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Zircon LA-ICP-MS U-Pb Age and Island-Arc Origin of the Bayanhua Gabbro in the Hegenshan Suture Zone, Inner Mongolia 被引量:11
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作者 WANG Jinfang LI Yingjie LI Hongyang 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2017年第6期2316-2317,共2页
Objective The Bayanhua Nb-enriched gabbro is newly discovered in the Diyanmiao-Meilaotewula SSZ-type ophiolitic m61ange belt of the Hegenshan suture zone, Inner Mongolia. Nb-enriched arc gabbros are usually believed ... Objective The Bayanhua Nb-enriched gabbro is newly discovered in the Diyanmiao-Meilaotewula SSZ-type ophiolitic m61ange belt of the Hegenshan suture zone, Inner Mongolia. Nb-enriched arc gabbros are usually believed to result from partial melting of the mantle wedge peridotites metasomatized by slab melts derived from the subducting oceanic slab, which represent arc magmatic markers of the oceanic subduction zone. However, whether the Hegenshan ocean basin of the Paleo-Asian Ocean was in its subduction stage in the Early Permian requires further study for a final conclusion, and what is the evolution process of the oceanic subduction and lithospheric mantle of the Hegenshan suture zone remains speculative for the lack of further definitely petrological and chronological evidence and constraints. Therefore, this study carried out zircon LA-ICP-MS U-Pb geochronology and geochemistry on the Bayanhua Nb-enriched gabbro to discuss its origin, in order to provide new evidence for the tectonic evolution of the Hegenshan suture zone of the eastern Central Asian Orogenic Belt. 展开更多
关键词 Zircon LA-ICP-MS U-Pb Age and island-arc Origin of the Bayanhua Gabbro Inner Mongolia
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The Characteristics and Mechanism of Island-Arc Volcanism on the Central and Southern Fildes Peninsula, King George Island, Antarctica
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作者 Li Zhaonai Liu Xiaohan Shang Ruxiang Fei Zhenbi Institute of Geology Chinese Academy of Geological Science.Institute of Geology,Academia Sinica. 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 1992年第1期39-57,共19页
The volcanic rock series on the Fildes Peninsula is the product of the later subduction of the Pacific platebeneath the Antarctic plate. It consists mainly of basalt, basaltic andesite and andesite with minor dacite. ... The volcanic rock series on the Fildes Peninsula is the product of the later subduction of the Pacific platebeneath the Antarctic plate. It consists mainly of basalt, basaltic andesite and andesite with minor dacite. Itsisotopic ages range from 64.6±1 to 43±2 Ma, belonging to Palaeocene to Eocene. Volcanism in the area maybe divided into two phases. The contents of major oxides, rare earth elements (REE) and trace elements in vol-canic rocks formed in different phases show regular changes, which are mainly related to the rock associationsof these phases. Isotope geochemical studies indicate that the primitive magma in the area originating by par-tial melting in the upper mantle underwent fractional crystallization and ascended to the high-level (shallow)magma chamber. Before eruption the primitive basalt-andesitic magma was subjected to differentiation in thehigh-level magma chamber, forming zones of derivative magmas of different compositions. In various phasesmagma-conducting faults experienced periodic extension and cut through various derivative magma zones indifferent parts of the peninsula, leading to the eruption of magmas of different compositions on the surface andthe formation of volcanic rock associations of corresponding compositions. 展开更多
关键词 rock ANTARCTICA The Characteristics and Mechanism of island-arc Volcanism on the Central and Southern Fildes Peninsula Arc
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Huanggang Intrusive Complexin Northern Tongbai Area:Island-Arc Tectonic Environment and Its Geological Significance 被引量:3
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作者 Zhang Li Zhang Hongfei Faculty of Earth Sciences, China University of Geosciences, Wuhan 430074 《Journal of Earth Science》 SCIE CAS CSCD 1998年第3期37-41,共5页
The Huanggang intrusive complex in northern Tongbai area was formed in Early Paleozoic. It mainly consists of ultra basic, basic, intermediate and acid rocks, dominated by intermediate and basic rocks. The complex be... The Huanggang intrusive complex in northern Tongbai area was formed in Early Paleozoic. It mainly consists of ultra basic, basic, intermediate and acid rocks, dominated by intermediate and basic rocks. The complex belongs to calc alkaline series. Geochemical characteristics of major and trace elements show that the complex was derived from the fractional crystallization of co source magma. It is suggested that the complex was formed in island arc tectonic environment and was closely related to the northward subduction of the Erlangping back arc basin. Thus, the subduction of the back arc basin can induce the island arc type magmatism similar to the one formed in the setting of ocean plate subduction. 展开更多
关键词 Huanggang intrusive complex island arc tectonic environment geochemistry northern Tongbai area North Qinling.
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Late Palaeogene emplacement and late Neogene-Quaternary exhumation of the Kuril island-arc root (Kunashir island) constrained by multi-method thermochronometry 被引量:2
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作者 J.De Grave F.I.Zhimulev +4 位作者 S.Glorie G.V.Kuznetsov N.Evans F.Vanhaecke B.McInnes 《Geoscience Frontiers》 SCIE CAS CSCD 2016年第2期211-220,共10页
The Kuril islands constitute a volcanic island arc-trench system, stretching from eastern Hokkaido (Japan) to Kamchatka (Russia) along the northwestern Pacific subduction system, The current arc consists of severa... The Kuril islands constitute a volcanic island arc-trench system, stretching from eastern Hokkaido (Japan) to Kamchatka (Russia) along the northwestern Pacific subduction system, The current arc consists of several volcanic islands mainly with Neogene basement and capped by several, predominantly andesitic, active subduction stratovolcanoes, Kunashir Island is the southwestern-most island of the arc, just off the Hokkaido coast and represents the study area in this paper. The island is composed of a Lower Complex of mainly late Miocene to Pliocene volcanic rocks, covered by an Upper Complex of younger (basaltic) andesitic lava flows and tuffs on which currently four active volcanic edifices are built. In the Lower Complex sub-volcanic and deeper-seated intrusives of the so-called Prasolov and Dokuchaev magmatic complexes are found, More differentiated, tonalitic-granodioritic rocks were collected from these small intrusive bodies. An early Oligocene zircon LA-ICP-MS U/Pb age of 31 Ma for the Prasolov Complex was obtained, showing that the basement of Kunashir Island is older than previously thought. Thermochronometry (apatite fission-track and U-Th-Sm/He and zircon U-ThJHe analyses) further shows that the magmatic basement of the island was rapidly exhumed in the Pleistocene to present levels in a differential pattern, with He-ages ranging from 1.9 to 0.8 Ma. It is shown that the northern section of the island was hereby exhumed more intensely. 展开更多
关键词 Kuril island arc Kunashir island Northwest pacific THERMOCHRONOMETRY Zircon U-Pb dating
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Implications of ε_(Nd) -La/ Nb, Ba/Nb, Nb/Th Diagrams to Mantle Heterogeneity─Classification of Island-arc Basalts and Decomposition of EMII Component 被引量:1
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作者 李曙光 《Chinese Journal Of Geochemistry》 EI CAS 1995年第2期117-127,共11页
A group of εNd-La/Nb, Ba/Nb, Nb/Th diagrams are used to study mantleheterogeneity. Island-arc basalts (IAB) are distributed in a triangle of these diagrams.Three end-member components (the MORB-type depleted mantle, ... A group of εNd-La/Nb, Ba/Nb, Nb/Th diagrams are used to study mantleheterogeneity. Island-arc basalts (IAB) are distributed in a triangle of these diagrams.Three end-member components (the MORB-type depleted mantle, the fiuid released fromsubducted oceanic crust and the sediments from the continental crust) of the source ofIAB may be displayed in these diagrams. Two types of IAB are identified. They areof the two-component type (with little continental sediments), such as the basalts fromAleutians and New Britain, and the three-component type, such as those from Sunda,Lesser Antilles and Andes. In addition, the EMII type mantle-derived rocks may alsobe divided into two groups. One is exemplifled by continental flood basalts and someperidotite xenoliths, similar to IAB, with high La/Nb and Ba/Nb and low Nb/Th ratios.The other includes the Samoa-type oceanic island basalts, with low La/Nb and Ba/Nband high Nb/Th ratios. The corresponding two sub-components of EMII are EMIIM,which is related to the metasomatism of lithosphere mantle by fluids released from thesubducted oceanic crust, and EMIISR, related to the intervention of recycling continentalsediments into the convective mantle. 展开更多
关键词 钕同位素 示踪元素 火山岩 玄武岩 表生交代变质作用
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Newly developed evidence for the original Tethysan island-arc volcanic rocks in the southern segment of the South Lancangjiang Belt 被引量:1
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作者 沈上越 冯庆来 +1 位作者 魏启荣 张志斌 《Chinese Journal Of Geochemistry》 EI CAS 2007年第1期91-97,共7页
This paper re-describes the characteristics of pre-Ordovician (Pt3) metamorphic volcanic rocks in the Huimin-Manlai region of Yunnan Province from the aspects of petrographic characteristics, rock assemblage, petroche... This paper re-describes the characteristics of pre-Ordovician (Pt3) metamorphic volcanic rocks in the Huimin-Manlai region of Yunnan Province from the aspects of petrographic characteristics, rock assemblage, petrochemistry, REE, trace elements, lead isotopes and geotectonic setting. The metamorphic volcanic rocks maintain blasto-intergranular and blasto-andesitic textures; the volcanic rocks are characterized by a basalt-andesite-dacite assemblage; the volcanic rocks are basic-intermediate-intermediate-acid in chemical composition, belonging to semi-alkaline rocks, with calc-alkaline series and tholeiite series coexisting, and they are characterized by low TiO2 contents; their REE distribution patterns are of the LREE-enrichment right-inclined type; the volcanic rocks are enriched in large cation elements and commonly enriched in Th and partly depleted in Ti, Cr and P, belonging to the Gondwana type as viewed from their Pb isotopic composition; petrochemically the data points fall mostly within the field of island-arc volcanic rocks. All these characteristics provided new evidence for the existence of original Tethysan island-arc volcanic rocks in the region studied. 展开更多
关键词 澜沧江南部地带 原始特提斯岛弧 火山岩 新发育证据
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大地幔楔的两个深部碳循环圈:差异及宜居效应
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作者 李曙光 汪洋 刘盛遨 《地学前缘》 EI CAS CSCD 北大核心 2024年第1期15-27,共13页
本文总结评述了西太平洋板块深俯冲及在东亚地幔过渡带滞留和与之相关的晚白垩世和新生代东亚板内玄武岩共同构成的大地幔楔板内深部碳循环圈存在的证据;探讨了大地幔楔板内碳循环圈与岛弧系统碳循环圈在地幔碳酸盐化交代介质、碳酸盐... 本文总结评述了西太平洋板块深俯冲及在东亚地幔过渡带滞留和与之相关的晚白垩世和新生代东亚板内玄武岩共同构成的大地幔楔板内深部碳循环圈存在的证据;探讨了大地幔楔板内碳循环圈与岛弧系统碳循环圈在地幔碳酸盐化交代介质、碳酸盐种属、氧化还原反应及碳酸盐化地幔部分熔融发生机制等方面的差异和对显生宙大气氧含量保持稳定及温室效应周期性变化的影响;并指出了定量估计深俯冲碳酸盐歧化反应还原成金刚石而留在地幔过渡带和通过板内玄武质火山返还大气的碳各自所占有比例应是未来需研究的重要课题。 展开更多
关键词 岛弧碳循环圈 板内碳循环圈 大地幔楔 宜居气候
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北秦岭饭铺闪长岩的岩石成因及其构造意义
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作者 刘晓宇 韩旭 +3 位作者 梁涛 李龙明 任升莲 李加好 《地质科学》 CAS CSCD 北大核心 2024年第1期52-64,共13页
饭铺闪长岩的岩石成因模型可为深入认识北秦岭古生代中性岩浆作用的活动规律及深部过程提供进一步的限定。饭铺岩体两件样品的锆石U-Pb同位素年龄值分别为422.1±5.5 Ma和424.2±5.2 Ma,表明其形成于晚志留世。其锆石的^(176)Hf... 饭铺闪长岩的岩石成因模型可为深入认识北秦岭古生代中性岩浆作用的活动规律及深部过程提供进一步的限定。饭铺岩体两件样品的锆石U-Pb同位素年龄值分别为422.1±5.5 Ma和424.2±5.2 Ma,表明其形成于晚志留世。其锆石的^(176)Hf/^(177)Hf比值介于0.282560~0.282676,ε_(Hf)(t)值介于-8.48~14.45,T_(DM2)为1938~488 Ma。地球化学分析结果显示,饭铺岩体属钙碱性系列,均具有富硅、碱、钙和镁,Mg^(#)值介于41.7~57.4。在微量元素蛛网图中,饭铺岩体具有Nb、Ta、Ti异常。饭铺岩体的稀土总量为117×10^(-6)~171×10^(-6),(La/Yb)_(N)比值范围是6.71~18.1,δEu值介于0.82~0.95,表现为轻稀土元素富集、重稀土元素亏损的配分特征,未显示明显的负Eu异常。饭铺岩体形成于岛弧构造环境,岩浆起源于下地壳,可能受到少量幔源物质的混合,推测是商丹洋向北深俯冲作用的产物。 展开更多
关键词 饭铺闪长岩 锆石U-PB定年 晚志留世 岛弧 北秦岭
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西准噶尔南部晚石炭世中-酸性火山岩成因机制及其对准噶尔洋闭合时限的约束
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作者 支倩 任蕊 +4 位作者 段丰浩 黄家瑄 朱钊 张新远 李永军 《地学前缘》 EI CAS CSCD 北大核心 2024年第3期40-58,共19页
西准噶尔地区广泛分布石炭纪岩浆岩类,了解它们的成因和形成机制可为揭示准噶尔洋盆晚古生代构造格局和发展演化以及约束古大洋闭合时限提供重要依据。本文报道了西准噶尔南部哈拉阿拉特山地区晚石炭世中酸性火山岩的岩石学、锆石U-Pb... 西准噶尔地区广泛分布石炭纪岩浆岩类,了解它们的成因和形成机制可为揭示准噶尔洋盆晚古生代构造格局和发展演化以及约束古大洋闭合时限提供重要依据。本文报道了西准噶尔南部哈拉阿拉特山地区晚石炭世中酸性火山岩的岩石学、锆石U-Pb年代学以及地球化学特征。岩石学研究表明其岩性主要为安山岩、英安质安山岩、流纹英安斑岩和流纹岩。LA-ICP-MS锆石U-Pb定年结果表明哈拉阿拉特山地区中酸性火山岩年龄为308~305 Ma,为晚石炭世中晚期。中酸性火山岩均相对富集轻稀土和大离子亲石元素,亏损Nb、Ta等高场强元素,富钠贫钾,属于低钾拉斑中钾钙碱性系列岛弧火山岩。其中安山岩和英安质安山岩具有较高SiO_(2)(56.15%~66.13%)、Al_(2)O_(3)(16.03%~17.94%)、Na_(2)O(3.44%~5.59%)、Sr((364~576)×10^(-6))含量和Na_(2)O/K_(2)O(3.20~6.40)、Sr/Y(33.5~55.6)比值,贫MgO(1.59%~2.68%)、Y((10.0~16.0)×10^(-6))和Yb((1.08~1.83)×10^(-6))的特征,并且具有Eu正异常(δEu=1.09~1.22),属于典型的埃达克岩,是经俯冲的洋壳板片在石榴角闪岩相发生部分熔融而成,且熔融产生的埃达克质熔体在上升过程中未与上覆地幔橄榄岩发生明显交代作用;流纹岩和流纹英安斑岩具有高的SiO_(2)(69.59%~75.03%)和全碱(w(Na_(2)O+K_(2)O)=7.81%~8.89%)、极低的TFe 2O 3(0.94%~1.57%)和MgO(0.12%~0.97%)含量以及弱负Eu异常(δEu=0.63~1.00)等特征,为准铝质I型流纹岩,是下地壳镁铁质岩石部分熔融的产物,很可能有少量幔源岩浆混入。综合本文数据并结合研究区大量前人已发表的岩浆岩类研究成果,认为西准噶尔南部地区在晚石炭世中晚期仍处于岛弧弧后盆地演化体系,准噶尔洋的闭合时限可能至少推迟至早二叠世早期之后。 展开更多
关键词 岛弧火山岩 晚石炭世 弧盆体系 西准噶尔南部 准噶尔洋
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Identification of the island-arc magmatic zone in the Lianghe-Raofeng-Wuliba area, south Qinling and its tectonic significance 被引量:15
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作者 赖绍聪 张国伟 杨瑞瑛 《Science China Earth Sciences》 SCIE EI CAS 2000年第S1期69-81,共13页
Detailed studies indicate that a typical island-arc magmatic zone exists in the Lianghe-Raofeng-Wuliba area of south Qinling. This is characterized by continental marginal andesite and bimodal volcanic rock associatio... Detailed studies indicate that a typical island-arc magmatic zone exists in the Lianghe-Raofeng-Wuliba area of south Qinling. This is characterized by continental marginal andesite and bimodal volcanic rock association which was formed in a rift environment within an oceanic island-arc. The island-arc magmatic zone is the product of Devonian-Carboniferous oceanic crust sub-duction and rifting of Mianlue ancient oceanic basin. The presence of the island-arc magmatic zone suggests that the Mianxian-Lueyang suture zone had extended to the Bashan arcuate area. The Sunjiahe volcanic rock association of the Xixiang Group formed in a volcanic-arc setting which should have a close relationship with Mianlue suture zone. 展开更多
关键词 island-arc VOLCANIC rock association GEOCHEMISTRY TECTONIC SETTING south Qinling.
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北秦岭二郎坪群抱树坪组沉积时代与构造环境
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作者 翟文建 张永 +2 位作者 唐国胜 赵焕 翟文芳 《地质论评》 CAS CSCD 北大核心 2024年第1期59-82,共24页
二郎坪群抱树坪组作为北秦岭早古生代重要的沉积记录,其研究程度较低。本文通过对抱树坪组内火山岩夹层和花岗斑岩脉进行岩石学、地球化学和锆石U-Pb测年研究,旨在进一步确定其沉积时代与构造环境。研究结果表明:豫西夏馆地区抱树坪组... 二郎坪群抱树坪组作为北秦岭早古生代重要的沉积记录,其研究程度较低。本文通过对抱树坪组内火山岩夹层和花岗斑岩脉进行岩石学、地球化学和锆石U-Pb测年研究,旨在进一步确定其沉积时代与构造环境。研究结果表明:豫西夏馆地区抱树坪组火山岩夹层已变质为(黑云)阳起钠长片岩,常与黑云石英片岩呈“互层状”产出;岩石原岩为安山质凝灰岩,具有相对低的SiO_(2)(52.56%~62.04%)、较高的Al_(2)O_(3)(10.70%~18.55%)、低的MgO(4.06%~6.21%)和FeO^(T)/MgO(1.23~1.81),富集轻稀土元素和大离子亲石元素Rb、Th、U、K,相对亏损高场强元素Nb、Ta、P、Ti,具镁安山质岩石的特点;结合地球化学特征及前人研究认为,抱树坪组可能形成于活动陆缘弧后盆地。获得黑云阳起钠长片岩原岩的结晶锆石U-Pb年龄为446.0±1.7 Ma,以及侵入其中花岗斑岩脉的成岩年龄为430.0±3.0 Ma,首次将抱树坪组的形成时代准确地限定为晚奥陶世至早志留世。综合区域研究成果认为,小寨组和抱树坪组在地层层序和地层时代上符合广义二郎坪群的划分方案,但大庙组、火神庙组及由小寨组和抱树坪组构成的整体三者在形成时代上表现为近于同时性,在空间上主体呈现近平行关系,可能主体属时代大体相当的不同沉积环境的产物;在大地构造属性方面,认为二郎坪群是在约470 Ma之前由于商丹洋向北俯冲而形成的火山岛弧,在470~436 Ma转化为弧后盆地,至约430 Ma之前最终完成消减闭合。 展开更多
关键词 二郎坪群 抱树坪组 火山岩 晚奥陶世—早志留世 火山岛弧—弧后盆地
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Characteristics of the island-arc pillow lavas from southeast Yunnan Province, and its tectonic implications for Paleo-Tethys in South China 被引量:5
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作者 Yunpeng Dong Bingquan Zhu 《Chinese Science Bulletin》 SCIE EI CAS 2000年第8期753-758,共6页
Based on the geological mapping, it is suggested that the pillow lavas exposed in Jianshui area in southeastern Yunnan Province are emplaced into the western part of Shizong-Mile faults, the boundary between the Yangt... Based on the geological mapping, it is suggested that the pillow lavas exposed in Jianshui area in southeastern Yunnan Province are emplaced into the western part of Shizong-Mile faults, the boundary between the Yangtze and Cathaysian blocks, and mainly composed of tectonic massive of basalts and basaltic andsites. The geological and geochemical studies show that these lavas erupted in an island arc tectonic setting, which suggests that there existed the subduction of oceanic crust between the Yangtze and Cathaysian blocks. The paleontological fossils in the sedimentary interlayers between the volcanic rocks indicate that these pillow lavas erupted during Carboniferous-Permian. The geologic and geochemical evidence suggested that there existed an eastern branch of Paleo-Tethys between the Yangtze and Cathaysian blocks in southeastern Yunnan, South China. 展开更多
关键词 southeastern Yunnan Province island arc pillow LAVA geochemistry TECTONIC evolution.
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准噶尔盆地石北凹陷岛弧环境下火山-沉积建造特征及源储发育模式——以石炭系姜巴斯套组为例 被引量:5
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作者 熊伟 王越 +4 位作者 熊峥嵘 梅文科 白仲才 蔡倩茹 宋智华 《石油实验地质》 CAS CSCD 北大核心 2023年第4期656-666,共11页
准噶尔盆地石北凹陷位于盆地东部的陆梁隆起带北部,前期针对石北凹陷石炭系火山岩圈闭勘探一直未获突破。近期完钻的准北6井揭示了其石炭系姜巴斯套组自生自储型油气藏具有较大的勘探潜力,但以往针对这类储层的成因及分布研究较少。为... 准噶尔盆地石北凹陷位于盆地东部的陆梁隆起带北部,前期针对石北凹陷石炭系火山岩圈闭勘探一直未获突破。近期完钻的准北6井揭示了其石炭系姜巴斯套组自生自储型油气藏具有较大的勘探潜力,但以往针对这类储层的成因及分布研究较少。为了深入研究石北凹陷岛弧环境下火山—沉积建造特征及其源储发育模式,在前人研究的基础上,利用钻井岩心、地震及测试资料,结合烃源岩地球化学特征分析,对姜巴斯套组火山—沉积建造、烃源岩特征进行了系统研究,建立了岛弧控制下的火山岩—火山碎屑沉积岩—烃源岩发育模式,以期为具有相同沉积背景的地区油气勘探提供理论依据。研究表明,石北凹陷姜巴斯套组中基性火山岩形成于与俯冲相关的岛弧环境,火山建造主要为近火山口爆发相、近火山口溢流相、远火山口爆发相,沉积建造以岛弧侧翼的扇三角洲相凝灰质砂砾岩、砂岩与远岛弧低洼地带的滨浅海相凝灰质泥岩为主;姜巴斯套组凝灰质泥岩为一套处于成熟—高熟阶段的中等烃源岩,呈北西—南东向条带状分布,厚度分布在100~500 m之间;姜巴斯套组火山岛弧间歇喷发,远岛弧低洼地带凝灰岩与滨浅海凝灰质泥岩互层状分布,凝灰质泥岩与扇三角洲砂砾岩、岛弧火山岩具有良好的源储配置关系,两类储层为下一步重点勘探方向。 展开更多
关键词 火山—沉积建造 烃源岩 姜巴斯套组 岛弧 石北凹陷 准噶尔盆地
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Magmatism-Related Thermal Simulation of Volcanic Arcs in the Molucca Sea Bidirectional Subduction System
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作者 YU Lei ZHANG Jian +2 位作者 DONG Miao FANG Gui Yu Lupeng 《Journal of Ocean University of China》 SCIE CAS CSCD 2023年第4期939-948,共10页
The bidirectional subduction system,island arc magmatic activities,and thermal structure of the forearc basin in the Molucca Sea are taken into consideration in this study.The active volcanic arcs on both sides of the... The bidirectional subduction system,island arc magmatic activities,and thermal structure of the forearc basin in the Molucca Sea are taken into consideration in this study.The active volcanic arcs on both sides of the bidirectional subduction zone in the Molucca Sea are undergoing arc-arc collisions.We applied a finite element thermal simulation method to reconstruct the thermal evolution history of the Molucca Sea Plate based on geophysical data.Then,we analyzed the thermodynamic characteristics of island arc volcanism on both sides of the bidirectional subduction zone.The results showed that at 10Myr,the oceanic ridge of the Molucca Sea Plate was asymmetrically biased to the west,causing this bidirectional subduction to be deeper in the west than in the east.Furthermore,the oceanic ridge subducted under the Sangihe arc at 5.5Myr,causing intermittent cessation of volcanic activities.Due to the convergence of bidirectional subduction,the geothermal gradient in the top 3km depth of the forearc area between the Sangihe and Halmahera arcs decreased from about 60℃km^(−1) at 4Myr to about 38℃km^(−1) today.Finally,within the 45–100 km depth range of the sliding surface of the subduction,anomalously high-temperature zones formed due to shear friction during the bidirectional subduction. 展开更多
关键词 Molucca Sea bidirectional subduction zone ARC thermal simulation:island-arc magmatism
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川西义敦岛弧燕山期岩体带多种稀有金属矿(化)脉的发现及其意义 被引量:1
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作者 彭宇 郝雪峰 +4 位作者 唐屹 梁斌 潘蒙 杨荣 范俊波 《地质论评》 CAS CSCD 北大核心 2023年第6期2359-2363,共5页
稀有金属是战略性新兴产业的关键性矿产资源,无论是在高端装备制造业还是在新能源汽车领域均发挥着不可替代的作用,其重要性越来越突显,其中锂、铍、钽是当前稀有金属中关注度最高的3个矿种(王登红等,2017)。川西义敦地区位于松潘—甘... 稀有金属是战略性新兴产业的关键性矿产资源,无论是在高端装备制造业还是在新能源汽车领域均发挥着不可替代的作用,其重要性越来越突显,其中锂、铍、钽是当前稀有金属中关注度最高的3个矿种(王登红等,2017)。川西义敦地区位于松潘—甘孜义敦岛弧带内(图1),属松潘—甘致稀有金属成矿带西侧的石渠—义敦—贡山—巍山稀有金属成矿亚带。 展开更多
关键词 稀有金属 义敦岛弧 川西地区
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新疆东天山照壁山金铅锌多金属矿床地质特征及矿床成因
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作者 张雪琴 徐登峰 +5 位作者 赵云 薛春纪 刘一浩 李旭广 陈波 游延祥 《矿床地质》 CAS CSCD 北大核心 2023年第6期1121-1138,共18页
照壁山金铅锌多金属矿床位于东天山博格达岛弧带中部,是近年来新发现的矿床。矿体赋存于柳树沟组第三岩性段火山岩-火山碎屑岩中,以脉状、浸染状矿化为主,发育硅化、明矾石化蚀变,其成矿过程可分为3个阶段:①石英-黄铁矿-毒砂阶段(Ⅰ);... 照壁山金铅锌多金属矿床位于东天山博格达岛弧带中部,是近年来新发现的矿床。矿体赋存于柳树沟组第三岩性段火山岩-火山碎屑岩中,以脉状、浸染状矿化为主,发育硅化、明矾石化蚀变,其成矿过程可分为3个阶段:①石英-黄铁矿-毒砂阶段(Ⅰ);②石英-金-黄铁矿-闪锌矿-方铅矿阶段(Ⅱ);③石英-黄铁矿-黄铜矿阶段(Ⅲ)。赋矿围岩为双峰式火山岩组合,玄武岩高Mg(Mg^(#)=36.25%~58.77%)、富钠贫钾(w(Na_(2)O/K_(2)O)=1.95~27.35),铝饱和指数(A/CNK)在1.25~1.69之间,属过铝质拉斑玄武岩系列,较高的La/Nb(2.49~3.83)、Ba/Nb(41.00~315.38)、Ba/La(14.50~92.45)比值,反映了玄武质岩浆受到了一定的地壳物质混染,Rb、Ba、K等元素相对富集,Th、Nb、Ta等元素相对亏损,具有板内玄武岩的特征;流纹岩具有较高的全碱含量(w(Na_(2)O+K_(2)O)=9.50~12.45),属钾玄岩系列,轻微富集轻稀土,富集Rb、U、K等元素,亏损Nb、Ta、Sr、Ti等元素,反映了流纹岩来源于地壳物质的部分熔融;石英脉中的流体包裹体主要为气液两相,均一温度为194.2~253.5℃(Ⅱ)、156.7~201.6℃(Ⅲ),盐度为7.9%~13.2%(Ⅱ)、7.3%~12.4%(Ⅲ),成矿流体表现为中温、中低盐度、低氧逸度、低pH值特征;δD_(v-SMOW)变化范围为-115.7‰~-95.4‰,δO_(v-SMOW)变化范围为-0.51‰~7.19‰,表明成矿流体为岩浆热液与大气降水的混合热液。结合系统的地质、地球化学对比,文章推测照壁山金铅锌多金属矿床为中硫型浅成低温热液矿床。 展开更多
关键词 地质特征 矿床成因 浅成低温热液 博格达岛弧带 东天山
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西天山伊犁山间坳陷二叠系乌郎组玄武岩地球化学特征及构造环境判别
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作者 杨德敏 刘陈明 +4 位作者 王明 杜勇 马伟 唐娇 刘德利 《新疆地质》 CAS CSCD 2023年第3期307-314,共8页
西天山二叠纪构造演化对哈萨克斯坦-准噶尔板块与塔里木-华北板块重建具重要意义,目前对该时期西天山构造环境认识存在争议。通过对新源县山口水电站东剖面乌郎组开展实测剖面研究发现,剖面包含玄武岩-凝灰岩-砂岩等,表现出溢流相-喷发... 西天山二叠纪构造演化对哈萨克斯坦-准噶尔板块与塔里木-华北板块重建具重要意义,目前对该时期西天山构造环境认识存在争议。通过对新源县山口水电站东剖面乌郎组开展实测剖面研究发现,剖面包含玄武岩-凝灰岩-砂岩等,表现出溢流相-喷发相-沉积相组合,具5个火山喷发韵律等,表明该地区乌郎组形成于陆缘环境。通过对乌郎组玄武岩主量、微量、稀土元素进行分析发现,样品里特曼指数(σ)为1.6~6.71,AR为1.28~1.97,为钙碱-碱性准铝质玄武岩;ΣREE为-88.21×10^(-6)~285.73×10^(-6),LR/HR为3.31~6.49,属轻稀土富集型玄武岩。(Rb/Yb)_(N)为3.04~4.61,Nb/Ta为20.70~40.83,Zr/Hf为16.09~64.58,为受陆壳、火山弧影响交代地幔源残余玄武岩。通过Sm/Yb-Sm图解分析发现,火山岩浆对应俯冲深度可能起源于上地幔120~150km。据玄武岩源区特征判别岩浆物源为石榴石二辉橄榄岩带,深度熔融。结合区域以往研究和Hf/3-Th-Ta图解认为,该地区乌郎组形成于陆缘岛弧环境。 展开更多
关键词 乌郎组 玄武岩 地球化学 构造环境 陆缘岛弧
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新疆西天山阔库确科铁铜矿区成矿岩体锆石微量元素地球化学特征及其地质意义
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作者 顾枫华 章永梅 +1 位作者 彭义伟 王佳琳 《矿床地质》 CAS CSCD 北大核心 2023年第6期1159-1174,共16页
新疆西天山北缘的博罗科努晚古生代岛弧带出露大量中酸性侵入体,并发育一系列斑岩-矽卡岩型铁铜多金属矿床。文章对该岛弧带中部阔库确科矽卡岩型铁铜矿床成矿岩体中的锆石开展了微量元素地球化学研究,查明了锆石成因、形成物理化学条... 新疆西天山北缘的博罗科努晚古生代岛弧带出露大量中酸性侵入体,并发育一系列斑岩-矽卡岩型铁铜多金属矿床。文章对该岛弧带中部阔库确科矽卡岩型铁铜矿床成矿岩体中的锆石开展了微量元素地球化学研究,查明了锆石成因、形成物理化学条件及其对成矿的启示意义等。数据显示,与成矿密切相关的正长花岗岩和闪长岩中锆石均表现为重稀土元素富集、轻稀土元素亏损,正长花岗岩中锆石的∑REE介于(627~1625)×10^(-6),闪长岩中锆石的∑REE介于(345~1439)×10^(-6)。锆石Ti温度计显示正长花岗岩锆石的结晶温度集中在598~810℃;闪长岩锆石结晶温度为651~932℃,正长花岗岩的氧逸度(ΔFMQ+4.25)高于闪长岩(ΔFMQ-1.01)。成矿岩体锆石均形成于封闭的岩浆体系中,主要为岩浆锆石,少量闪长岩中的锆石可能在岩浆晚期遭受了富集轻稀土元素的热液改造。锆石形成构造背景属于大陆岛弧环境。成矿岩体锆石的Ce^(4+)/Ce^(3+)值明显高于区域内不成矿岩体的Ce^(4+)/Ce^(3+)值,其中正长花岗岩锆石中更高的Ce^(4+)/Ce^(3+)值表明,阔库确科矿区内志留系与正长花岗岩发生接触交代形成的矽卡岩中可能有更大的Cu成矿潜力。 展开更多
关键词 锆石微量元素 氧逸度 成矿岩体 博罗科努成矿带 新疆西天山
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阿拉善右旗特拜金矿赋矿变沉积岩地球化学特征、源区属性及构造意义 被引量:1
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作者 程先钰 田健 +3 位作者 李以科 董满华 曹侃 张天福 《华北地质》 2023年第1期42-49,60,共9页
本次对阿拉善右旗特拜金矿赋矿变沉积岩进行地球化学分析,主要岩性为云母石英片岩、变质粉砂岩、变质岩屑石英砂岩等;主量元素SiO_(2)平均含量62.39%,Al_(2)O_(3)平均含量15.40%,Fe_(2)O_(3)平均含量6.57%,MgO平均含量3.84%,CaO平均含量... 本次对阿拉善右旗特拜金矿赋矿变沉积岩进行地球化学分析,主要岩性为云母石英片岩、变质粉砂岩、变质岩屑石英砂岩等;主量元素SiO_(2)平均含量62.39%,Al_(2)O_(3)平均含量15.40%,Fe_(2)O_(3)平均含量6.57%,MgO平均含量3.84%,CaO平均含量2.31%,K_(2)O平均含量2.65%,Na_(2)O平均含量2.09%。ΣREE配分模式曲线一致,LREE/HREE=5.75~8.34,平均为7.18,(La/Yb)_(N)=5.39~8.38,平均6.83,Eu负异常明显,轻稀土元素相对重稀土元素明显富集;微量元素中相对稳定元素比值如La/Sc、Th/Sc、Cr/Zr显示出物源来自上地壳长英质;Rb-K_(2)O图解、Ni-TiO_(2)图解和La/Yb-ΣREE图解表明其母岩主要来源于花岗岩,结合古水流特征以及碎屑锆石年龄证据等推测物源可能来自北大山地区花岗岩。结合特拜赋矿变沉积岩岩石组合特征、构造特征和地球化学特征,认为其源岩形成于大陆岛弧构造环境。 展开更多
关键词 阿拉善地块 特拜金矿 赋矿地层 变沉积岩 地球化学 大陆岛弧
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新疆塔城结勒迪克增闪长岩体特征及其含矿性
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作者 刘伟 殷勇 +2 位作者 杨忠明 安乐 刘鑫 《地质通报》 CAS CSCD 北大核心 2023年第5期700-713,共14页
新疆准噶尔盆地西北缘属中亚造山-成矿带,是中国重要的铜多金属成矿带之一,区内侵入岩的成因及含矿性研究,对进一步提高本区地质矿产勘查程度具有重要的现实意义。针对新疆塔城结勒迪克增闪长岩体,在研究其地质特征、矿化赋存特征的基础... 新疆准噶尔盆地西北缘属中亚造山-成矿带,是中国重要的铜多金属成矿带之一,区内侵入岩的成因及含矿性研究,对进一步提高本区地质矿产勘查程度具有重要的现实意义。针对新疆塔城结勒迪克增闪长岩体,在研究其地质特征、矿化赋存特征的基础上,利用其岩石地球化学数据,结合前人的年代学资料,初步探讨了该岩体的岩石成因、构造环境、含矿性及其与成矿作用的关系等,为该区地质找矿提供一些基础参考。新疆塔城结勒迪克增闪长岩序列由灰色细斑闪长玢岩、粗斑闪长玢岩、细-中粒闪长岩和灰白色黑云母石英闪长岩4个侵入期次组成。岩体岩石硅、镁、钾含量低而钠、铝、铁含量高;弱准铝质,为亚碱性系列岩石;富集Rb、Ba、Th等大离子亲石元素,亏损Nb、Ta、Y、Yb等高场强元素;稀土元素含量较低,配分模式呈右倾曲线,为轻稀土元素富集型,具Ce、Eu弱负异常。该闪长岩序列侵入成岩时代为早石炭世末期,形成于岛弧构造环境,属造山前I型科迪勒拉花岗岩,源岩成分可能来自岛弧型火山岩的部分重熔或同源岩浆演化。经对比研究,结勒迪克增闪长岩体内部各侵入期次Au、Ag、Cu、As、Pb等主要金属元素含量较高且浓集程度不同,Cu、Au等成矿元素分异程度较高,反映出区内多金属成矿与该岩体上侵强烈的岩浆热液作用密切相关。该岩体具备形成斑岩型铜矿、热液型金矿的岩浆岩条件。 展开更多
关键词 闪长岩 地球化学特征 岛弧 多金属成矿 含矿性 结勒迪克增 新疆
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