基于重力数据的翁通爪哇海台密度结构研究  

Crustal Density Structure of Ontong Java Plateau Based on Gravity Data

作　　者：于鸿铭 宫伟[1,2] 徐冲 邢军辉[1,2] 林琦 Yu Hongming;Gong Wei;Xu Chong;Xing Junhui;Lin Qi(College of Marine Geosciences,Ocean University of China,Qingdao 266100,China;Key Laboratory of Submarine Geosciences and Prospecting Techniques,Ministry of Education,Qingdao 266100,China;Qingdao Institute of Marine Geology,China Geological Survey,Ministry of Natural Resources,Qingdao 266237,China)

机构地区：[1]中国海洋大学海洋地球科学学院,山东青岛266100 [2]中国海洋大学海底科学与探测技术教育部重点实验室,山东青岛266100 [3]自然资源部中国地质调查局青岛海洋地质研究所,山东青岛266237

出　　处：《中国海洋大学学报（自然科学版）》2024年第11期103-115,共13页Periodical of Ocean University of China

基　　金：国家自然科学基金项目(41906048,91858215)资助。

摘　　要：翁通爪哇海台位于太平洋西侧,是世界上体积最大、地壳最厚的海台,也是少数正在与岛弧汇聚的海台之一。本文利用可用的自由空气重力异常数据反演了翁通爪哇海台的地壳密度结构。结果显示,研究区内翁通爪哇海台的地壳密度由南西向北东逐渐降低,在研究区南西侧的斯图尔特隆起附近有高密度入侵现象。本文认为,海台地壳密度差异是由于92 Ma前的第二期地幔柱事件中,基性较强、密度较大的新一期岩浆对原始海台不同区域的差异性影响造成的;高密度入侵可以用20~25 Ma前翁通爪哇海台与所罗门弧的碰撞事件来解释,该碰撞事件使海台地壳深部的部分高密度玄武岩熔体沿斯图尔特隆起内部新产生的或被重新激活的断层、裂缝上升,形成高密度入侵体。The Ontong Java Plateau(OJP),located in the west Pacific Ocean,is the largest oceanic plateau with the thickest crust in the world,and is one of the few plateaus that are converging with the island arc.In this paper,we used available free-air gravity anomaly data to invert the crustal density structure of OJP.The results show that the crustal density of the OJP in the study area gradually decreases from southwest to northeast,and there is a high-density intrusion in the southwest side near the Stewart Rise.We suggest that the crustal density difference could result from the different influence of the basaltic and dense magma on different areas in the second phase of the mantle plume event(~92 Ma ago),and the high-density intrusion could be explained by the collision event between the OJP and the Solomon Arc 20~25 Ma ago which caused the ascent of the basaltic melt from the deep of the plateau crust along newly created or reactivated faults and fissures within the Stewart Rise,resulting in high-density intrusive bodies.

关 键 词：翁通爪哇海台 洋底高原 密度反演 地壳密度结构 

分 类 号：P738.2[天文地球—海洋地质] P736.1[天文地球—海洋科学]