Early Cretaceous dinoflagellate cycsts from ODP Hole 123-765C

Results of a preliminary study of Early Cretaceous dinocyst assemblages from Site 765 on the Argo Abyssal Plain, off northwestern Australia, are presented. The palynological sequence is interpreted in terms of Australian zones and is, in descending order, the late Aptian Diconodinium davidii Zone (Cores 123-765C-33R to -39R), the middle to early Aptian Odontochitina operculata Zone (Cores 123-765C-40R to -49R), the Barremian Muderongia australis Zone (Cores 123-765C-50R to -54R), and the Berriasian lower Batioladinium reticulatum Zone (Core 123-765C-59R). The dating of the sequence as late Aptian to Berriasian on the basis of dinocysts is supported, in part, by data concerning associated foraminiferal, radiolarian, and calcareous nannofossil suites.

Aptian to Cenomanian dinoflagellate cysts from the Mazagan Plateau

Eighty-eight samples of Aptian to lower Cenomanian sediments of Sites 545 and 547, DSDP Leg 79, from the Mazagan Plateau area (offshore Northwest Africa) were analyzed for palynomorphs. The very rich dinoflagellate cyst assemblages make it possible to narrow shipboard age determinations and to correlate Sites 545 and 547. The distribution of 174 dinoflagellate cyst taxa is tabulated in this study and the biostratigraphic value of selected dinoflagellate cysts is discussed. Additional taxonomic remarks are made about some species. The new dinoflagellate cyst species Aptea almohadensis, Occisucysta hinzü, O. mazaganensis, and the subspecies Maghrebinia perforata (Clarke and Verdier, 1967) Below, 1981 ssp. mirabilis are described.