论文部分内容阅读
对出露于北秦岭周至黑河小王涧黄草坪南罗汉寺岩群(弧前盆地沉积楔形体)中的英安质晶屑凝灰岩,进行了锆石SHRIMP U-Pb同位素测年研究,获得该群晶屑凝灰岩形成时代为(491±5)Ma,反映该岩群跨及早奥陶世。结合商丹带北侧广泛发育的加里东期岛弧花岗岩带和前人在其他地区测定该岩群的最新年代信息,认为本次测年数据为北秦岭古生代洋盆消减及板块汇聚过程,提供了重要的同位素年代学依据。同时,为研究商丹蛇绿构造混杂岩带俯冲碰撞的增生造山过程,提供了有力的时代佐证。
The zircon SHRIMP U-Pb isotope dating study was conducted on the amphibolite-bearing quartzites exposed in the South Luohanji Group of Huangcaoping, Xiaowangjian, Heihe, The formation age of the group of conglomerate tuff is (491 ± 5) Ma, which indicates that this group of rocks cross over the Early Ordovician. Combined with the widely developed Caledonian island arc granite belt on the northern side of the Shangdan belt and its predecessors’ determination of the latest age information of this group of rock masses, this dating data is considered as the abatement and plate convergence process of the North Qinling Paleozoic ocean basin An important isotopic chronological basis. At the same time, it provides a powerful evidence for the study of the hypergrustogenesis process of the subduction collision of the Shendan ophiolite melange belt.