Neoproterozoic stratigraphic comparison of the Lesser Himalaya (India) and Yangtze block (south China): Paleogeographic implications

摘要

Recent studies of terminal Neoproterozoic rocks (ca. 590–543 Ma) in the Lesser Himalaya of northwestern India and the Yangtze block (south China) reveal remarkably similar facies assemblages and carbonate platform architecture, with distinctive karstic unconformities at comparable stratigraphic levels. These similarities suggest that south China may have been located close to northwestern India during late Neoproterozoic time, an interpretation permitted by the available, yet sparse paleomagnetic data. Additional parallels in older rocks of both blocks—similar rift-related siliciclastic-volcanic successions overlying metamorphic basement, and comparable glaciogenic intervals of possibly Sturtian and Marinoan or Varanger age—suggest that this spatial relationship may have developed earlier in the Neoproterozoic. With the exception of basal Cambrian phosphorite and comparable small shelly fossils, stratigraphic contrasts between northern India and south China and increasing biogeographic affinity between south China and northwestern Australia suggest that south China may have migrated toward northwestern Australia during the Cambrian.