PALYNOLOGY (POLLEN, SPORES AND DINOFLAGELLATES) AND CRETACEOUS STRATIGRAPHY OF THE DAKHLA OASIS, CENTRAL EGYPT

A re-assessment of the Cretaceous succession in the Dakhla area, centr al Egypt, is presented on the basis of new palynological evidence from the Six Hills and Maghrabi Formations. Miospore ages for the Six Hill s Formation range from Early Neocomian to Late Barremian-Early Aptian( ?). The upper Six Hills (to lower Abu Ballas?) interval is the only un it that yielded marine dinoflagellates in addition to terrestrially de rived miospores. Marine influence was thus effective below the base of the marine Abu Ballas Formation, which is here regarded as Early Apti an in age. The overlying Sabaya Formation could range down into the Ap tian. Miospore assemblages from the Maghrabi Formation in the Dakhla a rea contain the new species Retimonocolpites variplicatus, tricolpates and tricolporates, but no triporates, which favours an Albian to Earl y Cenomanian age. Maghrabi assemblages in the Kharga area include trip orates, which is broadly consistent with a Late Cenomanian to Turonian age. The formation may thus be diachronous, becoming younger from wes t to east. It is concluded that an eastward shift of the depocentre to ok place from the Dakhla area in Early Cretaceous time to the Kharga a rea in Albian to Late Cretaceous time. (C) 1998 Elsevier Science Limit ed.