地层证据——对大别造山带汇聚历史的制约  

Stratigraphic evidence for the convergence history in the Dabie orogenic belt

作　　者：李双应[1] 金福全[1] 王道轩[1] 李任伟[2] 孟庆任[2] 杨栋栋[1] 

机构地区：[1]合肥工业大学,合肥230009 [2]中国科学院地质与地球物理研究所,北京100029

出　　处：《地质科学》2011年第2期288-307,共20页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：国家自然科学基金项目(编号:40972082;40572076);国家重点基础研究发展计划项目(编号:G1999075507)资助

摘　　要：大别造山带的汇聚演化历史一直存在不同的认识,来自扬子陆块和华北陆块显生宙以来的地层记录以及北淮阳地区的地层记录可能为两个陆块的汇聚模式提供制约。通过对扬子陆块与华北陆块显生宙以来岩相古地理进行比较,其中3个阶段相似,2个阶段差别很大。以浊积岩发育作为俯冲阶段的标志,磨拉石建造出现作为闭合的标志,显生宙以来,大别造山带曾经历了两次俯冲和两次汇聚,俯冲时间分别是晚奥陶世一早志留世和早三叠世,汇聚的时间分别为中-晚泥盆世和中三叠世,早期的汇聚具有软碰撞特征,以上认知得到了北淮阳地区地层、古生物和沉积记录的支持,同时也与大别山造山带榴辉岩的同位素年龄数据基本吻合。高压-超高压变质岩在晚三叠世处于快速折返阶段,早侏罗世以前到达地表,其平均折返隆升速率为3.9～6.6 mm/a。There has been controversy for the joining models and history of the Dabie orogenic belt, however stratigraphic evidence from Yangtze and North China Blocks,and the north Huaiyang region will provide limit to the join models between the both blocks. By means of Phanerozoic petrofacies palaeogeography comparison between Yangtze and North China Blocks, their characteristics were similar in three stages, and different in another two stages. Given the development of turbidites as a sign of the block subduction, molasses formation as a sign of closure, there have been two times of convergence and two times of subduction since Neoproterozoic Era,which the time of subduction might be in Later Ordovician-Early Silurian and Early Triassic respectively, and time of the convergence might happen in Middle-Late Devonian and Middle Triassic respectively, and the first convergence should be a weak collision. The data of strata, paleontology fossils, and sedimentary records from the northern of Huaiyang region support the above understandings, and they are consistent with the isotope dating of HP-UHP metamorphic rocks in the Dabie orogenic belt. The UP-UHP metamorphic rocks were in the rapid exhumation in Late Triassic period, and came to earth surface before Early Jurassic,which speed of their exhumation and uplift was average 3.9 - 6.6 mm/a.

关 键 词：大别造山带 俯冲和闭合 地层记录岩相古地理扬子和华北陆块 

分 类 号：P542[天文地球—构造地质学] P531[天文地球—地质学]