The Baiyingaol Formation in the north area of East Ujimqin Banner,Inner Mongolia consists of mainly acid volcanic rocks.Zircon SHRIMP dating of rhyolitc tuff with crystals in BaiyingaolaoFormation shows that the age of Baiyingaolao formation volcanic rocks is 121.9±2.4Ma,which belongs to Early Cretaceous volcanic product.The geochemical characteristics of Baiyingaolao formation show that they have high-K cale alkaline rocks,and have weak aluminous characteristics.The rocks are obviously rich in Rb,Th,U,K,and poor in Ba and Sr,as well as HFSE of Nb,Ta,Zr,Ti and Hf.LREE are relative richer than HREE.The factional distillation of HREE shows that Eu have obvious superior negative anomaly(δEu average are between 0.19 and 0.48)Comprehensive researches indicate that Baiyingaolao formation volcanic rocks have the characteristics of A2-type granites and should be the result of stretching setting that related to the subduction of Pacific Plate during Early Cretaceous.
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维普
