冲绳海槽及邻区重力异常特征及其地质意义  

Gravity Anomaly and Its Geological Implications of the Okinawa Trough and Adjacent Areas

作　　者：尚鲁宁[1] 张训华[2,3] 韩波[2,3] 

机构地区：[1]中国海洋大学环境科学与工程学院,山东青岛266100 [2]国土资源部海洋油气资源与环境地质重点实验室,山东青岛266071 [3]青岛海洋地质研究所,山东青岛266071

出　　处：《中国海洋大学学报（自然科学版）》2016年第6期68-73,共6页Periodical of Ocean University of China

基　　金：国家重点基础研究发展计划项目(2013CB429701)资助~~

摘　　要：通过分析冲绳海槽及邻区自由空间重力异常和布格重力异常的分布特征,对其构造地质学意义进行了定性研究。冲绳海槽空间重力异常和布格重力异常较高,与其下地幔物质上涌引起的质量盈余有关;海底正向地形单元、基底隆起等具有较高的空间重力异常,而地壳浅部低密度岩浆房表现为较低的空间重力异常;布格重力异常及其上延结果反映了地壳厚度的变化,冲绳海槽地壳显著减薄,台湾地区地壳显著增厚;琉球岛弧及弧前布格重力异常受菲律宾海板片俯冲和岛弧地壳结构的共同影响,俯冲洋壳与琉球岛弧地壳的接触带位于琉球海沟以西,大致与120mGal布格重力异常等值线相对应。Tectonic characteristics of the Okinawa Trough and adjacent areas were studied through detailed analysis of free-air gravity and Bouguer gravity anomalies.Both high free-air and Bouguer gravity anomalies indicates the excess mass induced by the upwelling of the mantle beneath the Okinawa Trough.Submarine topographic highs and basement highs generates high free-air anomalies,whereas the shallow buried low density melt reseviors within the crust are corresponding to low free-air anomalies.Bouguer gravity anomaly and its upward continuations show the variation of the crustal thickness.The Okinawa Trough has extremly thinned crust,whereas the low Bouguer gravity anomaly of Taiwan indicates thickened crust produced by the orogenesis.The Bouguer gravity anomaly of the Ryukyu Arc and forearc areas is influenced by both the subducting Philippine Sea slab and the Ryukyu crust.The subducting oceanic crust contacts with the obducting Ryukyu crust in the forearc area,and the 120 mGal isoline of Bouguer anomaly roughly delineates this boundary.

关 键 词：冲绳海槽 重力异常 海底构造 

分 类 号：P736.1[天文地球—海洋地质]