Gondwana Research最新文献

{"title":"Tectonic evolution of the Qiangtang Basin (northern Tibet): Constraints from detrital zircon geochronology","authors":"Yanxiong Zhang ,&nbsp;Bo Zheng ,&nbsp;Jie Dai ,&nbsp;Gideon Rosenbaum ,&nbsp;Jian Wang","doi":"10.1016/j.gr.2024.08.019","DOIUrl":"10.1016/j.gr.2024.08.019","url":null,"abstract":"<div><div>The Mesozoic evolution of the Qiangtang Basin in the Tibetan Plateau, which potentially hosts oil and gas resources, is not fully understood, particularly in the context of the opening and closure of the Tethyan oceans. To better understand the tectonic evolution of the Qiangtang Basin and the history of sedimentation, we obtained 788 new U-Pb detrital zircon ages from 12 sandstone samples. Our results show that the provenance of the Mesozoic strata varies both in space and time. In the central part of the basin (Central Qiangtang), older sedimentary rocks are characterized by unimodal age spectra (300–233 Ma) that indicate a proximal arc source. Trace-element compositions of Permian to Triassic zircons from Lower Triassic strata are characteristic of crystallization in arc and backarc environments, thus supporting previous suggestions that the Qiangtang Basin formed as a backarc basin during subduction of the Paleo-Tethys oceanic lithosphere. Younger (Upper Triassic and Jurassic) strata in the Qiangtang Basin received detrital zircons from diverse sources that included Cambrian to Triassic magmatic rocks and Paleozoic strata in the Central Qiangtang, and Triassic flysch deposits in the Songpan-Garze Terrane. We suggest that this change in provenance — from a unimodal arc source that produced zircons in Lower–Middle Triassic rocks to the diverse provenance recognized in the Upper Triassic strata — marks the closure of the Paleo-Tethys Ocean during the Late Triassic. Jurassic sedimentation in the Qiangtang Basin occurred during the expansion of the Meso-Tethys Ocean (Early–Middle Jurassic) and the subsequent subduction of this ocean (since the Callovian). During the Early Cretaceous, the closure of the Meso-Tethys Ocean led to an uplift and a sedimentary hiatus that marked the end of marine sedimentation in the Qiangtang Basin.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"136 ","pages":"Pages 202-218"},"PeriodicalIF":7.2,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transcrustal magmatic systems in NE China: Insights from Early Cretaceous metaluminous–peraluminous–peralkaline rock associations in the southern Great Xing’an Range","authors":"Li Tian ,&nbsp;Jun Gou ,&nbsp;Deyou Sun ,&nbsp;Duo Zhang ,&nbsp;Zhao Feng ,&nbsp;Zhonghua He","doi":"10.1016/j.gr.2024.08.017","DOIUrl":"10.1016/j.gr.2024.08.017","url":null,"abstract":"<div><div>The generation and evolution of crustal-scale magmatic systems are important in revealing the continental crust differentiation. In the Bayangeer-Aliwula area of Inner Mongolia, metaluminous–peraluminous–peralkaline rock assemblages provide a rare opportunity to evaluate Early Cretaceous magmatic systems. This study presents new geochemical data, including whole-rock and zircon geochemistry, zircon U–Pb dating, and Hf–O isotopic analysis of rocks formed between 132 and 121 Ma. The metaluminous rocks exhibit low SiO₂ (55.35–65.65 wt%), low Rb/Sr (0.08–0.24) and (La/Yb)_N (4.88–7.58) ratios, and positive ε_Hf(t) values (+4.9 to +8.7). These features, along with enrichment in large-ion lithophile elements and depletion in Nb and Ta, suggest formation via partial melting of fluid-metasomatised lithospheric mantle. By contrast, peraluminous rocks have high SiO₂ (69.37–80.58 wt%), a high differentiation index (DI = 88–95), and Fe-index (0.84–0.95), resembling highly fractionated I-type granites. They show high Rb/Sr (0.77–3.35) and (La/Yb)_N (5.79–22.75) ratios, and positive ε_Hf(t) values (+6.7 to +10.8), combined with the modelling results, indicating origin from partial melting of K-rich mafic lower crust followed by magma fractionation. Peralkaline rocks display typical ferroan A-type granite characteristics (Zr + Nb + Ce + Y = 906–4292 ppm; Fe-index = 0.96–0.99), with high SiO₂ (74.02–77.50 wt%), high Rb/Sr (6.17–121.38), and (La/Yb)_N ratios (2.19–17.72), and positive ε_Hf(t) values (+3.1 to +9.6). Zircon geochemistry characteristics suggest that peralkaline and peraluminous felsic melts are different batches extracted from the same magma reservoir. Further analysis, including hyperbola diagrams and zircon oxygen isotope compositions, suggests peralkaline magma formation through the mixing of altered oceanic crust fluids and peraluminous melts after melt extraction. During Early Cretaceous, the transcrustal magmatic system provides a reasonable explanation for the petrogenesis of various contemporaneous rocks in the study area in southern Great Xing’an Range.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"136 ","pages":"Pages 183-201"},"PeriodicalIF":7.2,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prolonged arc accretion during growth of juvenile crust in the Arabian Nubian Shield: Insights from the granitoids of northern Ethiopia","authors":"Mulubrhan Gebreslassie ,&nbsp;Shao-Bing Zhang ,&nbsp;Liang Zhang ,&nbsp;Ting Liang ,&nbsp;Xiang-Ping Zha","doi":"10.1016/j.gr.2024.09.002","DOIUrl":"10.1016/j.gr.2024.09.002","url":null,"abstract":"<div><div>The Arabian Nubian Shield (ANS) is one of the largest juvenile continental crust formed after the Archean. To determine the timing and understand the mechanism of its early crustal growth, we conducted geochronological and geochemical studies on granitoids from northern Ethiopia. A plagiogranite, dated at 929.7 ± 2.2 Ma, represents one of the early granitoids from the ANS. It shows low K₂O, TiO₂, and REE contents, flat REE pattern and absence of Eu anomaly. Moreover, it exhibits (⁸⁷Sr/⁸⁶Sr)_i, Ɛ_Nd(t) and Ɛ_Hf(t) values of 0.70341, +5.0 and +8.4, respectively. Its zircon δ¹⁸O value is 4.8‰, lower than the mantle value. These characteristics suggest that it was derived from partial melting of altered oceanic crust. The oxygen fugacity obtained from zircon trace elements is ΔFMQ+1.3, consistent with a subduction setting.</div><div>Other plutons have much younger ages ranging from 860 to 840 Ma and are mainly medium K, I-type granitoids. These granitoids show low MgO, Ni and Cr contents, low Sr/Y, (La/Yb)_N, Nb/Ta and Zr/Sm ratios. They exhibit whole-rock (⁸⁷Sr/⁸⁶Sr)_i values of 0.70236–0.70304, Ɛ_Nd(t) values of 4.2–5.2, Ɛ_Hf(t) values of 5.8–7.6 and zircon Ɛ_Hf(t) values of 5.5–10.4, slightly lower than coeval depleted mantle. Furthermore, they exhibit fractionated REE patterns, enrichments in LILE and depletion in HFSE. These geochemical features suggest that these granitoids were generated by remelting of arc crust. Compiled data show that the associated basaltic rocks are of arc affinity, which confirms the coeval development of arc magmatism in the southern ANS. Our results suggest that the growth of juvenile crust in the southern ANS started from the early Neoproterozoic and peaked at ca. 880 to 800 Ma, much earlier than those in the northern ANS. The prolonged history accounts for the growth of the vast juvenile crust in the ANS.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"137 ","pages":"Pages 56-78"},"PeriodicalIF":7.2,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142424201","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Two-stage Mesozoic oceanic subduction and related mantle metasomatism beneath the South Qiangtang terrane with implications for post-collisional magmatism","authors":"Neng Gong ,&nbsp;Sheng-Qiang Zhang ,&nbsp;Hui Qi ,&nbsp;Guo-Li Yuan ,&nbsp;Jun Li ,&nbsp;Gen-Hou Wang ,&nbsp;Xiao Liang ,&nbsp;Zhi-Bo Liu","doi":"10.1016/j.gr.2024.09.001","DOIUrl":"10.1016/j.gr.2024.09.001","url":null,"abstract":"<div><div>Subduction-related metasomatism at convergent margins is a crucial process for the lithosphere evolution of the overriding plate. In the central Tibetan Plateau, tectonic transitions and related mantle metasomatism history of the oceanic subduction beneath the South Qiangtang terrane (SQT) remain ambiguous, which impeded understanding the geological evolution of the SQT during the Mesozoic and interpreting the geodynamic process responsible for the Cenozoic post-collisional magmatism. This paper integrated the new and published geochronological and geochemical data from the Jurassic-Cretaceous magmatic rocks in the western part of the SQT to explore the variations of magmatism and processes of mantle modifications. The Jurassic arc magmatism is characterized by the southward younging migration with increasing zircon ε_Hf (t) values and the east–west linear distribution of ca. 155–150 Ma slab-derived adakites. After a magmatic gap at ca. 145–130 Ma, the Early Cretaceous magmatism (130–100 Ma) with distinct juvenile isotopic compositions reinitiated firstly in the south of the Jurassic magmatic belt. In comparison, a younger phase of felsic rocks (120–100 Ma) spatially and geochemically overlaps the northern Jurassic granitoids with ancient crustal sources. These spatial–temporal-geochemical covariations of magmatism could be best explained by the southward transference of oceanic subduction at the earliest Cretaceous that was induced by the Jurassic accretion of an oceanic plateau onto the SQT. Under such subduction regimes, several high-Nb mafic rocks in the northern and southern magmatic belts which were formed by partial melting of the slab-melts-metasomatized lithospheric mantle respectively recorded the Jurassic and Cretaceous mantle metasomatism beneath the SQT, based on their spatial and geochemical relationships with two phases of the adakites. Combined with other geological evidence, these results contribute to elucidating the Mesozoic geodynamic evolution of the oceanic subduction beneath the SQT, which further has implications on the deep dynamic processes responsible for post-collisional magmatism.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"136 ","pages":"Pages 219-235"},"PeriodicalIF":7.2,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142320085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seismic tomography reveals contrasting styles of subduction-channel and mantle-wedge exhumation controlled by upper plate divergent motion","authors":"Stefano Solarino ,&nbsp;Marco G. Malusà ,&nbsp;Elena Eva ,&nbsp;Anne Paul ,&nbsp;Stéphane Guillot ,&nbsp;Silvia Pondrelli ,&nbsp;Simone Salimbeni ,&nbsp;Liang Zhao","doi":"10.1016/j.gr.2024.08.016","DOIUrl":"10.1016/j.gr.2024.08.016","url":null,"abstract":"<div><p>In fossil subduction zones associated with massive exhumation of (ultra)high-pressure ((U)HP) rocks such as the Western Alps, the geometry and behavior of subduction-channel and mantle-wedge rocks during exhumation are still poorly constrained by independent geophysical observations. Here we use a new local earthquake tomography model of the entire fossil subduction zone of the Western Alps based on data collected during the CIFALPS and CIFALPS2 passive seismic experiments, and the first receiver-function profile across the Ligurian Alps, to investigate the styles of subduction-channel and mantle-wedge exhumation as a function of increasing upper-plate divergence motion. In the northern Western Alps (low divergence), a thickened subduction channel can be detected, but no exhumed mantle wedge is found beneath the Gran Paradiso (U)HP dome. In the southern Western Alps (intermediate divergence), an exhumed mantle wedge is detected beneath the Dora-Maira (U)HP dome above a serpentinized subduction channel. In the Ligurian Alps (high divergence), an exhumed mantle wedge and a former subduction channel are detected at much shallower levels beneath the Voltri-Valosio (U)HP dome, and above a shallow-dipping lower-plate Moho. In this latter case, the lower boundary of the exhumed subduction channel is the most evident seismic-velocity interface, which may be easily misinterpreted as a true Moho. Similar Moho-like interfaces are found beneath the exhumed (U)HP domes of eastern Papua New Guinea and the Dabie Shan, which suggests that the results of the CIFALPS experiments may be used as a reference case for the interpretation of other (U)HP terranes worldwide.</p></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"136 ","pages":"Pages 169-182"},"PeriodicalIF":7.2,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1342937X2400265X/pdfft?md5=79ecd1a1ebbc58572cf9f5095084b118&pid=1-s2.0-S1342937X2400265X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142230799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Editorial Board (IFC)","authors":"","doi":"10.1016/S1342-937X(24)00258-2","DOIUrl":"10.1016/S1342-937X(24)00258-2","url":null,"abstract":"","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"135 ","pages":"Page IFC"},"PeriodicalIF":7.2,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1342937X24002582/pdfft?md5=db16f093986b479a825f316a6d8ce1f9&pid=1-s2.0-S1342937X24002582-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142168467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stable carbon isotope chemostratigraphy of the base of the Callovian in Greenland","authors":"Ricardo L. Silva ,&nbsp;Peter Alsen","doi":"10.1016/j.gr.2024.08.011","DOIUrl":"10.1016/j.gr.2024.08.011","url":null,"abstract":"<div><p>D’Orbigny named the Callovian stage after Kellaways in Wiltshire, UK, in the 1850 s. However, agreement on its boundaries and, more recently, on the position and location of the Global Boundary Stratotype Section and Point (GSSP) for the base of the Callovian has proven difficult for the last 170 years. This is mainly due to the lack of agreement on the appropriate index fossil and its regional and global correlations, as well as the location of the stratotype section. Stable carbon isotope chemostratigraphy and event stratigraphy are now essential tools for aiding in the definition of GSSPs. In this study, stable carbon isotopic analysis of 91 samples from east Greenland’s Middle Jurassic shallow marine sandstones of the Pelion Formation (Store Koldewey and Hold with Hope) and correlative and well-dated offshore siltstones and mudstones of the Fossilbjerget Formation (Jameson Land) is used to discriminate several isotopic events previously observed in other European basins and propose the early Callovian (δ¹³C_TOC) positive carbon isotopic excursion as a secondary marker for defining the Callovian GSSP. The early Callovian (δ¹³C_TOC) positive carbon isotopic excursion is a fundamental tool for superregional correlation between candidate GSSPs and Standard Auxiliary Boundary Stratotypes. It can also help establish a chronological order (synchronous vs diachronous) of species occurrences between different locations.</p></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"136 ","pages":"Pages 84-91"},"PeriodicalIF":7.2,"publicationDate":"2024-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1342937X24002533/pdfft?md5=ea0f6788235063c8727fc739096c034b&pid=1-s2.0-S1342937X24002533-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142147923","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Connectedness between artificial intelligence, clean energy, and conventional energy markets: Fresh findings from CQ and WLMC techniques","authors":"Sunil Tiwari ,&nbsp;Salahuddin Khan ,&nbsp;Kamel Si Mohammed ,&nbsp;Yuriy Bilan","doi":"10.1016/j.gr.2024.08.013","DOIUrl":"10.1016/j.gr.2024.08.013","url":null,"abstract":"<div><p>In line with achieving the objectives of COP27 and SDG7, this paper examines the interdependence of the Artificial Intelligence market, clean energy, and conventional energy markets from 19th December 2017 to 5th May 2023 by using Cross-Quantilogram (CQ) and Wavelet Locale Multiple correlations (WLMC) techniques. Heatmaps of CQ show a bidirectional relationship between the AI market and clean energy at lag one with negative cross-quantile dependence evident throughout most quantiles, especially in normal market conditions. It also indicates a positive relationship between AI return rates and the clean energy market, but only when both datasets are in the same extreme quantiles (10th and 90th). Additionally, WMLC results reveal that time, scale, and investment horizons influence the interaction between AI and clean and non-clean energy industries. A considerable positive association exists between the AI market and traditional energy markets, ranging from 0.6 to 0.8. However, during the pandemic, this dependency turned negative, and it has since been minor, with an uptick in co-movement during Russia – Ukraine conflict. Several policy implications are suggested for the clean energy and conventional energy markets in line with AI.</p></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"136 ","pages":"Pages 92-103"},"PeriodicalIF":7.2,"publicationDate":"2024-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142147928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Marine Fe cycling linked to dynamic redox variability, biological activity and post-depositional mineralization in the 1.1 Ga Mesoproterozoic Taoudeni Basin, Mauritania","authors":"Mohamed Ghnahalla ,&nbsp;Olivier Rouxel ,&nbsp;Ernest Chi Fru ,&nbsp;Olabode M. Bankole ,&nbsp;Mohamed Salem Sabar ,&nbsp;Ahmed Abd Elmola ,&nbsp;Ibtissam Chraiki ,&nbsp;Fatima Abdelfadel ,&nbsp;Claude Fontaine ,&nbsp;Alain Trentesaux ,&nbsp;Rayane El Ghastalany ,&nbsp;El Houssein Abdeina ,&nbsp;Abderrazak El Albani","doi":"10.1016/j.gr.2024.08.012","DOIUrl":"10.1016/j.gr.2024.08.012","url":null,"abstract":"<div><p>The concentration of redox sensitive trace metals (RSTEs) and their isotopic composition preserved in Precambrian marine sediments, are critical for the reconstruction of ocean–atmosphere oxygenation history. Particularly, the concentration of Fe, its redox speciation, and isotopic distribution, have gained widespread use for inferring the biogeochemical processes that controlled Fe cycling in Precambrian oceans linked to the reconstruction of Earth surface redox budget. However, questions remain about the biotic and abiotic processes involved in Fe cycling in these ancient oceans, including the impact of post-depositional alterative processes on the reliability of the Fe redox proxy. Here we present a multi-proxy mineralogical and geochemical study of the ∼1.1 Ga Atar and El Mreiti strata of the Taoudeni Basin in Mauritania, to better constrain pathways involved in Fe cycling, linked to Fe mineralogy, redox speciation, isotopic ratios during this time and metamorphism. We compare unmetamorphosed sedimentary deposits with facies metamorphosed by dolerite sill intrusion. The results reveal the occurrence of diagenetic Fe minerals in the basal unmetamorphosed samples associated with light δ⁵⁶Fe signatures, reflecting dominant anoxic conditions that promoted microbial dissimilatory Fe reduction. Notably, δ⁵⁶Fe composition of these rocks reveal several fluctuations in evolving seawater redox state from oxic to anoxic/sulfidic conditions associated with changes in sea level stand and periods of full bottom water oxygenation and redox stratification. Overall, Ce anomalies suggest a general up sequence increase in seawater oxygen content. Metamorphosed rocks display heterogeneous δ⁵⁶Fe distribution, consisting of light and heavy signatures associated with secondary Fe-bearing minerals produced by metamorphic and metasomatic overprinting of carbonated rocks by hot circulating fluids. The results thus indicate metamorphic overprinting of primary seawater δ⁵⁶Fe promoted by increased mobility of reactive Fe during post-depositional metamorphic transformation. They show that post-depositional metamorphic/metasomatic overprinting complicates direct reconstruction of seawater biogeochemical Fe cycling and redox state using δ⁵⁶Fe systematics.</p></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"136 ","pages":"Pages 33-52"},"PeriodicalIF":7.2,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142147925","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"South Tibetan Detachment System (STDS), NW Himalaya: A possible Cambro–Ordovician tectonic terrane boundary, and its Cenozoic remobilization","authors":"Gargi G. Deshmukh ,&nbsp;A.K. Jain ,&nbsp;P.K. Mukherjee ,&nbsp;Saurabh Singhal ,&nbsp;Rahul Dixit ,&nbsp;D.C. Srivastava","doi":"10.1016/j.gr.2024.08.008","DOIUrl":"10.1016/j.gr.2024.08.008","url":null,"abstract":"<div><p>The South Tibetan Detachment System is an important extensional fault zone, separating the Greater Himalayan Sequence from the overlying Tethyan Himalayan Sequence, and is well exposed in the upper reaches of the Dhauliganga valley, NW Himalaya. This fault system is characterized by the occurrence of an extensive Cambro–Ordovician granite belt between Sutlej and Dhauliganga valleys, although only a few small granitoids intrude the high-grade mylonite gneiss of the Greater Himalayan Sequence in its immediate footwall. These bodies yielded U-Pb zircon crystallization ages between 498.92 ± 5.5 Ma and 486.54 ± 2.3 Ma. This work postulates that the South Tibetan Detachment System evolved as a major proto-tectonic marginal extensional terrane boundary during the Cambro–Ordovician Kurgiakh/Bhimphedian Orogeny, when it was the conduit for emplacement of the Cambro–Ordovician granite belt. Denudation of the Neoproterozoic Greater Himalayan Sequence and the Paleozoic granites on its footwall provided approximately ∼ 10 km thick sediments into the Tethyan Basin due to this fault system as a master growth fault. Reactivation of this fault system controlled further melting and emplacement of the Higher Himalayan Leucogranite belt during the Cenozoic. Zircon growth is observed in two distinct modes: pulsative from the Late Eocene to Early Oligocene, with peaks at 33.99 ± 1.07 Ma, 30.53 ± 0.32 Ma and 25.03 ± 0.54 Ma; and in the continuous mode from 23.68 ± 0.94 Ma to 13.30 ± 0.30 Ma, in the Miocene, for nearly 10.0 myr. These datasets reveal some of the oldest pulsative movements in the Late Eocene–Early Oligocene during crustal thickening, thrusting and associated metamorphism, followed by continuous extension during the Miocene. Data from the South Tibetan Detachment System are distinct in character, and do not support either its eastwards younging or diachronous movements along the Dhauliganga valley.</p></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"136 ","pages":"Pages 142-168"},"PeriodicalIF":7.2,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142162313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}