地质科学2024，Vol.59Issue(6)：1708-1721,14.DOI:10.12017/dzkx.2024.117
西太平洋雅浦海沟弧前辉长岩的成因及其地质意义:来自矿物地球化学的制约
Genesis and geological significance of the Yap forearc gabbro in the western Pacific:Constraints from mineral geochemistry
摘要
Abstract
Subduction zones are the key link between the surface and the deep earth.The evolution of subduction zones and the internal material transfer mechanism are not clear enough.One of the difficulties is the lack of carriers to record the early arc magmatic process.The Yap subduction zone is widely believed to represent the early stage of the evolution of the subduction zone system.At present,the geochemical research on the Yap Island arc is relatively insufficient,especially the lack of research on mineralogy and single mineral geochemistry.This work analyzes the major and trace element compositions of plagioclase and clinopyroxene from five gabbro in the southern forearc area of the Yap Island arc based on EMPA and LA⁃ICP⁃MS.Compared with samples from arcs and back⁃arc basins,the clinopyroxene and plagioclase of the gabbro in this study are more depleted in rare earth elements(REE),especially in light REE,while also depleted in high field strength elements(HFSE)such as Zr and Hf and enriched in large ion lithophile elements(LILE).The plagioclase in the gabbro shows high Al2O3 and high An contents,with an An value as high as 92.51,significantly higher than that of the back⁃arc basins.Combined with the previous work,we further determined that the magma of these gabbro originated from the forearc environment and may be the product of partial melting of the depleted mantle.The exposure of these forearc plutonic intrusive rocks(gabbro)further verifies the intense tectonic erosion process caused by the collision between the Caroline ridge and the Yap Island arc,and the gabbro may record key information on the initial stage of the subduction zone.关键词
雅浦海沟/俯冲带/辉长岩/岛弧演化Key words
Yap Trench/Subduction zone/Gabbro/Island arc evolution分类
天文与地球科学引用本文复制引用
王政刚,陈灵,唐立梅,田原..西太平洋雅浦海沟弧前辉长岩的成因及其地质意义:来自矿物地球化学的制约[J].地质科学,2024,59(6):1708-1721,14.基金项目
国家自然科学基金面上项目(编号:41976072)资助 （编号:41976072）
