Cretaceous-Paleocene palynology from the Cote D'ivoire-Ghana Transform Margin, sites 959, 960, 961, and 962

Abstract

A set of 204 Cretaceous and Paleocene samples from Holes 959D, 960A, 960C, 961A, 961B, 962B, 962C (barren), and 962D of the Cote d'Ivoire-Ghana Transform Margin (Leg 159) were palynologically analyzed. Three main types of palynofacies were distinguished. The first type indicates strong terrestrial depositional conditions and characterizes lithologic Unit V of Hole 959D, Subunit VB and most samples of Subunit VA of Hole 960A, and Unit III of Holes 961A and 961B. The presence of some stratigraphically significant spores and pollen grains indicates a late Barremian-middle Albian age for Unit V of Holes 959D and 960A, and a middle Albian age for Unit III of Holes 961A and 961B. The second type of palynofacies reveals mixed terrestrial and marine depositional conditions. This type was observed in Subunit IIC of Hole 962B and Unit III of Hole 962D. The occurrence of stratigraphically significant spore, pollen grain, and dinoflagellate cyst species argues for a Cenomanian age for these units in Holes 962B and 962C. The third type of palynofacies indicates clearly marine environmental conditions. This type is found in Subunit IVA and Unit III of Hole 959D, where highly diversified dinocyst assemblages (73 species, among them the following three new ones: Spiniferites bejuii n. sp., Spiniferites sp. G, and Xenascus ghanaensis n. sp.) were identified. Based on the presence of several Late Cretaceous and Paleocene markers, precise age determinations are possible for this part of Hole 959D: Subunit IVA and the lowermost cores of Unit III are probably early Coniacian in age; subsequent cores of Unit III are Santonian, Campanian, Maastrichtian, Danian and, at the top, late Thanetian in age.