonics globally. [ABSTRACT FROM AUTHOR]

The Central Asian Orogenic Belt (CAOB) is one of the biggest accretionary orogens in the world. With the development of laser ablation‐inductively coupled plasma‐mass spectrometry (LA‐ICP‐MS), large data of detrital zircon U–Pb and Hf isotopes have been published for decades, which leads to better understanding of the tectonic evolution and geodynamics of the CAOB. We compiled the data about the information of articles, samples and their analytical methods and results, then checked and corrected. These data are available to support future research activities in the CAOB, northern China, for example, the provenance analysis, climate changes and paleogeographic reconstruction. [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]

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]

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]

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]

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 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]

A major new Neoproterozoic orogenic system belonging to the larger Pan-African deformational realm, the Saharides, is described in North Africa, which formed from about 900 to 500 Ma ago. The Saharides, a Turkic-type orogenic complex similar to the Altaids of central and northwestern Asia, involved major subduction-accretion complexes occupying almost the entire Arabian Shield and much of Egypt and the small inliers of such complexes farther west to, and including, the Ahaggar mountains. These complexes are formed at least by half from juvenile material representing at least 5 million km2 new continental crust formed during the Neoproterozoic. The Saharides involved no continental collisions until the very end of their history, but evolved by subduction and strike-slip stacking of arc material mainly by pre-collisional coast-wise transport of arc fragments shaved off the Congo/Tanzania cratonic nucleus in a manner very similar to the development of the Nipponides in east Asia, parts of the North American Cordillera and the Altaids. The entire Sahara is shown to be underlain by a double orocline much like the Hercynian double orocline in western Europe and northwestern Africa and not by an hypothetical 'Saharan Metacraton'. The method here followed may be a fruitful procedure to untangle the structure of some of the Precambrian orogenic belts before life evolved sufficiently to make biostratigraphy feasible. [ABSTRACT FROM AUTHOR]

The Lajishan area, located in the South Qilian orogenic Belt, north‐eastern Tibetan Plateau, contains a compositionally diverse range of Cambrian to early Ordovician felsic intrusions that reflect the early Palaeozoic tectonic evolution of the Central Qilian Belt. This paper presents new geochemical, Sr─Nd and Lu─Hf isotopic, and zircon U─Pb data for the Tadong, Huangcaoshan, and Yindonggou plutons in the eastern Lajishan area. LA‐ICPMS U─Pb ages of 517.4 ± 1 Ma for the Tadong pluton which is the first find Late Cambrian granitoids in this area, 467 ± 1 Ma for the Huangcaoshan pluton and 446 ± 1 Ma for the Yindonggou pluton. The new data indicate that the Tadong pluton and Huangcaoshan pluton belong to I‐type granite. Their A/CNK values range from 0.82 to 1.03, suggesting a close relationship with I‐type granitoids. Their trace‐element geochemical characteristics include enrichments in the LILEs, pronounced depletions in Nb and Ta, enrichment of the LREEs relative to the HREEs, and Eu anomalies. These features are similar to those of I‐type volcanic‐arc magmas. Combined with Hf and Sr─Nd isotopic data, The Tadong pluton generated by the mixing of melts was derived from the partial melting of the Precambrian basement and mantle‐derived magmas. The Huangcaoshan pluton was derived from juvenile crust with contamination. The Yindonggou pluton shows A‐type characteristics, their A/NCK is 0.88–1.07, and 10000 × Ga/Al is higher than 2.6. They were characteristic with high Sr, low Y, low Yb, and enriched LREE. Combined with Hf and Sr─Nd isotopic data, the Yindonggou pluton was generated by the partial melting of oceanic slab material and was crustally contaminated associated with slab breakoff. Combined previous research suggests that Tadong pluton and Huangcaoshan pluton formed from southern subduction of the South Qilian ocean into the Central Qilian Belt; the Yindonggou pluton formed in collisional setting. [ABSTRACT FROM AUTHOR]

The paper reports the results of 40Ar/39Ar geochronological studies of the muscovite–quartz–albite metasomatites of the ore bodies and host rocks of the Albyn deposit located in the Selemdzha–Kerbi structural zone of the eastern part of the Mongol–Okhotsk Fold Belt. To a first approximation, the age of the hydrothermal ore process responsible for the formation of the Albyn deposit can be estimated within an interval of 131–130 Ma. At the same time, we cannot exclude the existence of an earlier stage of this process at ~135 Ma, although this assumption requires further substantiation. A close age estimate (~134–130 Ma) was obtained earlier for the ore metasomatites of the Malomyr deposit located in the same structural zone. There are no data on the magmatic manifestations of close age within the considered region, which makes it impossible to relate the ore mineralization of the Albyn deposit with magmatic processes. At the same time, the age of the thermal event superimposed on the host rocks of the Afanasiev Formation is 131 ± 3 Ma, which likely indicates the regional nature of this event. We suggest that a significant role in the mobilization, redistribution of ore matter, and formation of the Albyn deposit was played by large-scale deformations accompanied by hydrothermal activity. [ABSTRACT FROM AUTHOR]

The Northeast India and its adjacent areas converge among the three different plates, viz. Eurasia, India and Sunda plates. The tectonic interaction of Northeast India and underlying dynamics of the Himalayas as well as the Indo-Burma Ranges might cause the Assam Syntaxis. The area of study is located between latitude 23°–28°N and longitude 88°–96°E and situated in one of the most seismically active tectonic provinces in the world with seismic zone-V. This area had demonstrated several thrust faults activities and tectonic evident accomplishments during the recent past. The complicated geotectonic setups inspirits various smaller magnitude earthquakes, and the current seismicity shows seismic activities are still enduring in the Shillong Plateau, Arakan-Yoma fold belt, Bengal Basin, Naga Hills, Mikir Hills, Upper–Lower Brahmaputra Valley and Mismi Hills of Himalayan foothills. It is imperative to obtain wide-ranging learning tectonic configuration, thrust faults delineation for improved geoscientific study. Parts of the areas are extremely unreachable, and very limited thrust faults were marked by studying GIS map received from the various agencies and field geological study. During the past studies, most of the prominent lineaments/thrusts are marked; however, many active and hidden thrust faults are still unidentified. Seismic data can provide better information about the thrust faults locations, but due to small number of seismic data, the information is not adequate. In this paper, attempt has been made to study and reinterpret the available ground gravity data of northeastern parts of India for understanding thrust fault locations using various applications of gravity derivatives like analytical signal, horizontal gravity gradient, tilt derivative, horizontal tilt angle derivative and Cos(θ) analysis. Source edge detection technique has also been premeditated to categorize thrust fault locations. It is understandable that the low gravity is observed at Assam Valley which contributed sediment accumulations and higher gravity anomaly observed at Shillong Plateau and Bengal Basin containing denser formations. Bouguer gravity data is used after isostatic correction assuming Airy's isostasy root depth model and first-order trend removal using least square technique. The derived thrust fault locations from the present study are superimposed with the existing thrust-fault locations for correlation. Some additional thrust faults are narrated which are not previously mapped. It is also suggested that Brahmaputra Thrust, Dauki Fault, Naga Thrust, Disang Thrust and Kopili Fault have key responsibility for high seismicity and tectonic movement causing upliftment and depression that encouraged some anticlockwise rotation in the area. [ABSTRACT FROM AUTHOR]

The Altai‐Junggar‐Tianshan collage in southern Altaids is an important metallogenic domain in Central Asia that contain world‐class copper‐iron‐nickel deposits. As an accretionary‐type metallogenic system, the metallogenic processes of the Altai‐Junggar‐Tianshan collage is essential in understanding the genetic mechanism of ore deposits in general. Here in this paper we present a brief introduction to the project on the western part of the Southern Altaids, entitled "The deep structure and metallegenic processes of the North China accretionary metallogenic systems". This project mainly focuses on the deep structure and metallogenic background of the Altai‐Junggar‐Tianshan collage by integrated studies from field geology, structural mapping, geochemistry and geophysical exploration. Multiple new geological and geophysical methods will be applied to make transparency of the Kalatongke and Kalatage ore clusters. This will update our understanding of the geodynamic processes of metallogenesis and lead to the development and foundation of new metallogenic theories in accretionary orogens. [ABSTRACT FROM AUTHOR]

A great number of magmatic Cu‐Ni deposits (including Kalatongke in Xinjiang and Hongqiling in Jilin) are distributed over a distance of almost 3000 km across the Tianshan‐Xingmeng Orogenic Belt, from Tianshan Mountains in Xinjiang in the west, to Jilin in eastern China in the east. These deposits were formed during a range of magmatic episodes from the Devonian to the Triassic. Significant magmatic Cu‐Ni‐Co‐PGE deposits were formed from the Devonian period in the Nalati arc (e.g. Jingbulake Cu‐Ni in Xinjiang), Carboniferous period in the Puerjin‐Ertai arc (e.g. Kalatongke Cu‐Ni‐Co‐PGE in Xinjiang), Carboniferous period in the Dananhu‐Touquan arc (e.g. Huangshandong, Xiangshan and Tulaergen in estern Tianshan, Xinjiang) to Triassic period in the Hulan arc (e.g. Hongqiling Cu‐Ni in Jilin). In addition to the overall tectonic, geologic and distribution of magmatic Cu‐Ni deposits in the Tianshan‐Xingmeng Orogenic Belt, the metallogenic setting, deposit geology and mineralization characteristics of each deposit mentioned above are summarized in this paper. Geochronologic data of Cu‐Ni deposits indicate that, from west to east, the metallogenic ages in the Tianshan‐Xingmeng Orogenic Belt changed with time, namely, from the Late Caledonian (∼440 Ma), through the Late Hercynian (300–265 Ma) to the Late Indosinian (225–200 Ma). Such variation could reflect a gradual scissor type closure of the paleo Asian ocean between the Siberia Craton and the North China Craton from west to east. [ABSTRACT FROM AUTHOR]

To characterize the polyphase palaeokarst development of Wumishan formation in Jizhong depression, the data of outcrops, cores, thin sections, SEM, core plugs, drilling relief and leakage, and carbon isotope have been analyzed in this paper. The results reveal that the polyphase palaeokarst was petrography controlled of microbial dolostone and grain dolostone, and was identified as three phases: (1) poly-period eogenetic karst during Wumishan depositional environment, (2) two-period telogenetic karst in Triassic and Cretaceous, and (3) hydrothermal karst in Paleogene. The eogenetic karst was related to high frequent sea level fluctuations with development of vugs and selective dissolution porosities which distributed at the top of microbial dolostone and grain dolostone layers. The origin of the telogenetic karst was related to Indosinian and Yanshan orogeny which formed widespread fold belts and thrust faults, and provided the endokinetic force and a strong topography difference. Each period's telogenetic karst was characteristic of one-period fracture-cave system, and the Cretaceous telogenetic karst was stronger than the Triassic telogenetic karst in karst intensity. Moreover, the karst intensity increased downward in superimposed telogenetic karst zones. Hydrothermal karst was related to volcanic activities and provided the hydrothermal environment for its formation. It was featured by solution-enlarged porosities and new forming porosities. The microbial dolostone and grain dolostone layers with three-phase palaeokarst were the best exploration targets for high-quality reservoirs. This paper rebuilds a suitable karst model to show the palaeokarst evolution process. [ABSTRACT FROM AUTHOR]

The Korean Peninsula (KP) occupies a junction area of three big tectonic domains that are the Paleo-Central Asian Orogenic Belt, Paleo-Tethyan Orogenic Belt and the Western Pacific Orogenic Belt. Therefore the KP is a key area to understand the Northeast Asian and even global geotectonic evolution. In terms of geological unit division, the KP has long been thought to be closely tied with the mainland of China, with using collective term the Sino-Korea Craton for the North China Craton (NCC). However, such correlation suffered from the absence of relevant geological information in North Korea (NK). To bridge this knowledge gap, our group carries out a long-term collaborative study between the two-sides of the KP and China，and organized united field investigation in the North Korea, South Korea (SK) and China as possible. This paper introduces general geology in the North Korea，and simply make comparison with the NCC and South Korea. These pioneering works culminated in the following summaries. (1) The KP comprises three major Precambrian massifs, i.e., Rangnim, Gyeonggi and Yeongnam massifs. The Rangnim and Gyeonggi massifs are separated by the Imjingang Structural Belt, while the Gyeonggi and Yeongnam massifs are separated by the Ogcheon Structural Belt. (2) The basement of the Rangnim massif is correlated with that of the NCC. The characteristic metamorphic rocks of high- temperature/high-pressure granulite facies including meta- sedimentary rocks (kondalites and meta-sandstones and marbles) with ~1.9–1.8 Ga metamorphic ages occur in the three massifs, similar to the NCC. (3) The Proterozoic rift sedimentary sequences are developed in the NCC and North Korea, but Lower Paleoproterozoic strata are rare, and Neoproterozoic strata are more developed in North Korea relative to the NCC. (4) Two main Paleozoic basins within the Rangnim massif and within the Gyeonggi and Yeongnam massifs are the Phyongnam basin and Taebaeksan Basin. Both of them have a similar Paleozoic tectono-stratigraphy to the NCC. (5) Although the nature and tectonic significance of the Imjingang belt remains controversial, it doesn't show characteristics and natures of collisional orogenic belt. (6) The eclogite-bearing Hongseong Complex (HSC) is located in the southwestern part of the Gyeonggi Massif in South Korea, but no similar rock unit has been found in North Korea. (7) Mesozoic igneous rocks are widespread throughout the northern and southern parts of the KP. Triassic magmatism is related to Indosinian orogeny. Jurassic and Cretaceous igneous rocks are different and irregular from those in the NCC on age and spatial-temporal distribution. This paper also suggests several key and controversial academic issues that are worthwhile to study in the future. Unlabelled Image • The Archean Rangrim massif is divideded into the Rangrim and Kwanmo submassifs, high-grade region and greenstone belt, respectively. • Early Paleoproterozoic rocks underwent metamorphism up to granulite facies, which may be correlated to the Jiao-Liao-Ji mobile belt in the NCC. • Proterozoic rift sequences in North Korea are similar to those in the NCC with rare late Paleoproterozoic strata and more Neoproterozoic strata. • Both main Paleozoic basins, the Phyongnam basin in NK and the Taebaeksan Basin in SK, have a similar Paleozoic tectono-stratigraphy to the NCC. • Mesozoic igneous rocks are extensively distributed in the KP. [ABSTRACT FROM AUTHOR]

The Longshan area is located in the junction zone between the Qinling and eastern Qilian orogenic belts. Early Palaeozoic igneous rocks in this area can provide important insights into the evolution of Shangdan Ocean. This paper reports new petrology, chronology, major and trace element geochemistry, Sr–Nd isotope, and zircon Lu–Hf isotopic compositions for the Early Silurian pyroxene diorite in the Longshan area. The pyroxene diorite has a zircon U–Pb age of 432 ± 1 Ma (MSWD = 0.25, n = 27). The pyroxene diorite intrusion displays low SiO2 (53.34 to 56.32 wt.%), high Na2O (3.11% to 3.79 wt.%) and Sr (1112 to 1234 ppm) contents, and moderate Mg# (52.70 to 55.00) values, high Sr/Y (67 to 84) ratios, depleted in Y and HREE; these features are identical with the low‐Si adakite or sanukitoids that derived from melting of metasomatized mantle wedge. The pyroxene diorite intrusion has evolved Sr–Nd isotopic compositions, (87Sr/86Sr) i = 0.705286 to 0.705310, εNd(t) = −3.4 to −3.9. Zircons from the pyroxene diorite display variable εHf(t) values of −3.6 to +0.1. These features suggest that the pyroxene diorite intrusion was derived from a hydrous melting metasomatized mantle wedge which has been modified by slab melts. The occurrence of pyroxene diorite indicates an Early Silurian active continental margin setting in the south‐eastern Qilian Orogenic Belt. [ABSTRACT FROM AUTHOR]

Magnetotelluric (MT) data from 49 broadband and 23 long period stations, covering periods between 10−3 and 104 s, were measured along a NNW-SSE profile of approximately 470 km, crossing the Parnaíba Basin, Borborema Province and São Francisco Craton in northeastern Brazil. The geotectonic scenario of the study region comprehends a complex structural framework formed during the Brasiliano orogenic collage. The MT data were processed to obtain the impedance tensor estimates for each MT site using a robust technique and then followed by a dimensional analysis via both the rotational invariants (WAL invariants) of the magnetotelluric tensor and the phase tensor. The two approaches indicated a three-dimensional nature of the region, allowing to proceed to 3D inversion, despite the data distribution along a profile. Several inversion trials of the full impedance tensor, tipper and tipper combined with impedance tensor resulted in a final 3D resistivity model, which suggests a division of the profile into three major zones. A sub horizontal resistive crustal block, interpreted as being part of the Parnaíba block, characterizes the western zone. A mosaic of resistive and conductive zones, which integrates the extended fold belt of the Borborema Province, composes the central zone. In the interface between the central and the eastern zones, there is a sub vertical conductive region limiting two resistive blocks, interpreted as a suture zone. This suture divides tectonic provinces and is supposed to be related with a Neoproterozoic collisional system. The 3D MT imaging recovered the structural framework under the Parnaiba Basin and marked the main lineaments. The paper suggests a distinct tectonic evolution for the complex assemblage of blocks in Northeast Brazil. • The 3D MT imaging allowed drawing a crustal model that recovers existing structures in great depth along the study region. • The 3D MT imaging recovered the structural framework under the Parnaiba Basin and marked the main lineaments. • The paper suggests a distinct tectonic evolution for the complex assemblage of blocks in Northeast Brazil. [ABSTRACT FROM AUTHOR]

Jurassic coal-bearing strata are widely distributed in the North China Craton (NCC) and other areas of northern China. These coal-bearing strata were previously considered to be Early-Middle Jurassic in age based on plant fossils, particularly the fossil assemblage of Coniopteris-Phoenicopsis. Since coal-bearing strata are interbedded with volcanic units in the basins of the Yanshan Fold-and-Thrust Belt (YFTB), northern NCC, isotopic dating of the volcanic units can therefore provide age constraints on the coal-bearing strata and the Coniopteris‒Phoenicopsis assemblage. In this paper, we performed a systematic geological survey and present the results of zircon U-Pb dating of the volcanic units and a pluton in typical basins of the YFTB. These data, combined with the results of previous studies, indicate that the ages of the Nandaling/Xinglonggou, Haifanggou, Jiulongshan, and Tiaojishan/Lanqi formations are 180-168, 169-161, 161-157, and 161-153 Ma, respectively. The ages of the interbedded coal-bearing Yaopo and Beipiao formations are constrained to be 169-161 and 177-169 Ma, respectively. Our results demonstrate that both the coal-bearing strata and the Coniopteris‒Phoenicopsis assemblage are Middle Jurassic in age, which is younger than that previously considered. This fossil assemblage plays a critical role in age constraints on the Jurassic coal-bearing strata. The refinement of its age permits a more precise dating of the coal-bearing strata, especially in northwestern China, where datable interbedded volcanic units are lacking. Stratigraphical framework for the Jurassic strata of Yanshan region is established. The fossil assemblage of Coniopteris‒Phoenicopsis occurred in Middle Jurassic. The Jurassic coal-bearing strata in northern China are mainly Middle Jurassic. [ABSTRACT FROM AUTHOR]

The South Tianshan Terrane (STT) is located in the boundary between the south‐western Central Asian Orogenic Belt (CAOB) and the Tarim Craton and is a key area for understanding the geologic and tectonic history of the craton and the orogenic belt. In this paper, we report detrital zircon ages from the Late Palaeozoic and Mesozoic clastic sedimentary rocks from the southern part of STT. In combination with the U–Pb ages for felsic igneous and meta‐igneous rocks exposed in the STT and adjacent tectonic units, we identify several distinct age populations. Provenance analysis suggests that the detrital zircon grains were predominately derived from the felsic magmatic rocks in the Tarim Craton and South Tianshan Terrane. The pre‐Neoproterozoic age populations may be associated with the early history of the Tarim Craton. Several pulses of Neoproterozoic magmatism are revealed by our dataset, presumably related to the assembly and break‐up of the supercontinent Rodinia. The 995 to 901 Ma detrital zircon grains were likely sourced from magmatic rocks associated with the assembly of Neoproterozoic Tarim to Australia. Among the age population of 886 to 752 Ma, the older group might be related to the subduction‐related magmatism after the assembly of Rodinia, and the younger one records a protracted magmatic event in a continental rift‐related setting associated with the break‐up of Rodinia. Two younger Neoproterozoic age populations (736 to 694 Ma and 665 to 610 Ma), showing narrow spreads with weak peaks, represent the waning stages of igneous activities related to the break‐up of Rodinia. Regarding the Palaeozoic evolution, together with other evidence, our data indicate a two‐stage subduction model for the SW Palaeo‐Asian Ocean. The 490 to 384 Ma age population corroborates the existence of Early Palaeozoic continental arc magmatism at the northern margin of Palaeozoic Tarim generated by the bidirectional subduction of the South Tianshan Ocean. After a ~30 My period of tectonomagmatic quiescence, the second stage is marked by the northward subduction of the South Tianshan Terrane during Late Devonian to Early Carboniferous. The final collision of Tarim and the south‐western CAOB likely occurred during the Late Carboniferous, followed by syn‐ and post‐collisional magmatism, as represented by the 320 to 265 Ma age population. Based on the detrital zircon ages in conjunction with the Hf isotopic features of zircons from Palaeozoic igneous rocks, our study does not support the model of large‐scale Phanerozoic net continental growth in the South Tianshan Terrane. [ABSTRACT FROM AUTHOR]

Abstract—The paper reports first geochemical data on the Cambrian sedimentary rocks of the Mel'gin trough of the Bureya continental massif, as well as geochronological data on detrital zircons from these rocks. It is established, that sandstones of the Chergilen and Allin formations of the Mel'gin trough are dominated by detrital zircons with Late Riphean (peaks on relative probability plots at 0.78, 0.82, 0.94, and 1.04 Ga) and Early Riphean (peaks on relative probability plots at 1.38, 1.45, 1.64 Ga) ages. Single grains have Middle Riphean, Early Proterozoic and Late Archean ages. We can suppose that the sources of Late Riphean detrital zircons in sandstones of the Chergilen and Allin formations are rocks of gabbro‒granitoids (940‒933 Ma) and granite‒leucogranite (804‒789 Ma) associations identified in the Bureya continental massif. It is impossible to determine which rocks were sources for Middle Riphean and older detrital zircons in the Cambrian sedimentary rocks of the Bureya continental massif, because the pre-Late Riphean complexes have not been identified yet in its structure. The most probable geodynamic setting for the accumulation of the Cambrian deposits of the Mel'gin trough is an active continental margin, which is consistent with manifestation of the Early Cambrian granitoids magmatism. [ABSTRACT FROM AUTHOR]

This paper reports on the physical–chemical parameters and vertical distribution of different types of fluid inclusions in quartz from the Au-bearing interval of the Kola Superdeep Borehole. We assume that gold ore mineralization was formed when a deep flux of CO2 interacted with brines at depths of 10 205–9269 m due to tectonic factors. In this paper, we discussed the role of these processes in the formation of the orogenic gold deposits including the gold mineralization of the Southern Pechenga structural zone. [ABSTRACT FROM AUTHOR]

This paper reports the first results of U–Pb LA-SF-ICP-MS dating of detrital zircons from terrigenous deposits of the Miniseishor Formation, Nyarovei Group of the Kharbei Anticlinorium, the Polar Urals, presumably of Middle Riphean age, located at the Upper Precambrian Polar Ural section base. The data obtained give grounds for constraining the lower age interval of the Miniseishor deposit to the turn of 600 Ma ago. In addition, these data are indicative of the fact that identification of the Nyarovei Group as a Middle Riphean stratigraphic unit is wrong. The whole Nyarovei section was formed in a relatively narrow age interval at the end of the Late Riphean. Erosion products of the adjacent deeply metamorphosed rocks played a key role in the development of deposits throughout this group. [ABSTRACT FROM AUTHOR]

This paper presents the results of U–Th–Pb geochronological study of detrital zircons from cement of the Jurassic conglomerates of the Strelka Depression extending in the sublatitudinal direction along the border between the southern margin of the Selenga-Stanovoy superterrane and the Mongol–Okhotsk fold belt. It has been shown that Paleoproterozoic and Neoarchean zircons overwhelmingly dominate in the conglomerate cement. This indicates that the main input of the material to the sedimentation basin was carried from the Southeast border of the North Asian craton (from the north in modern coordinates). In our opinion, the Strelka Depression formed after the completion of orogenic processes associated with the formation of the Mongol–Okhotsk structure. [ABSTRACT FROM AUTHOR]

This paper presents zircon U-Pb-Hf isotopic compositions and whole-rock geochemical data for monzogranites and mafic-ultramafic complexes of the Maxingdawannan area in the western end of the east Kunlun orogenic belt, western China. The data are used to determine the ages, petrogenesis, magma sources, and geodynamic setting of the studied rocks. U-Pb zircon dating indicates that monzogranites and gabbros of the complexes were emplaced at 399 and 397 Ma, respectively. The monzogranites are shoshonitic, with high SiO 2, Al2O 3 and total-alkali contents, and low TFeO, MgO, TiO 2 and P2O5 contents. The mafic-ultramafic complexes are characterized by low SiO2 contents. The monzogranites display enrichment in light rare-earth elements (LREE) and large-ion lithophile elements (LILE), depletion in heavy REEs (HREE) and high-field-strength elements (HFSE), and negative Eu anomalies (Eu/Eu*=0.36–0.48). The mafic-ultramafic complexes are also enriched in LREEs and LILEs, and depleted in HREEs and HFSEs, with weak Eu anomalies (Eu/Eu*=0.84–1.16). Zircon εHf(t) values for the monzogranites and mafic-ultramafic complexes range from −6.68 to 1.11 and −1.81 to 6.29, with zircon model ages of 1 812–1 319 Ma (TDM2) and 1 087–769 Ma (TDM1), respectively. Hf isotopic data indicate that primary magmas of the monzogranites are originated from partial melting of ancient lower crust during the Paleo-Mesoproterozoic, with a juvenile-crust component. Primitive magmas of the mafic-ultramafic complexes are likely originated from a depleted-mantle source modified by slab-derived fluids and contaminated by crustal components. Geochemical data and the geological setting indicate that Devonian intrusions in the Maxingdawannan area are related to northward subduction of the Proto-Tethys oceanic lithosphere. [ABSTRACT FROM AUTHOR]