| 摘要: |
| 采用中国科学院海洋研究所“科学1号”调查船及国家海洋局“向阳红9号”调查船,于20世纪90年代以来在冲绳海槽宫古段进行海底地形及反射地震调查,所取得的数据,首次详细展示了冲绳海槽宫古段南北长约200km区域内海底火山的形态及其空间分布特征。在本段冲绳海槽发育的中轴火山和岛弧火山,分别位于中央地堑和海槽盆地东部边缘紧靠琉球岛弧的西侧。岛弧火山连续性强,总体上自东北而西南都有分布;中轴火山不如岛弧火山的连续性强,只在崂山段、黄岛段、胶南段、莱西段、城阳段和李沧段分布。中轴火山是在中央地堑之后发育的。中轴火山的发育不仅改变了原来中央地堑的位置,也改变了原来中央地堑的形态。中央地堑的左旋雁行排列,以及其形态的改变都是由于中轴火山发育的结果。中央地堑的右旋展布以及海底火山对中央地堑的改造,标志着冲绳海槽的演化已经在拉张和沉降的基础上进入到一个更高级的演化阶段(海底扩张),在岩浆供应不太充足的条件下,海底火山活动是冲绳海槽低速扩张的一种形式,海底扩张沿中央地堑正在进行。 |
| 关键词: 冲绳海槽宫古段 中央地堑 形态分布 海底火山 海底扩张 |
| DOI： |
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| 基金项目:中国科学院知识创新工程重要方向项目,KZCX2-YW-211-01号;海洋所领域前沿项目,20032217号。 |
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| TOPOGRAPHY AND DISTRIBUTION OF CENTRAL GRABEN VOLCANOES IN MIYOKO SECTION OF OKINAWA TROUGH |
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LUAN Xi-Wu, YUE Bao-Jing
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Key Lab of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071
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| Abstract: |
| Based on geophysical data obtained in recent years by R/V “Science 1” of Institute of Oceanology, Chinese Academy of Sciences (IOCAS) and R/V “Xiangyanghong 9” of State Oceanic Administration (SOA) in a 200-km long zone of Miyoko Section of Okinawa Trough, the topography and distribution of central graben volcanoes inside the trough was studied in great detail for the first time. Two volcanic chains have been clearly recognized whose central axis located within the central graben and the island arc volcanic chain which located at the west side of Ryukyu Island Arc in this section. The island volcanic chain has a good continuity, but the axis volcanic chain is sporadic comparatively. From seismic profile, we understand that the development of central axis volcanic chain is after the development of central graben and has effect on the topography and distribution of central graben. None of transform faults is found in this section, but we believe that in the low spreading cases, when there is short of magma supply, it is reasonable that the formation of new oceanic crust took the form of volcanism. So, this paper pointed out that the volcanism within the central graben is a form of new crust formation, and sea floor spreading is on going along the central graben of Okinawa Trough. |
| Key words: Okinawa Trough Miyoko Section, Central graben, Topography and distribution, Volcano, Sea floor spreading |
