Stratigraphic distribution of Globigerinoides ruber in the upper Middle Miocene to Early Pliocene of western Niger Delta, Nigeria

摘要

In well MJI-20, western NIGER Delta of Nigeria, Globigerinoides ruber is found in samples ranging from Middle Miocene to lower Pliocene levels, and is the predominant taxon among the planktonic foraminifera recovered from upper Middle Miocene on- wards. Within the sampled interval, the species exhibits some morphological variations especially in the shape and size of the apertures. Its occurrence can be divided into four zones. In the first zone, between 7, 353 and 7, 133 feet below seafloor, the species occurs frequently But not abundantly, with form variant c, succeeded by from d, in the latest part of Zone N. 13 (Globigerinoides ruber Zone).