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Slab rollback and microcontinent subduction in the evolution of the Zambales Ophiolite Complex(Philippines):A review 被引量:2
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作者 Graciano P.Yumul Jr. Carla B.Dimalanta +11 位作者 Ricky C.Salapare Karlo L.Queano Decibel V.Faustino-Eslava Edanjarlo J.Marquez Noelynna T.Ramos Betchaida D.Payot Juan Miguel R.Guotana Jillian Aira S.Gabo-Ratio Leo T.Armada Jenielyn T.Padrones Keisuke Ishida Shigeyuki Suzuki 《Geoscience Frontiers》 SCIE CAS CSCD 2020年第1期23-36,共14页
New radiolarian ages show that the island arc-related Acoje block of the Zambales Ophiolite Complex is possibly of Late Jurassic to Early Cretaceous age.Radiometric dating of its plutonic and volcanichypabyssal rocks ... New radiolarian ages show that the island arc-related Acoje block of the Zambales Ophiolite Complex is possibly of Late Jurassic to Early Cretaceous age.Radiometric dating of its plutonic and volcanichypabyssal rocks yielded middle Eocene ages.On the other hand,the paleontological dating of the sedimentary carapace of the transitional mid-ocean ridge-island arc affiliated Coto block of the ophiolite complex,together with isotopic age datings of its dikes and mafic cumulate rocks,also yielded Eocene ages.This offers the possibility that the Zambales Ophiolite Complex could have:(1)evolved from a Mesozoic arc(Acoje block)that split to form a Cenozoic back-arc basin(Coto block),(2)through faulting,structurally juxtaposed a Mesozoic oceanic crust with a younger Cenozoic lithospheric fragment or(3)through the interplay of slab rollback,slab break-off and,at a later time,collision with a microcontinent fragment,caused the formation of an island arc-related ophiolite block(Acoje)that migrated trench-ward resulting into the generation of a back-arc basin(Coto block)with a limited subduction signature.This Meso-Cenozoic ophiolite complex is compared with the other oceanic lithosphere fragments along the western seaboard of the Philippines in the context of their evolution in terms of their recognized environments of generation. 展开更多
关键词 OPHIOLITE slab rollback RADIOLARIANS SUBDUCTION Zambales Philippines
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Petrogenesis and Geodynamic Implications of Early Cretaceous(~130 Ma)Magmatism in the Baingoin Batholith,Central Tibet:Products of Subducting Slab Rollback
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作者 LI Faqiao TANG Juxing +7 位作者 WANG Nan LIU Zhibo SONG Yang ZHANG Jing MA Xudong FU Bin LI Haifeng HAN Songhao 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2022年第6期1960-1978,共19页
The Baingoin batholith is one of the largest granitic plutons in the North Lhasa terrane.Its petrogenesis and tectonic setting have been studied for decades,but remain controversial.Here we report data on geochronolog... The Baingoin batholith is one of the largest granitic plutons in the North Lhasa terrane.Its petrogenesis and tectonic setting have been studied for decades,but remain controversial.Here we report data on geochronology,geochemistry and isotopes of Early Cretaceous granitoids within the Baingoin batholith,which provide more evidence to uncover its petrogenesis and regional geodynamic processes.The Early Cretaceous magmatism yields ages of 134.4–132.0 Ma and can be divided into I-type,S-type and highly fractionated granites.The I-and S-type granites exhibit medium SiO2,high K_(2)O/Na_(2)O with negativeεNd(t)andεHf(t)values,whereas,the albite granites have very high SiO_(2)(79.04%–80.40%),very low K_(2)O/N_(2)O,negativeεNd(t)and a large variation inεHf(t).Our new data indicate that these granitoids are derived from unbalanced melting in a heterogeneous source area.The granodiorites involved had a hybrid origin from partial melting of basalt-derived and Al-rich rocks in the crust,the porphyritic monzogranites being derived from partial melting of pelitic rocks.The albite granites crystallized from residual melt separated from K-rich magma within the‘mush’process and underwent fractionation of K-feldspar.We believe that the Early Cretaceous magmatism formed in an extensional setting produced by the initial and continuous rollback of a northward-subducting slab of the NTO. 展开更多
关键词 petraluminous granites highly fractionated granites Baingoin batholith subducting slab rollback TIBET
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Partitioning Anatolian Kinematics into Tectonic Escape and Slab Rollback Dominated Domains
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作者 Jiannan Meng Timothy M.Kusky +2 位作者 Erdin Bozkurt Hao Deng Ozan Sinoplu 《Journal of Earth Science》 SCIE CAS CSCD 2024年第3期758-768,共11页
Anatolia is the global archetype of tectonic escape,as witnessed by the devastating 2023 Kahramanmaraş Earthquake sequence,and the 2020 Samos Earthquake,which show different kinematics related to the framework of the ... Anatolia is the global archetype of tectonic escape,as witnessed by the devastating 2023 Kahramanmaraş Earthquake sequence,and the 2020 Samos Earthquake,which show different kinematics related to the framework of the escape tectonics.Global Positioning System(GPS)motions of the wedge-shaped plate differ regionally from northwestwards to southwestwards(from east to west).Anatolia was extruded westward from the Arabian-Eurasian collision along the North and East Anatolian fault systems,rotating counterclockwise into the oceanic free-faces of the Mediterranean and Aegean,with dramatic extension of western Anatolia in traditional interpretations.However,which is the dominant mechanism for this change in kinematics,extrusion related to the Arabia/Eurasia collision or rollback of the African slab beneath western Anatolia is still unclear.To assess the dominant driving mechanisms across Anatolia,we analyze recent GPS velocity datasets,and decomposed them into N-S and E-W components,revealing that westward motion is essentially constant across the whole plate and consistent with the slip rates of the North and East Anatolia fault zones,while southward components increase dramatically in the transition area between central and western Anatolia,where a slab tear is suggested.This phenomenon is related to different tectonic driving mechanisms.The ArabiaEurasia collision drives the Anatolian Plate uniformly westwards while western Anatolia is progressively more affected by the southward retreating African subducting slab west of the Aegean/Cypriot slab tear,which significantly increases the southward component of the velocity field and causes the apparent curve of the whole modern velocity field.The 2020 and 2023 earthquake focal mechanisms also confirm that the northward colliding Arabian Plate forced Anatolia to the west,and the retreating African slab is pulling the upper plate of western Anatolian apart in extension.We propose that the Anatolian Plate is moving westwards as one plate with an additional component of extension in its west caused by the local driving mechanism,slab rollback(with the boundary above the slab tear around Isparta),rather than separate microplates or a near-pole spin of the entire Anatolian Plate,and the collisionrelated extrusion is the dominant mechanism of tectonic escape. 展开更多
关键词 TECTONICS NEOTECTONICS tectonic escape slab rollback Anatolian Plate GPS velocity field geodynamics.
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祁连拉脊山中段中奥陶世石英二长斑岩成因及其动力学意义
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作者 陶璐 余庆 +4 位作者 张柳 孙达 肖行才 闫芳 朱柳琴 《资源环境与工程》 2024年第5期473-485,共13页
花岗岩类广泛分布于地球地壳中,主要为壳源物质岩浆作用的产物,其地球化学组成、岩石组合特征及时空分布规律等信息记录了源区性质、岩浆演化过程及岩浆形成的动力学机制。以祁连拉脊山中段克前垭口石英二长斑岩为研究对象,通过对其开... 花岗岩类广泛分布于地球地壳中,主要为壳源物质岩浆作用的产物,其地球化学组成、岩石组合特征及时空分布规律等信息记录了源区性质、岩浆演化过程及岩浆形成的动力学机制。以祁连拉脊山中段克前垭口石英二长斑岩为研究对象,通过对其开展岩相学、锆石U-Pb年代学、全岩地球化学及Sr-Nd同位素研究,并结合区域内已有的同时期岩浆作用的研究,探讨石英二长斑岩的岩石成因及其形成的深部动力学背景。研究结果显示,石英二长斑岩的年龄为(466±5)Ma。在地球化学组成上,其具有相对较高的SiO 2(63.57%~64.04%)和Na_(2)O(7.08%~7.36%)以及相对较低的CaO(1.19%~2.52%)和K_(2)O(1.53%~1.96%)含量;在微量元素蛛网图上,其表现为富集Ba、U及Pb,亏损Zr、Hf及Sr;此外,其具有轻微的Eu负异常(Eu*=0.80~0.91)以及较为明显轻重稀土元素分异((La/Yb)N=13.0~15.7);其Sr、Nd同位素组成较为均一,初始Sr同位素和εNd(t)分别介于0.7054~0.7062和0.87~1.03。综合研究表明,克前垭口石英二长斑岩形成于加厚新生玄武质地壳物质的部分熔融;其与研究区同时期岩浆岩具有向缝合带逐渐变年轻的趋势,指示了俯冲板片回转的深部动力学过程;拉脊山构造带内470~460 Ma的花岗岩类的(La/Yb)N值整体具有持续降低的趋势,记录了由板片回转引发的岩石圈持续拉张过程。 展开更多
关键词 花岗岩类 岩石成因 板片回转 祁连造山带
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冈底斯带南部桑日高分异I型花岗岩的岩石成因及其动力学意义 被引量:30
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作者 王珍珍 刘栋 +3 位作者 赵志丹 闫晶晶 石卿尚 莫宣学 《岩石学报》 SCIE EI CAS CSCD 北大核心 2017年第8期2479-2493,共15页
冈底斯岩浆岩带位于西藏南部的拉萨地体南缘,它形成于特提斯洋和印度-亚洲大陆长期俯冲碰撞过程中,是青藏高原花岗岩最发育的地区。前人对冈底斯岩浆带中各类型花岗岩的成因、源区、时空分布以及其地球动力学意义进行了详细大量的研究,... 冈底斯岩浆岩带位于西藏南部的拉萨地体南缘,它形成于特提斯洋和印度-亚洲大陆长期俯冲碰撞过程中,是青藏高原花岗岩最发育的地区。前人对冈底斯岩浆带中各类型花岗岩的成因、源区、时空分布以及其地球动力学意义进行了详细大量的研究,但是对高分异花岗岩的具体成因、演化过程以及在70~65Ma拉萨地块的地球动力学演化过程研究较少。本文选择冈底斯南缘白垩纪末桑日花岗岩进行研究,揭示了桑日花岗岩的岩石学特征、锆石U-Pb年龄、锆石Hf同位素特征和地球化学特征。本文样品LA-ICP-MS测得的锆石U-Pb年龄为67~66Ma。桑日花岗岩属于高钾钙碱性系列,具有高Si O2(74.26%~76.93%)、高K2O+Na2O(7.87%~8.56%),低P2O5(0.02%~0.04%)和Ca O(0.28%~1.00%),以及富集K、Rb、Th,亏损Nb、P、Ti的高分异I型花岗岩的特征。在锆石Hf同位素上,桑日花岗岩εHf(t)>0(+4.6^+10.9),且具有Hf不均一的特征。结合前人研究,本文认为桑日花岗岩是高分异I型花岗岩,在特提斯洋板块北向俯冲过程中,板片回转,俯冲洋壳脱水产生的流体进入地幔楔,引发地幔楔发生部分熔融产生镁铁质幔源物质并底侵上涌,导致浅部地壳发生部分熔融,并与幔源岩浆混合,从而在浅部形成混源岩浆房,最终在侵位与成岩后期经历高程度的分异演化形成的。 展开更多
关键词 冈底斯 桑日花岗岩 高分异I型花岗岩 板片回转
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中国东南部晚中生代A型花岗岩类与古太平洋板块俯冲-后撤 被引量:12
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作者 夏炎 刘磊 徐夕生 《矿物岩石地球化学通报》 CAS CSCD 北大核心 2016年第6期1109-1119,1070-1071,共11页
本文综述了中国东南部晚中生代A型花岗岩类的分布和成因的研究进展。按其形成时代和空间分布,将该区的A型花岗岩类分为4个带,即赣南-闽西南带、湘桂粤带、赣杭带和沿海带,并进行了年代学、地球化学和岩石组合的对比分析。在此基础上,讨... 本文综述了中国东南部晚中生代A型花岗岩类的分布和成因的研究进展。按其形成时代和空间分布,将该区的A型花岗岩类分为4个带,即赣南-闽西南带、湘桂粤带、赣杭带和沿海带,并进行了年代学、地球化学和岩石组合的对比分析。在此基础上,讨论了4个分带的形成与古太平洋板块向中国东南大陆俯冲和后撤的过程。 展开更多
关键词 中国东南部 晚中生代 A型花岗岩类 古太平洋板块俯冲 俯冲板片后撤
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华南陆块东部晚中生代岩浆作用的深部动力学过程 被引量:4
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作者 郭锋 赵亮 +3 位作者 张晓兵 吴扬名 张博 张峰 《大地构造与成矿学》 EI CAS CSCD 北大核心 2022年第3期416-434,共19页
本文总结和回顾了过去几年来本研究团队在华南陆块东部(主要是东南沿海地区)开展的火成岩岩石地球化学研究进展,并重点探讨了晚中生代(白垩纪)岩浆作用的深部动力学过程,取得了以下主要认识:①华南晚中生代镁铁质岩浆作用记录了古太平... 本文总结和回顾了过去几年来本研究团队在华南陆块东部(主要是东南沿海地区)开展的火成岩岩石地球化学研究进展,并重点探讨了晚中生代(白垩纪)岩浆作用的深部动力学过程,取得了以下主要认识:①华南晚中生代镁铁质岩浆作用记录了古太平洋板块从俯冲到后撤‒撕裂的深部动力学过程,其地幔源区的富集组分从进俯冲时期的板片上覆沉积物逐渐过渡到后撤‒撕裂阶段的下部镁铁质洋壳;②长英质火山岩的地壳源区从俯冲阶段的低温(700~810℃)含水下地壳转变为后撤‒撕裂阶段的高温(790~860℃)贫水陆壳;③东南沿海地区晚中生代经历了强烈的弧地壳增生和置换作用,形成了具有“等同位素效应”的双峰式侵入杂岩体。我们提出的板片俯冲‒后撤‒撕裂模式同样适用于解释华南陆块东部早中生代构造‒岩浆演化的深部的动力学机制。 展开更多
关键词 板片俯冲‒后撤‒撕裂作用 地壳演化 古太平洋 晚中生代岩浆作用 华南陆块
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Petrogenesis of Early Carboniferous Alkaline Basalt from the Wusun Mountain:Implications for Tectonic Evolution of the Western Yining Block,NW China 被引量:3
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作者 WANG Zuopeng LV Yan +4 位作者 LI Hai LI Yongjun ZHOU Yanlong LI Ganyu YANG Gaoxue 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2021年第4期1128-1138,共11页
Late Paleozoic volcanic rocks are well exposed in the Yining Block,NW China,and are predominately composed of andesites,rhyolites and volcaniclastics as well as minor basalts.Study of the petrology,whole-rock geochemi... Late Paleozoic volcanic rocks are well exposed in the Yining Block,NW China,and are predominately composed of andesites,rhyolites and volcaniclastics as well as minor basalts.Study of the petrology,whole-rock geochemistry and zircon U-Pb dating for the Early Carboniferous alkaline basalts from Wusun Mountain,western Yining Block,constrains their petrogenesis and tectonic evolution.The alkaline basalts consist mainly of plagioclases,mostly albite and labradorite,as well as clinopyroxenes and olivines;zircon U-Pb dating indicates their formation at ca.350 Ma.Geochemically,the basaltic samples have low SiO_(2)contents,and high TiO_(2),Al_(2)O_(3)and alkaline contents,coupled with high Na_(2)O/K_(2)O ratios,displaying an alkaline basalt affinity.They show remarkable LILE enrichment and HFSE depletion.Meantime,these samples have relatively high TFe_(2)O_(3),MgO,and Mg#values as well as Ni and Cr,relatively high Sm/Yb and U/Th,suggesting origination from a mantle source metasomatized by slab fluids.They formed in a transitional tectonic setting from arc to intraplate,showing a typical affinity of back-arc basin basalts.The alkaline basalts were likely generated in a nascent back-arc extension setting resulting from slab rollback of the southern Tianshan oceanic lithosphere.A bidirectional subduction model seems more reasonable for the evolution of the southern Tianshan Ocean.These new data will provide a new tectonic model for Late Paleozoic tectonic evolution of the western Yining Block. 展开更多
关键词 PETROLOGY geochemistry isotopic dating alkaline basalt slab rollback Yining Block CAOB
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Petrogenesis and Tectonic Implications of the Latest Cretaceous Intrusive Rocks from the Eastern Gangdese Belt,Southeast Tibet 被引量:1
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作者 CHEN Yanfei CHEN Xuanhua +5 位作者 ZHANG Zeming SHAO Zhaogang TIAN Zuolin DONG Xin QIN Shengkai YUAN Yuelei 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2022年第3期891-903,共13页
The latest Cretaceous magmatic activity in the eastern segment of the Lhasa terrane provides important insights for tracking the magma source and geodynamic setting of the eastern Gangdese batholith,eastward of easter... The latest Cretaceous magmatic activity in the eastern segment of the Lhasa terrane provides important insights for tracking the magma source and geodynamic setting of the eastern Gangdese batholith,eastward of eastern Himalayan Syntaxis.Detailed petrological,geochemical and geochronological studies of the intrusive rocks(monzodiorites and granodiorites)of the eastern Gangdese batholith are presented with monzodiorites and granodiorites giving zircon U-Pb crystallization dates of 70-66 Ma and 71-66 Ma withεHf(t)values of−4.8 to+6.2 and−1.9 to+5.3,respectively.These rocks are metaluminous to weakly peraluminous I-type granites showing geochemically arc-related features of enrichment in LREEs and some LILEs,e.g.,Rb,Th,and U,and depletion in HREEs and some HFSEs,e.g.,Nb,Ta,and Ti.The rocks are interpreted to be derived from partial melting of mantle material and juvenile crust,respectively,which are proposed to be triggered by Neo-Tethyan slab rollback during northward subduction,with both experiencing ancient crustal contamination.The studied intrusive rocks formed in a transitional geodynamic setting caused by Neo-Tethyan oceanic flat subduction to slab rollback beneath the eastern Gangdese belt during the latest Cretaceous. 展开更多
关键词 Neo-Tethyan ocean slab rollback regional tectonics eastern Gangdese batholith Tibet
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Neotethyan Ophiolites and Their Geodynamic Evolution During the Mesozoic: A Global Overview
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作者 Yildirim DILEK 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2020年第S01期76-77,共2页
Neotethyan ophiolites evolved in multiple seaways separated by Gondwana–derived ribbon continents within an eastward widening, latitudinal oceanic realm(Neotethys) throughout the Mesozoic. Opening and closure of thes... Neotethyan ophiolites evolved in multiple seaways separated by Gondwana–derived ribbon continents within an eastward widening, latitudinal oceanic realm(Neotethys) throughout the Mesozoic. Opening and closure of these seaways were diachronous events, resulting in E–W variations in the timing of oceanic crust production and ophiolite emplacement. The Neotethyan ophiolites are highly diverse in their crustal–mantle structures and compositions, isotopic fingerprints, and sedimentary cover types, pointing to major differences in their mantle melt sources and tectonic and paleogeographic settings of magmatic construction(Dilek and Furnes, 2019). The Jurassic Western Alpine and Ligurian ophiolites in Europe and their counterparts in southern and northern Iberia formed in a narrow basin(Western Tethys) that developed between Europe and North Africa–Adria–Iberia. Their peridotites represent exhumed, continental lithospheric mantle, and the ophiolites display a Hess–type oceanic crustal architecture with MORB geochemical signatures(Dilek and Furnes, 2011). All these ophiolites were incorporated into continental margins from the downgoing oceanic lithosphere of the Western Tethys. Triassic, Jurassic and Cretaceous ophiolites east of Adria formed in different Neotethyan seaways(Dilek et al., 1990), and their rift–drift, seafloor spreading and suprasubduction zone(SSZ) magmatic construction involved multiple episodes of melting, depletion and refertilization of previously or actively subduction metasomatized mantle sources. Deep mantle recycling processes through subduction zone tectonics and/or plume activities played a major role in their melt evolution, and in the incorporation of mantle transition zone(MTZ) materials into their peridotites(Fig. 1;Dilek and Yang, 2018;Xiong et al., 2019). Tectonic mélanges structurally beneath these ophiolites include Permo–Triassic, OIB–type extrusive rocks, indicating that the initial dismantling of the Pangea supercontinent that led to the opening of the Triassic and Jurassic ocean basins within the Neotethyan realm was associated with plume magmatism(Dilek, 2003 a;Yang and Dilek, 2015). This plume signature is absent in the Permo–Triassic magmatic record of the Western Tethys to the west. The Cretaceous ophiolites around the Arabia(Dilek et al., 1990;Dilek and Delaloye, 1992;Dilek and Eddy,1992) and India sub-continents(Fareeduddin and Dilek, 2015) occur discontinuously along a ~9000-km-long belt from SW Anatolia to SE Tibet and Indo-China. The majority of these ophiolites have a Penrose–type oceanic crustal architecture(Dilek, 2003 b) and display SSZ geochemical affinities, complete with a MORB–IAT–BON progression of their chemo-stratigraphy(Fig. 1;Dilek and Thy, 1998;Dilek et al., 1999;Dilek and Furnes, 2014;Saccani et al., 2018). They evolved above a N–dipping, Trans–Tethyan subduction–accretion system that was situated in sub-tropical latitudes within the Neotethyan realm. The Trans–Tethyan subduction–accretion system was segmented into two major domains(Western and Eastern domains) by the NNE–SSW–oriented, sinistral Chaman–Omach–Nal transform fault plate boundary. This Cretaceous intraoceanic arc–trench system was analogous to the modern Izu–Bonin–Mariana(IBM) and Tonga arc–trench systems in the western Pacific in terms of its size. Diachronous collisions of the Arabia and India sub-continents with this segmented Trans-Tethyan arc–trench system resulted in the southward emplacement of the SSZ Neotethyan ophiolites onto their passive margins in the latest Mesozoic(Dilek and Furnes, 2019). A separate N–dipping subduction system, dipping beneath Eurasia to the north during much of the Jurassic and Cretaceous, was consuming the Neotethyan oceanic lithosphere and was responsible for the construction of a composite magmatic arc belt extending discontinuously from Southern Tibet to Northern Iran. Slab rollback along this northern subduction system produced locally developed forearc–backarc oceanic lithosphere that was subsequently collapsed into the southern margin of Eurasia. The existence of these two contemporaneous, Ndipping subduction systems within Neotethys led to its rapid contraction and the fast convergence of India towards Eurasia during the late Mesozoic–early Cenozoic(Dilek and Furnes, 2019). It was the collision with Eurasia of the India sub-continent with the accreted ophiolites around its periphery in the Late Paleogene that produced the Himalayan orogeny. 展开更多
关键词 Neotethyan ophiolites MORB ophiolites suprasubduction zone(SSZ)ophiolites trans–Tethyan subduction–accretion system slab rollback and forearc extension
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西昆仑造山带晚奥陶世侵入岩的岩石成因:对原特提斯洋俯冲过程的制约 被引量:3
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作者 陶再礼 尹继元 +5 位作者 袁超 肖文交 陈文 陈岳龙 王雅美 杨帆 《岩石学报》 SCIE EI CAS CSCD 北大核心 2022年第11期3321-3340,共20页
西昆仑造山带发育有大量的早古生代岩浆岩,它们的形成与原特提斯洋俯冲-碰撞密切相关,然而,对于这些岩浆岩的岩石成因和形成的构造背景仍然存在较大的争议。本文对西昆仑造山带早古生代阿喀孜二长岩和赛图拉石英闪长岩岩体开展了详细的... 西昆仑造山带发育有大量的早古生代岩浆岩,它们的形成与原特提斯洋俯冲-碰撞密切相关,然而,对于这些岩浆岩的岩石成因和形成的构造背景仍然存在较大的争议。本文对西昆仑造山带早古生代阿喀孜二长岩和赛图拉石英闪长岩岩体开展了详细的矿物学、锆石U-Pb年代学、全岩地球化学和Sr-Nd-Hf-O同位素研究,以探讨这些侵入岩的岩浆源区与成因,揭示原特提斯洋在这一时期的构造演化过程。这两个岩体的LA-ICP-MS锆石U-Pb年龄分别为456±2Ma和452±2Ma,指示它们形成于晚奥陶世。阿喀孜二长岩具有富碱(K_(2)O+Na_(2)O=10.5%~11.8%)、富钾(K_(2)O/Na_(2)O=1.20~1.44)特征,相对低MgO(0.89%~0.97%)、TiO_(2)(0.42%~0.45%)含量,富集Rb、Th、U等大离子亲石元素,且具有较高的全岩锆饱和温度(T_(Zr)=814~862℃),属于钾质碱性岩石。该岩体具有较高的(^(87)Sr/^(86)Sr)_(i)值(0.72057~0.72186),负的全岩ε_(Nd)(t)值(-5.1~-4.5)和负的锆石ε_(Hf)(t)值(-7.6~-3.4),以及较高的锆石δ^(18) O值(5.39‰~7.94‰),表明其源区可能为伸展环境下古老基性下地壳部分熔融。赛图拉石英闪长岩SiO_(2)含量为56.8%~58.6%,全碱(Na_(2)O+K_(2)O)含量为5.75%~6.39%,具有较低的铝饱和指数(A/CNK=0.85~0.89),相对高的MgO含量(2.93%~3.41%)以及Mg^(#)值(~45),为高钾钙碱性系列岩石。它们富集大离子亲石元素(Rb、Ba、Th)和亏损高场强元素(Nb、Ta、Ti),且具有微弱的Eu异常(δEu=0.72~0.77),类似于俯冲带岩浆岩地球化学特征。这些石英闪长岩具有相对高的(^(87)Sr/^(86)Sr)_(i)比值(0.71317~0.71322),负的全岩ε_(Nd)(t)值(-5.6~-5.1)和负的锆石ε_(Hf)(t)值(-7.8~-2.9),与同时期来源于富集地幔的基性岩同位素特征相似,表明赛图拉石英闪长岩岩浆可能是由俯冲板片流体交代的富集地幔楔部分熔融形成,并在岩浆演化的过程中经历了橄榄石、辉石、角闪石、磷灰石和Fe-Ti氧化物等矿物的分离结晶作用。结合同位素和数字模拟计算(Rhyolite-MELTS)结果表明,赛图拉石英闪长岩可能由塔里木克拉通南缘玄武质岩浆的分离结晶而成。综合前人研究,本文提出晚奥陶世阿喀孜二长岩和赛图拉石英闪长岩形成于原特提斯洋向北俯冲相关的活动大陆边缘环境,该时期原特提斯洋板片回撤,诱发软流圈地幔的上涌,从而产生了大量的弧岩浆岩。 展开更多
关键词 西昆仑造山带 原特提斯洋 奥陶纪 富集地幔楔 板片回撤
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钨的地球化学性质与华南地区钨矿成因 被引量:17
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作者 祝红丽 张丽鹏 +1 位作者 杜龙 隋清霖 《岩石学报》 SCIE EI CAS CSCD 北大核心 2020年第1期13-22,共10页
在地球演化早期的强还原条件下,钨表现为中等亲铁元素,因此地球中>90%的钨进入地核。在地幔和地壳的演化过程中,钨是极度不相容亲石元素,从而导致钨元素在地壳中的丰度约是地幔丰度的250倍。钨在岩浆熔体中主要以钨酸的形式迁移,在... 在地球演化早期的强还原条件下,钨表现为中等亲铁元素,因此地球中>90%的钨进入地核。在地幔和地壳的演化过程中,钨是极度不相容亲石元素,从而导致钨元素在地壳中的丰度约是地幔丰度的250倍。钨在岩浆熔体中主要以钨酸的形式迁移,在成矿热液中主要以氟、硼化合物或其络合物的形式运移。钨的矿化需要其在部分熔融、岩浆演化和晚期热液等各阶段逐渐富集。中国是世界上钨矿产资源最丰富的国家,约占世界总储量的60%以上,其中绝大多数矿床产在华南地区,与华南大规模的中生代岩浆活动具有密切的时空联系。微量元素特征(高Rb/Sr和K/Rb比值,低Nb/Ta和Zr/Hf比值)显示它们往往经历了强烈的岩浆分异,这可能与这些花岗岩通常具有高挥发分含量(如F)有关。岩浆中高的F含量对钨的富集和矿化十分重要,它可以降低熔体固相线、粘度和密度,有利于提高岩浆的结晶分异程度,因而使得高度不相容的钨元素在岩浆演化过程和后期热液阶段的富集与矿化。富挥发分岩浆的形成可能与俯冲板块后撤,软流圈物质上涌导致的多硅白云母等富F矿物的高温分解有关。研究表明,华南南岭地区侏罗纪的钨矿化花岗岩主要形成于太平洋板块的俯冲后撤,而华南南部晚白垩世钨成矿作用与新特提斯洋的俯冲后撤有关。 展开更多
关键词 钨矿 花岗岩 华南地区 岩浆演化 板块后撤
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内蒙古中部苏尼特左旗地区阿巴嘎组火山岩地球化学特征及成因
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作者 张祥信 高永丰 雷世和 《地质通报》 CAS CSCD 北大核心 2019年第4期643-655,共13页
内蒙古中部苏尼特左旗地区阿巴嘎组火山岩主要由安山岩组成。岩石富碱、高钾和铝、低镁。富集大离子亲石元素(LILEs)Rb、Ba、U、K和轻稀土元素(LREE),相对亏损高场强元素(HFSEs),具明显的Nb、Ta和Ti负异常和Pb正异常。稀土元素总量较高... 内蒙古中部苏尼特左旗地区阿巴嘎组火山岩主要由安山岩组成。岩石富碱、高钾和铝、低镁。富集大离子亲石元素(LILEs)Rb、Ba、U、K和轻稀土元素(LREE),相对亏损高场强元素(HFSEs),具明显的Nb、Ta和Ti负异常和Pb正异常。稀土元素总量较高,轻、重稀土元素分馏强烈且属轻稀土元素富集型,具弱负Eu异常。主量、微量元素地球化学特征表明,阿巴嘎组安山岩为钾质火山岩,岩浆上升演化过程中经历了斜长石和铁镁矿物的分离结晶作用,无地壳物质的混染。阿巴嘎组钾质火山岩的形成与新生代太平洋板片俯冲密切相关,其岩浆来源于滞留的俯冲太平洋板片释放流体交代的富集陆下岩石圈地幔,是在板内伸展体制下含金云母石榴子石二辉橄榄岩低程度部分熔融的产物。这种板内伸展体制可能是新生代滞留于地幔过渡带中的太平洋板片俯冲后撤引起的。 展开更多
关键词 阿巴嘎组 钾质火山岩 地球化学 俯冲板片后撤 内蒙古中部
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俯冲板块的动力学性质对平板俯冲的影响:数值模拟
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作者 朱致远 吴本君 《高校地质学报》 CAS CSCD 北大核心 2021年第2期240-248,共9页
平板俯冲是地球上一种独特的俯冲模式,主要发生在南美洲地区,与该地区的地震、火山等构造地质现象有着密切联系。平板俯冲的形成机制和影响因素仍然需要进一步地研究。文章通过数值模拟的方法,研究了俯冲板块的动力学性质对于平俯冲板... 平板俯冲是地球上一种独特的俯冲模式,主要发生在南美洲地区,与该地区的地震、火山等构造地质现象有着密切联系。平板俯冲的形成机制和影响因素仍然需要进一步地研究。文章通过数值模拟的方法,研究了俯冲板块的动力学性质对于平俯冲板片形态的影响。模拟实验结果表明,俯冲板块的厚度和密度差(与地幔)对平板俯冲的形成有着决定性的影响。合适的俯冲板块厚度(70 km左右)有利于在俯冲过程中形成平板片。厚度较大的板片难以发生弯曲,阻碍了平板片的形成。俯冲板块与地幔的密度差越小,越容易形成平板俯冲,平板片的长度也越长。俯冲板片的密度差太大也不利于形成平板片。此外,高粘度的俯冲板块容易形成平板俯冲,俯冲板块的粘度与形成的平板片的长度也成正比。研究还发现,平板俯冲的形成伴随着海沟后撤速率的减小。参考模型重现了智利中部平板俯冲的形态,为研究该地区的平板俯冲机制提供了新认识。 展开更多
关键词 平板俯冲 俯冲板块 海沟后撤 数值模拟
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Origin of high heat flow in the back-arc basins of Sumatra:An opportunity for geothermal energy development
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作者 Luhut Pardamean Siringoringo Benyamin Sapiie +1 位作者 Alfend Rudyawan I Gusti Bagus Eddy Sucipta 《Energy Geoscience》 EI 2024年第3期135-150,共16页
Volcanic arcs such as the Barisan Mountains have been identified as attractive areas for the utilization of geothermal energy,as exemplified by Ulubelu in Lampung and Sarulla in North Sumatra.However,environmental fac... Volcanic arcs such as the Barisan Mountains have been identified as attractive areas for the utilization of geothermal energy,as exemplified by Ulubelu in Lampung and Sarulla in North Sumatra.However,environmental factors in the Barisan Mountains remain a primary obstacle to the exploration and exploitation of geothermal energy.The back-arc basins of Sumatra exhibit the highest heat flow worldwide;however,the heat source in this area remains a controversial issue.This study aims to investigate the origin of the high heat flow in the back-arc basins of Sumatra(North,Central,and South Sumatra basins)based on geothermal data from 384 oil wells and the current literature for geological evaluation.The findings of this study indicate that the back-arc basins of Sumatra experienced severe extensional deformation during the Tertiary Period through a large pull-apart and slab rollback mechanism.This deformation resulted in the thinning of the continental crust in this region(27-32 km)and the formation of multiple normal faults.Consequently,the presence of magma resulting from mantle upwelling implies a high heat flow in the back-arc basins of Sumatra.This condition ranks the back-arc basins of Sumatra among the highest heat flow regions of the world,with heat flows>100 mW/m^(2).These findings indicate that the back-arc basins of Sumatra have significant opportunities to exploit their geothermal energy potential.This study provides novel insights into the potential of geothermal energy,particularly in the back-arc basins of Sumatra. 展开更多
关键词 Back-arc basin of Sumatra slab rollback Extensional deformation Heat flow Geothermal energy
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Effect of F-Rich Fluids on the A-Type Magmatism and Related Metal Mobilization:New Insights from the Fogang-Nankunshan-Yajishan Igneous Rocks in Southeast China 被引量:7
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作者 Xing Ding Koulin Su +2 位作者 Haibo Yan Jinlong Liang Weidong Sun 《Journal of Earth Science》 SCIE CAS CSCD 2022年第3期591-608,共18页
About 45%of tungsten,~20%of tin,and~9%of fluorite of known world reserves are associated with Late Mesozoic igneous rocks,Southeast(SE)China.Here we demonstrate that Fogang granite,the largest inland batholith,is main... About 45%of tungsten,~20%of tin,and~9%of fluorite of known world reserves are associated with Late Mesozoic igneous rocks,Southeast(SE)China.Here we demonstrate that Fogang granite,the largest inland batholith,is mainly of A2-type that is commonly found in post-orogenic settings and experienced plate subduction induced metasomatism.In contrast,the Yajishan syenite and Nankunshan granite intruding the Fogang granite~20 Ma later are of A1-type formed in intraplate settings.We found that F-rich fluid fractionation,which could make the decline of Ga/Al ratio,total(Nb+Y+Ce+Zr)and Zr concentrations,Nb/Ta and Zr/Hf ratios,leads to chemical variations of a few Fogang granites changing from A2-type to highly fractionated or I-and S-type granitoids.Crystal and Frich fluid fractionations,as well as crustal contamination most likely derived from the Fogang granite,result in some Nankunshan granites developing from A1-type into A2-type.These late-or post-magmatic processes should be taken into account carefully when discriminating the petrogenetic types of igneous rocks,especially for the A2-type suites.Combining with the distribution of 180-140 Ma A1-and A2-type igneous rocks,rare metal deposits,and fluorite deposits in SE China,we highlight the significant role of slab-released F-rich fluids in formation of A-type suites and subsequent chemical differentiation and rare metal and fluorine mineralization.A model of flat-slab northeastward rollback is thus proposed,in which the subduction front reached somewhere near Fogang and then started to roll back at~165 Ma.The inland Jurassic granites of SE China represent a unique locality for formation of A-type suites and their associated mineralization.These granites are not anorogenic,but they are the result of slab rollback from a flat slab,founding of that slab at shallow levels,and metasomatism of by F-rich fluids related to slab heating by the asthenosphere. 展开更多
关键词 A-type granite alkaline F-rich fluids slab rollback rare metal rare earth elements Nb/Ta
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Zircon U-Pb dating and Lu-Hf isotope study of intermediate-mafic sub-volcanic and intrusive rocks in the Lishui Basin in the middle and lower reaches of Yangtze River 被引量:1
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作者 Lijuan Wang Jianping Huang +4 位作者 Jinhai Yu W. L. Griffin Rucheng Wang Shaoqin Zhang Yinghe Yang 《Chinese Science Bulletin》 SCIE EI CAS 2014年第27期3427-3440,共14页
Eight Mesozoic sub-volcanic and intrusive rocks in the Lishui Basin have been selected for zircon U-Pb dating and Lu-Hf isotopic analysis. The Laohutou, Datongshan,Daweizhuang, Yeshanao, Yanwaqiao, Xibeishan, Changsha... Eight Mesozoic sub-volcanic and intrusive rocks in the Lishui Basin have been selected for zircon U-Pb dating and Lu-Hf isotopic analysis. The Laohutou, Datongshan,Daweizhuang, Yeshanao, Yanwaqiao, Xibeishan, Changshantou and Jianshan porphyrites yield concordant early Cretaceous ages of 130.5 ± 1.6 Ma, 136.0 ± 3.4 Ma, 132.7 ±2.7 Ma, 127.0 ± 1.9 Ma, 129.4 ± 1.7 Ma, 133.2 ± 2.1 Ma,131.1 ± 2.3 Ma and 127.4 ± 1.8 Ma, respectively. Zircon eHf(t) values for these rocks range from-3.54 to-9.11, mostly between-3.54 and-5.93, suggesting sources similar to those for coeval igneous rocks in other volcanic basins along the middle and lower reaches of Yangtze River. Considering the geochemical characteristics of coeval magmatic rocks in the middle and lower reaches of Yangtze River and its adjacent areas, this paper proposes a model of slab rollback to explain the Mesozoic magmatism in the east-central part of China continent. In the middle-late Jurassic to early Cretaceous(170–135 Ma), the Pacific plate started to subduct beneath the Eurasian continent, producing a compressive tectonic setting,and magmatism progressed from coast to the inland. The magmas of this period were derived mostly from partial melting of ancient crust. After *135 Ma, the subduction weakened, and the rollback of the subducted Pacific plate produced an extensional environment. This led to the formation of volcanic basins, the partial melting of enriched mantle sources and less ancient crust, and the intrusion of voluminous intermediate-mafic igneous rocks. 展开更多
关键词 锆石U-Pb定年 长江中下游 Hf同位素 火山盆地 次火山岩 侵入岩 丽水 基性
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Geochemical Variations of the Late Paleozoic Granitoids from the Baolidao Arc-Accrection Belt in Southeastern Segment of Central Asia Orogenic Belt:Implications for Tectonic Transition from Early Carboniferous to Early Permian
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作者 Xueni Zhang Qingdong Zeng Fengjun Nie 《Journal of Earth Science》 SCIE CAS CSCD 2022年第3期719-735,共17页
Compositional changes in successively erupted felsic rocks can be used to infer physical changes in lower crustal conditions and to enhance the understanding of the tectonic regime.This study presents geochronological... Compositional changes in successively erupted felsic rocks can be used to infer physical changes in lower crustal conditions and to enhance the understanding of the tectonic regime.This study presents geochronological,geochemical and isotopic data for two I-type granitic plutons in the Sonid Left Banner of the Central Asian Orogenic Belt.Our new data,together with compiled I-type granitoid data,reveal the presence of magma compositional transition at~305 Ma in the Baolidao arc-accretion belt.The early stage granitoids(330-305 Ma)are medium-K calc-alkaline with higher Sr/Y ratios.The late stage granitoids(305-270 Ma)are high-K calc-alkaline with lower Sr/Y ratios.The two-stage granitoids have roughly similar predominately positive Sr-Nd-Hf isotope values,but with a decreasing trend from the early to late stages.Geochemical data indicate that the early stage granitoids were generated by dehydration melting of juvenile mafic crust at amphibole-dominated depths.In contrast,the late stage granitoids were produced by dehydration melting of a mixed lithology containing juvenile K-rich mafic lower crust and supracrustal materials at the plagioclase-stable crustal level.We propose that the compositional transition of these granitoids can be linked with different slab behaviors of the northward subducting Paleo-Asian oceanic plate,and also with the back-arc tectonic settings. 展开更多
关键词 Central Asian Orogenic Belt Baolidao arc belt I-type granitoids compositional transition geochemical data slab steepening and rollback back-arc closure
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