九州帕劳海脊地壳结构及其形成演化的研究综述  

Reviews of the Study on Crustal Structure and Evolution of the Kyushu-Palau Ridge

作　　者：张洁[1,2] 李家彪[1,2] 丁巍伟[1,2] 

机构地区：[1]国家海洋局第二海洋研究所,浙江杭州310012 [2]国家海洋局海底科学重点实验室,浙江杭州310012

出　　处：《海洋科学进展》2012年第4期595-607,共13页Advances in Marine Science

基　　金：国家自然科学基金项目--南海西南次海盆中脊3D地震成像及其构造演化(91028006);国家自然科学基金项目--南海北部珠江海底峡谷现代沉积过程研究(41106046);海洋公益性行业科研专项--外大陆架划界与国际海底资源关系评估辅助决策系统研制和示范应用(201205003);国家海洋局第二海洋研究所基本科研业务费专项--西南印度洋中脊热液喷口区深部构造3D地震成像(JT1101);国家海洋局第二海洋研究所基本科研业务费专项--现代珠江海底峡谷物质沉积与运移(JT1002)

摘　　要：九州-帕劳海脊(KPR)位于菲律宾海中央,近南北走向。形成于太平洋板块向西的俯冲,裂离于帕里西维拉海盆和四国盆地的弧后扩张,是老的伊豆-小笠原-马里亚纳岛弧(IBM)的残留弧。裂离期间同时受到垂向旋转应力和水平挤压力的共同作用,这是形成九州-帕劳海脊现今狭长的几何形态的主要原因之一。九州-帕劳海脊南北部地壳结构可总结为P波波速为7.1～7.3km/s下地壳;P波波速为6.1～6.3km/s的中地壳;P波波速为4.5～5.5km/s上地壳。九州-帕劳海脊北段,30°N以北区和25°N以南区的地壳厚度普遍在10～15km,25°～30°N之间的地壳厚度普遍大于15km。九州-帕劳海脊的中段的地壳厚度变化较大,而且未识别出中地壳的存在,为不成熟的岛弧地壳。海脊南段与北段相似,具三层的地壳结构,但地壳厚度小于北侧,基本上大于10km。整个九州-帕劳海脊处的地壳厚度普遍厚于两侧海盆的地壳厚度。The kyushu-Palau Ridge （KPR） is situated in the center of the Philippine Sea and extends in a north-south direction. It was formed by the westward subduction of the Pacific Plate and then separated from the Shikoku and Parece Vela Basins by back-arc spreading. It is therefore considered to be a remnant arc of the old Izu-Ogasawara （Bonin）-Mariana Island Arc （IBM）. During the spreading both the horizontal compression stress and the vertical rotation stress act on it, forming the present KPR with a narrow mor- phology. The crustal structure in the northern and southern parts of the KPR can be characterized with a P-wave velocity of 7.1~7.3 km/s in the lower crust, a P-wave velocity of 6.1~6.3 km/s in the middle crust and a P-wave velocity of 4.5~5.5 km/s in the upper crust. In the northern segment of the KPR, the thickness of the crust ranges generally from 10 km to 15 km to the north of 30~N and the south of 25~N. In the region between 30~N and 25~N the thickness of the crust is commonly greater than 15 km. In the mid- dle segment of the KPR, the crust thickness varies greatly and the middle crust has not been recognized, being probably an immature crust of island arc. Similarly, the southern segment of the KPR consists also of a three-layer crust structure, but the crust thickness there is smaller than the northern segment, being roughly thicker than 10 kin. The thickness of the crust beneath the KPR is generally thicker than that of the basins on both sides of the ridge.

关 键 词：菲律宾海板块 九州-帕劳海脊 伊豆-小笠原-马里亚纳岛弧 地壳结构 形成机制 构造演化 

分 类 号：P736.14[天文地球—海洋地质]