武当地块与扬子陆核区新元古代早期沉积岩碎屑锆石U-Pb年代学对比及其地质意义

Comparison of detrital zircon U-Pb geochronology between the Wudang block and the Yangtze continental nucleus in terms of Neorproterozoic sedimentary rocks

系统收集并总结了武当地块与扬子陆核区(崆岭地区)已发表的新元古代沉积岩中碎屑锆石的U-Pb年代学数据,对二者的相互关系进行分析,并讨论了扬子克拉通北缘新元古代时期的构造演化过程及特征。对前人发表的年代学数据进行的统计和对比结果表明,武当地块沉积岩中碎屑锆石年龄谱记录了~710Ma和~2.5Ga的年龄峰值,同时缺乏>3.0Ga年龄的锆石,表明其沉积物质来源可能并非扬子陆核区,其在新元古代之前可能作为一个独立的微陆块与扬子陆核区(崆岭地区)分离开来,二者于新元古代中期发生碰撞拼合而成为一个整体。

In this paper, the authors discussed the relationship between the Wudang block and the Yangtze continental nucleus （the Kongling area） and the evolution of the Northern Yangtze Craton during the Neoproterozoic, based on the collection of published detrital zircon U-Pb data from the Neoproterozoic sedimentary rocks in this area. Through the comparison between the data from the two regions, two major age populations （~710 Ma and^2.5 Ga） were found for the Wudang block, meanwhile, the absence of old ages （〉3.0 Ga） is obvious, indicating that the sedimentary source might not have come from the Yangtze continental nucleus. The Wudang block might have been a microcontinent, which was separated from the Yangtze continental nucleus （represented by the Kongling area） before the Neoproterozoic, and then collided with the latter again during the middle Neoproterozoic to form a complete body.