Petrology And Geochemistry Of Early Jurassic Intrusive Rocks In The Central Jilin Province

In this paper, detailed field investigation and petrography of early Jurassic intrusive rocks in central Jilin Province were carried out. On this basis, systematic zircon U-Pb chronology and petrographic studies were carried out. The Origin and Tectonic Setting of Early Jurassic Igneous Rock. The early Jurassic igneous rocks in the study area are mainly composed of a gabbro, diorite, quartz diorite, granodiorite and monzogranite, and granite and fine-grained diorite(or gabbro) Magmatic mixing is obvious; The Early Jurassic magmatism in the study area is a bimodal intrusive assemblage. The diorite and granodiorite rocks show two kinds of magmas(basic magmas represented by gabbro and granites) Of the acid magma) mixed in different proportions of the results; These early Jurassic igneous rocks all show the geochemical properties of arc igneous rocks, and the combination of the early Jurassic calc-alkaline volcanic rocks in eastern Jilin and the spatial variation of the early Jurassic igneous rocks from continental margin to intracontinental, Their origin should be related to the subduction of the paleo-Pacific plate under the Eurasian continent. The Early Jurassic bimodal igneous assemblage in the central part of Jilin Province is formed in the back-arc extensional environment of plate subduction.