Provenance and Its Evolution of the Ca-thaysia Block in the Late Neoproterozoic-Early Paleozoic and Implication on the Reconstruc-tion of the Gondwana Supercontinent
As a significant component of Gondwanaland,the South China Block holds a crucial role in recon-structing the paleogeographic framework of the supercontinent.In this study,we have compiled and com-pared lithostratigraphic,geochronological,and geochemical data from Cryogenian-Ordovician clastic sedi-mentary rocks across multiple sub-basins within the Cathaysia Block,situated in the southeastern portion of the South China Block.The abundance of siliceous and conglomeratic rocks,along with local unconformities in certain layers,suggests a proximal deposition during the late Cryogenian,followed by a late Ediacaran transgression and middle Cambrian uplift.Australia and India were the primary sources of zircons in the early(1300～1000 Ma)and late Grenvillian(1000～900 Ma)age,respectively,while detritus from East Antarctica contributed to a lesser extent.Notably,India served as a prolonged source terrane for the Cryogenian-Ordovi-cian basin in the Cathaysia Block,whereas western Australia shifted from being a major to a secondary sedi-ment supplier during the late Ediacaran.Intrinsic 850～700 Ma magmatic rocks that were exposed during the middle Cambrian uplift of the Cathaysia Block,in response to the far-field stress effects of the external tecton-ic movement,contributed as one of the provenances.Thus,the Cathaysia Block was inferred to be located in the northern margin of Eastern Gondwana during the late Neoproterozoic-early Paleozoic and had persistent connections with India and Australia,adjacent to East Antarctica.During the Gondwana assembly,the forma-tion,uplift,and exhumation of the Pan-African orogenic belts in India and Australia influenced the prove-nance variations of sedimentary basins in the Cathaysia Block.
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