塔北哈拉哈塘流纹岩的离子探针锆石U-Pb年代学：对塔里木溢流玄武岩主期喷发时代的约束

SIMS Zircon U-Pb Age of a Rhyolite Layer from the Halahatang Area,Northern Tarim,NW China:Constraint on the Eruption Age of Major Pulse of Tarim Flood Basalt

塔里木北部哈拉哈塘地区存在流纹岩覆盖于玄武岩之上的迭置关系。对上层流纹岩采用SIMS锆石U-Pb法精确测定其年龄为287.3±2.0 Ma。该年龄限定该区玄武岩的喷发时代不晚于287 Ma,证明塔里木溢流玄武岩的主喷发期应不晚于287 Ma,而非前人提出的大约275 Ma。

eismological interpretation revealed that basalts are overlain by rhyolite in the Halahatang area,Northern Tarim,Northwest China.The overlying rhyolite is dated by SIMS zircon U-Pb method,yielding a precise concordia age of 287.3±2.0 Ma,which limits the latest eruption age of the underlying basalt and reveals that the eruption age of the main pulse of the Tarim flood basalt is before 287 Ma,not ~275 Ma.