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Study on the Tectonics and Sedimentation of the Arc-arc Collision Type sedimentary Basins

弧-弧碰撞型沉积盆地构造与沉积研究

基本信息

批准号：
07454118
负责人：
AMANO Kazuo
金额：
$ 1.09万
依托单位：
Ibaraki University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1997
项目状态：
已结题

项目摘要

The south Fossa Magna is well known as a zone consisting of islands which belonged to the paleo-Izu-Bonin arc and collided and accreted to the Honshu arc due to the movement of the Philippine Sea plate in a north-west direction. There were four times after 15Ma. The purpose of this study is to clarify the relationship between multiple collision tectonics and sedimentation in the South Fossa Magna. The results are summarized as follows.(1) The trough-fill sediments related to the collision of the Tanzawa block are mainly composed of turbidite and debrite. They show a trend of change of clast type and upward coarsening sequences reflecting the upheaval movement of the hinterland according to the collision of the Tanzawa block.(2) The geological features of the Misaka block (second collision) was not well understood. Sedimentological studies clarified that the Misaka block constitutes a set of forearc, volcanic arc and backarc rift zone.(3) The Kushigatayama block that was thought to be the first collided massif in the South Fossa Magna is mainly composed of re-sedimented hyaloclastite and mass flow deposits. These facts show that the Kushigatayama block must have been a forearc or backarc region.(4) some of the dykes older than 2Ma, distributed in the area to the north of the Tonoki-Aikawa tectonic line, rotated clockwise about 34 degrees based on paleo-magnetic studies. This indicates that part of the Honshu arc rotated clockwise accompanied by the blocks.

南Fossa Magna是一个众所周知的由岛屿组成的区域，这些岛屿属于古伊豆-波宁弧，由于菲律宾海板块向西北方向的运动而碰撞并增加到本州弧。15Ma之后有4次。本研究的目的是阐明南大窝地区多次碰撞构造与沉积的关系。结果总结如下：(1)与坦泽地块碰撞有关的槽状充填沉积物主要由浊积岩和碎屑组成。它们表现出碎屑类型变化和向上粗化序列的趋势，反映了由于坦泽地块的碰撞而引起的腹地隆起运动。(2) Misaka地块（第二次碰撞）地质特征尚不清楚。沉积学研究表明，Misaka地块由一套弧前、火山弧和弧后裂谷带组成。(3) Kushigatayama地块主要由再沉积透明碎屑岩和块状流沉积组成，被认为是南大窝的第一个碰撞地块。这些事实表明，Kushigatayama地块一定是一个弧前或弧后区域。(4)古地磁研究表明，分布在桐木-相川构造线以北的部分岩脉年龄在2Ma以上，沿顺时针方向旋转约34度。这表明本州弧的一部分随着木块顺时针旋转。