Mesozoic high-K granitic rocks from the eastern Dabie Mountains, Central China and their geological implications

The Mesozoic high-K granitic intrusions from the eastern Dabie Mountains, C entral China, can be divided into three superunits namely the Yaohe, Penghe and Huangbai superunits. The Yaohe superunit is compositionally dominated by quartz monzonite extending as a band in NW direction which is differentl y foliated, contains numerous dioritic enclaves and has been dated as 174 M a. The Penghe superunit, widely distributed in the field, varies in composi tion but is dominated by quartz monzonitic and granitic rocks, which is mas sive in structure, has well developed with dioritic enclaves and is aged in 125-127 Ma. The Huangbai superunit is mainly composed of granitic composit ion which is massive in structure, rarely contains dioritic enclaves and is aged in 120-111 Ma. These three superunits of granitic intrusions can also be clearly distinguished in geochemistry. They have recorded an orogenic p rocess of the Dabie Mountains from the end of regional metamorphism to the overprinting of the circum-Pacific tectonic regime.