CHRONOLOGY AND ITS GEOLOGICAL IMPLICATION OF THE GRANITES IN HADUOHE-AERBENGELE AREA, INNER MONGOLIA

Geochronogic study on the previously decided Permian granites in Haduohe-Aerbengele area, Inner Mongolia obtains the U-Pb SHRIMP zircon ages of 133.2±1.7 Ma and 127.0±2.0 Ma for granite and granite-porphyry, respectively, suggesting a Cretaceous age. The lithogeochemical study shows that both the granite and granite-porphyry are calc-alkaline, belonging to S-type granite. The rare earth elements are well fractionated, without significant Eu anomaly. The rocks present no evident differences to the typical granite (SI-type) in the region, showing a complex tectonic setting of late collisionorogeny during Late Yanshanian stage. Multiple collision-orogeny movements took place from Variscan to Late Yanshanian in the region. The magmatic activities are related to the transition of Paleo-Asia tectonic domain and the superposition of marginal-Pacific tectonic domain.