共查询到18条相似文献，搜索用时 453 毫秒
1.
《海洋地质与第四纪地质》2021,41(5)
研究海底热液系统及其岩浆环境,可为了解西太平洋流固界面跨圈层物质与热交换过程,揭示板块俯冲过程的岩浆活动和资源环境效应提供研究支撑。为此,研究了冲绳海槽热液活动的岩浆环境、马努斯海盆的热液柱以及弧后盆地和洋中脊背景下的硫化物与玄武岩的同位素组成,对冲绳海槽热液区附近玄武岩、安山岩、粗安岩、英安岩、流纹岩及其基性岩浆包体进行了岩相学、矿物学以及主量元素、微量元素和同位素组成分析,对马努斯海盆PACMANUS和Desmos热液区的热液柱及海水进行了测量,在海底热液区岩浆混合过程及时间尺度、透视冲绳海槽深部岩浆房及岩浆演化过程和岩浆对热液系统物质贡献研究方面获新进展,揭示了俯冲蛇纹岩对琉球构造带南部岩浆活动的影响,论证了熔体包裹体对弧后盆地岩浆演化的指示,获得了冲绳海槽玄武质岩浆来源新证据,揭示了弧后盆地与洋中脊硫化物和玄武岩中铁、铜、锌的来源及其同位素在硫化物形成和岩浆活动过程中的分馏情况,明确了热液柱的物理、化学空间结构与物质组成特征,以及热液柱的扩散受深度和底流流速的影响,且热液柱扩散过程中溶解铁浓度异常比溶解锰的维持时间更长。未来,发展非传统稳定同位素和挥发份测试技术,进一步了解西太平洋板块俯冲环境下热液活动与岩浆作用的关系,将有助于海底热液系统及其成矿过程研究获得新进展。 相似文献
2.
冲绳海槽火山岩--揭示弧后盆地早期扩张动力学过程的钥匙 总被引：3，自引：2，他引：3
简述了冲绳海槽火山岩的研究意义、研究历史、现状及存在问题，提出了今后深入研究的思路与展望，指出应基于现代地球化学理论和方法，从板块构造沟弧盆体系岩浆作用的角度，将冲绳海槽这一典型幼年期弧后盆地中复杂多变的火山岩作整合型归纳和思考，既揭示不同岩石系列的成因联系，又注重将岩浆作用与构造环境相结合，并在与成熟弧后盆地火山岩的对比中揭示弧后盆地早期扩张过程中岩浆作用的特性、规律与标志，以揭示弧后盆地早期扩张的构造动力学过程。 相似文献
3.
4.
为了进一步理解构造地质过程对弧后盆地热液活动及成矿作用的影响和控制,以实测和收集的多波束资料为基础,对冲绳海槽南部多个海底热液活动区的地形地貌特征进行了精细刻画。结合前人研究成果,从构造地质学的角度分析了热液区地形地貌的成因机制。结果表明,冲绳海槽南部热液区均为海底火山成因地貌,不同热液区的海底地貌分属于不同类型岩浆作用的产物:D海丘受岛弧和弧后盆地岩浆作用的双重影响,A海丘群由岛弧为主的多源岩浆作用产生,C海丘和B海丘群属于琉球火山岛弧,雨花海丘形成于造山期后地壳伸展导致的岩浆上涌。冲绳海槽中央地堑与琉球火山岛弧的交汇处有利于形成大规模岩浆和地热活动。琉球火山岛弧的岩浆活动存在时空迁移,与海槽构造演化过程中由分散式裂陷向中心式裂陷的转换有关。唐印热液区的存在表明台湾北火山带在槽底北缘及陆坡区仍具有较强的岩浆和地热活动性,是未来冲绳海槽南部海底热液调查的重要靶区之一。 相似文献
5.
《海洋地质与第四纪地质》2021,41(1)
熔体包裹体是在矿物生长过程中被包裹的硅酸盐小液滴,由于寄主矿物的保护,受最小程度的后期岩浆作用影响,可以有效的保留原始岩浆组成、地幔源区性质及岩浆演化过程等重要信息。熔体包裹体的研究可以弥补传统全岩因受后期复杂地质过程影响而导致部分信息失真的不足。文章简要总结了熔体包裹体的主要研究领域及分析测试技术,概述了国内外关于西太平洋典型弧后盆地火山岩中熔体包裹体研究的相关进展。冲绳海槽、劳海盆及北斐济海盆内熔体包裹体的研究证明了地幔源区不均一性的特征,明确了岩浆物质来源及俯冲物质在源区的加入;马里亚纳海槽和马努斯海盆熔体包裹体内挥发份研究指示了俯冲板片物质对弧后盆地岩浆源区挥发份组成的贡献;马努斯海盆熔体包裹体中金属元素浓度分析表明岩浆流体可为海底热液系统提供成矿金属;此外,马里亚纳海槽和冲绳海槽熔体包裹体测温实验反映出岩浆多期次的演化过程。尽管熔体包裹体在西太平洋弧后盆地岩浆活动的很多方面有了一定研究,但各弧后盆地研究参差不齐、综合研究程度低。将来在进一步完善熔体包裹体测试分析手段基础上,加大熔体包裹体在弧后盆地的研究力度,有助于我们更清晰地认识弧后盆地岩浆源区物质组成,明确俯冲作用下弧后盆地岩浆来源及物质转化机制。 相似文献
6.
在对冲绳海槽及邻区构造地质学和热液地质学调查研究成果进行全面总结的基础上,将深部地球动力学机制、冲绳海槽形成演化、岩浆作用过程、热液系统结构、流体循环模式和成矿作用特征等多方面的问题,纳入到统一的框架下,探讨了冲绳海槽构造地质过程对热液活动和成矿作用的控制机理。分析认为,区域中尺度地幔流引起了东亚大陆边缘岩石圈向东的蠕散,并驱动了菲律宾海板块沿琉球海沟向欧亚板块之下的俯冲。在弧后小尺度地幔对流、岩石圈减薄、板片反卷和俯冲后退的共同作用下,冲绳海槽发生弧后张裂。张裂作用在岩石圈内形成了网状破裂系统,为岛弧和弧后岩浆上涌提供了通道,并且引起了不同来源岩浆的干扰和混合。侵位到地壳浅部的岩浆为热液活动提供了热源和主要成矿物质来源,是影响热液活动分布的主要因素。沉积层覆盖改变了流体的浅部循环结构和原始流体成分。热液区内普遍存在的流体相分离过程,导致了广域成矿作用的发生。 相似文献
7.
冲绳海槽现代张裂的地球物理特征 总被引：3，自引：0，他引：3
杨文达 《海洋地质与第四纪地质》2004,24(3):77-82
位于东海陆架与琉球岛弧之间的冲绳海槽为板块俯冲作用形成的弧后断陷盆地,具有独特的构造地貌特征。自中新世末以来历经了4个强烈拉张的演化时期,目前已达到张裂的高级阶段。地球物理资料显示,海槽中的现代拉张作用仍在进行,表现在海槽轴部快速沉降形成地堑槽,对称分布的张性断裂,晚更新世—全新世以来的岩浆活动,从老至新排列的磁异常务带以及高地热流、频繁的地震活动等,充分体现了冲绳海槽的现代扩张特点。 相似文献
8.
冲绳海槽的地质构造属性 总被引：12，自引：4，他引：12
冲绳海槽构造属性是地学界争论的问题之一,迄今已提出过断陷盆地、坳陷盆地、弧间盆地、弧后盆地、边缘海盆、张裂盆地等多种看法。本文作者在多次赴冲绳海槽调查和系统总结前人研究成果的基础上提出,冲绳海槽是一条现代活动裂谷,具有一系列典型的裂谷构造特征,其活动机制属于与洋壳俯冲作用有关的弧后裂谷。 相似文献
9.
琉球沟弧盆系的海底热流分布特征及冲绳海槽热演化的数值模拟 总被引：9，自引：0，他引：9
以１９９３－１９９５年对琉球沟弧盆系各个航次的热流数值进行了搜集整理，发现这一地区热流的分布特征和构造特征有明显的对应关系，大致上呈出现东西分带南北分块的分布特征，冲绳海槽有极高的热流值，而琉球海沟则有极低的热流值，这和板块的撞碰，俯冲，弧后扩张模式相吻合，用二维热传导平流议程用有限单元法对冲绳海槽进行的地球动力学热模拟显示，冲绳海槽的高热流值和海槽内的岩浆活动有着密切关系，如果不考虑海槽中岩浆因 相似文献
10.
东海陆架外缘隆褶带是菲律宾海板块俯冲带陆侧弧后裂陷盆地(陆架盆地与冲绳海槽)之间的水下残留火山弧.其地球物理特征、地层组成、岩浆活动及地质构造等均具有“东西分带、南北分块”之特征.本隆褶带的形成始于第三纪初,当时为陆缘弧;中新世末以后,由于琉球弧后冲绳海槽的张裂作用,遂成为古琉球弧的残留弧.其形成机理受东海构造格局控制,与菲律宾海板块的俯冲作用及俯冲带的东向迁移有关,东海隆褶带的形成和构造演化大致经历了四个阶段:(1)断隆火山弧(E1+2)、(2)褶隆火山弧(E3)、(3)褶隆残留弧(N1)和(4)消亡残留弧(N2～Q).最后一个阶段隆褶带与陆架盆地整体沉降,接受了厚约1500m的上新世-第四纪浅海相沉积. 相似文献
11.
Petrologic perspectives on tectonic evolution of a nascent basin (Okinawa Trough) behind Ryukyu Arc：A review 总被引：9，自引：2，他引：7
Okinawa Trough is a back-arc, initial marginal sea basin, located behind the Ryukyu Arc–Trench System. The formation and evolution of the Okinawa Trough is intimately related to the subduction process of the Philippine Sea Plate beneath the Eurasian Plate since the late Miocene. The tectonic evolution of the trough is similar to other active back-arcs, such as the Mariana Trough and southern Lau Basin, all of which are experiencing the initial rifting and subsequent spreading process. This study reviews all petrologic and geochemical data of mafic volcanic lavas from the Okinawa Trough, Ryukyu Arc, and Philippine Sea Plate, combined with geophysical data to indicate the relationship between the subduction sources(input) and arc or back-arc magmas(output) in the Philippine Sea Plate–Ryukyu Arc–Okinawa Trough system(PROS). The results obtained showed that several components were variably involved in the petrogenesis of the Okinawa Trough lavas: sub-continental lithospheric mantle underlying the Eurasian Plate, Indian mid-oceanic ridge basalt(MORB)-type mantle, and Pacific MORB-type mantle. The addition of shallow aqueous fluids and deep hydrous melts from subducted components with the characteristics of Indian MORB-type mantle into the mantle source of lavas variably modifies the primitive mantle wedge beneath the Ryukyu and subcontinental lithospheric mantle(SCLM) beneath the Okinawa Trough. In the northeastern end of the trough and arc, instead of Indian MORB-type mantle, Pacific MORB-type mantle dominates the magma source. Along the strike of the Ryukyu Arc and Okinawa Trough, the systematic variations in trace element ratios and isotopic compositions reflect the first-order effect of variable subduction input on the magma source. In general, petrologic data, combined with geophysical data, imply that the Okinawa Trough is experiencing the "seafloor spreading" process in the southwest segment, "rift propagation" process in the middle segment, and "crustal extension" process in the northeast segment, and a nascent ocean basin occurs in the southwest segment. 相似文献
12.
Geochemical and isotopic characteristics of volcanic rocks from the northern East China Sea shelf margin and the Okinawa Trough 总被引：8，自引：2，他引：6
ZENG Zhigang YU Shaoxiong WANG Xiaoyuan FU Yongtao YIN Xuebo ZHANG Guoliang WANG Xiaomei CHEN Shuai 《海洋学报(英文版)》2010,29(4):48-61
Volcanic rocks both from the northern East China Sea (NECS) shelf margin and the northern Okinawa Trough are subalkaline less aluminous,and lower in High Field Strength Elements (HFSE).These rocks are higher in Large Ion Lithophile Elements (LILE),thorium and uranium contents,positive lead anomalies,negative Nb-Ta anomalies,and enrichment in Light Rare Earth Elements (LREE).Basalts from the NECS shelf margin are akin to Indian Ocean Mid-Ocean Ridge Basalt (MORB),and rhyolites from the northern Okinawa Trough have the highest 207 Pb/ 204 Pb and 208 Pb/ 204 Pb ratios.The NECS shelf margin basalts have lower 87 Sr/ 86 Sr ratios,ε N d and σ 18 O than the northern Okinawa Trough silicic rocks.According to 40 K– 40 Ar isotopic ages of basalts from the NECS shelf margin,rifting of the Okinawa Trough may have been active since at least 3.65–3.86 Ma.The origin of the NECS shelf margin basalt can be explained by the interaction of melt derived from Indian Ocean MORB-like mantle with enriched subcontinental lithosphere.The basalts from both sides of the Okinawa Trough may have a similar origin during the initial rifting of the Okinawa Trough,and the formation of basaltic magmas closely relates to the thinning of continental crust.The source of the formation of the northern Okinawa Trough silicic rocks was different from that of the middle Okinawa Trough,which could have been generated by the interaction of basaltic melt with an enriched crustal component.From the Ryukyu island arc to East China,the Cenozoic basalts have apparently increasing trends of MgO contents and ratios of LREE to Heavy Rare Earth Elements (HREE),suggesting that the trace element variabilities of basalts may have been influenced by the subduction of the Philippine Sea plate,and that the effects of subduction of the Philippine Sea plate on the chemical composition of basaltic melts have had a decreasing effect from the Ryukyu island arc to East China. 相似文献
13.
The Okinawa Trough(OT) is a back-arc basin at an initial spreading stage that is under the influence of subduction of the Philippine Sea Plate. In this study, we analyzed the geochemical compositions of basaltic glass in the OT and discussed the effects of different magmatic sources, evolution, and subducted components in basalts. Our results showed that the middle and southern regions of the OT exhibit characteristics consistent with an iron-rich tholeiite series. Trace element proportions conform to the typical spider diagram pattern characteristic of back-arc basin basalts, rich in large ion lithophile elements(LILEs) including Rb, Ba, Pb, U, and Th, while depleted in high field-strength elements(HFSEs) including Nb, Ta, Zr, Hf, and Ti. The distribution of rare earth elements(REEs) is also consistent with enrichment by right-leaning light rare earth elements(LREEs).The addition of enriched mantle type I(EMI) materials as well as mantle heterogeneity may have led to variable degrees of enrichment in different regions. The magma source of the middle trough has undergone crystallization towards pyroxene, while development of plagioclase was restricted partly, and the crystallization of spinel and olivine ceased altogether. At the same time, crystallization of the southern OT magma source was dominated by olivine and including the formation of plagioclase, pyroxene, and magnetite(or titanomagnetite). Finally, the results of this study showed that 90% Th, 95% Ba in the southern basalt, 50%–70% Th and 70%–90% Ba in the middle basalt originated from subducted component. Different subducted component influence may be due to different subduction zone structural feature. 相似文献
14.
南冲绳海槽岩石圈构造动力作用机制探讨 总被引：8，自引：1，他引：8
由最新获得的重磁、地震和多波束地形数据 ,结合多尺度的地幔流动力分析 ,展示了南冲绳海槽岩石圈构造动力的多样性特征和其内在的联系。从上新世开始的三幕张性断陷活动是在以前的压性断裂构造的基础上发展起来的 ,向岛弧侧迁移 ,岩浆、火山活动主要集中在正断层与平移断层的交汇处。深部动力源可归结为上地幔对流产生的菲律宾海板块俯冲 ,引起岛弧岩石圈挤压褶皱而向海沟旋张掀斜 ,产生弧后岩石圈的张性构造 ;进一步引起弧后软流圈挤压隆起 ,岩石圈与软流圈耦合作用导致海槽断陷张裂、岩浆活动。冲绳海槽仍是一个软流圈在汇聚的弧后盆地。全球性左旋压扭滑移背景 ,琉球海沟南段俯冲受阻小、强度大 ,台湾—吕宋的北向挤压 ,使海槽表现为剪张性 ,由平移断层调控使张性断裂左旋雁行排列 ,整个海槽张性构造由北往南推进 ,张应力方向由NW过渡到NNW。 相似文献
15.
16.
北部湾玄武岩地幔源区性质的地球化学示踪及其构造环境 总被引：9，自引：0，他引：9
北部湾发育一系列上新世玄武岩，其全岩K—Ar年龄为5．9—2．4Ma，是伴随北部湾盆地拉张而形成的一次较大规模的岩浆活动。岩石化学和微量元素地球化学研究表明，该玄武岩属于碱性玄武岩系，具有OIB型微量元素配分模式，形成于较均一的地幔源区，具有以EM2型地幔端元为主、混有HIMU和EMl型端元的地幔源区性质，形成于地幔柱或地幔热点的构造环境。北部湾盆地与红河剪切断裂带具有相同的地幔源区，而与受太平洋板块影响的地幔源区差别较大。玄武岩形成和北部湾盆地拉张主要受印度板块向欧亚板块俯冲导致的红河断裂带大规模剪切走滑控制，5Ma左右红河断裂带由左行走滑剪切转变为右行走滑剪切的构造性质转换可能是导致地幔异常扰动和岩浆活动的地球动力学机制。 相似文献
17.
Glass inclusions in volcanic rocks in the Okinawa Trough back-arc basin:constraints on magma genesis and evolution 总被引：1，自引：0，他引：1
INTROOUcr1ONThe Okinawa Trough is a typical marginal back-arc basin, where its oPening began in rela-tively recent years* There is a great controversy about the origin of its initial magYna. haltand acid volcanic pumice make up the bimedal volcanism in the Okinawa Trough. MOSt of geol-ogists believed that the acid pumice was the preduct of extremely crystal fractionation of baseltInagTna, but the others argued that it should com from the melting of lower-crust. Som de-tailed petrolOgic… 相似文献
18.
Ling Chen Limei Tang Jichao Yang Xiaohu Li Wei Wang Fengyou Chu Jie Zhang 《海洋学报(英文版)》2021,40(11):147-161
We present major and trace element data of lava recovered from the northern Yap Trench in the western Pacific and discuss their petrogenesis and tectonic implications within the framework of interactions between the Caroline Ridge and Yap Trench. Rocks were collected from both landward and seaward trench slopes and exhibited geochemical characteristics similar to backarc basin basalt (BABB) and mid-ocean ridge basalt (MORB), including high Fe content, tholeiitic affinity, high TiO2 value at a given FeOT/MgO ratio, Ti/V ratio between 20 and 50, low Ba/Nb ratio and Th/Nb ratio, and trace element patterns commonly displayed by BABB and MORB, which are distinct from arc lava. These rocks seem to have been generated during mantle upwelling and decompression melting at a spreading center. However, compared with typical forearc lava produced by seafloor spreading in the Mariana forearc region, such as the early Eocene forearc basalts and late Neogene forearc lava in the southernmost Mariana Trench, the Yap Trench lava is derived from a more fertile mantle and feature a more minor subduction component; thus, they cannot be the products of forearc mantle decompression melting. We suggest that the landward slope lava represents backarc basin crust that was overthrust onto the forearc lithosphere during the collision of the Caroline Ridge with the Yap Trench (20–25 Ma), which played a key role in the evolution of the Yap subduction system. Moreover, the seaward slope lava represents the subduction plate crust that accreted onto the deep trench during the collision. This collision event resulted in the cessation of Yap Arc magmatism; thus, the Yap Trench volcanic rocks (<25 Ma) previously suggested to be arc magma products may actually represent the nascent island arc lava with a lower subduction component than in the mature Mariana Arc lava. 相似文献