• 集群首页
  • 关于我们
  • 期刊群

宗务隆构造带东段宗务隆群碎屑锆石年代学及其构造意义

Detrital Zircon Geochronology of the Zongwulong Group in the Eastern Segment of the Zongwulong Tectonic Belt and Its Tectonic Significance

  • 摘要: 位于青藏高原东北缘的宗务隆构造带,夹持于南祁连、柴达木北缘和西秦岭构造带之间,其形成、演化与特提斯构造域密切相关。目前,对于宗务隆群的形成时代、物质来源及构造演化仍有较多争议。笔者以该构造带东段的宗务隆群碎屑岩为研究对象,分析其碎屑锆石U-Pb同位素年龄、微量元素特征及Hf同位素组成。研究结果显示,宗务隆群的沉积时代不早于中二叠世,碎屑锆石U-Pb年龄主要集中在早古生代和晚古生代,峰值分别为~431 Ma和~269 Ma。微量元素特征碎屑锆石来源于与弧相关的大陆地壳锆石,与南侧乌兰−青海南山一带的岩浆活动可以对应;年龄谱的分析表明:宗务隆构造带东西段的构造演化具有不同的历程,东段发育有限洋盆且可能是古特提斯洋最北部的分支,西段则无相关洋盆发育。

     

    Abstract: The Zongwulong tectonic belt is situated at the northeastern margin of the Tibetan Plateau, constrained between the South Qilian, North Qaidam margin, and West Qinling tectonic belts. Its tectonic evolution is closely associated with the northeastern Tethyan tectonic domain. Current academic debates persist regarding the formation age of the Zongwulong Group, its material provenance, and the evolutionary history of the tectonic belt. This study focuses on the clastic rocks of the Zongwulong Group in the eastern segment of the tectonic belt, employing detrital zircon U-Pb geochronology, trace element analysis, and Hf isotopic composition investigations. Results demonstrate that the depositional age of the Zongwulong Group postdates the Middle Permian. Detrital zircon U-Pb ages predominantly cluster in the Early Paleozoic and Late Paleozoic, with prominent peaks at ~431 Ma and ~269 Ma. Trace element characteristics indicate that these detrital zircons originated from arc-related continental crustal sources, correlating with magmatic activities in the southern Wulan-Qinghai Nanshan region. Comparative analysis of age spectra reveals distinct tectonic evolutionary processes between the eastern and western segments of the Zongwulong belt. The eastern segment developed a limited oceanic basin, potentially representing the northernmost branch of the Paleo-Tethys Ocean, whereas the western segment shows no evidence of oceanic basin development.

     

/

返回文章
返回