Zircon U-Pb Chronology of Volcanic Rocks in the Hailaer Basin, NE China and Its Geological Implications
Chen Chongyang
Gao Youfeng
Wu Haibo
Qu Xuejiao
Liu Zhiwen
Bai Xuefeng
Wang Pujun
Abstract：The Hailaer basin is located in the west of the Great Xing'an Range,and there are many sets of volcanic sedimentary rocks in the basin.Determining the age of the formation of volcanic rocks can provide reliable evidence for the stratigraphic cor-relation of the basin and the Great Xing'an Range,and the tectonic evolution in Northeast China as well.LA-ICP-MS zircon U-Pb dating for 4 volcanic rock samples from coring well in the Hailaer basin (HB)is presented in this paper.Their formation time and tectonic setting focusing on the intra-/inter-basinal stratigraphic correlation are discussed.The dating results show that volcanic rocks with ages of Late Triassic-early Early Jurassic (214.4±4.3 Ma)do exist in the HB.And the whole volcanic succession in the region can be subdivided into 4 stages of eruption including Middle-Late Carboniferous (320-290 Ma),Late Triassic-early Early Jurassic (224-197 Ma),Late Jurassic-early Early Cretaceous (152-138 Ma),and late Early Cretaceous (128-117 Ma).Combined with geochemical characteristics,temporal and spatial distribution characteristics of the magma in the Great Xing'an Range area,as well as the characteristics of the seismic profile of the basin,it is suggested that the Middle-Late Carboniferous magmatic rocks (320-290 Ma)were probably formed in a post-collision extensional setting related to the collision and merging of the Songnen and Ergun-Xing'an blocks.The Late Triassic-early Early Jurassic volcanic rocks (224-197 Ma)were probably formed in a post-collision extensional setting related to the closure of Paleo-Asian Ocean,which indi-cates Paleo-Asian Ocean tectonic domain affects the Great Xing'an Range area extended to the early Early Jurassic at least and the collision of the Mongolia Okhotsk Ocean possibly started in the early Jurassic at the earliest.The Late Jurassic-early Early Cretaceous (152-138 Ma)and the Late Early Cretaceous (128 -117 Ma)volcanic rocks were probably formed in a post-collision extensional setting related to the closure of Mongolia Okhotsk Ocean.Some ages of Paleoproterozoic-Neoproterozoic zircon dating are obtained,which might have been captured from some crystal rocks of Proterozoic crystalline basement in the blocks underneath the HB.
Keywords：chronologyHailaer basinvolcanic rocksXing'anling GroupBudate Grouptectonic evolutionpetrology
Publication Date：2016-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：16( 1259-1274 )