摘要
江南元古宙古岛弧的基底变质岩主要由浅变质的岛弧火山—沉积岩系组成。根据Sm-Nd同位素年龄资料,古岛弧西段基底变质岩的形成时间为早元古宙,中段为中元古宙中-晚期,东段为晚元古宙早期,形成时间持续长达13亿年左右。在9亿年前左右,江南古岛弧与华夏古陆发生碰撞拼贴,从而结束了江南古岛弧的演化史。
Metamorphic basement of the jiangnan Proterozoic Paleo-island arc mainly consists of low-grade metamorphic volcanic sedimentary rocks. According to the Sm-Nd isochron ages, the volcanic activities in the arc lasted as long as 1300 Ma. The western part of the arc was formed in the Early-Proterozoic Era, the middle part in the Middle Proterozoic Era, and the eastern part in the early Late-Proterozoic Era. This temporal variation may be attributed to a gradual transition of plate subduction. The evolution history of the jiangnan Proterozoic Poleoisland arc ended about 900 Ma ago as a result of the collision between the arc and Cathvsia.
出处
《南京大学学报（自然科学版）》
CAS
CSCD
1993年第3期460-467,共8页
Journal of Nanjing University（Natural Science）
关键词
变质岩
钐同位素
钕同位素
Sm-Nd isotope
metamorphic rocks
Jiangnan Proterozoic Poleoisland Arc
