NONMARINE CRETACEOUS PALYNOLOGY OF NORTHERN KORDOFAN, SUDAN, WITH NOTES ON FOSSIL SALVINIALES (WATER FERNS)

A palynological investigation of 164 samples from 18 water wells in no rthern Kordofan, Sudan, enabled the recognition of five informal zones based on pollen and spore assemblages ranging in age from Albian to M aastrichtian. The youngest (late Campanian- Maastrichtian) assemblages are restricted to the Bagbag Basin, whereas Albian - Cenomanian (to T uronian) sediments are widespread to the east and west of the Bagbag a rea. Impressions of Salvinia floating leaves from outcrops of the uppe r Hamrat el Wuz Formation, western part of the study area, are among t he oldest occurrences of this water fern and indicate a Campanian - Ma astrichtian age for these sediments. The vertical distribution of hygr ophilous (pteridophytic spores) versus xerophilous (ephedroids and pos sibly small, weakly sculptured tricolporates) elements in the palynofl oras suggests widespread moist of even aquatic habitats in the Albian - Cenomanian and Campanian - Maastrichtian. A shift towards drier cond itions occurred in the late Cenomanian - Turonian. Throughout the Cret aceous, however, there may have been extensive arid/semiarid areas of non-deposition and seasonally dry periods. Some characteristics of the local palynofloras are attributed to its inner continental position. Rare Albian - Cenomanian and Campanian - Maastrichtian dinoflagellates could be interpreted as lacustrine phytoplankton rather than as evide nce for marine influence.