摘要
扬子陆块在古-中元古代时期经历了较为强烈的岩浆-变质-沉积-成矿等地质事件,这些事件是理解该陆块陆壳演化和成矿效应内在联系及动力学的关键,也是探讨该陆块在Columbia超大陆中古地理重建的前提。本文以古-中元古代地质单元出露较为完整的扬子西南缘为重点研究对象,在总结已有资料的基础上,对扬子陆块古-中元古代时期地质事件进行剖析和讨论,明确了扬子陆块西南缘在古-中元古代时期经历了由Columbia超大陆初始裂解引起的陆内裂谷相关的沉积作用,岩浆侵位及矿产富集等地质过程。通过与全球陆块进行对比,发现相似的裂谷的相关沉积-岩浆-成矿事件在劳伦大陆西北部、澳大利亚北部及Siberian克拉通都有体现。本文认为扬子陆块在2. 4～2. 3 Ga通过增生拼贴到劳伦大陆Rae克拉通。在共同经历过Columbia超大陆聚合的峰期变质作用(2. 03～1. 81 Ga)之后,超大陆开始逐步裂解并形成大陆内部裂谷,最终在古元古代后期(～1. 66～1. 60 Ga)扬子陆块和Columbia超大陆主体分离。
The extensive metamorphic,sedimentary,magmatic and mineralization events,occurred in Paleo-to Meso-proterozoic in the Yangtze Block,are the key to understand the internal relations and dynamics of the continental crustal evolution and mineralization effect of the block,and the precondition to discuss the paleo-geographical reconstruction of the Yangtze Block in the Columbia supercontinent. The southwestern Yangtze Block is the key research object of this study due to the exposure of relatively completed Paleo-to Meso-proterozoic units. On the basis of summarizing the existing data,we have analyzed and discussed geological events of the Yangtze Block in Paleo-to Meso-proterozoic,and then have clarified that the Paleo-to Meso-proterozoic geological processes including sedimentation,magmatism,and mineralization in the southwestern Yangtze Block were associated to the continental rifting induced by the early breakup of the Columbia supercontinent. Detailed comparison with other blocks/terranes of the earth indicates that similar rift-related sedimentation-magmatism-mineralization events occurred in the northwestern Laurentia,northern Australia,and Siberian cratons. It is believed that the Yangtze Block was firstly accreted to the Rae Craton of Laurentia at 2. 4-2. 3 Ga,then had experienced the peak metamorphism at 2. 03-1. 81 Ga resulted from the aggregation of Columbia supercontinent,subsequently had experienced the continental rifting(at 1. 75 Ga) which occurred gradually within the Columbia supercontinent,and finally was separated away from the main body of Columbia supercontinent at late Mesoproterozoic(~ 1. 66-1. 60 Ga).
作者
王伟
卢桂梅
黄思访
薛尔堃
WANG Wei;LU Gui-mei;HUANG Si-fang;XUE Er-kun(State Key Laboratory of Geological Processes and Mineral Resources,School of Earth Sciences, China University(Wuhan )of Geosciences,Wuhan 430074,China)
出处
《矿物岩石地球化学通报》
CAS
CSCD
北大核心
2019年第1期30-52,I0003,共24页
Bulletin of Mineralogy, Petrology and Geochemistry
基金
国家自然科学基金项目(NSFC41572170)
