Geochemical Characteristics and Petrogenesis of Hongbaoshan-Jianquan Mafic-Ultramafic Intrusions in East Tianshan, Xinjiang

Located in the Kawabulake area of east Tianshan, the Hongbaoshan-Jianquan manfic-ultramafic intrusions exhibit as vein and lenticular, with outcropped area of ~8km². It mainly consists of dunite, peridotite and wehrlite. The geochemical data shows that these intrusions belong to magnesian ultramafic rocks, which are characterized by high Mg^# and gently LREE-rich pattern with low ∑REE values (0.96×10^-6~10.02×10^-6) and enrichment of LREE ((La/Yb)_N=2.14~4.08). Additionally, they are enriched LILE (Rb and Sr) and HFSE (U and Pb), and depleted HFSE (Nb(Ta), Hf and Ti). The δEu values vary from 0.63 to 1.08, which may be related with the crystallization of plagioclase.The geochemical diagrams of major and trace elements correlation indicate that the primary magma of Hongbaoshan-Jianquan intrusions is cal-alkaline basaltic magma that formed in mantle, their diagenesis are mainly controlled by the magmatic crystallization, and contaminated by the crust during upward of magma.