Journal of Asian Earth Sciences: X最新文献

{"title":"Geochemistry of ferromanganese nodules in the soil of Okinawa Island, Japan: Paleoclimatic implications and discrimination scheme of the nodule origins","authors":"Keishiro Azami ,&nbsp;Kazutaka Yasukawa ,&nbsp;Yasuhiro Kato","doi":"10.1016/j.jaesx.2022.100127","DOIUrl":"10.1016/j.jaesx.2022.100127","url":null,"abstract":"<div><p>Shimajiri–Mahji refers to dark-red soil covering Ryukyu limestone that is characterized by buried ferromanganese (Fe–Mn) nodules, and it is widely distributed in Okinawa Island, southwestern Japan. The formation environment of the Fe–Mn nodules is considered closely related to the pedogenetic process of Shimajiri–Mahji because the mineral assemblage of the nodules is similar to that of the surrounding soil. There are two competing hypotheses about the formation environment of the Fe–Mn nodules: marine or terrestrial. In this study, the chemical composition of the Fe–Mn nodules was analyzed to determine their origin. The low Ni and Cu contents and the positive Ce and negative Y anomalies of the Fe–Mn nodules are inconsistent with the geochemical features associated with formation in the deep ocean and shallow seas or lakes, respectively. In contrast, the geochemical features of the Fe–Mn nodules correspond to formation in terrestrial soil, especially in terra rossa. An elemental map of the Mn/Fe ratio and computed tomography results demonstrated that the Fe–Mn nodules have a layered structure, which indicates a temporal change in the redox potential of Shimajiri–Mahji. This may be attributed to changes in the soil moisture owing to the variable intensity of the East Asian monsoon and climate change. A new discrimination diagram based on Al/Na and Co/Rb ratios was developed for classifying the formation environments of Fe–Mn nodules, which may help improve understanding of the formation history of soils and sediments containing them.</p></div>","PeriodicalId":37149,"journal":{"name":"Journal of Asian Earth Sciences: X","volume":"8 ","pages":"Article 100127"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590056022000482/pdfft?md5=6211e126e744b3441d05159f8051e0ec&pid=1-s2.0-S2590056022000482-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46566767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tsunami hazard and risk zoning for Qurayyat in northeast Oman coast: Worst-case credible scenarios along the Makran Subduction Zone, Western Asia","authors":"Zaid Al-Habsi ,&nbsp;Mohamed Hereher ,&nbsp;Issa El-Hussain ,&nbsp;Rachid Omira ,&nbsp;Maria Ana Baptista ,&nbsp;Ahmed Deif ,&nbsp;Talal Al-Awadhi ,&nbsp;Noura Al-Nasiri","doi":"10.1016/j.jaesx.2022.100103","DOIUrl":"10.1016/j.jaesx.2022.100103","url":null,"abstract":"<div><p>This paper investigates the deterministic tsunami hazard scenarios to assess the potential impact on the Qurayyat coast, northeast Oman. It assesses the maximum tsunami hazard characteristics with a focus on the zoning of tsunami hazard related to the human ability to stand within the inundation areas. Additionally, probabilities of buildings damage and small vessels loss are presented using fragility functions adapted from published studies of the 2011 Great East Japan Tsunami. Two worst-case credible tsunamigenic scenarios from Makran Subduction Zone (MSZ) were selected: 7.2Mw and 8.8Mw earthquake scenarios from western and eastern segments of the MSZ, respectively. A validated nonlinear shallow water numerical code with nested grids is used to simulate the tsunamis for each scenario over a 15 m-resolution grid for the Qurayyat region. Our results show that 8.8Mw earthquake corresponds to the maximum probable tsunami scenario posing the most severe threat. This scenario causes tsunami waves reaching 4.9 m and leads to a maximum runup height, maximum flow depth, and maximum inundation of 5.2 m, 3.8 m and 1.5 km, respectively. Furthermore, the tsunami hazard zoning for human stability suggests five hazard levels, ranging from “very low” to “very high” and the flooded buildings are classified into six damage levels, ranging from “minor” to “washed away”. The probabilities of buildings damage are high for minor and moderate damage levels. The vessels are classified based on their weight and location of motor. Obtained probabilities of vessels loss show that the outboard motor vessels would suffer greatest loss than inboard and the heavier ones.</p></div>","PeriodicalId":37149,"journal":{"name":"Journal of Asian Earth Sciences: X","volume":"8 ","pages":"Article 100103"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S259005602200024X/pdfft?md5=6a55a239940b4af3ee76958c24825a78&pid=1-s2.0-S259005602200024X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"54647878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study of hydrochemical and geochemical characteristics and solute fluxes in Upper Ganga Basin, India","authors":"M.K. Sharma,&nbsp;Pradeep Kumar,&nbsp;Parul Prajapati,&nbsp;Kunarika Bhanot,&nbsp;Udita Wadhwa,&nbsp;Garima Tomar,&nbsp;Rakesh Goyal,&nbsp;Beena Prasad,&nbsp;Babita Sharma","doi":"10.1016/j.jaesx.2022.100108","DOIUrl":"10.1016/j.jaesx.2022.100108","url":null,"abstract":"<div><p>Himalayan rivers are considered the most sensitive of all the ecosystems to the impact of climate change. In the present investigation, hydrochemical processes controlling the meltwater chemistry of the rivers Bhagirathi, Alaknanda and Ganga in the Upper Ganga Basin, India have been studied simultaneously creating a large database for the first time. For this purpose, an extensive water quality assessment in Upper Ganga Basin has been carried out by collecting water samples from all three rivers on monthly basis from September 2016 to May 2018 and analysing these samples for hydro-chemical parameters. Hydro-chemical characteristics revealed that sulphide oxidation and carbonation- the two proton producing reactions govern the chemical weathering processes pertaining in the rivers. One of the most peculiar findings of the study is the dominance of carbonate dissolution in the whole stretch of River Alaknanda, while the dominance of sulphide oxidation in River Bhagirathi upto Dabrani revealing the continuum of Gangotri glacial processes followed by carbonate dissolution upto Haridwar. The principal component analysis further supports this weathering process in the basin.</p></div>","PeriodicalId":37149,"journal":{"name":"Journal of Asian Earth Sciences: X","volume":"8 ","pages":"Article 100108"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590056022000299/pdfft?md5=307ace00eeca74db4bef296d1ae06ab3&pid=1-s2.0-S2590056022000299-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48954713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fault associated with the 1967 M 6.3 Koyna earthquake, India: A review of recent studies and perspectives for further probing","authors":"Kunal Modak,&nbsp;Sunil Rohilla,&nbsp;Nagaraju Podugu ,&nbsp;Deepjyoti Goswami,&nbsp;Sukanta Roy","doi":"10.1016/j.jaesx.2022.100123","DOIUrl":"10.1016/j.jaesx.2022.100123","url":null,"abstract":"<div><p>The Koyna region in western India, characterized by recurrent seismic activity over more than five decades and confined largely within a 20 km × 30 km area and ∼10 km in depth, is a classical site to study earthquake processes. The largest earthquake in the region, the <em>M</em> 6.3 Koyna earthquake of December 1967, formed a ∼NNE-SSW trending surface rupture, known as Donichawadi fissure zone. The fissure zone, mapped originally over a length of ∼4 km and width of ∼200 m between Nanel and Kadoli by the Geological Survey of India (GSI) in the wake of the earthquake, comprises en-echelon fractures, near-vertical fissures, oblique or diagonal tensional cracks, mole tracks, soil lumps and laterite boulders in paddy cultivated land. We review the Donichawadi fissure zone in the light of extensive seismological data acquired in the past five decades, surface mapping studies, recent geophysical studies, soil-gas helium studies over the fissure zone during 1996–1997, chemical and noble gas isotope compositions of formation gases, and subsurface fracture data from downhole image logs in a 3 km - deep scientific borehole drilled in 2017. Integration of the datasets provide clinching evidence that the Donichawadi fissure zone is the surface manifestation of a deeper crustal fault (referred as Donichawadi fault) that has been active for more than 55 years and yield critical new insights on the geometry, distribution and possible subsurface disposition of the fissures and the associated fractures in the subsurface. We conclude that the Donichawadi fault offers a potential target for further deep probing through scientific drilling, downhole measurements and long-term monitoring to gain new insights into the genesis of triggered earthquakes in the area.</p></div>","PeriodicalId":37149,"journal":{"name":"Journal of Asian Earth Sciences: X","volume":"8 ","pages":"Article 100123"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590056022000445/pdfft?md5=fdd61a7dee4fcb73da114fa1ad5326dc&pid=1-s2.0-S2590056022000445-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45265488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Meta-bauxite deposit in the Tavşanlı Zone, NW Turkey: A new locality for gem-quality diaspore formation","authors":"İbrahim Gündoğan","doi":"10.1016/j.jaesx.2022.100114","DOIUrl":"10.1016/j.jaesx.2022.100114","url":null,"abstract":"<div><p>The tectonic units of Sakarya Zone (Pontides) and Tavşanlı Zone (Anatolides) are exposed in the Mihalıççık area of central Anatolia. A Cretaceous accretionary complex that forms the İzmir-Ankara-Erzincan suture zone separates the units. Within this region, the Tavşanlı Zone is made up of a coherent series and tectonically overlying late Cretaceous mélange, which has undergone blueschist facies metamorphism. Coherent series consist of strongly retrogressed schists and conformably overlying platform-type thick marbles, known as the İnönü marbles.</p><p>The İnönü marbles contain meta-bauxite lenses in the lower levels, which can be classified as karstic bauxites deposited in the karst holes within the original limestone. Considering the general stratigraphy of the Tavşanlı Zone, a middle Jurassic age can be envisaged for the bauxite formation. Geochemical data suggest that the bauxites were largely derived from redeposited argillic sediments, with minor and variable inputs from the weathering of intermediate to acidic rock. The mineral assemblage of the meta-bauxite consists of diaspore, chloritoid, muscovite, paragonite, Al-spinel (hercynite), magnetite, hematite and ilmenite. In addition, apatite, rutile, monazite, xenotime and zircon occur as accessory minerals. Limonite, goethite, akaganeite and kaolinite also formed during the latest stage of alteration. P-T conditions for the meta-bauxites are estimated as 20–27 kbar and 330–470 °C that are indicative of formation under high-P / low-T blueschist facies conditions.</p><p>The meta-bauxites are cut by veins of diaspore, muscovite-paragonite, goethite, calcite and ankerite, and include gem-quality diaspore crystals up to 6 cm long. Textural evidence indicates that the diaspore formation is related to the extraction of aluminium from the meta-bauxite body and migration of Al-rich fluids into the shear zones during the last stage of the high-P metamorphism. During exhumation of the Tavşanlı Zone, these veins were brecciated by brittle deformation and the fractured minerals were cemented by granoblastic calcite and ankerite during the latest stage of the vein formation.</p></div>","PeriodicalId":37149,"journal":{"name":"Journal of Asian Earth Sciences: X","volume":"8 ","pages":"Article 100114"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590056022000354/pdfft?md5=b7dca69cd2c83ea4f1a34c23eae30c26&pid=1-s2.0-S2590056022000354-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43239729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Potential seismicity by impoundment of the Baihetan Reservoir, Xiaojiang Fault Zone, Southwest China","authors":"Tiantian Dou,&nbsp;Huihong Cheng,&nbsp;Huai Zhang,&nbsp;Yaolin Shi","doi":"10.1016/j.jaesx.2022.100106","DOIUrl":"10.1016/j.jaesx.2022.100106","url":null,"abstract":"<div><p>Baihetan reservoir, the second-largest hydropower station in China, is located at the east boundary of the Sichuan-Yunnan block, one of the most seismic active zones in continental China. Many studies have shown that the potential risk of reservoir-induced seismicity will ramp up when the crustal stress field is remarkably perturbed following its impoundment. In this work, based on the fully-coupled poroelastic theory, we built models with different parameters to quantitatively analyze the displacement and stress field changes caused by the Baihetan reservoir impoundment. The preliminary results show that the maximum subsidence reaches about 0.3 m, and the stress change is about 0.4 MPa at 5 km after five years of impoundment. Most strikingly, we find a significant increase of Coulomb Failure Stress Change (ΔCFS) on the fault planes at the vicinities of the surrounding Xiaojiang Fault, Daliangshan Fault, and Lianfeng Fault, suggesting high reservoir induced seismicity risks. However, the occurrence of induced/triggered earthquakes is not only related to the regional tectonic loading, but also the rock strength. Moreover, the reservoir water level rise rate will lead to different spatial–temporal patterns of the induced micro-seismicity, however, this difference will gradually disappear as the reservoir continues to operate, and the large earthquake is mainly affected by geological tectonics.</p></div>","PeriodicalId":37149,"journal":{"name":"Journal of Asian Earth Sciences: X","volume":"8 ","pages":"Article 100106"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590056022000275/pdfft?md5=4b7b7c7e5a16633c449248f0f32f5ba0&pid=1-s2.0-S2590056022000275-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48018678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geochemistry and Sr-Nd isotopic studies of Precambrian gneisses from central Aravalli Craton, NW India: Implications for crustal evolution and reworking","authors":"Ismail Samiullah Hamidullah ,&nbsp;Md. Erfan Ali Mondal ,&nbsp;Iftikhar Ahmad ,&nbsp;Waliur Rahaman ,&nbsp;Jitendra Kumar Dash","doi":"10.1016/j.jaesx.2022.100125","DOIUrl":"10.1016/j.jaesx.2022.100125","url":null,"abstract":"<div><p>The Aravalli Craton of the Indian shield constitutes heterogeneous basement lithologies (Banded Gneissic Complex; BGC), and among them, the granitoids are the most voluminous lithology. The BGC comprises two lithotectonic units, viz., BGC-I and BGC-II. The BGC-II has been further classified as amphibolite facies Mangalwar and granulite facies Sandmata Complexes. In the present study, the gneisses of the Mangalwar Complex are geochemically categorized into (i) low-and high-pressure sodic gneisses and (ii) potassic gneisses. The sodic gneisses are metaluminous and characterized by high Sr/Y and La_N/Yb_N ratios; and exhibit subduction-related negative anomalies of Nb and Ti. The ε_Nd (t = 2992 Ma) ranges from +2.3 to +3.1, with an average Nd-depleted mantle model age (T_DM) of 3.06 Ga. The whole-rock Sm-Nd isochron age is ∼3.0 Ga (2992 ± 340 Ma). Genetically, the sodic gneisses originated from the melting of an enriched precursor (oceanic plateau) in an arc environment. These gneisses show strong correlations with the gneisses from BGC-I depicting similar geochemical signatures. In contrast, the potassic gneisses are characterized by slightly higher SiO₂ along with high K₂O and high large-ion lithophile elements and negative Eu anomalies along with negative ε_Nd (t = 1.7 Ga) (−13.2 to −3.9), higher initial ⁸⁷Sr/⁸⁶Sr isotopic ratios and average T_DM = 2.87 Ga. These geochemical features of the potassic gneisses indicate that they were derived from the reworking of the pre-existing TTG-like (sodic gneisses) crust during the Paleoproterozoic Era.</p></div>","PeriodicalId":37149,"journal":{"name":"Journal of Asian Earth Sciences: X","volume":"8 ","pages":"Article 100125"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590056022000469/pdfft?md5=d675c09ab4a6f7e9144013dbc2a8bb19&pid=1-s2.0-S2590056022000469-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48552647","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spinel crystals in mantle ultramafic xenoliths as the source of P-T conditions of alteration above the magma chamber beneath the Avacha Volcano (Kamchatka)","authors":"Viktor Sharapov ,&nbsp;Yuri Semenov ,&nbsp;Grigory Kuznetsov ,&nbsp;Anatoly Boguslavsky","doi":"10.1016/j.jaesx.2022.100119","DOIUrl":"10.1016/j.jaesx.2022.100119","url":null,"abstract":"<div><p>This study focuses on the ability of spinel crystals in ultramafic xenoliths, like zircon, to store the primary composition and structure when exposed to magma fluid flows or the thermal heating of ultramafic fragments in magma flows during volcanic eruptions. Mantle ultramafic rock xenoliths from explosives of the Avacha Volcano in Kamchatka have different facies of their metasomatic changes above the magma chamber. An alternative hypothesis of their source is from fragments of layered mafic intrusions containing spinels, which store initial petrogenetic records of the original magma melt. Experiments were conducted to prove this idea using a Budker Institute of Nuclear Physics (INP SB RAS) unit. Large scales of change in the composition and structure of spinel crystals were caused by the hot fluids from melted xenolith sites.</p></div>","PeriodicalId":37149,"journal":{"name":"Journal of Asian Earth Sciences: X","volume":"8 ","pages":"Article 100119"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590056022000408/pdfft?md5=c8cd00bf801b057c11c06aa63f4aa97d&pid=1-s2.0-S2590056022000408-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48655246","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Concealed anatomy and new geological features beneath desert areas of NW India – Constrained from high resolution aero-geophysical data","authors":"Debojit Talukdar ,&nbsp;Ashish Kumar Raul ,&nbsp;Ch Ravi Kumar ,&nbsp;Antony Selinraj ,&nbsp;Niroj Kumar Sarkar ,&nbsp;Bijay Kumar Sahu ,&nbsp;Manoranjan Mohanty ,&nbsp;K.V. Maruthi","doi":"10.1016/j.jaesx.2022.100126","DOIUrl":"10.1016/j.jaesx.2022.100126","url":null,"abstract":"<div><p>The vast swathe of area in the Trans-Aravalli region between the western part of the South Delhi Fold Belt and eastern part of the Barmer basin, north-western India exhibits limited geological information due to thick sand cover of the Thar Desert. The present study is to unravel the hidden architecture of the above area using recently acquired high-resolution aero-magnetic data. Here, our interpreted results brought out a buried ring structure in the northern part and NW-SE trending constellation of linear magnetic highs in the southern part. Considering the regional geological milieu, our study correlates the buried ring structure with a possible remnant volcanic cone of the Neoproterozoic silicic Malani Large Igneous Province. Secondly, the significant NW-SE trending linear magnetic highs in the south possibly represents a humongous dyke swarm activity, facilitated by the intricate network of fractures. The orientation of these magnetic linear are conspicuously similar with the Deccan linked Sarnu-Dandali dykes and regional Barmer-Cambay rift system. The northwestern portion of study area displays high magnetic and gravity responses of long wavelength features indicating crustal heterogeneity. The study for the first time documents two concealed structures, which may hold a link of Neoproterozoic Malani and Mesozoic Deccan magmatic pulses.</p></div>","PeriodicalId":37149,"journal":{"name":"Journal of Asian Earth Sciences: X","volume":"8 ","pages":"Article 100126"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590056022000470/pdfft?md5=2690eebef1844be78cd138e4b0354d7a&pid=1-s2.0-S2590056022000470-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46123541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Petrology of the Paleogene shoshonitic volcanism in north Sarab area, NW Iran: Geochemical, Ar-Ar dating and Sr-Nd-Pb isotopic constraints","authors":"Somaye Heidari ,&nbsp;Amir Ali Tabbakh Shabani ,&nbsp;Shohreh Hassanpour ,&nbsp;Reza Maghdour-Mashhour","doi":"10.1016/j.jaesx.2022.100109","DOIUrl":"https://doi.org/10.1016/j.jaesx.2022.100109","url":null,"abstract":"<div><p>This study reports the earliest presumably known collisional magmatism of the NW Iran–eastern Turkey–Caucasus region from the north of Sarab city in East Azarbaijan province, NW Iran. Volcanic rocks of the area comprise alternating lava flows of mainly alkalibasalt, andesite, trachyandesite, dacite and pyroclastics (tuff and ignimbrite) affiliated with high-K calk-alkaline to shoshonitic magmatic series. Ar–Ar geochronology of the glass, matrix and plagioclase laths revealed crystallization time restricted to Late Eocene to Early Oligocene (34.90–30.69 Ma) which is coincident with the onset of the Arabian-Eurasian continental collision. Geochemical data show LREE enrichment compared with HREE and Nb and Ti depletion, indicating that they are subduction related. The Sr-Nd-Pb isotopic data reflect the incorporation of oceanic sediment into the magma source. We suggest that the volcanic rocks were generated from a metasomatised subcontinental lithospheric mantle source through 5 to 10 vol% partial melting in an extensional back arc basin by the Neotethys slab roll-back under the Iranian plateau.</p></div>","PeriodicalId":37149,"journal":{"name":"Journal of Asian Earth Sciences: X","volume":"8 ","pages":"Article 100109"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590056022000305/pdfft?md5=27201bba02f71496f0bf48bc79b8fe04&pid=1-s2.0-S2590056022000305-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71761321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}