欧亚板块东缘新生代盆地成因:右行剪切拉分作用

GENESIS OF CENOZOIC BASINSIN THE EASTERN MARGIN OF EURASIA PLATE:DEXTRAL PULLING APART

许浚远 张凌云

Xu Junyan Zhang Lingyun

欧亚板块东缘新生代盆地具有惊人相似的几何学特征,盆地边界均为Y 断裂及R,R'断裂,平面形态呈准菱形(或Z形),均为右行剪切拉分盆地。此拉分始于印度板块与欧亚板块碰撞,成形于欧亚板块向北退却与太平洋板块之间的右行剪切作用。太平洋西北边缘独特的裂谷型"弧后盆地"现象,恰是特有的印度板块与欧亚板块碰撞造成的。据沉降及变形特征,其构造演化可划分为3 个一级阶段:右行走滑拉分裂谷阶段(始新世中期-中新世早期)、挤压隆起阶段(中新世中期) 和后裂谷沉降阶段(中新世中晚期-第四纪)。

All Cenozoic basinsin the east margin of Eurasia Plate have delimited by Y,Rand R'fractures.Such geo metrical similarities between the basins of different magnitudes suggest that all of them are dextral pull apart basins. The dextral pulling apartstarted at the beginning of collision between India and Eurasia Plates and developed during the north retreat process of Eurasia Plate which led to right lateral shearing subduction zone between Pacific and Eura sia Plates.The unique backarc basins resulted from the unique collision between India and Pacific Plates.The tectonic evolution ofthem can be divided intothree first order stages:(1)pull-apart rifting (45 Ma～17 or 15 Ma)stage;(2) compression uplifting (around 17 Ma～15 Ma);(3)postrfifting (17 or 15 Ma～0 Ma)stage.

10.11743/ogg19990301