摘要
为了解扬子陆块西北缘新元古代拉伸纪(1000~720 Ma)岩浆活动和构造演化历史,该文统计了扬子陆块北东缘至西南缘45个岩浆岩岩体的全岩元素、Sm-Nd同位素、锆石U-Pb年龄及Hf同位素数据。根据岩石组合和地球化学特征,可以将扬子西北缘拉伸纪岩浆活动划分为3个阶段,早于855 Ma、855~770 Ma和晚于770 Ma。通过统计和对比3个阶段岩浆岩地球化学特点认为,扬子西北缘洋壳俯冲和岛弧岩浆侵位在1000~900 Ma进入停止期,在900~855 Ma开始进入长期弧陆碰撞和增生造山向碰撞后伸展阶段,至830 Ma之后,扬子陆块边缘进入到全面的大陆裂谷背景,并伴有与Rodinia超大陆裂解有关的岩浆作用。
To understand the Neoproterozoic Tonian(1000 to 720 Ma)magmatism and tectonic evolution history of the northwestern margin of the Yangtze Block,the whole rock elements,Sm-Nd isotopes,zircon U-Pb ages and Hf isotopes of 45 magmatic rocks from the NE to SW margin of the Yangtze Block were collecteded and compared.According to the rock assemblages and geochemical characteristics,the extensional magmatic activity in the northwestern margin of the Yangtze Block can be divided into three stages:Earlier than 855 Ma,855 to 770 Ma,and later than 770 Ma.The oceanic subduction and island arc magmatism ceased during 1000 to 900 Ma,and entered the stage of long-term arc-continent collision and post-collision extension of accretionary orogeny from 900 to 855 Ma.After 830 Ma,the NW margin of the Yangtze Block entered a comprehensive continental rift setting accompanied rift magmatism due to the breakup of Rodinia.
作者
张晓琪
赵达成
李章志贤
陈立辉
ZHANG Xiaoqi;ZHAO Dacheng;LI Zhangzhixian;CHEN Lihui(Department of Geology/State Key Laboratory of Continental Dynamics,Northwest University,Xi′an 710069,China)
出处
《西北大学学报（自然科学版）》
CAS
CSCD
北大核心
2021年第6期1042-1056,共15页
Journal of Northwest University（Natural Science Edition）
基金
国家自然科学基金资助项目(91962212,42173005)。
