New U–Pb age and geochemical constraints on the stratigraphy and distribution of the Lantau Volcanic Group, Hong Kong

Seven new high precision U–Pb single crystal zircon ages are reported from Jurassic and early Cretaceous volcanic rocks in the Hong Kong Special Administrative Region (SAR). These ages are used in combination with Zr vs. TiO2 ratios to refine the stratigraphy of the Lantau Volcanic Group on Lantau Island and in adjoining districts in Hong Kong. As a result, three major unconformities are proposed and the rift-controlled paleogeography of the region, which influenced the development of the Lantau Caldera and lacustrine basins during the latest Jurassic to earliest Cretaceous, is clarified. The data also suggest the possibility that the base of the Cretaceous System may be preserved within the sequence.