首页 > 最新文献

Gondwana Research最新文献

英文 中文
Tectono-magmatic evolution of the Indian crust in western Himalayas during Paleoproterozoic: Insights from Nanga Parbat and Indus syntaxis in northern Pakistan 古近古生代喜马拉雅山西部印度地壳的构造-岩浆演化:从巴基斯坦北部的南迦帕尔巴特山和印度河综脉获得的启示
IF 7.2 1区 地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY Pub Date : 2024-10-19 DOI: 10.1016/j.gr.2024.10.006
Muhammad Sajid , Michael Wiedenbeck , Muhammad Arif , Johannes Glodny , Nowrad Ali , Humaad Ghani , Jessica A. Stammeier
The Paleoproterozoic tectono-magmatic history of the Indian plate has been modelled mostly based on investigations of the Indian parts with limited studies considering the Pakistani domains of the mountain range. In this study we investigate basement rocks and younger intrusions of the Indian crust from within the core of the Indus Syntaxis and the Nanga Parbat Syntaxis in northern Pakistan, with the goal of establishing a chronology for the entire tectono-magmatic progression of northwestern Indian plate margin, including the source rocks that were ultimately involved in the formation of younger magmatic pulses. We present in-situ zircon U-Pb geochronology and O-isotopes complemented by whole rock geochemistry of granitoids and paragneisses that yielded evidence for two distinct, large-scale Paleoproterozoic magmatic events that took place in ∼ 1860 Ma and ∼ 2200 Ma in the Indian crust. Later, leucogranites (6.4 ± 0.1 Ma) intruded into the Nanga Parbat basement that were the result of melting of the basement induced by rapid uplift. The δ18OSMOW compositions of zircons from our basement samples range between 7.5 to 9.1 ‰, indicating the derivation of parental magma from the crustal source while the younger leucogranite is somewhat lighter with δ18O ranging between 7.06 to 8.23 ‰. Geochemical data show extensional tectonic settings for the basement rocks that have an A-type affinity, again pointing to a crustal precursor. We propose little to no δ18O exchange took place between the young anatectic melt and basement rocks during crustal evolution. Moreover, geochemical signatures record the crystallization of basement rocks dominated the northwestern margin of Indian plate in a post-orogenic setting in an overall extensional tectonic realm. Based on these observations, we infer that the northwestern Indian margin has experienced a large-scale magmatism during Paleoproterozoic associated with the amalgamation of the Columbia supercontinent.
印度板块的古新生代构造-岩浆史模型主要是基于对印度部分的研究,而对巴基斯坦境内山脉的研究有限。在这项研究中,我们调查了印度地壳的基底岩石和较年轻的侵入体,这些岩石来自巴基斯坦北部的印度河综合地轴和南加帕尔巴特综合地轴的核心区域,目的是为印度西北板块边缘的整个构造-岩浆演化过程建立年表,包括最终参与形成较年轻岩浆脉冲的源岩。我们展示了原位锆石U-Pb地质年代学和O-同位素,并辅以花岗岩和片麻岩的全岩地球化学,这些证据表明印度地壳在1860Ma∼和2200Ma∼发生了两次不同的、大规模的古新生代岩浆事件。后来,白云岩(6.4 ± 0.1 Ma)侵入南迦帕尔巴特基底,这是快速隆升引起基底熔化的结果。基底样本的锆石成分δ18OSMOW介于7.5至9.1‰之间,表明母岩浆来自地壳源,而较年轻的白榴石成分较轻,δ18O介于7.06至8.23‰之间。地球化学数据显示,基底岩石具有A型亲和力的延伸构造背景,这再次表明了地壳的前身。我们认为,在地壳演化过程中,年轻的无极性熔体与基底岩石之间几乎没有发生δ18O交换。此外,地球化学特征记录了印度板块西北边缘基底岩石的结晶过程,该过程是在整体伸展构造背景下的后成因环境中进行的。根据这些观察结果,我们推断印度西北边缘在古近古生代经历了与哥伦比亚超大陆汞齐化有关的大规模岩浆活动。
{"title":"Tectono-magmatic evolution of the Indian crust in western Himalayas during Paleoproterozoic: Insights from Nanga Parbat and Indus syntaxis in northern Pakistan","authors":"Muhammad Sajid ,&nbsp;Michael Wiedenbeck ,&nbsp;Muhammad Arif ,&nbsp;Johannes Glodny ,&nbsp;Nowrad Ali ,&nbsp;Humaad Ghani ,&nbsp;Jessica A. Stammeier","doi":"10.1016/j.gr.2024.10.006","DOIUrl":"10.1016/j.gr.2024.10.006","url":null,"abstract":"<div><div>The Paleoproterozoic tectono-magmatic history of the Indian plate has been modelled mostly based on investigations of the Indian parts with limited studies considering the Pakistani domains of the mountain range. In this study we investigate basement rocks and younger intrusions of the Indian crust from within the core of the Indus Syntaxis and the Nanga Parbat Syntaxis in northern Pakistan, with the goal of establishing a chronology for the entire tectono-magmatic progression of northwestern Indian plate margin, including the source rocks that were ultimately involved in the formation of younger magmatic pulses. We present in-situ zircon U-Pb geochronology and O-isotopes complemented by whole rock geochemistry of granitoids and paragneisses that yielded evidence for two distinct, large-scale Paleoproterozoic magmatic events that took place in ∼ 1860 Ma and ∼ 2200 Ma in the Indian crust. Later, leucogranites (6.4 ± 0.1 Ma) intruded into the Nanga Parbat basement that were the result of melting of the basement induced by rapid uplift. The δ<sup>18</sup>O<sub>SMOW</sub> compositions of zircons from our basement samples range between 7.5 to 9.1 ‰, indicating the derivation of parental magma from the crustal source while the younger leucogranite is somewhat lighter with δ<sup>18</sup>O ranging between 7.06 to 8.23 ‰. Geochemical data show extensional tectonic settings for the basement rocks that have an A-type affinity, again pointing to a crustal precursor. We propose little to no δ<sup>18</sup>O exchange took place between the young anatectic melt and basement rocks during crustal evolution. Moreover, geochemical signatures record the crystallization of basement rocks dominated the northwestern margin of Indian plate in a post-orogenic setting in an overall extensional tectonic realm. Based on these observations, we infer that the northwestern Indian margin has experienced a large-scale magmatism during Paleoproterozoic associated with the amalgamation of the Columbia supercontinent.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"137 ","pages":"Pages 299-317"},"PeriodicalIF":7.2,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142532594","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}
引用次数: 0
Heterogeneous water distribution in between peridotite xenoliths from Kaapvaal Craton kimberlites: Constraints on diamond barren nature of kimberlites 卡普瓦尔克拉通金伯利岩橄榄石间的异质水分布:金伯利岩金刚石贫瘠性质的制约因素
IF 7.2 1区 地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY Pub Date : 2024-10-16 DOI: 10.1016/j.gr.2024.10.004
Sahroz Khan , Nóra Liptai , István J. Kovács , Yana Fedortchouk , Tivadar M. Tóth
Nominally anhydrous mantle minerals (olivine, pyroxenes, garnets, etc.) in 11 peridotite xenoliths from four different uneconomic and economic Kaapvaal Craton kimberlite pipes (Matsoku, Thaba Putsoa, Pipe 200 and Bultfontein) have been investigated using Fourier transform infrared spectroscopy (FTIR). All xenoliths contain accessories of garnet, diopside, chromite, and phlogopite. High orthopyroxene content (>30 mol vol.%) in most xenoliths from all kimberlites and its interconnected channel-like nature hint towards hydrous siliceous fluid metasomatism. Peridotite xenoliths from uneconomic kimberlites show development of phlogopite and clinopyroxene (± chromite) forming veins and in garnet rims suggesting metasomatism by alkaline silico-carbonatite (possibly kimberlite-related) melt. The xenoliths contain significant H2O in olivine (17–62 ppm), orthopyroxene (21–230 ppm), and clinopyroxene (87–833 ppm), whereas garnets are dry and only show IR absorbance bands at > 3,670 cm−1 for contamination of hydrous minerals. Compared to the economic kimberlites in the Kaapvaal Craton, the uneconomic kimberlite xenoliths from this study have lower orthopyroxene and olivine H2O content. In the xenoliths affected by garnet breakdown metasomatism, the H2O content of orthopyroxene and olivine is higher and lower, respectively. The structural hydroxyl distribution profile across olivine and higher inter-mineral water partition coefficient, suggest diffusion of hydrogen and possible re-equilibration. Statistical analysis of the olivine spectra suggests that hydrogen bands at 3540, 3624, 3638, and 3672 cm−1 are a good discriminant of economic and uneconomic kimberlites and in literature, they are associated with metasomatism, weathering-associated processes, high water activity, and oxygen fugacity. The lower water concentration in xenoliths from uneconomic kimberlite from the margin of the craton than the economic kimberlites from the interior of the Kaapvaal Craton and identified metasomatism hints towards dehydration of xenoliths by water-poor and CO2-rich melts in tectonized cross-lithospheric zones causing diamond resorption and may be responsible for the diamond-poor nature of uneconomic kimberlites in northern Lesotho.
采用傅立叶变换红外光谱法(FTIR)对来自四个不同的非经济和经济卡普瓦尔克拉顿金伯利岩管道(Matsoku、Thaba Putsoa、Pipe 200 和 Bultfontein)的 11 块橄榄岩异长岩中的标称无水地幔矿物(橄榄石、辉石、石榴石等)进行了研究。所有独居石都含有石榴石、透辉石、铬铁矿和辉绿岩。来自所有金伯利岩的大多数闪长岩中的正长石含量较高(30 mol vol.%),其相互连接的通道状性质暗示了水硅质流体变质作用。来自非经济金伯利岩的橄榄石闪长岩显示出辉绿岩和霞石(±铬铁矿)形成的矿脉以及石榴石边缘的发育,这表明是碱性硅碳酸盐岩(可能与金伯利岩有关)熔体的变质作用。橄榄石(17-62 ppm)、正长石(21-230 ppm)和菱镁矿(87-833 ppm)中的析出物含有大量的 H2O,而石榴石是干燥的,仅在 > 3,670 cm-1 处显示出红外吸光度带,表明受到含水矿物的污染。与卡普瓦尔克拉通的经济金伯利岩相比,本研究中的非经济金伯利岩的正长石和橄榄石 H2O 含量较低。在受石榴石击穿变质作用影响的闪长岩中,正长石和橄榄石的 H2O 含量分别较高和较低。橄榄石的羟基结构分布图和较高的矿物间水分配系数表明氢的扩散和可能的再平衡。橄榄石光谱的统计分析表明,3540、3624、3638 和 3672 cm-1 处的氢带可以很好地区分经济金伯利岩和非经济金伯利岩。与来自卡普瓦尔克拉通内部的经济金伯利岩相比,来自克拉通边缘的非经济金伯利岩的析出物中的水浓度较低,而且已查明存在变质作用,这表明在构造化的跨岩石圈地带,贫水和富含二氧化碳的熔体使析出物脱水,导致金刚石重吸收,这可能是莱索托北部非经济金伯利岩贫乏金刚石的原因。
{"title":"Heterogeneous water distribution in between peridotite xenoliths from Kaapvaal Craton kimberlites: Constraints on diamond barren nature of kimberlites","authors":"Sahroz Khan ,&nbsp;Nóra Liptai ,&nbsp;István J. Kovács ,&nbsp;Yana Fedortchouk ,&nbsp;Tivadar M. Tóth","doi":"10.1016/j.gr.2024.10.004","DOIUrl":"10.1016/j.gr.2024.10.004","url":null,"abstract":"<div><div>Nominally anhydrous mantle minerals (olivine, pyroxenes, garnets, etc.) in 11 peridotite xenoliths from four different uneconomic and economic Kaapvaal Craton kimberlite pipes (Matsoku, Thaba Putsoa, Pipe 200 and Bultfontein) have been investigated using Fourier transform infrared spectroscopy (FTIR). All xenoliths contain accessories of garnet, diopside, chromite, and phlogopite. High orthopyroxene content (&gt;30 mol vol.%) in most xenoliths from all kimberlites and its interconnected channel-like nature hint towards hydrous siliceous fluid metasomatism. Peridotite xenoliths from uneconomic kimberlites show development of phlogopite and clinopyroxene (± chromite) forming veins and in garnet rims suggesting metasomatism by alkaline silico-carbonatite (possibly kimberlite-related) melt. The xenoliths contain significant H<sub>2</sub>O in olivine (17–62 ppm), orthopyroxene (21–230 ppm), and clinopyroxene (87–833 ppm), whereas garnets are dry and only show IR absorbance bands at &gt; 3,670 cm<sup>−1</sup> for contamination of hydrous minerals. Compared to the economic kimberlites in the Kaapvaal Craton, the uneconomic kimberlite xenoliths from this study have lower orthopyroxene and olivine H<sub>2</sub>O content. In the xenoliths affected by garnet breakdown metasomatism, the H<sub>2</sub>O content of orthopyroxene and olivine is higher and lower, respectively. The structural hydroxyl distribution profile across olivine and higher inter-mineral water partition coefficient, suggest diffusion of hydrogen and possible re-equilibration. Statistical analysis of the olivine spectra suggests that hydrogen bands at 3540, 3624, 3638, and 3672 cm<sup>−1</sup> are a good discriminant of economic and uneconomic kimberlites and in literature, they are associated with metasomatism, weathering-associated processes, high water activity, and oxygen fugacity. The lower water concentration in xenoliths from uneconomic kimberlite from the margin of the craton than the economic kimberlites from the interior of the Kaapvaal Craton and identified metasomatism hints towards dehydration of xenoliths by water-poor and CO<sub>2</sub>-rich melts in tectonized cross-lithospheric zones causing diamond resorption and may be responsible for the diamond-poor nature of uneconomic kimberlites in northern Lesotho.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"137 ","pages":"Pages 331-348"},"PeriodicalIF":7.2,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142532596","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}
引用次数: 0
The Permian – Triassic boundary in Peninsular India and the extinction of the Glossopteridales 印度半岛的二叠纪-三叠纪界线和蝶形目动物的灭绝
IF 7.2 1区 地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY Pub Date : 2024-10-15 DOI: 10.1016/j.gr.2024.10.005
Anju Saxena , Christopher J. Cleal , Kamal Jeet Singh
The Glossopteridales was a distinctive order of gymnospermous seed-plants that occurred widely in the Permian of Gondwana. Some authors have suggested that they may also have occurred in the Triassic and so had survived the catastrophic Permian – Triassic extinction event. This suggestion was mainly based on records from peninsular India such as from the Panchet Formation, which traditionally was regarded as Triassic in age. This paper reviews the evidence for a Triassic age for these floras and it is argued that they are in fact late Permian. There is no clear evidence that the Glossopteridales survived the P/T biotic crisis in India and only unequivocal evidence is in China that they survived into the Triassic.
裸子植物门(Glossopteridales)是一种独特的裸子植物门,广泛分布于冈瓦纳的二叠纪。一些学者认为,它们可能也曾出现在三叠纪,因此在二叠纪-三叠纪的大灭绝中幸存了下来。这一观点主要是基于印度半岛的记录,如传统上被认为是三叠纪的潘切特地层。本文回顾了这些植物群三叠纪年龄的证据,并认为它们实际上是二叠纪晚期的植物群。没有明确的证据表明蝶形花类在印度经历了二叠纪/三叠纪的生物危机,只有中国有明确的证据表明它们存活到了三叠纪。
{"title":"The Permian – Triassic boundary in Peninsular India and the extinction of the Glossopteridales","authors":"Anju Saxena ,&nbsp;Christopher J. Cleal ,&nbsp;Kamal Jeet Singh","doi":"10.1016/j.gr.2024.10.005","DOIUrl":"10.1016/j.gr.2024.10.005","url":null,"abstract":"<div><div>The Glossopteridales was a distinctive order of gymnospermous seed-plants that occurred widely in the Permian of Gondwana. Some authors have suggested that they may also have occurred in the Triassic and so had survived the catastrophic Permian – Triassic extinction event. This suggestion was mainly based on records from peninsular India such as from the Panchet Formation, which traditionally was regarded as Triassic in age. This paper reviews the evidence for a Triassic age for these floras and it is argued that they are in fact late Permian. There is no clear evidence that the Glossopteridales survived the P/T biotic crisis in India and only unequivocal evidence is in China that they survived into the Triassic.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"137 ","pages":"Pages 318-330"},"PeriodicalIF":7.2,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142532595","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}
引用次数: 0
Upper mantle scale enrichment of Cenozoic intraplate magmatism in Northeast Asia: He-Sr-Nd-Pb-O isotope geochemistry of the basalts around the Korean peninsula 东北亚新生代板内岩浆活动的上地幔尺度富集:朝鲜半岛周围玄武岩的 He-Sr-Nd-Pb-O 同位素地球化学研究
IF 7.2 1区 地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY Pub Date : 2024-10-14 DOI: 10.1016/j.gr.2024.09.016
Donghwan Kim , Hyunwoo Lee , Mi Jung Lee , Changkun Park , Andrea Luca Rizzo
The Earth’s mantle is considered to be geochemically heterogeneous, which is reflected by the diverse compositions of oceanic island basalts (OIB). The mantle enrichment resulting in this is primarily attributed to the influx of recycled crustal materials into the mantle through subduction. Additionally, the sub-continental lithospheric mantle (SCLM) complicates the elucidation of mantle heterogeneity. From this perspective, Northeast Asia, where the Pacific stagnant slab in the mantle transition zone and the SCLM distribution are presented, is the suitable site for examining the upper mantle scale enrichment. Here we report He-Sr-Nd-Pb-O isotope compositions of Cenozoic basalts found around the Korean Peninsula to illustrate the source lithology and components that caused mantle heterogeneity. Our measured helium isotope ratios ranging from 5.7 to 7.3 Ra (3He/4He ratio of air, Ra = 1.39 x 10-6) are mostly within the SCLM range (6.1 ± 0.9 Ra) but lower than the mid-ocean ridge basalt range (MORB; 8 ± 1 Ra). The Sr-Nd-Pb isotope compositions of the basalts generally display a mixture of depleted MORB mantle (DMM), enriched mantle 1 (EM1), and enriched mantle 2 (EM2) components. In addition, the basalts have δ18Oolivine (vs. V-SMOW) values ranging from 4.7 to 5.7 ‰ that deviate from the DMM range (δ18Oolivine = 5.1 ± 0.2 ‰). Our isotopic analysis results highlight the role of a pyroxenite source in the metasomatized SCLM in the genesis of basalts, and the low 3He/4He ratios of the basalts indicates a significant contribution of SCLM. Moreover, the delaminated cratonic SCLM and asthenosphere-lithosphere interaction are scenarios for the low 3He/4He ratios. Therefore, we propose that mixing of DMM (high 3He/4He ratio; 7 to 9 Ra) and the metasomatized SCLM (low 3He/4He ratio; 5 to 7 Ra) allowed enrichment within the upper mantle scale for the Cenozoic intraplate magmatism in Northeast Asia.
地球的地幔被认为是地球化学异质的,这反映在大洋岛屿玄武岩(OIB)的不同成分上。造成这种情况的地幔富集主要归因于通过俯冲作用将回收的地壳物质涌入地幔。此外,次大陆岩石圈地幔(SCLM)也使地幔异质性的阐释变得更加复杂。从这个角度来看,地幔过渡带太平洋停滞板和SCLM分布的东北亚是研究上地幔尺度富集的合适地点。在此,我们报告了在朝鲜半岛周围发现的新生代玄武岩的 He-Sr-Nd-Pb-O 同位素组成,以说明造成地幔异质性的源岩性和成分。我们测量到的氦同位素比值从5.7到7.3 Ra(空气的3He/4He比值,Ra = 1.39 x 10-6)不等,大部分在SCLM范围内(6.1 ± 0.9 Ra),但低于洋中脊玄武岩范围(MORB;8 ± 1 Ra)。玄武岩的 Sr-Nd-Pb 同位素成分一般显示出贫化 MORB 地幔(DMM)、富集地幔 1(EM1)和富集地幔 2(EM2)成分的混合物。此外,玄武岩的δ18Oolivine(vs. V-SMOW)值在 4.7 至 5.7 ‰之间,偏离了 DMM 的范围(δ18Oolivine = 5.1 ± 0.2 ‰)。我们的同位素分析结果表明,在玄武岩的成因过程中,变质SCLM中的辉绿岩源起着重要作用,玄武岩的低3He/4He比值表明SCLM起了重要作用。此外,板块状SCLM的分层和岩石圈与星体层的相互作用也是3He/4He比值低的原因。因此,我们认为,DMM(高3He/4He比值;7-9 Ra)和变质SCLM(低3He/4He比值;5-7 Ra)的混合使得东北亚新生代板内岩浆活动在上地幔尺度内富集。
{"title":"Upper mantle scale enrichment of Cenozoic intraplate magmatism in Northeast Asia: He-Sr-Nd-Pb-O isotope geochemistry of the basalts around the Korean peninsula","authors":"Donghwan Kim ,&nbsp;Hyunwoo Lee ,&nbsp;Mi Jung Lee ,&nbsp;Changkun Park ,&nbsp;Andrea Luca Rizzo","doi":"10.1016/j.gr.2024.09.016","DOIUrl":"10.1016/j.gr.2024.09.016","url":null,"abstract":"<div><div>The Earth’s mantle is considered to be geochemically heterogeneous, which is reflected by the diverse compositions of oceanic island basalts (OIB). The mantle enrichment resulting in this is primarily attributed to the influx of recycled crustal materials into the mantle through subduction. Additionally, the sub-continental lithospheric mantle (SCLM) complicates the elucidation of mantle heterogeneity. From this perspective, Northeast Asia, where the Pacific stagnant slab in the mantle transition zone and the SCLM distribution are presented, is the suitable site for examining the upper mantle scale enrichment. Here we report He-Sr-Nd-Pb-O isotope compositions of Cenozoic basalts found around the Korean Peninsula to illustrate the source lithology and components that caused mantle heterogeneity. Our measured helium isotope ratios ranging from 5.7 to 7.3 R<sub>a</sub> (<sup>3</sup>He/<sup>4</sup>He ratio of air, R<sub>a</sub> = 1.39 x 10<sup>-6</sup>) are mostly within the SCLM range (6.1 ± 0.9 R<sub>a</sub>) but lower than the mid-ocean ridge basalt range (MORB; 8 ± 1 R<sub>a</sub>). The Sr-Nd-Pb isotope compositions of the basalts generally display a mixture of depleted MORB mantle (DMM), enriched mantle 1 (EM1), and enriched mantle 2 (EM2) components. In addition, the basalts have δ<sup>18</sup>O<sub>olivine</sub> (vs. V-SMOW) values ranging from 4.7 to 5.7 ‰ that deviate from the DMM range (δ<sup>18</sup>O<sub>olivine</sub> = 5.1 ± 0.2 ‰). Our isotopic analysis results highlight the role of a pyroxenite source in the metasomatized SCLM in the genesis of basalts, and the low <sup>3</sup>He/<sup>4</sup>He ratios of the basalts indicates a significant contribution of SCLM. Moreover, the delaminated cratonic SCLM and asthenosphere-lithosphere interaction are scenarios for the low <sup>3</sup>He/<sup>4</sup>He ratios. Therefore, we propose that mixing of DMM (high <sup>3</sup>He/<sup>4</sup>He ratio; 7 to 9 R<sub>a</sub>) and the metasomatized SCLM (low <sup>3</sup>He/<sup>4</sup>He ratio; 5 to 7 R<sub>a</sub>) allowed enrichment within the upper mantle scale for the Cenozoic intraplate magmatism in Northeast Asia.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"137 ","pages":"Pages 349-364"},"PeriodicalIF":7.2,"publicationDate":"2024-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142532597","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}
引用次数: 0
Cuartel Ophiolite: Structure, timing and exhumation mechanisms for a Cadomian suture zone in the peri-Gondwanan Realm (SW Iberia) Cuartel蛇绿岩:近贡瓦南地块(伊比利亚西南部)卡多米安时期缝合带的结构、时间和掘起机制
IF 7.2 1区 地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY Pub Date : 2024-10-09 DOI: 10.1016/j.gr.2024.10.002
Diana Moreno-Martín , Rubén Díez Fernández , Richard Albert , Sonia Sánchez Martínez , Esther Rojo-Pérez , Axel Gerdes , Ricardo Arenas
The Cadomian Orogeny formed as an accretionary orogen surrounding Gondwana. The structure resulting from the Cadomian Orogeny is pervasively reworked during the Paleozoic, within the frame of the Variscan Cycle. In SW Iberia (Mina Afortunada Massif), a tectonometamorphic and geochronological analysis revealed two Cadomian deformation phases. The first phase (DC1; 586 Ma, U-Pb dating in inherited metamorphic garnet from Mina Afortunada Gneiss) is associated with ophiolite accretion during the closure of a back-arc or intra-arc basin (Cuartel Ophiolite). A metamorphic fabric related to this phase is preserved as an internal foliation in Ediacaran (meta)sedimentary rocks. The second phase (DC2; 515–485 Ma) is constrained by the age of the igneous protolith of Mina Afortunada Gneiss (∼515 Ma), which is affected by a penetrative foliation formed during DC2, and by the unconformable deposit of Ordovician sediments, which are not affected. The telescoping of metamorphic isograds during DC2 and the geometry of detachment faults associated with this phase suggest extensional tectonics as the driving mechanism for the early exhumation of the Cadomian suture zone in Mina Afortunada Massif. The superimposition of Variscan folds and shear zones onto the Cadomian structures contributed to the subsequent exhumation of the Cadomian suture zone. The analysis and reconstruction of Cadomian and Variscan structures, plus the geochronological data, allow us to correlate the Cuartel Ophiolite with the Mérida Ophiolite, being two pieces of the same, yet dismembered, Cadomian suture zone. The number of Cadomian suture zones in Gondwana does not coincide with that of Cadomian suture zone exposures. Reworked orogens such as the Cadomian could be subjected to duplication of their suture zones. Assessments regarding the Cadomian paleogeography should consider the multiplier effect of the structural overprints after ophiolite accretion.
卡多米造山带是围绕冈瓦纳形成的增生造山带。卡多米造山运动所形成的构造在古生代的瓦利斯坎周期框架内被普遍重塑。在伊比利亚西南部(Mina Afortunada Massif),构造变质和地质年代分析揭示了两个卡多米亚变形阶段。第一阶段(DC1;586 Ma,Mina Afortunada 片麻岩中的继承变质石榴石的 U-Pb 测定)与弧后或弧内盆地(Cuartel 蛇绿岩)关闭期间的蛇绿岩吸积有关。在埃迪卡拉(元)沉积岩中,与这一阶段有关的变质构造作为内部折线保存下来。第二阶段(DC2;515-485 Ma)受到米纳阿福图纳达片麻岩火成岩原岩(∼515 Ma)年龄的限制,该原岩受到 DC2 期间形成的穿透性褶皱的影响,同时也受到奥陶纪沉积物的不整合沉积的影响,该沉积物未受到影响。DC2期间变质等距线的伸缩以及与这一阶段相关的剥离断层的几何形状表明,延伸构造是Mina Afortunada地块卡多米期缝合带早期隆起的驱动机制。Variscan褶皱和剪切带叠加到Cadomian构造上,促进了Cadomian缝合带随后的隆起。通过分析和重建卡多米安构造和瓦里斯科构造,再加上地质年代数据,我们可以将夸特尔蛇绿岩和梅里达蛇绿岩联系起来,它们是同一条卡多米安缝合带的两个部分,但被肢解了。冈瓦纳的卡多米氏缝合带数量与卡多米氏缝合带出露的数量并不一致。像卡多米亚这样的重造造山带可能会出现缝合带重复的情况。在评估卡多米亚古地理时,应考虑蛇绿混杂岩增生后的构造叠加效应。
{"title":"Cuartel Ophiolite: Structure, timing and exhumation mechanisms for a Cadomian suture zone in the peri-Gondwanan Realm (SW Iberia)","authors":"Diana Moreno-Martín ,&nbsp;Rubén Díez Fernández ,&nbsp;Richard Albert ,&nbsp;Sonia Sánchez Martínez ,&nbsp;Esther Rojo-Pérez ,&nbsp;Axel Gerdes ,&nbsp;Ricardo Arenas","doi":"10.1016/j.gr.2024.10.002","DOIUrl":"10.1016/j.gr.2024.10.002","url":null,"abstract":"<div><div>The Cadomian Orogeny formed as an accretionary orogen surrounding Gondwana. The structure resulting from the Cadomian Orogeny is pervasively reworked during the Paleozoic, within the frame of the Variscan Cycle. In SW Iberia (Mina Afortunada Massif), a tectonometamorphic and geochronological analysis revealed two Cadomian deformation phases. The first phase (D<sub>C1</sub>; 586 Ma, U-Pb dating in inherited metamorphic garnet from Mina Afortunada Gneiss) is associated with ophiolite accretion during the closure of a back-arc or intra-arc basin (Cuartel Ophiolite). A metamorphic fabric related to this phase is preserved as an internal foliation in Ediacaran (meta)sedimentary rocks. The second phase (D<sub>C2</sub>; 515–485 Ma) is constrained by the age of the igneous protolith of Mina Afortunada Gneiss (∼515 Ma), which is affected by a penetrative foliation formed during D<sub>C2</sub>, and by the unconformable deposit of Ordovician sediments, which are not affected. The telescoping of metamorphic isograds during D<sub>C2</sub> and the geometry of detachment faults associated with this phase suggest extensional tectonics as the driving mechanism for the early exhumation of the Cadomian suture zone in Mina Afortunada Massif. The superimposition of Variscan folds and shear zones onto the Cadomian structures contributed to the subsequent exhumation of the Cadomian suture zone. The analysis and reconstruction of Cadomian and Variscan structures, plus the geochronological data, allow us to correlate the Cuartel Ophiolite with the Mérida Ophiolite, being two pieces of the same, yet dismembered, Cadomian suture zone. The number of Cadomian suture zones in Gondwana does not coincide with that of Cadomian suture zone exposures. Reworked orogens such as the Cadomian could be subjected to duplication of their suture zones. Assessments regarding the Cadomian paleogeography should consider the multiplier effect of the structural overprints after ophiolite accretion.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"137 ","pages":"Pages 255-273"},"PeriodicalIF":7.2,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142441099","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}
引用次数: 0
Neoproterozoic arc-magmatism of the Silet Terrane, Western Hoggar (Algeria), new constraints from zircon U-Pb-Hf isotope analyses and whole rock geochemistry 阿尔及利亚西霍加尔西莱特地层的新近新生代弧-岩浆作用,锆石U-Pb-Hf同位素分析和全岩地球化学的新制约因素
IF 7.2 1区 地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY Pub Date : 2024-10-09 DOI: 10.1016/j.gr.2024.10.003
Narimene Berrahmane , El-Hocine Fettous , Abderrahmane Bendaoud , Sid Ali Doukkari , Basem Zoheir , Armin Zeh
This study presents results of zircon U-Pb-Hf isotope analyses and whole-rock geochemistry applied to magmatic rocks of the Silet terrane in the Western Hoggar, forming a part of the Neoproterozoic arc exposed along the boundary between the LATEA metacraton and the Paleoproterozoic In Ouzzal terrane. According to zircon U-Pb geochronology four distinct pulses of Neoproterozoic granitoids magmatism are recognized in the Silet terrane: Tonian (c. 870–840 Ma), Late Tonian (c. 770 Ma), Latest Tonian (c. 730 Ma) and Late Cryogenian (c. 675 Ma).
Geochemical and Hf isotope data indicate a progressive shift in geotectonic settings. The c. 870–840 Ma Tonian TTG pulses (Tonalite-Trondhjemite-Granodiorite) in the North Silet batholith, with superchondritic εHf values (+5.8 to + 7.2), suggest formation in a subduction zone. The subsequent c. 770 Ma Late Tonian magmatism, characterized by mafic compositions, reflects a back-arc tectonic setting, as evidenced by high Ti/V ratios, low V contents, and εHf values of + 6.12 to + 8.95. The c. 730 Ma Latest Tonian magmatism, with more evolved acidic pulses, indicates hybrid mantle–crustal involvement (εHf + 6.53 to + 8.08). The Late Cryogenian intrusions (c. 675 Ma), featuring the lowest εHf values (+1.84 to + 4.09) and inherited c. 870 Ma zircons, suggest formation from the melting of Tonian TTGs during continental collision.
Integrating U-Pb dating with geochemical data provides a comprehensive view of the Silet terrane’s tectonic evolution, supporting a continental arc origin. Disparities in magmatism ages between the northern (c. 870–675 Ma) and southern (c. 740–640 Ma) segments of the Silet arc correlate with the diachronous collision/subduction of a V-shaped “Silet Ocean”, forming an introverted oceanic system (oceans that have formed by rifted continental blocks that were subsequently re‑joined in approximately the same position) within the broader West Gondwana context. Structural analysis indicates that the regional structures of the Silet arc were shaped in a WNW-ESE collisional transpressive regime during the Pan-African orogeny, offering new insights into the Neoproterozoic Silet arc’s geodynamic evolution and its paleogeographical location in the West Gondwana orogeny.
本研究介绍了对西霍加尔西莱特岩系岩浆岩进行锆石U-Pb-Hf同位素分析和全岩地球化学研究的结果,西莱特岩系是新元古代弧的一部分,沿LATEA metacraton和古元古代In Ouzzal岩系边界暴露。根据锆石U-Pb地质年代学,西莱特地层中新新生代花岗岩岩浆活动有四个不同的阶段:地球化学和 Hf 同位素数据表明,大地构造环境在逐渐发生变化。北锡勒特岩床中约 870-840 Ma 的托尼安 TTG 岩浆(托纳岩-特朗杰米岩-花岗闪长岩)具有超强εHf 值(+5.8 至 +7.2),表明其形成于俯冲带。随后的约 770 Ma 晚托尼安岩岩浆活动以黑云母成分为特征,反映了弧后构造环境,高 Ti/V 比值、低 V 含量以及 +6.12 至 +8.95 的 εHf 值就是证明。约 730 Ma 的最新托尼期岩浆活动,具有更多的酸性脉冲,表明地幔-地壳混合参与(εHf + 6.53 至 + 8.08)。晚冰元古代侵入体(约 675 Ma)的εHf 值最低(+1.84 至 +4.09),并继承了约 870 Ma 的锆石,这表明该侵入体是在大陆碰撞过程中由托尼安 TTGs 熔化形成的。西莱特弧北段(约 870-675 Ma)和南段(约 740-640 Ma)之间岩浆年龄的差异与 V 形 "西莱特洋 "的非同步碰撞/俯冲有关,在更广泛的西冈瓦纳背景下形成了一个内向海洋系统(由裂开的大陆块形成的海洋,随后在大致相同的位置重新接合)。结构分析表明,在泛非造山运动期间,西莱特弧的区域结构是在 WNW-ESE 碰撞转位机制中形成的,这为了解新近纪西莱特弧的地球动力演化及其在西冈瓦纳造山运动中的古地理位置提供了新的视角。
{"title":"Neoproterozoic arc-magmatism of the Silet Terrane, Western Hoggar (Algeria), new constraints from zircon U-Pb-Hf isotope analyses and whole rock geochemistry","authors":"Narimene Berrahmane ,&nbsp;El-Hocine Fettous ,&nbsp;Abderrahmane Bendaoud ,&nbsp;Sid Ali Doukkari ,&nbsp;Basem Zoheir ,&nbsp;Armin Zeh","doi":"10.1016/j.gr.2024.10.003","DOIUrl":"10.1016/j.gr.2024.10.003","url":null,"abstract":"<div><div>This study presents results of zircon U-Pb-Hf isotope analyses and whole-rock geochemistry applied to magmatic rocks of the Silet terrane in the Western Hoggar, forming a part of the Neoproterozoic arc exposed along the boundary between the LATEA metacraton and the Paleoproterozoic In Ouzzal terrane. According to zircon U-Pb geochronology four distinct pulses of Neoproterozoic granitoids magmatism are recognized in the Silet terrane: Tonian (c. 870–840 Ma), Late Tonian (c. 770 Ma), Latest Tonian (c. 730 Ma) and Late Cryogenian (c. 675 Ma).</div><div>Geochemical and Hf isotope data indicate a progressive shift in geotectonic settings. The c. 870–840 Ma Tonian TTG pulses (Tonalite-Trondhjemite-Granodiorite) in the North Silet batholith, with superchondritic εHf values (+5.8 to + 7.2), suggest formation in a subduction zone. The subsequent c. 770 Ma Late Tonian magmatism, characterized by mafic compositions, reflects a back-arc tectonic setting, as evidenced by high Ti/V ratios, low V contents, and εHf values of + 6.12 to + 8.95. The c. 730 Ma Latest Tonian magmatism, with more evolved acidic pulses, indicates hybrid mantle–crustal involvement (εHf + 6.53 to + 8.08). The Late Cryogenian intrusions (c. 675 Ma), featuring the lowest εHf values (+1.84 to + 4.09) and inherited c. 870 Ma zircons, suggest formation from the melting of Tonian TTGs during continental collision.</div><div>Integrating U-Pb dating with geochemical data provides a comprehensive view of the Silet terrane’s tectonic evolution, supporting a continental arc origin. Disparities in magmatism ages between the northern (c. 870–675 Ma) and southern (c. 740–640 Ma) segments of the Silet arc correlate with the diachronous collision/subduction of a V-shaped “Silet Ocean”, forming an introverted oceanic system (oceans that have formed by rifted continental blocks that were subsequently re‑joined in approximately the same position) within the broader West Gondwana context. Structural analysis indicates that the regional structures of the Silet arc were shaped in a WNW-ESE collisional transpressive regime during the Pan-African orogeny, offering new insights into the Neoproterozoic Silet arc’s geodynamic evolution and its paleogeographical location in the West Gondwana orogeny.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"137 ","pages":"Pages 234-254"},"PeriodicalIF":7.2,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142441199","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}
引用次数: 0
Crustal variations and tectonic implications across the South Yellow Sea based on active-source wide-angle seismic analyses 基于活动源广角地震分析的整个南黄海地壳变化及其构造影响
IF 7.2 1区 地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY Pub Date : 2024-10-05 DOI: 10.1016/j.gr.2024.10.001
Lihua Liu , Chuanchuan Lü , Tianyao Hao , Xunhua Zhang , Kwanghee Kim , Hanjoon Kim , Yonggang Guo
The South Yellow Sea and its environs are pivotal for unraveling the complexities of crustal dynamics and continental collision processes. A holistic assessment of deep structural variations from northern China to the Korean Peninsula is essential for a comprehensive and accurate determination of the tectonic affinity of the Korean Peninsula.Thus, we deployed a pioneering active-source seismic profile (Line2016) spanning the South Yellow Sea and the eastern onshore region of the Korean Peninsula, provides crucial insights into the collision dynamics between the Sino-Korean Block and the Yangtze Block. Our innovative approach, incorporating forward modeling, tomography, and finite-difference wavefield modeling, yielded a high-resolution crustal P-wave velocity model, addressing a significant knowledge gap in understanding the geological intricacies between northern China and the Korean Peninsula. The results confirmed and precisely located the West Marginal Fault of the Korean Peninsula, a significant crustal-scale tectonic structure, likely representing the eastern boundary between the Yangtze Block and the Sino-Korean Block. The study advocates for classifying the Korean Peninsula as part of the Sino-Korean Block, presenting evidence for the one-part affinity hypothesis. This collision resulted in the creation of two distinct suture zones—an orogenic belt in the northern part and a significant strike-slip fault zone in the eastern part of the South Yellow Sea. The study emphasizes the pivotal role of block morphology in regulating plate convergence, providing valuable insights for understanding similar phenomena in other collision zones.
南黄海及其周边地区对于揭示复杂的地壳动力学和大陆碰撞过程至关重要。因此,我们部署了一条横跨南黄海和朝鲜半岛东部陆上地区的开创性主动源地震剖面(Line2016),为了解中韩地块和长江地块之间的碰撞动力学提供了重要信息。我们的创新方法结合了前向建模、层析成像和有限差分波场建模,建立了高分辨率的地壳 P 波速度模型,解决了在了解中国北部和朝鲜半岛之间错综复杂的地质情况方面的重大知识空白。研究结果确认并精确定位了朝鲜半岛西缘断层,这是一个重要的地壳尺度构造,很可能代表了长江地块和中韩地块之间的东部边界。该研究主张将朝鲜半岛划为中韩地块的一部分,为 "一元亲缘假说 "提供了证据。这次碰撞产生了两个不同的缝合带--北部的造山带和南黄海东部的重要走向滑动断层带。该研究强调了块体形态在调节板块聚合中的关键作用,为理解其他碰撞带的类似现象提供了宝贵的启示。
{"title":"Crustal variations and tectonic implications across the South Yellow Sea based on active-source wide-angle seismic analyses","authors":"Lihua Liu ,&nbsp;Chuanchuan Lü ,&nbsp;Tianyao Hao ,&nbsp;Xunhua Zhang ,&nbsp;Kwanghee Kim ,&nbsp;Hanjoon Kim ,&nbsp;Yonggang Guo","doi":"10.1016/j.gr.2024.10.001","DOIUrl":"10.1016/j.gr.2024.10.001","url":null,"abstract":"<div><div>The South Yellow Sea and its environs are pivotal for unraveling the complexities of crustal dynamics and continental collision processes. A holistic assessment of deep structural variations from northern China to the Korean Peninsula is essential for a comprehensive and accurate determination of the tectonic affinity of the Korean Peninsula.Thus, we deployed a pioneering active-source seismic profile (Line2016) spanning the South Yellow Sea and the eastern onshore region of the Korean Peninsula, provides crucial insights into the collision dynamics between the Sino-Korean Block and the Yangtze Block. Our innovative approach, incorporating forward modeling, tomography, and finite-difference wavefield modeling, yielded a high-resolution crustal P-wave velocity model, addressing a significant knowledge gap in understanding the geological intricacies between northern China and the Korean Peninsula. The results confirmed and precisely located the West Marginal Fault of the Korean Peninsula, a significant crustal-scale tectonic structure, likely representing the eastern boundary between the Yangtze Block and the Sino-Korean Block. The study advocates for classifying the Korean Peninsula as part of the Sino-Korean Block, presenting evidence for the one-part affinity hypothesis. This collision resulted in the creation of two distinct suture zones—an orogenic belt in the northern part and a significant strike-slip fault zone in the eastern part of the South Yellow Sea. The study emphasizes the pivotal role of block morphology in regulating plate convergence, providing valuable insights for understanding similar phenomena in other collision zones.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"137 ","pages":"Pages 117-130"},"PeriodicalIF":7.2,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142424206","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}
引用次数: 0
Carboniferous–Triassic subduction in the Qinling orogen 秦岭造山带的石炭纪-三叠纪俯冲运动
IF 7.2 1区 地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY Pub Date : 2024-10-04 DOI: 10.1016/j.gr.2024.09.015
Thomas Bader , Lothar Ratschbacher , Leander Franz , Rolf L. Romer , Lifei Zhang , Christian de Capitani , Joseph Mullis , Marion Tichomirowa , Xiaowei Li
The Qinling–Tongbai–Hong’an–Dabie–Sulu Orogen links two cratons, North China and South China, and records the reorganization and transfer of plates from Rodinia to Gondwana and Eurasia. The formation of North Qinling at the southern North China margin (524–378 Ma) by subduction–accretion processes and the collision between North and South China (270–190 Ma) are pivotal for this reorganization. We outline the geological processes that link both events by combining phase equilibria modeling, conventional thermobarometry, U–Pb (zircon, titanite, garnet–staurolite) and 40Ar/39Ar and Rb–Sr (amphibole, micas) geochronology. The North Qinling experienced transpressional reactivation of shear zones, local fluid percolation, and metamorphism up to the lowest amphibolite facies (≲ 550 °C) until 324 Ma; protracted uplift and erosion with slow cooling (1 °C/Myr) led to its peneplanation prior to 260 Ma. The southerly abutting Wuguan Complex underwent two consecutive metamorphic events: while the older was diverse (600–750 °C, 0.5–1.2 GPa), the younger had a regionally homogeneous peak (590 °C, 0.9 GPa) at c. 324 Ma. Subduction and early exhumation of the South China margin occurred at 299–250 Ma in East Qinling. During the exhumation, medium-grade blueschists (500 °C, 1.0–1.3 GPa) were imbricated with low-grade rocks (300 °C, 0.5–1.0 GPa). Subsequent extensional doming with percolation of a low-salinity, hydrous fluid and south-vergent thrusting brought these rocks to near-surface levels by 200 Ma. New and published data indicate that plate convergence governed geologic processes to the south of North China not only before 378 Ma but protractedly or episodically until 190 Ma. This prolonged history is inconsistent with the amalgamation of North China to Gondwana but substantiates paleogeographic reconstructions with North China as a Paleozoic island continent. Carboniferous–Triassic subduction in the Qinling ultimately led to the welding of North China and South China, completing their transfer from Rodinia to Eurasia.
秦岭-桐柏-红安-大别-苏禄造山带连接了华北和华南两大板块,记录了从罗迪尼亚到冈瓦纳和欧亚大陆的板块重组和转移。华北南缘的北秦岭(524-378Ma)由俯冲-喷发过程形成,华北和华南之间的碰撞(270-190Ma)是这一重组的关键。我们结合相平衡模型、传统热压测量、U-Pb(锆石、榍石、石榴石-陶土)和40Ar/39Ar及Rb-Sr(闪石、云母)地质年代学,概述了将这两个事件联系起来的地质过程。秦岭北麓在324Ma之前经历了剪切带的换位再造、局部流体渗流和变质作用,直至最低的闪长岩面(≲ 550 °C);长期的隆起和侵蚀作用以及缓慢的冷却(1 °C/Myr)导致其在260Ma之前发生了倒平面化。南侧毗邻的武关岩群经历了两次连续的变质事件:较早的变质事件具有多样性(600-750 °C,0.5-1.2 GPa),而较晚的变质事件则在约324 Ma时出现了一个区域性的同质峰值(590 °C,0.9 GPa)。华南边缘的俯冲和早期掘起发生在秦岭东部的299-250 Ma。在掘起过程中,中品位蓝晶岩(500 °C,1.0-1.3 GPa)与低品位岩石(300 °C,0.5-1.0 GPa)交错。随后,低盐度、含水流体的渗滤作用和南向推移作用使这些岩石在200Ma时达到近地表水平。新公布的数据表明,板块辐合不仅在公元前378年之前支配着华北南部的地质过程,而且一直持续到公元前190年。这一漫长的历史与华北与冈瓦纳大陆合并的说法不一致,但却证实了华北作为古生代岛屿大陆的古地理重建。秦岭石炭纪-三叠纪的俯冲最终导致了华北与华南的融合,完成了从罗迪尼亚向欧亚大陆的转移。
{"title":"Carboniferous–Triassic subduction in the Qinling orogen","authors":"Thomas Bader ,&nbsp;Lothar Ratschbacher ,&nbsp;Leander Franz ,&nbsp;Rolf L. Romer ,&nbsp;Lifei Zhang ,&nbsp;Christian de Capitani ,&nbsp;Joseph Mullis ,&nbsp;Marion Tichomirowa ,&nbsp;Xiaowei Li","doi":"10.1016/j.gr.2024.09.015","DOIUrl":"10.1016/j.gr.2024.09.015","url":null,"abstract":"<div><div>The Qinling–Tongbai–Hong’an–Dabie–Sulu Orogen links two cratons, North China and South China, and records the reorganization and transfer of plates from Rodinia to Gondwana and Eurasia. The formation of North Qinling at the southern North China margin (524–378 Ma) by subduction–accretion processes and the collision between North and South China (270–190 Ma) are pivotal for this reorganization. We outline the geological processes that link both events by combining phase equilibria modeling, conventional thermobarometry, U–Pb (zircon, titanite, garnet–staurolite) and <sup>40</sup>Ar/<sup>39</sup>Ar and Rb–Sr (amphibole, micas) geochronology. The North Qinling experienced transpressional reactivation of shear zones, local fluid percolation, and metamorphism up to the lowest amphibolite facies (≲ 550 °C) until 324 Ma; protracted uplift and erosion with slow cooling (1 °C/Myr) led to its peneplanation prior to 260 Ma. The southerly abutting Wuguan Complex underwent two consecutive metamorphic events: while the older was diverse (600–750 °C, 0.5–1.2 GPa), the younger had a regionally homogeneous peak (590 °C, 0.9 GPa) at <em>c.</em> 324 Ma. Subduction and early exhumation of the South China margin occurred at 299–250 Ma in East Qinling. During the exhumation, medium-grade blueschists (500 °C, 1.0–1.3 GPa) were imbricated with low-grade rocks (300 °C, 0.5–1.0 GPa). Subsequent extensional doming with percolation of a low-salinity, hydrous fluid and south-vergent thrusting brought these rocks to near-surface levels by 200 Ma. New and published data indicate that plate convergence governed geologic processes to the south of North China not only before 378 Ma but protractedly or episodically until 190 Ma. This prolonged history is inconsistent with the amalgamation of North China to Gondwana but substantiates paleogeographic reconstructions with North China as a Paleozoic island continent. Carboniferous–Triassic subduction in the Qinling ultimately led to the welding of North China and South China, completing their transfer from Rodinia to Eurasia.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"137 ","pages":"Pages 171-208"},"PeriodicalIF":7.2,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142424297","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}
引用次数: 0
Classifying zircon: A machine-learning approach using zircon geochemistry 锆石分类:利用锆石地球化学的机器学习方法
IF 7.2 1区 地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY Pub Date : 2024-10-03 DOI: 10.1016/j.gr.2024.09.010
Jintao Kong , Hongru Yu , Junyi Sun , Huan Zhang , Miaomiao Zhang , Zhi Xia
This study presented a novel, rapid, and accurate method for determining zircon origin via a comprehensive analysis of a dataset containing 27,818 zircon trace element sets. This method integrated back propagation neural networks with the AdaBoost algorithm. The optimal classifier characterized as a linear combination of a two-layer neural network model, comprised 100 base classifiers and 400 hidden neurons. It was rigorously trained over 1000 iterations, which resulted in an unbiased error rate of 8.31%. To facilitate practical application, the classifier was integrated into a macro-enabled Excel spreadsheet.
本研究通过对包含 27,818 个锆石痕量元素集的数据集进行综合分析,提出了一种新颖、快速、准确的方法来确定锆石的来源。该方法将反向传播神经网络与 AdaBoost 算法相结合。最佳分类器的特征是双层神经网络模型的线性组合,由 100 个基本分类器和 400 个隐藏神经元组成。经过 1000 次迭代的严格训练,其无偏误差率为 8.31%。为便于实际应用,该分类器被集成到一个支持宏的 Excel 电子表格中。
{"title":"Classifying zircon: A machine-learning approach using zircon geochemistry","authors":"Jintao Kong ,&nbsp;Hongru Yu ,&nbsp;Junyi Sun ,&nbsp;Huan Zhang ,&nbsp;Miaomiao Zhang ,&nbsp;Zhi Xia","doi":"10.1016/j.gr.2024.09.010","DOIUrl":"10.1016/j.gr.2024.09.010","url":null,"abstract":"<div><div>This study presented a novel, rapid, and accurate method for determining zircon origin via a comprehensive analysis of a dataset containing 27,818 zircon trace element sets. This method integrated back propagation neural networks with the AdaBoost algorithm. The optimal classifier characterized as a linear combination of a two-layer neural network model, comprised 100 base classifiers and 400 hidden neurons. It was rigorously trained over 1000 iterations, which resulted in an unbiased error rate of 8.31%. To facilitate practical application, the classifier was integrated into a macro-enabled Excel spreadsheet.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"137 ","pages":"Pages 227-233"},"PeriodicalIF":7.2,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142441100","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}
引用次数: 0
Crustal structures and anisotropy in southeastern China: Continental collision and intraplate earthquakes 中国东南部的地壳结构和各向异性:大陆碰撞与板块内部地震
IF 7.2 1区 地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY Pub Date : 2024-10-02 DOI: 10.1016/j.gr.2024.09.011
H.B. Huang , K.Y. Wan , E.Y. He , H. Jiang , J. Guo , X.L. Qiu
<div><div>This study investigates the role of crustal structures and anisotropy in southeastern China regarding intraplate earthquakes within the context of concentrated and perturbed tectonic stresses. The region is characterized by a complex multiphase tectonic history,including the ongoing collision between the Philippine Plate and the South China Sea margin. Utilizing the teleseismic receiver function method, we offer a comprehensive depiction of the crustal structures and layered anisotropy in Guangdong and Fujian, two earthquake-prone areas. Our results reveal that the crustal anisotropy is stratified into two layers, with a slow axis perpendicular to the orogenic belt in the upper-middle crust, whereas the fast axis aligns perpendicularly at lower crust levels. The lateral heterogeneity and anisotropy of the crustal structure emphasize both the boundary delineation and differential movement between continental blocks. The observed increase in density and intensity of intraplate earthquakes across this boundary supports our conclusion regarding a connection between decoupled crustal deformation and seismicity. Specifically, the foliation of metamorphic rocks during the Mesozoic collision generated orogen-parallel fabrics in the upper-middle crust, while ductile shearing resulted in orogen-perpendicular fast directions at lower crust levels. In contrast, mismatch evolution between continental blocks reactivated by present collision provides stress conditions conducive to earthquake occurrence in southeastern China. Our findings provide valuable insights into mechanisms behind intraplate earthquakes as well as tectonic evolution within continental collision zones.</div><div>Plain Language Summary</div><div>The mechanism of intraplate earthquakes is a topic of great interest in the study of continental collision and regional tectonic evolution. The controlling factors behind these earthquakes are highly complex and uncertain. In this study, we aim to investigate the role of crustal structures and anisotropy in southeastern China within the context of intraplate seismic activity. This region, which is currently experiencing a collision between the Philippine Plate and the South China Sea Margin, has a multiphase tectonic history that includes remnants of paleo-Pacific subduction. By utilizing the receiver function method, we provide a detailed picture of crustal structures and layered anisotropy in Guangdong and Fujian, two earthquake-prone regions in southeastern China. Our findings reveal that anisotropy in the crust can be stratified into two layers: an upper-middle crust and a lower crust with a slow axis and a fast axis, both perpendicular to the orogeny, respectively. The lateral heterogeneity and anisotropy of the crustal structure highlight the boundary and differential movement between the continental blocks. The enhanced density and intensity of the intraplate earthquakes across this boundary provide evidence for a connection between
本研究探讨了中国东南部地壳结构和各向异性在集中和扰动构造应力背景下对板块内地震的作用。该地区具有复杂的多相构造历史,包括菲律宾板块与中国南海边缘正在发生的碰撞。利用远震接收函数方法,我们全面描述了广东和福建这两个地震多发地区的地壳结构和层状各向异性。我们的研究结果表明,地壳各向异性分为两层,中上层地壳的慢轴垂直于造山带,而下层地壳的快轴垂直于造山带。地壳结构的横向异质性和各向异性强调了大陆块之间的边界划分和差异运动。通过观察发现,跨越这一边界的板块内地震的密度和强度都有所增加,这支持了我们关于脱钩地壳变形与地震之间联系的结论。具体来说,中生代碰撞过程中变质岩的褶皱在中上地壳产生了与造山带平行的构造,而韧性剪切则在较低地壳水平产生了与造山带垂直的快速方向。与此相反,目前碰撞重新激活的大陆块体之间的错配演化为中国东南部地震的发生提供了有利的应力条件。我们的研究结果为了解板内地震背后的机制以及大陆碰撞带内的构造演化提供了有价值的见解。这些地震背后的控制因素非常复杂且不确定。本研究旨在探讨板内地震活动背景下中国东南部地壳结构和各向异性的作用。该地区目前正在经历菲律宾板块和南海边缘板块之间的碰撞,其构造历史具有多相性,包括古太平洋俯冲的遗迹。通过利用接收函数方法,我们详细描述了中国东南部两个地震多发地区--广东和福建的地壳结构和层状各向异性。我们的研究结果表明,地壳各向异性可分层为两层:中上层地壳和下层地壳,分别具有与造山带垂直的慢轴和快轴。地壳结构的横向异质性和各向异性突出了大陆块之间的边界和差异运动。跨越这一边界的板块内地震密度和强度的增强,为地壳变形与地震之间的脱钩联系提供了证据。具体而言,我们的观测结果表明:(1) 中生代大陆碰撞诱发了中上地壳的变质褶皱;(2) 韧性剪切是下地壳的特征;(3) 持续的碰撞导致了大陆块之间的错配演化,为地震的发生创造了有利的应力条件。
{"title":"Crustal structures and anisotropy in southeastern China: Continental collision and intraplate earthquakes","authors":"H.B. Huang ,&nbsp;K.Y. Wan ,&nbsp;E.Y. He ,&nbsp;H. Jiang ,&nbsp;J. Guo ,&nbsp;X.L. Qiu","doi":"10.1016/j.gr.2024.09.011","DOIUrl":"10.1016/j.gr.2024.09.011","url":null,"abstract":"&lt;div&gt;&lt;div&gt;This study investigates the role of crustal structures and anisotropy in southeastern China regarding intraplate earthquakes within the context of concentrated and perturbed tectonic stresses. The region is characterized by a complex multiphase tectonic history,including the ongoing collision between the Philippine Plate and the South China Sea margin. Utilizing the teleseismic receiver function method, we offer a comprehensive depiction of the crustal structures and layered anisotropy in Guangdong and Fujian, two earthquake-prone areas. Our results reveal that the crustal anisotropy is stratified into two layers, with a slow axis perpendicular to the orogenic belt in the upper-middle crust, whereas the fast axis aligns perpendicularly at lower crust levels. The lateral heterogeneity and anisotropy of the crustal structure emphasize both the boundary delineation and differential movement between continental blocks. The observed increase in density and intensity of intraplate earthquakes across this boundary supports our conclusion regarding a connection between decoupled crustal deformation and seismicity. Specifically, the foliation of metamorphic rocks during the Mesozoic collision generated orogen-parallel fabrics in the upper-middle crust, while ductile shearing resulted in orogen-perpendicular fast directions at lower crust levels. In contrast, mismatch evolution between continental blocks reactivated by present collision provides stress conditions conducive to earthquake occurrence in southeastern China. Our findings provide valuable insights into mechanisms behind intraplate earthquakes as well as tectonic evolution within continental collision zones.&lt;/div&gt;&lt;div&gt;Plain Language Summary&lt;/div&gt;&lt;div&gt;The mechanism of intraplate earthquakes is a topic of great interest in the study of continental collision and regional tectonic evolution. The controlling factors behind these earthquakes are highly complex and uncertain. In this study, we aim to investigate the role of crustal structures and anisotropy in southeastern China within the context of intraplate seismic activity. This region, which is currently experiencing a collision between the Philippine Plate and the South China Sea Margin, has a multiphase tectonic history that includes remnants of paleo-Pacific subduction. By utilizing the receiver function method, we provide a detailed picture of crustal structures and layered anisotropy in Guangdong and Fujian, two earthquake-prone regions in southeastern China. Our findings reveal that anisotropy in the crust can be stratified into two layers: an upper-middle crust and a lower crust with a slow axis and a fast axis, both perpendicular to the orogeny, respectively. The lateral heterogeneity and anisotropy of the crustal structure highlight the boundary and differential movement between the continental blocks. The enhanced density and intensity of the intraplate earthquakes across this boundary provide evidence for a connection between ","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"137 ","pages":"Pages 1-12"},"PeriodicalIF":7.2,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142424197","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}
引用次数: 0
期刊
Gondwana Research
全部 Acc. Chem. Res. ACS Applied Bio Materials ACS Appl. Electron. Mater. ACS Appl. Energy Mater. ACS Appl. Mater. Interfaces ACS Appl. Nano Mater. ACS Appl. Polym. Mater. ACS BIOMATER-SCI ENG ACS Catal. ACS Cent. Sci. ACS Chem. Biol. ACS Chemical Health & Safety ACS Chem. Neurosci. ACS Comb. Sci. ACS Earth Space Chem. ACS Energy Lett. ACS Infect. Dis. ACS Macro Lett. ACS Mater. Lett. ACS Med. Chem. Lett. ACS Nano ACS Omega ACS Photonics ACS Sens. ACS Sustainable Chem. Eng. ACS Synth. Biol. Anal. Chem. BIOCHEMISTRY-US Bioconjugate Chem. BIOMACROMOLECULES Chem. Res. Toxicol. Chem. Rev. Chem. Mater. CRYST GROWTH DES ENERG FUEL Environ. Sci. Technol. Environ. Sci. Technol. Lett. Eur. J. Inorg. Chem. IND ENG CHEM RES Inorg. Chem. J. Agric. Food. Chem. J. Chem. Eng. Data J. Chem. Educ. J. Chem. Inf. Model. J. Chem. Theory Comput. J. Med. Chem. J. Nat. Prod. J PROTEOME RES J. Am. Chem. Soc. LANGMUIR MACROMOLECULES Mol. Pharmaceutics Nano Lett. Org. Lett. ORG PROCESS RES DEV ORGANOMETALLICS J. Org. Chem. J. Phys. Chem. J. Phys. Chem. A J. Phys. Chem. B J. Phys. Chem. C J. Phys. Chem. Lett. Analyst Anal. Methods Biomater. Sci. Catal. Sci. Technol. Chem. Commun. Chem. Soc. Rev. CHEM EDUC RES PRACT CRYSTENGCOMM Dalton Trans. Energy Environ. Sci. ENVIRON SCI-NANO ENVIRON SCI-PROC IMP ENVIRON SCI-WAT RES Faraday Discuss. Food Funct. Green Chem. Inorg. Chem. Front. Integr. Biol. J. Anal. At. Spectrom. J. Mater. Chem. A J. Mater. Chem. B J. Mater. Chem. C Lab Chip Mater. Chem. Front. Mater. Horiz. MEDCHEMCOMM Metallomics Mol. Biosyst. Mol. Syst. Des. Eng. Nanoscale Nanoscale Horiz. Nat. Prod. Rep. New J. Chem. Org. Biomol. Chem. Org. Chem. Front. PHOTOCH PHOTOBIO SCI PCCP Polym. Chem.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
0
微信
客服QQ
Book学术公众号 扫码关注我们
反馈
×
意见反馈
请填写您的意见或建议
请填写您的手机或邮箱
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
现在去查看 取消
×
提示
确定
Book学术官方微信
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术
文献互助 智能选刊 最新文献 互助须知 联系我们:info@booksci.cn
Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。
Copyright © 2023 Book学术 All rights reserved.
ghs 京公网安备 11010802042870号 京ICP备2023020795号-1