Geophysical study of the Solomon islands plate convergence

所罗门群岛板块汇聚的地球物理研究

基本信息

批准号：
07044070
负责人：
SUYEHIRO Kiyoshi
金额：
$ 3.58万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for international Scientific Research
财政年份：
1995
资助国家：
日本
起止时间：
1995 至无数据
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07044070/
关键词：
Solomon Arc OBS MCS subduction oceanic plateau

项目摘要

The Solomon island arc area is a complex plate convergence Zone. On the northern side is the North Solomon Trench at which the Pacific plate with the Ontong Java plataeau seems to be in collision with the arc system. Another trench on the southern side is the San Cristobal Trench, where the Indo-Australian plate and the Solomon Sea plate are presently subducting beneath the Solomon arc.We have carried out a Japan-U.S.joint geophysical survey in the Solomon Sea region using the R/V Maurice Ewing equipped with a 130-ch multi-channel seismic reflection survey system and a 140-liter airgun array during the period of October 17 to November 19,1995. The Japanese side brought 18 digital compact ocean bottom seismographs (OBS's) which were placed along a 464-km long transect of the whole arc system. Airgun shooting was made for more than 4,000 km long covering the whole Solomon Islands region. Thus, we have succeeded in acquiring data to obtain the whole crustal structure and to test different collision models of the Ontong Java plateau. Preliminary look into the data shows that the subduction of the Ontong Java plateau seems to be ongoing despite the general notion that the present subduction is only from the southern side. Also, it is more likely that the plateau is mostly subducting rather than wedging upward onto the arc. This suggests that the fate of an oceanic plateau is such that it is mostly recycled into the mantle and does not significantly contribute to the increase of continental volume.

所罗门岛弧区是一个复杂的板块汇聚带。北侧是北所罗门海沟，太平洋板块与翁东爪哇高原似乎与弧系统发生碰撞。南侧的另一个海沟是圣克里斯托瓦尔海沟，印度-澳大利亚板块和所罗门海板块目前正在这里俯冲到所罗门弧之下。我们利用R在所罗门海地区进行了日美联合地球物理调查。 /V Maurice Ewing在10月17日至11月期间配备了130通道多道地震反射勘测系统和140升气枪阵列1995 年 19 月。日本方面带来了18台数字紧凑型海底地震仪（OBS），这些地震仪沿着整个弧线系统464公里长的横断面放置。气枪射击范围超过4000公里，覆盖了整个所罗门群岛地区。因此，我们成功地获取了数据，获得了整个地壳结构并测试了翁通爪哇高原的不同碰撞模型。对数据的初步研究表明，翁通爪哇高原的俯冲似乎仍在继续，尽管普遍认为目前的俯冲仅来自南侧。此外，更有可能的是，高原主要是在俯冲，而不是向上楔入弧上。这表明海洋高原的命运是它大部分被再循环到地幔中，并且对大陆体积的增加没有显着贡献。