Genesis and prospecting significance of Caledonian peraluminous granite in Kunlunhe area, East Kunlun

The Early Paleozoic peraluminous granites in the Kunlunhe area can provide important constraints on the Paleozoic collisional process and rare metal metallogenic genesis of the East Kunlun Orogenic Belt. This paper introduces the newly discovered Early Devonian ( 418 similar to 416Ma) peraluminous granite in the Kunlunhe area, whose lithology is biotite granodiorite, two -mica granodiorite and two -mica granite with its dark minerals all composed of biotite (). The peraluminous granites belong to a sodium -rich, weak peraluminous, high potassium and calc-alkaline series. These granite samples have averaged Na2O/K2O = 1. 13, and varied values of A/CNK = 1. 03 similar to 1. 10, ( La/Yb)(N) = 9.7 28, Y = 8.69 x 10(-6) similar to 23.4 x 10(-6) and Yb = 0. 67 x 10(-6) similar to 2.43 x 10(-6) with enrichment of LREE and weak depletion of HREE. They also have obvious Eu negative anomaly (Eu/Eu * = 0. 48 -0. 86), with relatively lower Rb/Sr (0. 34 similar to 1. 12) and Rb/Ba (0. 18 - 0. 32) ratios. Their (Sr-87/Sr-86), epsilon(Nd) ( t) and t(DM2) values are 0. 7045 - 0. 7083, -4. 94 similar to -1.64 and 1.56 similar to 1. 29Ga, respectively. Their measured zircon epsilon(Hf), (t) and t(DM2) are - 3. 3 similar to 2. 7 and 1.61 similar to 1. 28Ga, respectively. Its magma is originated from the partial melting of the ancient Proterozoic crust with the participation of mantle material or new crustal material from mantle. Combined with previous researches, there are two peraluminous granites series in the Kunlunhe area: the Late Silurian (425 similar to 422Ma) series and the Early Devonian (418 similar to 416Ma) series. Both of them are related to the melting of crust caused by subduction lithospheric slab break -off and mantle magma penetration in the Caledonian collision orogenic belt of East Kunlun. There is high Li, Be and Sn backgrounds with some obvious anomalies in the peraluminous granites distributed area, showing a good prospecting potential in the Kunlunhe area.