摘要
在北秦岭北西—北西西向显生宙造山带核部鉴别出与其斜交的北西向古构造带,可能为被改造了的北北西向新元古代造山带的残迹。强烈的区域变形(959～889Ma)和变质特别是高压变质(996～750Ma)以及S→I→A型花岗岩演化(959～725Ma)揭示,该造山带可能经历了同碰撞、晚碰撞到碰撞后伸展的碰撞造山旋回。由此推测,在该区新元古代时期可能发生了陆块的汇聚与裂解;当时造山带的原始方位及两侧汇聚陆块的边界可能是北北西向,汇聚方向可能是北东东向。
A NW-trending tectonic belt,possibly a trace of a modified NNW-trending Neoproterozoic orogenic belt,has been recognized in the core of the North Qinling NW-WNW-trending Phanerozoic orogenic belt which strikes obliquely to the strike of the former.Strong regional deformation(959-889Ma )and metamorphism,especially high-pressure metamorphism(996-750Ma ),as well as evolution of gran-ites from S type→I type→A type(959-725Ma )reveal that the Neoproterozoic belt possibly experienced a collisional orogenic cycle from syn-collision through late-collision to post-collision.This suggests that con-vergence and breakup of continental blocks may have occurred in the core of the Qinling belt in the Neoproterozoic.Moreover,the Neoproterozoic belt may have trended originally in a NNW-SSE direction and the direction of convergence may have been NEE.This study has great significance for the recon-struction of the Proterozoic orogenic belt and supercontinent in northern China.However,whether the convergence and assembly took place through the whole Qinling orogenic belt or not still needs further study.
出处
《地质通报》
CAS
CSCD
北大核心
2002年第8期516-522,共7页
Geological Bulletin of China
基金
国家自然科学基金项目(编号:40072065
140032010-C)
西北大学重点实验室基金资助。
关键词
新元古代
碰撞造山带
岩体区域变形
花岗岩
古构造
秦岭
regional deformation of plutons
granite evolution
NW trending
paleotectonics
Qinling orogenic belt
