Spatial and temporal variations of Late Mesozoic granitoids in Russian Far East area and their significance for geological setting

Based on systematic collection of ages and geochemical data, this paper has preliminarily established geochronological framework of the Late Mesozoic granitoids in Russian Far East area. These granitoids can be mainly divided into two periods, i.e., Jurassic period (178~151 Ma) and Early Cretaceous period (142~122 Ma). The Jurassic granitoids consist mainly of granites, granodiorites and quartz monzonite, and show metaluminous-peraluminous high-K, calc-alkaline granites characteristics. The Early Cretaceous granitoids consist mainly of granite, quartz diorite and quartz monzonite, and are characterized by peraluminous calc-alkaline, high-K-calc-alkaline and shoshonite granites. REE patterns of two periods of granitoids are all of right-inclined type, their HREE assume relatively flat curves and are enriched with large ion lithopile elements (such as U and K) and LREE. Compared with the Late Mesozoic granitoids in northeastern China, the Jurassic granitoids in Far East area show different tectonic settings, which is related to the subduction of the Okhotsk plate and the Pacific plate. The Early Cretaceous granitoids were formed in an extensional collapse period after the compressive orogeny of the Okhotsk belt or back-arc extension after the subduction of the Pacific plate.