Geochemical characteristics, zircon U-Pb ages and geological implications of the eastern Innermongolia in Yanggeliya Mountain intermediate-acid rock

The Yanggeliya Mountain is located in the Oroqen Autonomous Banner, Hulunbuir City, eastern Inner Mongolia. Syenogranite, monzoniticgranite and tonalite are the main rocks, and the LA-ICP-MS zircon U-Pb age indicates that the emplacement time is Early Cretaceous (130.4 ±1.1Ma) for syenogranite, 126.6 ±3.0Ma for monzoniticgranite, 131.6 ±1.1Ma and 130.7±1.5Ma for tonalite. The study of rock geochemistry shows that the granite body is characterized by rich silicon and alkali, and depletion of calcium, belonging to the quasi-aluminum-peraluminous, high-potassic, calcium-alkali series of rocks. The total amount of rare earths is relatively low, the fractionation between LREE and HREE is obvious, and the (La/Nb)_N values are between 9.14 and 24.86. The Eu has obvious positive anomalies (the δEu values are in the range of 1.03~1.53). As for trace elements, the values of K, La, Sr and Gd are obviously enriched, whereas Nb, Pr, P and Ti are depleted. Large ionic lithophile elements are enriched with relatively high field strength elements. The rock differentiation index DI averages 80.63. The above characteristics are similar to those of highly differentiated I-type granites. The source of magma was the crust-derived magma series, which was the product of the partial melting of continental crust rock, and the tectonic setting was a stretching environment which was closely related to subduction of ancient Pacific plate.