Pub Date : 2025-12-16DOI: 10.1016/j.jseaes.2025.106916
Xuemin Zhang , Angelo De Santis , Pan Xiong , Gianfranco Cianchini , Aisa Yisimayili , Saioa A. Campuzano , Na Yang , Serena D’Arcangelo , Jing Liu , Mariagrazia De Caro , Xinyan Li , Cristiano Fidani , Muping Yang , Martina Orlando , Xinyang Ouyang , Loredana Perrone , Hong Liu , Dario Sabbagh , Maoning Feng , Maurizio Soldani , Shukai Wang
This paper presents a comprehensive analysis on multiple parameters in the lithosphere, atmosphere and ionosphere, around the Wushi Mw7.1 earthquake that occurred on 22 January 2024, in Xinjiang, China. Typical perturbations were picked up with different methods, with a limited time period for lithospheric parameters of longer than 3 years, 90 days before and 10 days after for most atmospheric and ionospheric parameters, in a limited distance within Dobrovolsky’s area of about 1000 km. All the results show that about 60 anomalies were detected before the Wushi earthquake, with medium-term ones lasting about 1 year in the lithosphere, and short-term ones within 3 months in the atmosphere and ionosphere, where the outgoing long wave radiation covered the earthquake occurrence time from four days before to four days after, considered an imminent indicator. The thrust focal mechanism of this earthquake helps to explain the anisotropic feature in Earth’s resistivity and orientation in the electric field, and also the weak variations in the b-value. By combining ground-based and spaceborne observations, a few parameters clearly illustrated the approaching earthquake location, which makes a certain contribution to future earthquake prediction. The accumulating rate of all the anomalies exhibited a fast exponential trend, which illustrates both direct and indirect lithosphere-atmosphere–ionosphere coupling mechanisms during the preparation stage of the Wushi earthquake.
{"title":"The Lithosphere-Atmosphere-Ionosphere coupling (LAIC) processes around the 2024 Wushi (China) Mw7.1 earthquake","authors":"Xuemin Zhang , Angelo De Santis , Pan Xiong , Gianfranco Cianchini , Aisa Yisimayili , Saioa A. Campuzano , Na Yang , Serena D’Arcangelo , Jing Liu , Mariagrazia De Caro , Xinyan Li , Cristiano Fidani , Muping Yang , Martina Orlando , Xinyang Ouyang , Loredana Perrone , Hong Liu , Dario Sabbagh , Maoning Feng , Maurizio Soldani , Shukai Wang","doi":"10.1016/j.jseaes.2025.106916","DOIUrl":"10.1016/j.jseaes.2025.106916","url":null,"abstract":"<div><div>This paper presents a comprehensive analysis on multiple parameters in the lithosphere, atmosphere and ionosphere, around the Wushi M<sub>w</sub>7.1 earthquake that occurred on 22 January 2024, in Xinjiang, China. Typical perturbations were picked up with different methods, with a limited time period for lithospheric parameters of longer than 3 years, 90 days before and 10 days after for most atmospheric and ionospheric parameters, in a limited distance within Dobrovolsky’s area of about 1000 km. All the results show that about 60 anomalies were detected before the Wushi earthquake, with medium-term ones lasting about 1 year in the lithosphere, and short-term ones within 3 months in the atmosphere and ionosphere, where the outgoing long wave radiation covered the earthquake occurrence time from four days before to four days after, considered an imminent indicator. The thrust focal mechanism of this earthquake helps to explain the anisotropic feature in Earth’s resistivity and orientation in the electric field, and also the weak variations in the <em>b</em>-value. By combining ground-based and spaceborne observations, a few parameters clearly illustrated the approaching earthquake location, which makes a certain contribution to future earthquake prediction. The accumulating rate of all the anomalies exhibited a fast exponential trend, which illustrates both direct and indirect lithosphere-atmosphere–ionosphere coupling mechanisms during the preparation stage of the Wushi earthquake.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"297 ","pages":"Article 106916"},"PeriodicalIF":2.4,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797699","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}
Pub Date : 2025-12-16DOI: 10.1016/j.jseaes.2025.106917
Hai Jiang , Shao-Yong Jiang
A long-standing debate exists over the petrogenesis of Early Paleozoic granites of the South China Block, with the main issue being whether these granites originated from intracontinental orogenic processes. Here, we report new zircon U-Pb geochronology, whole-rock geochemistry, and Sr-Nd-Hf isotope data for two Silurian I-type granitoids in the Nanling domain, South China. The Meiziwo pluton, comprising granodiorite and monzogranite, and the Yaoling quartz porphyry have identical zircon U-Pb ages of ∼ 433 Ma. Rocks of both the Meiziwo and Yaoling plutons have I-type geochemical affinities and are metaluminous to peraluminous in composition (A/CNK = 0.94–1.27). They have low P2O5 contents that are negatively correlated with SiO2. They show chondrite-normalized rare earth element (REE) patterns with LREE enrichment and moderately negative Eu anomalies (Eu/Eu* = 0.50–0.73). They display enrichments in Rb, Th, U, and Pb, and depletions in Ba, Nb, Sr, and Ti in primitive mantle normalized plots. They also have high 87Sr/86Sri ratios (0.712160–0.715776), low εNd(t) (−10.9 to −8.8) and zircon εHf(t) (−12.5 to −6.3) values, indicative of derivation from partial melting of an ancient mafic lower crust, modified by crystal fractionation. The degree of fractionation in the Yaoling quartz porphyry lies intermediate between that of the Meiziwo granodiorite and monzogranite. It is proposed that the Wuyi-Yunkai orogeny originated as an intracontinental orogeny, likely linked to the far-field effects of plate interaction along the northern margin of eastern Gondwana. Widespread post-orogenic felsic magmatism with subordinate mafic components (ca. 435–415 Ma) marks a tectonic transition from compression to extension. This shift is interpreted to reflect lithospheric delamination and the initiation of intracontinental extension in the region.
{"title":"Petrogenesis of early Silurian I-type granitoids in the Nanling domain, South China: implications for the evolution of the Wuyi-Yunkai orogen","authors":"Hai Jiang , Shao-Yong Jiang","doi":"10.1016/j.jseaes.2025.106917","DOIUrl":"10.1016/j.jseaes.2025.106917","url":null,"abstract":"<div><div>A long-standing debate exists over the petrogenesis of Early Paleozoic granites of the South China Block, with the main issue being whether these granites originated from intracontinental orogenic processes. Here, we report new zircon U-Pb geochronology, whole-rock geochemistry, and Sr-Nd-Hf isotope data for two Silurian I-type granitoids in the Nanling domain, South China. The Meiziwo pluton, comprising granodiorite and monzogranite, and the Yaoling quartz porphyry have identical zircon U-Pb ages of ∼ 433 Ma. Rocks of both the Meiziwo and Yaoling plutons have I-type geochemical affinities and are metaluminous to peraluminous in composition (A/CNK = 0.94–1.27). They have low P<sub>2</sub>O<sub>5</sub> contents that are negatively correlated with SiO<sub>2</sub>. They show chondrite-normalized rare earth element (REE) patterns with LREE enrichment and moderately negative Eu anomalies (Eu/Eu* = 0.50–0.73). They display enrichments in Rb, Th, U, and Pb, and depletions in Ba, Nb, Sr, and Ti in primitive mantle normalized plots. They also have high <sup>87</sup>Sr/<sup>86</sup>Sr<sub>i</sub> ratios (0.712160–0.715776), low ε<sub>Nd</sub>(t) (−10.9 to −8.8) and zircon ε<sub>Hf</sub>(t) (−12.5 to −6.3) values, indicative of derivation from partial melting of an ancient mafic lower crust, modified by crystal fractionation. The degree of fractionation in the Yaoling quartz porphyry lies intermediate between that of the Meiziwo granodiorite and monzogranite. It is proposed that the Wuyi-Yunkai orogeny originated as an intracontinental orogeny, likely linked to the far-field effects of plate interaction along the northern margin of eastern Gondwana. Widespread post-orogenic felsic magmatism with subordinate mafic components (ca. 435–415 Ma) marks a tectonic transition from compression to extension. This shift is interpreted to reflect lithospheric delamination and the initiation of intracontinental extension in the region.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"297 ","pages":"Article 106917"},"PeriodicalIF":2.4,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797743","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}
Pub Date : 2025-12-15DOI: 10.1016/j.jseaes.2025.106915
Zhenmeng Sun , Xiangjie Cui , Xin Liu , Huan Liu , Xiancai Lu
The cation ordering mechanism and their influence on crystal structure evolution remain poorly understood. This study investigates the oscillatory zoned ferroan dolomite within moldic pores of micritic dolostone from the Ordovician Majiagou Formation in the eastern Ordos Basin, focusing on the site preference, distribution patterns of Fe in the dolomite structure, and its impact on the cation ordering process. Results show that from core to rim, the zoning exhibits increasing Fe content (0.27 mol%, 7.36 mol%, 10.55 mol%) with a corresponding decrease in Mg. Fe substitution primarily influences M–O bond lengths, leading to systematic changes in unit cell parameters: the a/b lattice parameters increase from 4.8066 Å to 4.8234 Å, the c lattice parameter from 16.0051 Å to 16.0690 Å, and the unit cell volume expands by approximately 1.1 %. Uniform strontium isotope compositions of the three zones indicate a homogeneous pore fluid derived from seawater. Further analysis via EXAFS spectroscopy, AC-TEM observation, and DFT calculations confirms that Fe2+ preferentially occupies Mg sites and tends to aggregate within Mg layers, forming nanoscale modulated structures and ordered domains. This causes local lattice distortion and defects, reducing the cation ordering degree from 0.45 to 0.30, while these regions may act as preferential sites for ordering progression. The study suggests that local migration and redistribution of trace elements in dolomite may facilitate structural ordering evolution. These findings provide a new crystal defect dynamics perspective for interpreting dolomite structural evolution, contributing to a better understanding of the “dolomite problem”.
{"title":"Fe occupancy in zoned ferroan dolomite and its constraints on dolomite ordering process: a case study on micritic dolostone of Ordovician Majiagou formation in eastern Ordos Basin, China","authors":"Zhenmeng Sun , Xiangjie Cui , Xin Liu , Huan Liu , Xiancai Lu","doi":"10.1016/j.jseaes.2025.106915","DOIUrl":"10.1016/j.jseaes.2025.106915","url":null,"abstract":"<div><div>The cation ordering mechanism and their influence on crystal structure evolution remain poorly understood. This study investigates the oscillatory zoned ferroan dolomite within moldic pores of micritic dolostone from the Ordovician Majiagou Formation in the eastern Ordos Basin, focusing on the site preference, distribution patterns of Fe in the dolomite structure, and its impact on the cation ordering process. Results show that from core to rim, the zoning exhibits increasing Fe content (0.27 mol%, 7.36 mol%, 10.55 mol%) with a corresponding decrease in Mg. Fe substitution primarily influences M–O bond lengths, leading to systematic changes in unit cell parameters: the <em>a/b</em> lattice parameters increase from 4.8066 Å to 4.8234 Å, the <em>c</em> lattice parameter from 16.0051 Å to 16.0690 Å, and the unit cell volume expands by approximately 1.1 %. Uniform strontium isotope compositions of the three zones indicate a homogeneous pore fluid derived from seawater. Further analysis via EXAFS spectroscopy, AC-TEM observation, and DFT calculations confirms that Fe<sup>2+</sup> preferentially occupies Mg sites and tends to aggregate within Mg layers, forming nanoscale modulated structures and ordered domains. This causes local lattice distortion and defects, reducing the cation ordering degree from 0.45 to 0.30, while these regions may act as preferential sites for ordering progression. The study suggests that local migration and redistribution of trace elements in dolomite may facilitate structural ordering evolution. These findings provide a new crystal defect dynamics perspective for interpreting dolomite structural evolution, contributing to a better understanding of the “dolomite problem”.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"298 ","pages":"Article 106915"},"PeriodicalIF":2.4,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145885703","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}
Pub Date : 2025-12-12DOI: 10.1016/j.jseaes.2025.106914
Peng-Fei Shan , Ming-Jian Cao , Noreen J. Evans , Le Wang , Yi Li , Yu-Suo Zhao , Ke-Zhang Qin
The Jinchang porphyry Au-Cu deposit in Northeast China has recently shown significant cobalt (Co) enrichment. Before the precipitation of Co-rich sulfides during the main mineralization stage, magnetite and hematite precipitation occurred. Based on the different morphological characteristics of magnetite, it can be classified into mushketovite Mag1 (aspect ratio > 5) and granular Mag2 (aspect ratio < 2) and further subdivided into four subtypes: Mag1-1, Mag1-2, Mag2-1 and Mag2-2. The platy Mag1 is mushketovite, replacing early hematite. The granular Mag2, with well-defined 120° triple junction textures, formed through fluid-assisted recrystallization processes. Mag1 has a trace element composition very similar to the precursor hematite, indicating that the trace element characteristics of Mag1 were inherited from hematite and do not reflect the trace element composition of the fluid at the time of its formation. Mag2 has higher contents of Ti, V, Al, Mg, Si, Mn, Co and Ni, reflecting the trace element characteristics of the fluid in equilibrium with Mag2 during its formation. The early precipitation of magnetite and hematite can effectively inhibit the premature incorporation of Co into sulfides, thereby promoting pre-enrichment of Co in the fluid. While the precipitation of magnetite and hematite can increase the Co/Fe ratio in the residual fluid, it does not directly cause the high Co enrichment in sulfides within the Jinchang deposit. However, the precipitation of magnetite facilitates the migration of Co from mafic magma into ore-forming fluids under acidic and oxidizing conditions, which may be a contributing factor to the Co enrichment in Jinchang deposit.
{"title":"Trace element geochemistry of magnetite and hematite from the Jinchang porphyry Au-Cu deposit, northeast China: Implications for fluid evolution and cobalt enrichment","authors":"Peng-Fei Shan , Ming-Jian Cao , Noreen J. Evans , Le Wang , Yi Li , Yu-Suo Zhao , Ke-Zhang Qin","doi":"10.1016/j.jseaes.2025.106914","DOIUrl":"10.1016/j.jseaes.2025.106914","url":null,"abstract":"<div><div>The Jinchang porphyry Au-Cu deposit in Northeast China has recently shown significant cobalt (Co) enrichment. Before the precipitation of Co-rich sulfides during the main mineralization stage, magnetite and hematite precipitation occurred. Based on the different morphological characteristics of magnetite, it can be classified into mushketovite Mag1 (aspect ratio > 5) and granular Mag2 (aspect ratio < 2) and further subdivided into four subtypes: Mag1-1, Mag1-2, Mag2-1 and Mag2-2. The platy Mag1 is mushketovite, replacing early hematite. The granular Mag2, with well-defined 120° triple junction textures, formed through fluid-assisted recrystallization processes. Mag1 has a trace element composition very similar to the precursor hematite, indicating that the trace element characteristics of Mag1 were inherited from hematite and do not reflect the trace element composition of the fluid at the time of its formation. Mag2 has higher contents of Ti, V, Al, Mg, Si, Mn, Co and Ni, reflecting the trace element characteristics of the fluid in equilibrium with Mag2 during its formation. The early precipitation of magnetite and hematite can effectively inhibit the premature incorporation of Co into sulfides, thereby promoting pre-enrichment of Co in the fluid. While the precipitation of magnetite and hematite can increase the Co/Fe ratio in the residual fluid, it does not directly cause the high Co enrichment in sulfides within the Jinchang deposit. However, the precipitation of magnetite facilitates the migration of Co from mafic magma into ore-forming fluids under acidic and oxidizing conditions, which may be a contributing factor to the Co enrichment in Jinchang deposit.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"297 ","pages":"Article 106914"},"PeriodicalIF":2.4,"publicationDate":"2025-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797744","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}
Pub Date : 2025-12-11DOI: 10.1016/j.jseaes.2025.106911
Yao Wang , Wenlong Ding , Ziyou Zhang , Shuaiyu Shi , Rui Xia , Mengyang Zhang , Hao Jian
The botryoidal dolomite within the Ediacaran Dengying Formation (Yangtze Craton, South China) represents distinctive features whose origins remain debated, having been variously interpreted as synsedimentary precipitates or as products of dolomitization on a carbonate platform. Detailed petrographic examination reveals two distinct subtypes based on crystal morphology and optical properties: fascicular slow dolomite (FSD) and radial slow dolomite (RSD). Integrated petrographic and geochemical analyses (δ13C, δ18O, rare earth element plus yttrium [REY] patterns, Y/Ho ratios, and clumped isotopes Δ47) constrain their contrasting origins. FSD—characterized by sinistral undulose extinction, dull-red to non-luminescence, relatively stable δ18O values (mean −2.76 ‰, VPDB), seawater-like REY patterns, and high Y/Ho ratios (≈ 38)—indicates precipitation from primary Dengying Formation seawater. Conversely, RSD exhibits straight extinction, euhedral rhombohedral terminations with bright luminescence, more negative δ18O values (mean −4.05 ‰, VPDB), positive Eu anomalies (Eu/Eu* = 1.41), and yields a clumped isotope temperature (TΔ47) of 98 °C. These characteristics collectively demonstrate that RSD precipitated from fluids resulting from the mixing of seawater with hydrothermal fluids. The distinct origins of FSD and RSD provide crucial evidence for the ‘dolomite sea’ hypothesis, indicating it was not uniformly persistent during the Ediacaran on the Yangtze Craton. FSD precipitation reflects an anoxic, alkaline marine environment, while RSD preserves evidence for episodic hydrothermal activity within this Ediacaran ‘dolomite sea’. This challenges the paradigm of uniform marine conditions during the Precambrian–Cambrian transition. Our findings highlight botryoidal dolomite as a sensitive archive of fluid–rock interactions, offering valuable insights into paleoenvironmental perturbations preceding the Cambrian explosion.
{"title":"The botryoidal dolomite of the Ediacaran Dengying Formation (Yangtze Craton): Multi-proxy constraints on the terminal Neoproterozoic “dolomite sea”","authors":"Yao Wang , Wenlong Ding , Ziyou Zhang , Shuaiyu Shi , Rui Xia , Mengyang Zhang , Hao Jian","doi":"10.1016/j.jseaes.2025.106911","DOIUrl":"10.1016/j.jseaes.2025.106911","url":null,"abstract":"<div><div>The botryoidal dolomite within the Ediacaran Dengying Formation (Yangtze Craton, South China) represents distinctive features whose origins remain debated, having been variously interpreted as synsedimentary precipitates or as products of dolomitization on a carbonate platform. Detailed petrographic examination reveals two distinct subtypes based on crystal morphology and optical properties: fascicular slow dolomite (<em>FSD</em>) and radial slow dolomite (<em>RSD</em>). Integrated petrographic and geochemical analyses (δ<sup>13</sup>C, δ<sup>18</sup>O, rare earth element plus yttrium [REY] patterns, Y/Ho ratios, and clumped isotopes Δ47) constrain their contrasting origins. FSD—characterized by sinistral undulose extinction, dull-red to non-luminescence, relatively stable δ<sup>18</sup>O values (mean −2.76 ‰, VPDB), seawater-like REY patterns, and high Y/Ho ratios (≈ 38)—indicates precipitation from primary Dengying Formation seawater. Conversely, RSD exhibits straight extinction, euhedral rhombohedral terminations with bright luminescence, more negative δ<sup>18</sup>O values (mean −4.05 ‰, VPDB), positive Eu anomalies (Eu/Eu* = 1.41), and yields a clumped isotope temperature (T<sub>Δ47</sub>) of 98 °C. These characteristics collectively demonstrate that RSD precipitated from fluids resulting from the mixing of seawater with hydrothermal fluids. The distinct origins of FSD and RSD provide crucial evidence for the ‘dolomite sea’ hypothesis, indicating it was not uniformly persistent during the Ediacaran on the Yangtze Craton. FSD precipitation reflects an anoxic, alkaline marine environment, while RSD preserves evidence for episodic hydrothermal activity within this Ediacaran ‘dolomite sea’. This challenges the paradigm of uniform marine conditions during the Precambrian–Cambrian transition. Our findings highlight botryoidal dolomite as a sensitive archive of fluid–rock interactions, offering valuable insights into paleoenvironmental perturbations preceding the Cambrian explosion.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"297 ","pages":"Article 106911"},"PeriodicalIF":2.4,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797722","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}
Pub Date : 2025-12-11DOI: 10.1016/j.jseaes.2025.106913
Chenghui Hu , Jian Wang , Lijun Shen , Ahmed Mansour , Shuang Pan , Shengwu Cheng , Yushan Zhang
The tectonic evolution of the Bangong–Nujiang Tethyan Ocean (BNTO), a key component of the eastern Tethyan realm, provides crucial insights into the geological evolution of the Qiangtang Basin and the reconstruction of the Tethyan paleogeographic framework. However, the magmatic response to the initiation of BNTO subduction remains poorly constrained, hindering efforts to reconstruct its tectonic evolution and decipher the Mesozoic tectonic setting of the Qiangtang Basin. We present whole-rock geochemistry, Sr–Nd isotopes, and zircon U–Pb ages for newly discovered andesites from Zhaquxiang, located along the southern margin of the Qiangtang Basin. The andesites formed during the Late Triassic (211.5 ± 4.8 Ma) and display arc-type geochemical signatures characterized by pronounced LREE–HREE fractionation, enrichment in LILEs, and depletion in HFSEs. They show relatively low initial 87Sr/86Sr ratios (0.704755−0.704966) and positive εNd(t) (+2.63 to +4.37). The andesites have high contents of SiO2 (61.5–62.7 wt%) and Al2O3 (17.3–17.8 wt%), but low values of Mg# (31–40), K2O (2.0–2.2 wt%), Cr (30–38 ppm), and Ni (21–24 ppm). They exhibit low Ba/Th and Ba/La, but high Th/Nd and (La/Sm)N ratios. These characteristics suggest that the andesites were derived from partial melting of subducted oceanic crust, triggered by the initial northward ocean–continent subduction of the BNTO. The onset of BNTO subduction is thus constrained to ca. 211.5 Ma, contemporaneous with the development of a back-arc rift basin tectonic system in the Qiangtang Basin.
{"title":"Constraints of newly discovered Late Triassic andesites in the South Qiangtang Block (Tibet) on the evolution of the Bangong-Nujiang Tethyan ocean","authors":"Chenghui Hu , Jian Wang , Lijun Shen , Ahmed Mansour , Shuang Pan , Shengwu Cheng , Yushan Zhang","doi":"10.1016/j.jseaes.2025.106913","DOIUrl":"10.1016/j.jseaes.2025.106913","url":null,"abstract":"<div><div>The tectonic evolution of the Bangong–Nujiang Tethyan Ocean (BNTO), a key component of the eastern Tethyan realm, provides crucial insights into the geological evolution of the Qiangtang Basin and the reconstruction of the Tethyan paleogeographic framework. However, the magmatic response to the initiation of BNTO subduction remains poorly constrained, hindering efforts to reconstruct its tectonic evolution and decipher the Mesozoic tectonic setting of the Qiangtang Basin. We present whole-rock geochemistry, Sr–Nd isotopes, and zircon U–Pb ages for newly discovered andesites from Zhaquxiang, located along the southern margin of the Qiangtang Basin. The andesites formed during the Late Triassic (211.5 ± 4.8 Ma) and display arc-type geochemical signatures characterized by pronounced LREE–HREE fractionation, enrichment in LILEs, and depletion in HFSEs. They show relatively low initial <sup>87</sup>Sr/<sup>86</sup>Sr ratios (0.704755−0.704966) and positive ε<sub>Nd</sub>(t) (+2.63 to +4.37). The andesites have high contents of SiO<sub>2</sub> (61.5–62.7 wt%) and Al<sub>2</sub>O<sub>3</sub> (17.3–17.8 wt%), but low values of Mg<sup>#</sup> (31–40), K<sub>2</sub>O (2.0–2.2 wt%), Cr (30–38 ppm), and Ni (21–24 ppm). They exhibit low Ba/Th and Ba/La, but high Th/Nd and (La/Sm)<sub>N</sub> ratios. These characteristics suggest that the andesites were derived from partial melting of subducted oceanic crust, triggered by the initial northward ocean–continent subduction of the BNTO. The onset of BNTO subduction is thus constrained to ca. 211.5 Ma, contemporaneous with the development of a back-arc rift basin tectonic system in the Qiangtang Basin.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"297 ","pages":"Article 106913"},"PeriodicalIF":2.4,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797723","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}
Pub Date : 2025-12-06DOI: 10.1016/j.jseaes.2025.106903
Rahul K. Choudhury , Pitambar Pati , Narendra K. Patel , Manoj K. Jaiswal
The current study in the Ganga foreland basin used 2202 channel offset orientations to establish their relationship with the neotectonics. The variation of the offset orientations acknowledge the directions of plate motion, regional stress field, compressional and extensional structures, subsurface basement ridges, and faults in the foreland. 53.52% offsets are aligned along the NE-SW, i.e., parallel to the plate movement direction, while the rest are aligned NW-SE, i.e., parallel to the Himalayan compressional trend, with the highest concentration along the N40°-60°E and N40°-60°W. The NW-SE stress imposed by the Indian plate’s compression develops various parallel faults and joints, followed by the channel offsets. The decreasing compression intensity away from the Himalayas creates fewer offsets parallel to it, and this trend continues up to the Delhi-Sargodha Ridge’s (DSR) influence at the basin’s southern edge. The NE-SW offsets in the central Ganga basin are influenced by the NE-SW trending faults and basement ridges. The variable strike-slip components along the basement faults contribute to the NE-SW offsets. More NW-SE offsets in the eastern part of the basin are correlated with a larger crustal shortening rate than the western part. The Yamuna-Ganga, Ganga-Ghaghara, Ghaghara-Rapti, Rapti-Gandak, and Gandak-Kosi interfluves record 42.67%, 43.66%, 42.31%, 50.17%, and 55.08% of offsets in NW-SE quadrants, respectively. The E-W trending longer offsets generally seen at the basin’s periphery are due to the strike-slip displacement. However, the E-W offsets in the eastern part of the basin are due to the shallow subsurface thrust splays parallel to the Himalayan Frontal Thrust (HFT).
{"title":"Tectonic control on the channel offset orientations in the Ganga foreland basin: A neotectonic perspective","authors":"Rahul K. Choudhury , Pitambar Pati , Narendra K. Patel , Manoj K. Jaiswal","doi":"10.1016/j.jseaes.2025.106903","DOIUrl":"10.1016/j.jseaes.2025.106903","url":null,"abstract":"<div><div>The current study in the Ganga foreland basin used 2202 channel offset orientations to establish their relationship with the neotectonics. The variation of the offset orientations acknowledge the directions of plate motion, regional stress field, compressional and extensional structures, subsurface basement ridges, and faults in the foreland. 53.52% offsets are aligned along the NE-SW, i.e., parallel to the plate movement direction, while the rest are aligned NW-SE, i.e., parallel to the Himalayan compressional trend, with the highest concentration along the N40°-60°E and N40°-60°W. The NW-SE stress imposed by the Indian plate’s compression develops various parallel faults and joints, followed by the channel offsets. The decreasing compression intensity away from the Himalayas creates fewer offsets parallel to it, and this trend continues up to the Delhi-Sargodha Ridge’s (DSR) influence at the basin’s southern edge. The NE-SW offsets in the central Ganga basin are influenced by the NE-SW trending faults and basement ridges. The variable strike-slip components along the basement faults contribute to the NE-SW offsets. More NW-SE offsets in the eastern part of the basin are correlated with a larger crustal shortening rate than the western part. The Yamuna-Ganga, Ganga-Ghaghara, Ghaghara-Rapti, Rapti-Gandak, and Gandak-Kosi interfluves record 42.67%, 43.66%, 42.31%, 50.17%, and 55.08% of offsets in NW-SE quadrants, respectively. The E-W trending longer offsets generally seen at the basin’s periphery are due to the strike-slip displacement. However, the E-W offsets in the eastern part of the basin are due to the shallow subsurface thrust splays parallel to the Himalayan Frontal Thrust (HFT).</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"297 ","pages":"Article 106903"},"PeriodicalIF":2.4,"publicationDate":"2025-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145749805","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}
The Tunka Fault, a major active structure in the southwestern Baikal Rift system, poses a significant seismic hazard, yet its paleoseismic history remains poorly constrained. We present new paleoseismic data from trenches across its eastern Tory segment, constrained with morphotectonic analysis and radiocarbon dating. Our results reveal two Holocene earthquakes, corresponding to the E2 and E3 events identified in previous studies along the Mondy, Tunka, and Main Sayan faults. These three faults have been interpreted as having produced seismic clusters at least four times in the Late Pleistocene-Holocene times. Our radiocarbon data allow constraining more tightly the ages of the E2 and E3 events to 3170–3399 and 8453–8540 cal yr BP, respectively. Morphotectonic analysis of the Tory site, together with published data along the adjacent section of the Tunka Fault, showed that the average amplitude of displacement per event along the slip vector was 2.1 m, corresponding to a magnitude of Mw 7.3. In some cases, all fault segments seem to have ruptured simultaneously over a length of 200 km, while in others cases, only segments striking E-W and NW-SE directions ruptured with a reverse slip component. Fault segments with normal slip component ruptured with a delay, but with a similar recurrence interval. These results highlight the potential for multi-fault ruptures in the Baikal region and challenge existing seismic hazard models. Our study provides critical input for revising probabilistic seismic hazard assessments and underscores the need to consider fault interaction in tectonic settings with complex block boundaries.
{"title":"New paleoseismological constraints on the seismic activity along the eastern Tunka Fault (SW Baikal Rift)","authors":"A.A. Chebotarev , A.V. Arzhannikova , S.G. Arzhannikov , J.-F. Ritz , A.V. Avagyan","doi":"10.1016/j.jseaes.2025.106901","DOIUrl":"10.1016/j.jseaes.2025.106901","url":null,"abstract":"<div><div>The Tunka Fault, a major active structure in the southwestern Baikal Rift system, poses a significant seismic hazard, yet its paleoseismic history remains poorly constrained. We present new paleoseismic data from trenches across its eastern Tory segment, constrained with morphotectonic analysis and radiocarbon dating. Our results reveal two Holocene earthquakes, corresponding to the E2 and E3 events identified in previous studies along the Mondy, Tunka, and Main Sayan faults. These three faults have been interpreted as having produced seismic clusters at least four times in the Late Pleistocene-Holocene times. Our radiocarbon data allow constraining more tightly the ages of the E2 and E3 events to 3170–3399 and 8453–8540 cal yr BP, respectively. Morphotectonic analysis of the Tory site, together with published data along the adjacent section of the Tunka Fault, showed that the average amplitude of displacement per event along the slip vector was 2.1 m, corresponding to a magnitude of Mw 7.3. In some cases, all fault segments seem to have ruptured simultaneously over a length of 200 km, while in others cases, only segments striking E-W and NW-SE directions ruptured with a reverse slip component. Fault segments with normal slip component ruptured with a delay, but with a similar recurrence interval. These results highlight the potential for multi-fault ruptures in the Baikal region and challenge existing seismic hazard models. Our study provides critical input for revising probabilistic seismic hazard assessments and underscores the need to consider fault interaction in tectonic settings with complex block boundaries.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"297 ","pages":"Article 106901"},"PeriodicalIF":2.4,"publicationDate":"2025-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145749806","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}
Pub Date : 2025-12-03DOI: 10.1016/j.jseaes.2025.106902
Nguyen Ngoc Long , David Gomez-Ortiz , Nguyen Kim Dung , Luan Thanh Pham
One of the important tasks in mapping geological structures is determining the horizontal boundaries of density structures. These boundaries can be estimated by using the edge detection techniques of gravity data. In this study, we apply several traditional edge enhancement filters along with recently developed techniques to the Bouguer gravity data to analyze structural trends and fault zones in the Ailaoshan Orogenic Belt, which is known as a significant suture zone between the South China Block and the Indochina Block. The edge recognition capabilities of these filters are examined using both noise-free and noisy synthetic gravity data before applying them to real gravity anomaly data of the belt. The structural features from the edge detection techniques are also confirmed by the Euler deconvolution method, where the result shows that the depth estimates in the Ailaoshan Orogenic Belt change from 0.9 to 4.7 km. The findings show that edge detection techniques produce anomaly maps that are well-correlated with the main tectonic framework of the study area, which trends NW-SE. These techniques are also helpful in identifying some structural features that are not visible at the surface, thus contributing to a more complete crustal framework of the Ailaoshan Orogenic Belt.
{"title":"Insights on the structural framework of the Ailaoshan Orogenic Belt from gravity data","authors":"Nguyen Ngoc Long , David Gomez-Ortiz , Nguyen Kim Dung , Luan Thanh Pham","doi":"10.1016/j.jseaes.2025.106902","DOIUrl":"10.1016/j.jseaes.2025.106902","url":null,"abstract":"<div><div>One of the important tasks in mapping geological structures is determining the horizontal boundaries of density structures. These boundaries can be estimated by using the edge detection techniques of gravity data. In this study, we apply several traditional edge enhancement filters along with recently developed techniques to the Bouguer gravity data to analyze structural trends and fault zones in the Ailaoshan Orogenic Belt, which is known as a significant suture zone between the South China Block and the Indochina Block. The edge recognition capabilities of these filters are examined using both noise-free and noisy synthetic gravity data before applying them to real gravity anomaly data of the belt. The structural features from the edge detection techniques are also confirmed by the Euler deconvolution method, where the result shows that the depth estimates in the Ailaoshan Orogenic Belt change from 0.9 to 4.7 km. The findings show that edge detection techniques produce anomaly maps that are well-correlated with the main tectonic framework of the study area, which trends NW-SE. These techniques are also helpful in identifying some structural features that are not visible at the surface, thus contributing to a more complete crustal framework of the Ailaoshan Orogenic Belt.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"297 ","pages":"Article 106902"},"PeriodicalIF":2.4,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145749804","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}
Pub Date : 2025-12-03DOI: 10.1016/j.jseaes.2025.106900
Rufei Peng , Chenlin Hu , Xin Li , Hongmei Su , Jonathan Atuquaye Quaye , Cheng Dong
South China Block (SCB) is situated in the Eastern Asian margin. During the crucial transitional Formation of the Permian-Triassic boundary in geological history, the SCB was located in a shallow sea environment within the low-latitude trade winds zone, accumulating marine sedimentary deposits. There are numerous studies concerned on the paleoecological and biological evolution of the SCB, but studies of paleogeography are few and the paleogeographic position of the SCB remains as a matter of debate. In this paper, we describe the sedimentary features of Late Permian (Lopingian) to Early Triassic in the Sichuan Basin, northwestern SCB, and present new magnetic fabrics for these sequences. The results of sedimentary differentiation and anisotropy of magnetic susceptibility indicated prevailing wind routes of 106.6° ± 4.3° east of north in the Late Permian and 118.2° ± 4.7° east of north in the Early Triassic. After correcting for a 70° clockwise rotation of the SCB since the Permian-Triassic boundary, the paleo-wind routes are reconstructed as 36.6° ± 4.3° and 48.2° ± 4.7° east of paleo-north for these periods. The study of the paleo-wind routes indicates that the SCB migrated northward from a near-equatorial position in the Late Permian (Lopingian) to a more distant location in the Early Triassic, marking significant movement within the Northern Hemisphere. The paleogeographic position of the SCB was determined by aligning its quantitatively reconstructed predominant paleo-wind routes with the latitudinal variation of Northern Hemisphere trade wind patterns. This analysis indicates that the SCB was located near the equator in the Late Permian and had migrated northward within the Northern Hemisphere by the Early Triassic. These findings provide insights into the paleoclimate and paleogeographic evolution of the SCB and offer data for other studies. Moreover, the methodology employed in this study serves as a useful reference for paleogeographic and paleoclimatic reconstructions of other ancient landmasses.
{"title":"Constraints of the paleo-trade wind route on the paleo-geography of the South China Block in the Late Permian (Lopingian)-Early Triassic","authors":"Rufei Peng , Chenlin Hu , Xin Li , Hongmei Su , Jonathan Atuquaye Quaye , Cheng Dong","doi":"10.1016/j.jseaes.2025.106900","DOIUrl":"10.1016/j.jseaes.2025.106900","url":null,"abstract":"<div><div>South China Block (SCB) is situated in the Eastern Asian margin. During the crucial transitional Formation of the Permian-Triassic boundary in geological history, the SCB was located in a shallow sea environment within the low-latitude trade winds zone, accumulating marine sedimentary deposits. There are numerous studies concerned on the paleoecological and biological evolution of the SCB, but studies of paleogeography are few and the paleogeographic position of the SCB remains as a matter of debate. In this paper, we describe the sedimentary features of Late Permian (Lopingian) to Early Triassic in the Sichuan Basin, northwestern SCB, and present new magnetic fabrics for these sequences. The results of sedimentary differentiation and anisotropy of magnetic susceptibility indicated prevailing wind routes of 106.6° ± 4.3° east of north in the Late Permian and 118.2° ± 4.7° east of north in the Early Triassic. After correcting for a 70° clockwise rotation of the SCB since the Permian-Triassic boundary, the paleo-wind routes are reconstructed as 36.6° ± 4.3° and 48.2° ± 4.7° east of paleo-north for these periods. The study of the paleo-wind routes indicates that the SCB migrated northward from a near-equatorial position in the Late Permian (Lopingian) to a more distant location in the Early Triassic, marking significant movement within the Northern Hemisphere. The paleogeographic position of the SCB was determined by aligning its quantitatively reconstructed predominant paleo-wind routes with the latitudinal variation of Northern Hemisphere trade wind patterns. This analysis indicates that the SCB was located near the equator in the Late Permian and had migrated northward within the Northern Hemisphere by the Early Triassic. These findings provide insights into the paleoclimate and paleogeographic evolution of the SCB and offer data for other studies. Moreover, the methodology employed in this study serves as a useful reference for paleogeographic and paleoclimatic reconstructions of other ancient landmasses.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"297 ","pages":"Article 106900"},"PeriodicalIF":2.4,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145694521","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}
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