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

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.