青海都兰东北部哈莉哈德山花岗片麻岩LA-ICP-MS锆石U-Pb年龄及构造意义

LA-ICP-MS zircon U-Pb age of the Halihadeshan granite-gneiss in northeastern Dulan, Qinghai, and its tectonic implications

摘要: 青海都兰东北部哈莉哈德山花岗片麻岩原岩为具有S-型花岗岩特征的酸性侵入岩。来自该片麻岩的20粒锆石的LA-ICP-MS U-Pb年龄测定表明,该片麻岩的原岩花岗岩岩浆于约950Ma侵位结晶,岩浆物源源区存在中—新元古代的物质成分。正确甄别哈莉哈德山花岗片麻岩的变质围岩是否隶属于全吉地块的达肯大坂岩群,是理解全吉地块与柴达木地块在新元古代时期构造演化关系的关键。

Abstract: The Halihadeshan granite-gneiss in northeast Dulan County of Qinghai Province has a protolith of S-type granites. LA-ICP-MS dating of 20 grains of zircon from this gneiss shows that the protolith magma was composed of Mesoproterozoic and Neoproterozoic materials, and that the protolith magma was emplaced and crystallized at ~950 Ma. The correct judgment as to whether the metamorphic wall rocks of the Halihadeshan granite-gneiss belong to Dakendaban Group of Quanji massif seems to be the key to understanding the tectonic evolution relationship between the Quanji massif and Qaidam block in Neoproterozoic period.