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Seamount chains and hotspot tracks:Superficially similar,deeply different
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作者 Edgardo Cañón-Tapia 《Geoscience Frontiers》 SCIE CAS CSCD 2023年第6期307-326,共20页
Nearly 80%of the seafloor extension has not been covered by high-resolution bathymetry,impeding direct observation of seamounts.Nevertheless,lists of seamount location and height at a global scale have been produced u... Nearly 80%of the seafloor extension has not been covered by high-resolution bathymetry,impeding direct observation of seamounts.Nevertheless,lists of seamount location and height at a global scale have been produced using different techniques.In this work four of such databases(publicly available)are compared with each other to assess their differences.Results identify large differences among databases that could have exerted strong influences on models of seamount production and associated geodynamic processes.Despite those differences,it is shown that all databases allow the identification of seamount lines both along the present-day Mid Ocean Ridge(MOR)system and on intraplate settings.Notably,those seamount lines do not coincide with the so-called hotspot tracks that commonly were defined by selectively focusing attention on the larger seamounts.Examination of all the databases also shows that distinction based only on seamount size between seamounts produced at Mid-Ocean Ridge(MOR)environments from those associated with mantle-plum fed-hotspot activity has been overestimated.This,combined with the fact that most seamount lines defined by the available databases can be traced back to past locations of MOR indicates that most of the present-day intraplate linear arrays of seamounts,which include some large seamounts,were not produced by the action of underlying mantle anomalies envisaged in the form of mantle plumes.The evidence presented here calls for a reassessment of the form in which volcanic and tectonic activities are conceptually related to each other. 展开更多
关键词 seamount origin chains of seamounts Spatial distribution of volcanism Intraplate volcanism Mid Ocean Ridge volcanism
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The formation of explosive volcanos at the circum-Pacific convergent margin during the last century 被引量:2
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作者 Fanfan TIAN Kun WANG +1 位作者 Guozhi XIE Weidong SUN 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2023年第1期75-83,共9页
The circum-Pacific convergent margin is known as"the Ring of Fire",with abundant volcano eruptions.Large eruptions are rare but very disastrous.It remains obscure how are large explosive volcanos formed and ... The circum-Pacific convergent margin is known as"the Ring of Fire",with abundant volcano eruptions.Large eruptions are rare but very disastrous.It remains obscure how are large explosive volcanos formed and where are the danger zones.Three largest eruptions since 1900,the Hunga Tonga-Hunga Ha’apai,the Mt.Pinatubo,and the Novarupta were found to be associated with subductions of volatile-rich sediments and located close to slab windows.Among them,the Hunga Tonga-Hunga Ha’apai is close to subducting seamount chains;the Mt.Pinatubo is right next to subducting fossil ridges.Both seamount chains and fossil ridges have water depths much shallower than the carbonate compensation depths(CCD)in the Pacific Ocean.Seismic image shows that a seamount is subducting towards the Novarupta volcano.Subduction of volatile-rich sediments and a slab window nearby are the two most important favorable conditions for catastrophic eruptions.Slab windows expose the mantle wedge to the hot asthenosphere,which increases the temperature and dramatically promotes the partial melting of the carbonate-fluxed domains,forming volatile-rich magmas that powered explosive eruptions. 展开更多
关键词 large explosive volcanos subducting seamount chains volatile-rich sediments slab windows TONGA
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无震脊或海山链俯冲对超俯冲带处的地质效应 被引量:13
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作者 鄢全树 石学法 《海洋学报》 CAS CSCD 北大核心 2014年第5期107-123,共17页
全球海底分布着众多的无震脊或海山链,且在太平洋、印度洋及大西洋均存在靠近俯冲带的海岭。除小安德列斯弧外的巴拉克达脊和蒂勃朗脊起源自转换断层外,一般认为它们由与板块构造动力学迥异的地幔柱动力学所形成的。在板块汇聚边缘处,... 全球海底分布着众多的无震脊或海山链,且在太平洋、印度洋及大西洋均存在靠近俯冲带的海岭。除小安德列斯弧外的巴拉克达脊和蒂勃朗脊起源自转换断层外,一般认为它们由与板块构造动力学迥异的地幔柱动力学所形成的。在板块汇聚边缘处,与扩张脊处所形成的正常洋壳一起,无震脊或海山链俯冲于陆缘弧或洋内弧之下,其对弧及弧后地区的地质效应(构造、地貌、地震以及岩浆作用等)有别于正常洋壳俯冲。无震脊或海山链的俯冲通常造成俯冲带地区的上驮板块的局部异常抬升、俯冲剥蚀作用效应的加强、海沟的向陆迁移以及地震强度的增加。同时,无震脊或海山链俯冲时,其携带的具富集地球化学特征的物质不仅影响着地幔地球化学,也对弧及弧后火山熔岩化学产生明显影响,并对超俯冲地区的热液矿床的形成产生重要影响。最后,本文指出了我国有关无震脊或海山链俯冲的可能的研究方向包括黄岩海山链俯冲对吕宋岛弧的可能影响、印度洋无震脊俯冲对青藏高原局部地区的影响,有我国学者参与的IODP344航次的研究对象——科科斯脊俯冲对哥斯达黎加地震成因的效应以及位于西太平洋地区靠近俯冲带的一些无震脊等。 展开更多
关键词 无震脊 海山链 超俯冲带 地质效应 地震 岩浆作用
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The geomorphological features and continuity of the Kyushu-Palau Ridge (KPR) 被引量:7
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作者 TANG Yong LI Mingbi +1 位作者 LI Jiabiao WU Zhaocai 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2011年第5期114-124,共11页
The Philippine Basin,surrounded by a series of oceanic trenches,is an independent deep ocean basin in the West Pacific Ocean.Its middle part is divided into three marginal sea sub-basins by the Kyushu-Palau and West M... The Philippine Basin,surrounded by a series of oceanic trenches,is an independent deep ocean basin in the West Pacific Ocean.Its middle part is divided into three marginal sea sub-basins by the Kyushu-Palau and West Mariana Ridges,namely,the West Philippine Basin,the Shikoku and Parece Vela Basins and the Mariana Trough.This paper,through the analysis of the geomorphologic features and gravity and magnetic characteristics of the basin and identification of striped magnetic anomalies,suggests that the entire Philippine Basin developed magnetic lineation of oceanic nature,and therefore,the entire basin is of the nature of oceanic crust.The basin has developed a series of special geomorphic units with different shapes.The KPR runs through the entire Philippine Basin.From the view of geomorphologic features,the KPR is a discontinuous seamount chain (chain-shaped seamounts) and subduction beneath the Japanese Island arc at the Nankai Trough which is the natural boundary between the basin and the Japanese Island arc.At the positions of 25 N,24 N,23 N and 18 N,obvious discontinuity is shown,which belongs to natural topographic discontinuity.Therefore,the KPR is topographically discontinuous. 展开更多
关键词 Kyushu-Palau Ridge (KPR) Philippine Basin seamount chain chain-shaped seamounts)
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南海中央海盆扩张期后海山链岩浆活动的热模拟研究 被引量:2
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作者 林巍 张健 李家彪 《海洋科学》 CAS CSCD 北大核心 2013年第4期81-87,共7页
壳幔黏性结构是影响南海中央海盆扩张期后海山链岩浆活动的主要因素,研究其岩浆活动发育机制具有重要的科学意义。利用重、磁、测深及岩样分析数据提供的地壳结构和热力学参数,通过FEM数值模拟,研究了南海中央海盆珍贝-黄岩海山链之下... 壳幔黏性结构是影响南海中央海盆扩张期后海山链岩浆活动的主要因素,研究其岩浆活动发育机制具有重要的科学意义。利用重、磁、测深及岩样分析数据提供的地壳结构和热力学参数,通过FEM数值模拟,研究了南海中央海盆珍贝-黄岩海山链之下黏性结构与岩浆熔融、运移活动的关系。根据黏性主要受压力和温度控制,但熔融期间的散热及脱水会增加黏性,设计了三种不同的黏性结构模型。计算结果表明:三种垂向黏性结构模型在不同的温度条件下,都可以使地幔熔融区最大熔融程度达到20%~25%。岩浆熔融程度与地幔热结构、熔融潜热和含水量有关,并受扩张速率影响,慢速扩张脊下的岩浆熔融程度相对较低。岩浆运移在扩张期后主要依靠减压熔融浮力,垂直上升至熔融区顶面后沿上倾面向脊轴运移。接近脊轴熔融带,部分熔融程度高,远离轴部熔融带,部分熔融程度较低。主要结论:南海中央海盆海底扩张期,海山链之下10 km深度具备形成拉斑玄武岩浆的条件;扩张期末,该地区25 km深度具备形成碱性玄武岩浆的条件。 展开更多
关键词 南海珍贝-黄岩海山链 扩张期后岩浆活动 黏性结构 减压熔融与上浮
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卡洛琳海山链成因及验证地幔柱成因假说的大洋钻探设想
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作者 张国良 《海洋地质与第四纪地质》 CAS CSCD 北大核心 2022年第5期172-177,共6页
地球上除了板块边界形成的岩浆活动之外,在板块内部也广泛存在大规模岩浆活动。其中,板内岩浆活动在大洋中形成了广泛的洋底高原和链状分布的海山。20世纪70年代,国际上提出“地幔柱”假说来解释洋底高原和有时间序列的海山链成因。“... 地球上除了板块边界形成的岩浆活动之外,在板块内部也广泛存在大规模岩浆活动。其中,板内岩浆活动在大洋中形成了广泛的洋底高原和链状分布的海山。20世纪70年代,国际上提出“地幔柱”假说来解释洋底高原和有时间序列的海山链成因。“地幔柱”假说认为,深部地幔物质上涌过程中包裹周围地幔物质,并在浅部上地幔发生高程度部分熔融,首先形成大规模洋底高原,接着在运动的板块之上形成有年龄序列的洋岛/海山链。然而,长期以来,并没有找到明确有成因联系的洋底高原-海山链系统,使得该假说一直没有得到证实。卡洛琳火山系统由西部的卡洛琳高原和东部卡洛琳洋岛/海山链组成。回顾了卡洛琳海山链火山岩已有研究成果,结果显示,卡洛琳海山链很可能是由一个年轻(约30 Ma)地幔柱形成。尽管如此,在卡洛琳洋底高原和东部海山链之间还有大量平顶海山尚未进行过火山岩采样研究,目前对该海山链系统是否由一个地幔柱“热点”连续形成还缺少明确证据。由于该区海山通常被沉积物或礁灰岩覆盖,常规采样困难。本文提出对该平顶海山区进行5个站位的钻探采样,并开展岩石学、年代学和地球化学研究,并与卡洛琳洋底高原和海山链进行详细对比,将有望检验“地幔柱”假说是否成立。 展开更多
关键词 地幔柱 洋底高原 海山链 板内火山 大洋钻探
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珍贝—黄岩海山链热-重力均衡动态调节机制 被引量:1
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作者 于磊 张健 +2 位作者 陈石 董淼 徐长仪 《地震学报》 CSCD 北大核心 2015年第4期565-574,711,共10页
珍贝—黄岩海山链作为我国南海的残留扩张中心,对其研究具有重要的科学意义.本文运用均衡学方法,通过重力异常数据反演了过珍贝—黄岩海山链剖面的地壳界面变化,同时计算了岩石圈热结构状态,在此基础上建立了珍贝—黄岩海山链的岩石圈... 珍贝—黄岩海山链作为我国南海的残留扩张中心,对其研究具有重要的科学意义.本文运用均衡学方法,通过重力异常数据反演了过珍贝—黄岩海山链剖面的地壳界面变化,同时计算了岩石圈热结构状态,在此基础上建立了珍贝—黄岩海山链的岩石圈地温结构模型.通过均衡分析方法,对剖面上测点的海底地形数据进行了热均衡和重力均衡分析,得到了热均衡和重力均衡形变量.结果表明,在珍贝—黄岩海山链高热流区域,热均衡作用可以产生最大约0.55km的形变,其重力均衡形变范围为0.77—1.89km.热均衡通过改变海底地形和地壳物质密度不断作用于重力均衡,重力又反过来作用于热均衡,形成了热均衡-重力均衡动态调节机制. 展开更多
关键词 珍贝-黄岩海山链 岩石圈 热均衡 重力均衡
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卡洛琳地幔柱活动减弱过程中岩浆成因和源区组成演化
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作者 赵晗 张国良 +1 位作者 张吉 王帅 《海洋地质与第四纪地质》 CAS CSCD 北大核心 2022年第4期122-134,共13页
地幔柱活动不同阶段具有不同的岩浆作用产物,由楚克(14.8~4.3 Ma)、波纳佩(8.7~<1 Ma)、科斯雷(2~1 Ma)等洋岛构成的卡洛琳海山链是地幔柱活动不同阶段的典型例子,研究该海山链中不同洋岛地球化学特征的差异有助于加深对地幔柱晚期... 地幔柱活动不同阶段具有不同的岩浆作用产物,由楚克(14.8~4.3 Ma)、波纳佩(8.7~<1 Ma)、科斯雷(2~1 Ma)等洋岛构成的卡洛琳海山链是地幔柱活动不同阶段的典型例子,研究该海山链中不同洋岛地球化学特征的差异有助于加深对地幔柱晚期活动规律的认识。本研究对获取的楚克、科斯雷样品进行全岩主量、微量元素及矿物电子探针分析,并与波纳佩岛进行对比。科斯雷和楚克由霞石岩和碱性玄武岩组成,在微量元素配分模式上体现出典型碱性洋岛玄武岩的特征。这些样品的橄榄石斑晶具有与辉石岩源区夏威夷OIB橄榄石类似的高Ni、低Ca-Mn的特征,反映其地幔源区可能存在辉石岩。科斯雷霞石岩橄榄石斑晶内存在含碳酸盐的熔体包裹体,反映CO_(2)在地幔熔融和岩浆成因过程中起到了重要作用。从楚克、波纳佩到科斯雷,La/Sm比值逐渐增大,地幔熔融程度逐渐降低。Nb/Nb^(*)随着La/Sm、Sm/Yb升高和SiO_(2)降低有逐渐降低的趋势,与地幔熔融程度降低过程中CO_(2)作用的增强有关。研究认为,楚克、波纳佩、科斯雷等洋岛火山岩的地球化学变化由卡洛琳地幔柱热点活动逐渐减弱导致,随着地幔柱活动性减弱,CO_(2)在火山岩成因上起到越来越明显的作用。 展开更多
关键词 地幔源区 碱性玄武岩 部分熔融程度 橄榄石 卡洛琳海山链
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Plate boundary processes of the Caroline Plate 被引量:2
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作者 Zhen ZHANG Sanzhong LI +3 位作者 Guangzeng WANG Yanhui SUO Gang WANG Pengcheng WANG 《Science China Earth Sciences》 SCIE EI CAS CSCD 2022年第8期1554-1567,共14页
The tectonic evolution of the Caroline Plate during the Oligocene to Early Miocene was mainly controlled by two fulcrums.The west fulcrum at Palau Island remained fixed during 29-25 Ma as the Ayu Trough rifted and pro... The tectonic evolution of the Caroline Plate during the Oligocene to Early Miocene was mainly controlled by two fulcrums.The west fulcrum at Palau Island remained fixed during 29-25 Ma as the Ayu Trough rifted and produced the abyssal hills parallel to its boundaries,and the Pacific Plate and part of the Caroline Plate subducted to the north.At the northeast corner of the Caroline Plate,the east fulcrum is surrounded by a series of arc seamount chains.These chains resulted from the convergence between the Caroline Plate and the Pacific Plate and crustal softening of the northeastern Caroline Plate induced by the Caroline Hotspot at~25 Ma.This softening of the crust also led to the dysfunction of the east fulcrum,and the west fulcrum migrated south,which caused dextral motion along the Ayu Rift and the development of an en echelon structure.The Yap Trench was a part of the spreading center in the Parece-Vela Rift at~29 Ma.However,sinistral motion along the Parece-Vela Rift at around 20-15 Ma led to the exposure of the subducted Yap Trench and left a triangular region with distinctive geophysical characteristics in the surrounding area. 展开更多
关键词 Caroline Plate Yap Trench Plate boundary seamount chain
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麦哲伦海山链富钴结壳成矿区域地质背景 被引量:2
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作者 梁德华 朱本铎 《南海地质研究》 2002年第1期84-90,共7页
本文根据我国调查成果和充分利用DSDP资料,通过综合研究分析认为:麦哲伦成矿区,实际上是一条呈北西方向展布的、规模宏大的海山链。该海山链包含十多座海山,每座海山均属平顶山类型。几乎每座海山都具有从山顶往下,由平坦→陡峭→缓坡... 本文根据我国调查成果和充分利用DSDP资料,通过综合研究分析认为:麦哲伦成矿区,实际上是一条呈北西方向展布的、规模宏大的海山链。该海山链包含十多座海山,每座海山均属平顶山类型。几乎每座海山都具有从山顶往下,由平坦→陡峭→缓坡变化的规律。即山顶平坦,海山上、中部山坡陡峭,海山中、下部山坡变缓。依据海山形态和其坡度的变化特点,每座海山可划分出台地、陡坡带和缓坡带等三个地貌单元,根据区域地层和海洋磁异常条带(M_(25)M_(38))展布特征综合分析,推断麦哲伦海山链所在的位置,原来是一条规模宏大的、走向北西的转换断层。该断层控制着麦哲伦海山链富钴结壳的成矿作用。 展开更多
关键词 麦哲伦海山链 富钴结壳 转换断层
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