Geochemistry and Tectonic Implications of the Aretuobie Pluton to South of the Mayinebo Suture Zone in Altay, Xinjiang

The Aretuobie monzonitic granite is located to the south side of the Mayinebo suture zone. It shares some characteristics of the A-type granite, such as high alkali and low alumina. However, comparing with typical A-type granite, it has relatively high MgO and CaO and low SiO₂. In trace elements, their total REE ranges from 277 ppm to 326 ppm and the ratios of LREE/HREE are bet ween 5.6 and 6.9. Negative Eu anomalies (δ_Eu=0.4-0.6) are present ed in the REE pat terns. The rocks are enriched in incompatible elements and havev ariable Sr, Ba, Nb, P and Ti troughs in their trace elements distribution patterns. Isot opically, they have low initial Sr ratios (0.70048-0.70547) and positive initial Nd values (2.6-3.2). Collectively, we suggest that the Aretuobie pluton was derived from partial melting of a juvenile maficlo wercrust in a postorogenic extensional background.