关键词: 二长花岗岩, 正长花岗岩, 碱性花岗岩, 锆石U-Pb年龄, 岩石学, 地球化学, 张广才岭北部

Abstract: In order to discuss the tectonic framework and evolution of the Northern Zhangguangcai Mountains, LA-MC-ICP-MS zircon U-Pb chronology, petrology, and petrogeochemistry studies were conducted on monzonitic granite, syenite granite and alkali-feldspar granite in this area. The zircon U-Pb ages of two monzonitic granites, one syenite granite, and one alkali feldspar granite are (191.4±1.1)Ma, (202.6±1.0)Ma, (190.8±1.5)Ma, and (198.1±1.0)Ma, respectively, in Early Jurassic. These granites are mainly classified as low aluminous, high potassium, and calc-alkaline series, have enrichment of large ion lithophile elements and lightly rare earth elements, like Rb, Ba, K, etc., whlie have depletion of high field strength elements and heavy rare earth elements, such as Nb, P, Ti, etc.. They exhibit characteristics of I-type granite, indicative of an active continental margin environment resulting from Paleo-Pacific plate subduction to Eurasia.

Key words: monzogranite, syenogranite, alkalifeldspar granite, zircon U-Pb age, petrogeochemistry, geochemistry, Nothern Zhangguangcai Mountains