Biogeographic constraints on the rift-drift-accretion history of the Sibumasu block

Abstract

From the biogeographic point of view, the Paleozoic geological history of the Sibumasu block can be divided into three stages: Cambrian-Ordovician stage with Australian faunal affinites; Silurian-Devonian stage with Rhenish-Bohemian faunal affinities; and Carboniferous-Permian stage, as an independent biotic province, which is different from both peri-Gondwanaland and Cathaysian biotas, in the Tethyan realm. Towards the end of the Permian, the Cathaysian elements were more important in the Sibumasu block, especially in its eastern margin, indicating that the Cathaysian and Sibumasu biotas were beginning to merge into a single province. All of these provide clues on the origin and rift-drift-accretion history of the Sibamasu block. In contrast with the prevalent viewpoints, the present paper expresses a quite different conclusion, Sibumasu rifted away from Gondwanaland in the middle Ordovician or earlier and sutured to the East Coontinent in the late Permian and early Triassic.