Response of Permian sediment provenance conversion in Hainan Island to the closure of the Eastern Paleo-Tethys Ocean

Abstract

From the late Permian to Early Triassic, the eastern part of the Paleo-Tethys Ocean was closed, and the Jinshajiang–Ailaoshan–Songma suture belt formed between the Yangtze Craton and the Indochina Block. The structural belt extends eastward to Hainan Island as the Changjiang–Qionghai fault, which controls the closure of the southern and northern parts of Hainan Island and the transformation of the sedimentary environment. This study focuses on the late Permian Nanlong Formation in Nanlong village, Dongfang County, western Hainan Island. Detrital zircon U–Pb ages from the Permian strata in southern and northern Hainan Island are used to discuss the provenance and sedimentary environment during the early and late Permian. The detrital zircon U–Pb ages from the upper Permian Nanlong Formation are 2800–900, 700–500, 500–400 and 400–320 Ma, with the majority falling into the 500–400 Ma range. The sedimentary environment on Hainan Island transitioned from early Permian semi-deep to deep-sea to late Permian coastal and shallow sea. The sediment provenance changed from a recycled orogen belt during the early Permian to a combination of recycled and arc orogen belt (Devonian–Carboniferous) during the late Permian. This reflects the closure of the east Paleo-Tethys Ocean during the late Permian that resulted in the collision and assembly of south and north Hainan Island and its relative uplift in the central part, which controlled the transition in sedimentary provenance and environment during the late Permian on Hainan Island.