Journal of Geodynamics最新文献

{"title":"Seismic deformation in the Adriatic Sea region","authors":"B. Orecchio,&nbsp;D. Presti,&nbsp;S. Scolaro,&nbsp;C. Totaro","doi":"10.1016/j.jog.2022.101956","DOIUrl":"10.1016/j.jog.2022.101956","url":null,"abstract":"<div><p>We present an overall analysis of the recent seismic activity occurred in the Adriatic Sea region, a strongly debated sector of the Mediterranean area, where several authors have proposed different models of plate configuration and kinematics. In the past, seismic investigations of this marine area have been strongly hampered by non-optimal network geometries, but data quality increase and recent methodological improvements lay the groundwork to attempt more accurate analyses including proper evaluations of result reliability. On these grounds, we investigated the seismic activity of the last decades by means of new hypocenter locations, waveform inversion focal mechanisms and seismogenic stress fields. We used the Bayloc non-linear probabilistic algorithm to compute hypocenter locations for the most relevant seismic sequences by carefully evaluating location quality and seismolineaments reliability. We also provided an updated database of waveform inversion focal mechanisms including original solutions estimated by applying the waveform inversion method Cut And Paste and data available from official catalogs. Then, focal mechanism solutions have been used to estimate seismogenic stress fields through different inversion algorithms. Seismic results indicate a relevant degree of fragmentation and different patterns of deformation in the Central Adriatic region. In particular, our analyses depicted two NW-SE oriented, adjacent volumes: (i) a pure compressive domain with NNE-trending axis of maximum compression characterizes the northeastern volume where the seismic activity occurs on W-to-NW oriented seismic sources; (ii) a transpressive domain with NW-trending axis of maximum compression characterizes the southwestern sector where thrust faulting preferentially occurs on ENE-to-NE oriented planes and strike-slip faulting on E-W ones. Joint evaluation of seismic findings of the present study and kinematic models proposed in the literature indicates just in the Central Adriatic region the presence of a broad deformation zone, accommodating a still evolving fragmentation of the Adriatic domain in two blocks rotating in opposite directions. On these grounds, the obtained results not only furnish new seismological evidence supporting the \"two-blocks model\" proposed by previous authors, but they also provide additional constraints, useful for better understanding and modeling the seismotectonic processes occurring in the Adriatic region.</p></div><div><h3>Data availability</h3><p>Data used in the present study were collected from catalogs and bibliographic sources indicated in detail in the article. Waveform inversions performed in this study used data available in the database EIDA, http://orfeus-eu.org/webdc3/ (accessed February 2022)</p></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49279607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Latest Cambrian stage of evolution of Precambrian continental crust in the Aktyuz high-pressure Complex (Chu-Kendyktas terrane; North Tien Shan): New evidence from the SW part of the Central Asian Orogenic Belt","authors":"Anfisa V. Skoblenko (Pilitsyna) ,&nbsp;Nadezhda A. Kanygina ,&nbsp;Andrey A. Tretyakov ,&nbsp;Kirill E. Degtyarev ,&nbsp;Truong Tai Nguyen ,&nbsp;Kwan-Nang Pang ,&nbsp;Victor S. Sheshukov ,&nbsp;Kseniya G. Erofeeva","doi":"10.1016/j.jog.2022.101955","DOIUrl":"10.1016/j.jog.2022.101955","url":null,"abstract":"<div><p>Metamorphic crustal formations of the Aktyuz block (SE part of the Chu-Kendyktas terrane; SW segment of the Central Asian Orogenic Belt) include garnet-bearing orthogneisses and gneissic granites of the Aktyuz Complex, garnet-bearing ortho- and paragneisses of the Kemin Complex and paragneisses with schists of the Kokdzhon Complex. The gneisses of the Aktyuz and Kemin Complexes associated with intensively altered eclogites, are referred to the retrogressed felsic granulites, which likely experienced high-pressure re-equilibration and dehydration melting under eclogite facies conditions. The eclogite-bearing garnet-mica gneisses of the Aktyuz Complex contain zircons with magmatic cores, overgrown by the rims with the low Th/U ratios of 0.005–0.05. The obtained age clusters of ca. 844 Ma and ca. 490 Ma likely characterize two stages of the rocks’ evolution in the late Neoproterozoic (emplacement of the gneisses’ protoliths) and in the latest Cambrian (high-pressure metamorphism of the gneisses’ protoliths). The garnet-epidote gneissic granites of the Aktyuz Complex and garnet-bearing chloritized orthogneisses of the Kemin Complex yielded late Neoproterozoic (Tonian) protoliths’ crystallization ages of 820–805 Ma, but these rocks do not show any evidence of the later re-equilibration and apparently avoided high-pressure metamorphism. Thus, the protoliths of the late Neoproterozoic orthogneisses represented by anorogenic granitoids, comprised Precambrian basement of the Aktyuz block in the Chu-Kendyktas terrane, and some part of the felsic rocks was involved into Early Palaeozoic subduction processes. Detrital zircons from the metasedimentary formations of the Kokdzhon and Kemin Complexes of the Aktyuz block display the main age peaks at 600, 800, 1000 Ma and weaker peaks at ∼1.5 and 2.5 Ga. The protoliths of the rocks were terrigenous lithologies, which are believed to have been formed after eroded felsic complexes of mostly Ediacaran, late Neoproterozoic, Mesoproterozoic and Palaeoproterozoic-to-Neoarchean ages, and accumulated during the Cambrian. The rocks likely made up sedimentary cover of the Chu-Kendyktas terrane and constituted the sand-siltstone-shale series. The presence of varisized rims of 495–471 Ma in the detrital zircons of the metasedimentary formations of the Kokdzhon and Kemin Complexes is consistent with the near-peak-to-retrograde stages of the latest Cambrian-Middle Ordovician metamorphic evolution of the rocks. The age estimates obtained for the crustal complexes of the Aktyuz block correlate well with those of the similar complexes known from the adjacent Issyk-Kul (North Tien Shan) terrane (Makbal Complex) and Zheltau terrane (Southern Kazakhstan; Koyandy Complex) in the SW part of the Central Asian Orogenic Belt.</p></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48240952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enigmatic crustal and upper mantle structure in the NE Sino-Korean Craton based on nuclear explosion seismic data","authors":"Xiaoqing Zhang ,&nbsp;Hans Thybo ,&nbsp;Irina M. Artemieva ,&nbsp;Tao Xu ,&nbsp;Zhiming Bai","doi":"10.1016/j.jog.2022.101957","DOIUrl":"10.1016/j.jog.2022.101957","url":null,"abstract":"<div><p>We interpret the crustal and upper mantle structure along ∼2500 km long seismic profiles in the northeastern part of the Sino-Korean Craton (SKC). The seismic data with high signal-to-noise ratio were acquired with a nuclear explosion in North Korea as source. Seismic sections show several phases including Moho reflections (PmP) and their surface multiple (PmPPmP), upper mantle refractions (P), primary reflections (PxP, PL, P410), exceptionally strong multiple reflections from the Moho (PmPPxP), and upper mantle scattering phases, which we model by ray-tracing and synthetic seismograms for a 1-D fine-scale velocity model. The observations require a thin crust (30 km) with a very low average crustal velocity (ca. 6.15 km/s) and exceptionally strong velocity contrast at the Moho discontinuity, which can be explained by a thin Moho transition zone (&lt; 5 km thick) with strong horizontal anisotropy. We speculate that this anisotropy was induced by lower crustal flow during delamination dripping. An intra-lithospheric discontinuity (ILD) at ∼75 km depth with positive velocity contrast is probably caused by the phase transformation from spinel to garnet. Delayed first arrivals followed by a long wave train of scattered phases of up to 4 s duration are observed in the 800–1300 km offset range, which are modelled by continuous stochastic velocity fluctuations in a low-velocity zone (LVZ) below the Mid-Lithospheric Discontinuity (MLD) between 120 and 190 km depth. The average velocity of this LVZ is about 8.05 km/s, which is much lower than the IASP91 standard model. This LVZ is most likely caused by rocks which are either partially molten or close to the solidus, which explains both low velocity and the heterogeneous structure.</p></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48369833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The fault and stress patterns of Western Transbaikalia","authors":"A.V. Cheremnykh,&nbsp;I.K. Dekabryov","doi":"10.1016/j.jog.2022.101959","DOIUrl":"10.1016/j.jog.2022.101959","url":null,"abstract":"<div><p>Stress patterns are reconstructed for large fault zones and the respective fault-bounded blocks in Western Transbaikalia (southeast of Lake Baikal). The reconstruction is based on analysis of structural measurements combined with slickenside data and earthquake mechanisms. The combination of several methods for stress inversion provides high quality of the results. The inferred diversity of local stress tensors is analyzed in terms of the hierarchy of crustal stresses unevenly distributed in space and time. The tectonic stress fields at the local, subregional, and regional levels result from changes in the magnitude of principal stresses and their respective switch during the evolution of fault zones. The reported regional paleostress reconstructions for rocks of different ages not only have confirmed the sequence of events in the Mesozoic-Cenozoic history of Western Transbaikalia but revealed additionally the previously unknown stress regime of strike-slip which existed there after the closure of the Mongolia-Okhotsk ocean. The heterogeneous patterns of local stress tensors indicate the absence of a single crustal stress field in the region.</p></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48976715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Arc-like magmatism in syn- to post-collisional setting: The Ediacaran Angra Fria Magmatic Complex (NW Namibia) and its cross-Atlantic correlatives in the south Brazilian Florianópolis Batholith","authors":"Vojtěch Janoušek ,&nbsp;Luana Moreira Florisbal ,&nbsp;Jiří Konopásek ,&nbsp;Petr Jeřábek ,&nbsp;Maria de Fátima Bitencourt ,&nbsp;Petr Gadas ,&nbsp;Vojtěch Erban ,&nbsp;Veronika Kopačková-Strnadová","doi":"10.1016/j.jog.2022.101960","DOIUrl":"10.1016/j.jog.2022.101960","url":null,"abstract":"<div><p>Ediacaran syn-tectonic plutonic rocks (amphibole gabbros, quartz diorites/tonalites to biotite- and muscovite-bearing granites) of the Angra Fria Magmatic Complex (Kaoko Belt, north-western Namibia) belong to two compositionally similar, magnesian, transitional tholeiitic–calc-alkaline suites, the Older (∼625–620 Ma) and the Younger (∼585–575 Ma). Both have counterparts in the broadly contemporaneous Florianópolis Batholith (southern Brazil), from which they were separated during the Cretaceous opening of the southern Atlantic. In the Angra Fria Magmatic Complex, the only unequivocal mantle contributions are identified in mingling zones of the Younger Suite and hybrid mafic–intermediate dykes of uncertain age. Previously published Hf-in-zircon isotopic data, together with new whole-rock geochemical and Sr–Nd isotopic signatures, underline an important role of crustal anatexis of a material with late Palaeoproterozoic to early Mesoproterozoic mean crustal residence (1.9–1.5 Ga). This interval resembles some of the published Nd model ages for Tonian ‘Adamastor Rift’-related felsic magmatic rocks in the Namibian Coastal and Uruguayan Punta del Este terranes. In detail, the Older Suite probably originated mainly by fluid-present melting of metabasalts and metatonalites, followed by (near) closed-system fractional crystallization (with or without accumulation) of amphibole ± plagioclase. For the Younger Suite, the principal process was the dehydration melting of relatively felsic lower crustal protoliths (metagreywackes or intermediate–acid orthogneisses &gt;&gt; metapelites), leaving garnet in the residue. Based on the geological context, the conspicuous enrichment of hydrous-fluid-mobile large ion lithophile over the conservative high field strength elements is not interpreted through a classic model of oceanic plate subduction, devolatilization, and fluxed-melting of the overriding mantle wedge. Instead, it is thought to reflect high-grade metamorphism of deeply buried continental crust and attendant water-fluxed melting of the overlying crustal lithologies, connected with inversion of the Tonian ‘Adamastor Rift’.</p></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47127466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quaternary deformation patterns in East–Central Iran, constrained by coseismic–postseismic displacements of the 2017 Hojedk triplet earthquake in the Kerman Province","authors":"Marzieh Khalili ,&nbsp;Yildirim Dilek ,&nbsp;Leila Zareian Ronizi","doi":"10.1016/j.jog.2022.101941","DOIUrl":"10.1016/j.jog.2022.101941","url":null,"abstract":"<div><p><span><span>The Central Iranian Microcontinent (CIM) in east-central Iran is located north of the active Arabia–Eurasia collision zone. Here, we report on the structure, deformation patterns, and earthquake occurrences along the dextral Lakar–Kuh and Godar fault systems in the CIM. The geometry of these fault systems marks a major restraining bend responsible for surface and rock uplift in the Plio–Pleistocene that produced the Mian Kuh mountain range. The 2017 Hojedk triplet earthquake (Mw = 5.8–6.0) occurred in the Mian Kuh Range. Sentinel–1 A Interferometer Synthetic Aperture Radar (InSAR) images (descending and ascending) were used to extract the coseismic displacements associated with the earthquake and its </span>aftershocks. The results indicate a maximum displacement of ∼20 cm, corresponding to hanging wall uplift along the radar Line-of-Sight (LOS) direction. The Geodetic Bayesian Inversion (GBIS) of the coseismic deformation indicates that the causative faults of the Hojedk earthquakes were two reverse faults with NW–SE–strikes and SW–dips, with minor dextral slip components. Given the </span>focal mechanism<span> solutions and the epicenter<span> locations of the triple earthquake sequence, we infer that these faults at the southern termination of the Lakar–Kuh Fault represent two segments (with different dip angles) of a previously unrecognized, blind reverse fault (a splay of the Godar Fault at depth). The Hojedk Earthquake and the geometry and kinematics of its causative faults highlight the strong potential of seismic hazard zones along the strike-slip fault systems in the CIM.</span></span></p></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48266880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stress evolution on major faults in Tien Shan and implications for seismic hazard","authors":"Yajin Pang","doi":"10.1016/j.jog.2022.101939","DOIUrl":"10.1016/j.jog.2022.101939","url":null,"abstract":"<div><p><span>Tien Shan tectonic belt has experienced intense seismicity and a series of destructive strong earthquakes. However, earthquake triggering effects and faulting interactions in this area are poorly understood. A 3D finite element model of Tien Shan tectonic belt is constructed, to investigate stress evolutions on major faulting zones driven by interseismic tectonic loading and historical strong earthquakes with M≥ 6.0 since 1900. The numerical results show Tien Shan is dominated by nearly N-S compression, with higher tectonic loading rate in southwest Tien Shan. 1906 Manas M7.7 earthquake exerted pronounced Coulomb stress increase on its adjacent faulting zones, especially in the </span>epicenter of 2016 Hutubi M6.0 earthquake. And three large earthquakes with M≥ 8.0, e.g., Chilik M8.3 earthquake in 1889, Kemin M8.0 earthquake in 1911 and Atushi M8.2 earthquake in 1902, increased the Coulomb stress by above 100 kPa in the epicenter of 1991 Keping M6.0 earthquake. While, stress perturbations by other strong earthquakes are limited, with slight Coulomb stress changes in the epicenters of their subsequent earthquakes. Overall, strong earthquakes with M&gt; 7.0 in Tien Shan, induced substantial Coulomb stress changes on the adjacent faulting zones. Stress evolutions on major faults reveal higher stress accumulation in southwest Tien Shan, east KQX fault, west BoA fault, and HMT fault, indicating higher seismic risk.</p></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49542579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"U-Pb geochronology and geochemistry of the Torud igneous rocks: Implications for post-collision Eocene magmatism in northeast Iran","authors":"Morteza Khalatbari Jafari ,&nbsp;Hassan A. Babaie ,&nbsp;Songjian Ao ,&nbsp;Wenjiao Xiao","doi":"10.1016/j.jog.2022.101942","DOIUrl":"10.1016/j.jog.2022.101942","url":null,"abstract":"<div><p><span>New geochemical and U-Pb isotopic data from the Torud volcanic and subvolcanic rocks and their associated dikes<span><span><span><span> exposed along the southern margin of the Sabzevar-Torud zone provide new evidence for Early-Middle Eocene, post-collision </span>magmatism<span> in northeast Iran. The 52–46 Ma (late Ypresian-Lutetian) U-Pb age interval of zircons<span> separated from these rocks confirm the paleontological age of nummulite-bearing limestone interlayers. Inherited zircons separated from these igneous rocks have a much wider range of U-Pb ages that include Archean, Paleoproterozoic, Mesoproterozoic, Carboniferous, Permian, Triassic, </span></span></span>Middle Jurassic<span>, and Late Cretaceous. Most volcanics and subvolcanic rocks display high-K calcalkaline and shoshonitic trends. Distinct crystal fractionation patterns of the volcanic and subvolcanic rocks suggest </span></span>magmatic differentiation in separate </span></span>magma chambers<span>. The studied rocks, depleted in the HFSE and enriched in the LILE, display nearly homogeneous isotopic Sr (0.7039–0.7055) and Nd (0.5126–0.5129) ratios and positive ɛNd values (0.08–0.56) indicating partial melting from an enriched lithospheric mantle source that was slightly contaminated with crustal material. Fluids, especially those released from the subducted slab, affected the composition of the source for the studied rocks. The magmatism occurred in the Torud area after the Late Cretaceous-Paleocene collision of the Central Iran microcontinent and Binalud-Kopeh-Dagh blocks and the Early-Middle Eocene break-off of the subducted slab.</span></p></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43605465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Salt diapirism in the eastern margin of the Pre-Caspian Basin: Insight from physical experiments","authors":"Jing Ziyan ,&nbsp;Li Guobin ,&nbsp;Zhang Yajun ,&nbsp;Xie Tianfeng ,&nbsp;Feng Yuan ,&nbsp;Zhao Binbin ,&nbsp;Wang Hongbin ,&nbsp;Dai Shuang ,&nbsp;Yang Zhaoping ,&nbsp;Yuan Xiaoyu ,&nbsp;Shi Zhongsheng ,&nbsp;Tian Xin","doi":"10.1016/j.jog.2022.101940","DOIUrl":"10.1016/j.jog.2022.101940","url":null,"abstract":"<div><p><span><span>Since the 1950 s, salt diapirism has been shown to be closely related to hydrocarbon accumulation and has been a hot spot of research activity in structural and petroleum geology. Many salt structural, such as salt wall, roller, pillow, welt and </span>anticline<span> have been formed in the Pre-Caspian Basin during the post-Kungurian (Lower Permian) times. Meanwhile, mechanisms of salt structure deformation and the influence of the sub-salt strata on salt diapirism is still unclear. Based on seismic data<span> and a geological model of the eastern margin of the Pre-Caspian Basin, physical simulation experiments of salt diapirism have been conceived. Performed to analyze, the dynamic process of salt structure deformation, and to clarify mechanisms of the salt diapirism and the relationships between the salt structures and the underlying strata. Differential loading seems to a principal mechanism accounting for sediment. The sedimentation rate of the overburden formations had a great impact on the salt structure forms and geometry. The physical experiments showed that: salt diapirism starts in the basin margin with </span></span></span>progradation of sediments and then continues down-slope toward the basin center. The height and width of the salt structures are influenced by dip angle of the sub-salt. The larger-scale salt structures occurred in the inner basin zones, followed the central slope zone and the basin margin with a large dip angle.</p></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43216439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lithosphere structure in the collision zone of the NW Himalayas revealed by alocal earthquake tomography","authors":"Irina Medved ,&nbsp;Ivan Koulakov ,&nbsp;Sagarika Mukhopadhyay ,&nbsp;Andrey Jakovlev","doi":"10.1016/j.jog.2022.101922","DOIUrl":"https://doi.org/10.1016/j.jog.2022.101922","url":null,"abstract":"<div><p><span><span>In this study, we obtained new 3D seismic tomography models of the crust and uppermost mantle beneath the northwestern </span>Himalayas down to a depth of 120 km. The data were provided by the India Meteorological Department (IMD) and complemented by the Global International Seismological Centre (ISC) Catalogue. The distribution of anomalies correlates with the main </span>geological features<span> of the region. Specifically, the mountain ranges of the Greater and Lesser Himalaya stand out as a low-velocity anomaly, and the Indian Plate is visible as a high-velocity anomaly underthrusting the Himalayas. The Indian Plate not only underthrusts northwards below the Himalayas, but also bends westwards as it gets closer to the Hindukush Region. A peculiar feature of the model is a high-velocity anomaly in the Kaurik Chango Rift, interpreted as a remnant of the oceanic crust, left after the Indotethys Ocean’s closure. In the seismically active Delhi-Haridwar Ridge, a low-velocity upper crustal layer is possibly associated with the sediments of the Indo-Gangetic Plain and with a large number of fault structures. The fragmentation of the Delhi-Haridwar Ridge softens the movement of the Indian Plate to the north, so that the Tethyan Himalaya crust in the area of the Kaurik Chango Fault has remained consolidated and manifests itself as a high-velocity anomaly.</span></p></div><div><h3>Data Availability</h3><p>The full directory of LOTOS code with data corresponding to this study is available at <span>https://doi.org/10.5281/zenodo.5519210</span><svg><path></path></svg> (accessed on 23 September 2021).</p></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2022-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72121357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}