A spore and pollen zonation of early cretaceous to tertiary nonmarine sediments of central Sudan

A continuing palynological investigation of more than forty exploratory wells drilled in the central Sudan began in 1978. Prior to this time, no deep drilling had been undertaken in the Sudan interior. The subsurface geology of this vast area was almost unknown because of the lack of outcrops. As a result of the new drilling and extensive geological and geophysical studies, central Sudan is now known to be part of the Central African rift system. The wells have penetrated thick nonmarine sand and shale sequences which reflect fluvial and lacustrine deposition in rift basins. A five‐part spore/pollen zonation of these sediments has been established as a result of study of more than 4000 well samples. Early, “middle,”; and Late Cretaceous, Paleogene, and Eocene/ Oligocene subsurface floral units have been recognized and paly‐nologically defined. The Sudan floras are related to the Africa‐South America floral province.