Abstract: This paper made a comprehensive study on the petrology, zircon morphology and LAICPMS UPb geochronology of the Hongliuxia and its peripheral volcanic rocks in the eastern sector of the Altyn Tagh Fault. The results show that there are two types of zircons in the samples. One is a type of longcolumnar magmatic zircons sampled from the volcanic neck, whose weighted average age is (1090±16) Ma (late Early Cretaceous), and it represents the formation age of Hongliuxia volcanic rocks. This age agrees well with previous results through different approaches. The other is a type of subrounded or oval inherited zircons sampled from the peripheral basalts, and most of them have the core mantle structure. The age distribution ranges from (138±2) to (2,376±74) Ma, which show the diverse age peaks. These inherited zircons are all captured from the Lower Cretaceous or/and earlier strata during the rising of basaltic magma. Their age peaks closely respond to the complex multiphase magma and tectonic events in the late Early Cretaceous or earlier time of the Altyn Tagh Fault. In addition, part of the age peaks coincident with the age of Paleozoic granite in the southern Altyn Tagh Terrane suggests that the Altyn Tagh Terrane was once connected to the Qilian Block.

Key words: Altyn Tagh Fault, Hongliuxia, basalt, inherited zircon, LAICPMS UPb age