ISSN 1009-6248CN 61-1149/P 双月刊

主管单位:中国地质调查局

主办单位:中国地质调查局西安地质调查中心
中国地质学会

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    乌兹别克南努拉套奥陶—志留纪碎屑岩物源示踪及其构造意义

    Source Tracer and Its Tectonic Significance of the Ordovician-Silurian Clastic Rocks in Southern Nuratau, Uzbekistan

    • 摘要: 对乌兹别克斯坦努拉套地区早古生代地质体的研究是恢复南天山西部土耳其洋构造格局及演化过程的关键,本次研究通过对南努拉套地区奥陶—志留纪碎屑岩进行物源示踪,分析了该区沉积物质来源及源区构造属性,进而对早古生代土耳其洋属性进行约束。研究结果表明,该套碎屑岩岩性以细粒杂砂岩为主,形成于近岸海滩相环境,且具有被动陆缘沉积特征。沉积物质来源于酸性岩浆岩和古老沉积岩。细砂岩中碎屑锆石年龄峰值主要集中在800 Ma,与Rodinia超大陆裂解事件时间相对应;次峰值为530 Ma、440 Ma,推断应与天山多地块拼贴事件相关。综合以上研究成果,认为早古生代土耳其洋盆展布为东西向,北部为活动陆缘,南部为被动陆缘,其被动陆缘沉积物供给主要来源于Rodinia超大陆裂解及天山多地块拼贴事件。

       

      Abstract: Research on the Early Paleozoic geological bodies exposed in Nuratau, Uzbekistan, is key to reconstruct the tectonic setting and evolution process of the Turkestan Ocean in the western south Tianshan.This paper analyzed the source of sedimentary material and the tectonic attributeby source tracing of the Ordovician-Silurian clastic rocksin southern Nuratau.The results show that this suite of clastic rocks is mainly comprised of fine-grained greywacke which formed inoffshore beach setting of passive continental margin. The lithology is of acidic magmatic rocks and old sedimentary rocks.The peak age of the detrital zircons in fine-grained sandstone is nearly 800Ma,which corresponds to Rodinia supercontinent cracking event;the secondary peak ages are 530Ma and 440Ma, suggesting a large terrane assembly event in the Early Paleozoic. The authors have reached the conclusion that in Early Paleozoic the Turkestan Ocean spread in the east-west direction with the active continental margin to the north and the passive continental margin to the south.Sedimentary materials of the passive continental margin were from the Rodinia supercontinent cracking event and the Early Paleozoic tectonic event.

       

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