Biostratigraphic study of Well DX has yielded Cretaceous miospores and dinoflagellates cysts which heightened the recognition of sequence boundaries (SB), Maximum Flooding Surfaces (MFS) and associated Systems Tracts. Five maximum flooding surfaces between 95.6Ma and 89.0Ma, four sequence boundaries between 96.4Ma and 93.0Ma and three depositional sequences were identified with varying average thicknesses of sediments interpreted from the gamma ray log and biostratigraphic data. The three depositional sequences interpreted are-depositional sequence I (96.4 Ma - 95.4 Ma) (8240 ft. - 8120 ft.), depositional sequence II (95.4 Ma - 94.0 Ma) (8120 ft. - 7850 ft.) and depositional sequence III (94.0 Ma - 93.0 Ma) (7850 ft. - 7550 ft.). All the depositional sequences fall within the third order cycle. The age of the well was attempted based on the presence of some selected marker fossils -
Ephedripites spp.,
Classopollis spp.,
Spiniferites
spp.,
Cyclonephelium distinctum,
Cyclonephelium vannophorum,
Subtilisphaera
spp.,
Eucomiidites spp.,
Triorites africaensis
,
Odontochitina costata
and
Droseridites senonicus
recovered from the studied intervals and was dated Albian - Santonian. The Sequence stratigraphic interpretations are useful in further deepening the knowledge of the subsurface geology of the studied well in Gongola Sub Basin, Upper Benue Trough of Nigeria.
