中国科学院南京地质古生物研究所机构知识库

The South China Block (SCB) has been regarded by many as an integral part of Gondwana, but proposed timing and processes for its accretion to Gondwana vary and remain contentious, largely owing to the lack of reliable Pan-African age paleomagnetic data and tectono-magmatic records from the SCB. Integrated in situ U-Pb ages and Hf-O isotope analyses of detrital zircons from geochronologically well-calibrated Ediacaran-Cambrian sedimentary rocks of western SCB reveal age populations of 2.51, 1.85, 1.20, 0.80, and 0.52 Ga. Detrital zircon age spectra indicate a major tectonic transition for the SCB during 0.56-0.54 Ga, interpreted to reflect the beginning of the collision between SCB-Indochina and NW India blocks. The collisional event lasted until early Ordovician, leading to the suturing of the SCB-Indochina to the northern margin of East Gondwana. Plain Language Summary The South China Block is thought to be a part of the Gondwana superterrane, which was composed of more than half of all continents 650-400 million years ago (Ma). However, questions of when and how the South China Block collided with Gondwana are yet to be answered. In this study, we conducted provenance analyses of sedimentary rocks whose depositional ages were known via radioisotopic dating and chemo-biostratigraphy in the western South China Block. The results reveal a change in tectonic setting of the South China Block at 560-540 Ma, interpreted as the onset of the collision between the South China Block and India along the northern margin of East Gondwana.