西菲律宾海盆DSDP-292站位熔岩的岩浆过程研究  

A study on the magmatic processes of lavas from cores of the drilling site DSDP-292 in the West Philippine Basin

作　　者：袁龙 鄢全树 石学法 YUAN Long;YAN Quan-shu;SHI Xue-fa(Key Laboratory of Marine Geology and Metallogeny,First Institute of Oceanography Ministry of Natural Resources,Qingdao,Shandong 266061 China;Laboratory for Marine Geology,Laoshan Laboratory,Qingdao,Shandong 266061,China;Key Laboratory of Deep Sea Mineral Resources Development,Shandong(preparatory),Qingdao,Shandong266061,China)

机构地区：[1]自然资源部第一海洋研究所,海洋地质与成矿作用重点实验室,山东青岛266061 [2]崂山实验室海洋地质过程与环境功能实验室,山东青岛266061 [3]山东省深海矿产资源开发重点实验室,山东青岛266061

出　　处：《矿物岩石地球化学通报》2023年第4期769-785,共17页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：崂山实验室科技创新项目(LSKJ202204103);国家重点研发计划项目(2017YFC0602305);国家自然科学基金资助项目(41322036);中国博士后科学基金资助项目(2023M734098);山东省“泰山学者”建设工程项目。

摘　　要：自新生代早期以来,菲律宾海板块发生了一系列的板内岩浆活动,形成了大量的海底高原(本哈姆高原和乌尔达内塔高原等)和小海山。关于这些海底高原和小海山的成因,目前仍存在争议,尤其是其深部动力学背景和精细的岩浆过程需要进一步制约。本文对深海钻探计划(DSDP)31航次(292站位)期间在本哈姆隆起获取的玄武岩中的斜长石和单斜辉石开展了详细的岩相学和原位主、微量元素地球化学分析。结果表明,斜长石具有多种不平衡特征,其核-边结构主要受到多期次岩浆补给影响。292站位熔岩的研究表明,本哈姆隆起熔岩至少经历了两期岩浆活动。温压计算结果表明,斜长石和单斜辉石斑晶的核部和边部分别形成于地壳深部和浅部岩浆房。结合本哈姆隆起其他位置样品的历史研究成果,本文认为本哈姆隆起具有板内的构造背景,可能与地幔柱有关。Since the Early Cenozoic,a series of intraplate magmatisms had occurred and a lot of oceanic plateaus(eg.Benham Plateau and Urdaneta Plateau)and seamounts had been formed.The petrogenesis of these oceanic plateaus and seamounts is still in debate,and their deep dynamic backgrounds and delicate magmatic processes are especially needed to be further constrained.In this study,we have carried out detailed petrographic and in situ geochamical studies of trace and major elements of plagioclases and clinopyroxenes in basalts collected from drlling cores of the DSDP-292 site in the Benham Rise.The results show that the plagioclases have various disequilibrium characteristics of core-rim textures which were mainly affected by the multi-phase magma replenishment.The Benham Rise basalts in the DSDP-292 site were formed at least by two times of magmatism.In addition,the calculated results of temperature and pressure of minerals in-dicate the cores and rims of the plagioclase and clinopyroxene phenocrysts were formed in the deep and shallow crustal magma chambers,respectively.Combined with results of the previous studies of samples collected in other site within the Benham Rise,it is believed that the Benham Rise coule be formed in association with the mantle plume in an intraplate tectonic background.

关 键 词：本哈姆隆起 岩浆活动 环带结构 岩浆混合 

分 类 号：P588.11[天文地球—岩石学]