海洋学报(中文版)
海洋學報(中文版)
해양학보(중문판)
ACTA OCEANOLOGICA SINICA
2014年
5期
107-123
,共17页
无震脊%海山链%超俯冲带%地质效应%地震%岩浆作用
無震脊%海山鏈%超俯遲帶%地質效應%地震%巖漿作用
무진척%해산련%초부충대%지질효응%지진%암장작용
aseismic ridge%seamount chain%supra-subduction zone%geological effects%earthquake%mag-matism
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。
全毬海底分佈著衆多的無震脊或海山鏈,且在太平洋、印度洋及大西洋均存在靠近俯遲帶的海嶺。除小安德列斯弧外的巴拉剋達脊和蒂勃朗脊起源自轉換斷層外,一般認為它們由與闆塊構造動力學迥異的地幔柱動力學所形成的。在闆塊彙聚邊緣處,與擴張脊處所形成的正常洋殼一起,無震脊或海山鏈俯遲于陸緣弧或洋內弧之下,其對弧及弧後地區的地質效應(構造、地貌、地震以及巖漿作用等)有彆于正常洋殼俯遲。無震脊或海山鏈的俯遲通常造成俯遲帶地區的上馱闆塊的跼部異常抬升、俯遲剝蝕作用效應的加彊、海溝的嚮陸遷移以及地震彊度的增加。同時,無震脊或海山鏈俯遲時,其攜帶的具富集地毬化學特徵的物質不僅影響著地幔地毬化學,也對弧及弧後火山鎔巖化學產生明顯影響,併對超俯遲地區的熱液礦床的形成產生重要影響。最後,本文指齣瞭我國有關無震脊或海山鏈俯遲的可能的研究方嚮包括黃巖海山鏈俯遲對呂宋島弧的可能影響、印度洋無震脊俯遲對青藏高原跼部地區的影響,有我國學者參與的IODP344航次的研究對象---科科斯脊俯遲對哥斯達黎加地震成因的效應以及位于西太平洋地區靠近俯遲帶的一些無震脊等。
전구해저분포착음다적무진척혹해산련,차재태평양、인도양급대서양균존재고근부충대적해령。제소안덕렬사호외적파랍극체척화체발랑척기원자전환단층외,일반인위타문유여판괴구조동역학형이적지만주동역학소형성적。재판괴회취변연처,여확장척처소형성적정상양각일기,무진척혹해산련부충우륙연호혹양내호지하,기대호급호후지구적지질효응(구조、지모、지진이급암장작용등)유별우정상양각부충。무진척혹해산련적부충통상조성부충대지구적상타판괴적국부이상태승、부충박식작용효응적가강、해구적향륙천이이급지진강도적증가。동시,무진척혹해산련부충시,기휴대적구부집지구화학특정적물질불부영향착지만지구화학,야대호급호후화산용암화학산생명현영향,병대초부충지구적열액광상적형성산생중요영향。최후,본문지출료아국유관무진척혹해산련부충적가능적연구방향포괄황암해산련부충대려송도호적가능영향、인도양무진척부충대청장고원국부지구적영향,유아국학자삼여적IODP344항차적연구대상---과과사척부충대가사체려가지진성인적효응이급위우서태평양지구고근부충대적일사무진척등。
There distributed numerous aseismic ridges and seamount chains in global seafloor .Of them , some remarkable ridges close to subduction zones exist in Pacific Ocean ,Indian Ocean and Atlantic Ocean . In addition to Barracuda and Tiburon ridges (close to the Lesser Antilles arc) originating from transform fault ,the genesis of most intra-plate aseismic ridges and seamount chains is related to mantle geodynamics (different from plate tectonics) .At plate convergent margins ,these aseismic ridges and seamount chains , together with normal oceanic crust formed in spreading mid-oceanic ridges ,have been or are subducted be-neath continental arc or intra-oceanic arc .The geological effects (e .g ,structure ,morphology ,earthquake and magmatism ) of the subduction of aseismic ridges and seamount chains on supra-subduction zones (SSZ) are obviously different from those of normal oceanic crust .The subduction of aseismic ridges and seamount chains often cause locally abnormal elevations of upper plate ,enhancing subduction-induced ero-sion ,landward displacement of trench ,and the enhancement of intensity of earthquakes .Meanwhile , w hen aseismic ridges and seamount chains are subducted ,they not only affect mantle geochemistry due to its entrained enriched geochemical characteristics ,but play a significant role on geochemistry of arc and back-arc lavas and the formation of hydrothermal deposits on the SSZ setting .Finally ,this paper point out possible research areas related to the subduction of aseimic ridges and seamount chains in China as follow s , such as possible effects of subduction of the Huangyandao seamount chain on Luzon arc ,effects of subduc-tion of several aseismic ridges in the Indian Ocean on local areas of Tibetan Plateau ,and effects of subduc-tion of the Cocos ridge on the Costa Rica seismogenesis (targeted area of IODP leg 344) ,and some aseis-mic ridges (close to the Subduction zone) dispersed in west Pacific ,etc .