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

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

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 onwards. Within the sampled interval, the species exhibit...

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Bibliographic Details
Published in:Micropaleontology Vol. 44; no. 2; pp. 173 - 186
Main Author: Adeniran, Victor B
Format: Journal Article
Language:English
Published: American Museum of Natural History 1998
Micropaleontology Press, American Museum of Natural History
Subjects:
Africa
Biostratigraphy
Bismuth
Cenozoic
distribution
Foraminifera
Geology
Globigerinacea
Globigerinidae
Globigerinoides
Globigerinoides ruber
Invertebrata
lower Pliocene
Marine
microfossils
Micropaleontology
middle Miocene
Miocene
Neogene
Niger Delta
Nigeria
Oceans
Petroleum
Petroleum geology
Pliocene
Protista
Rotaliina
Sediments
Specimens
Stratigraphy
Taxa
Tertiary
West Africa
ASE, Nigeria, Niger Delta
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Summary: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 onwards. 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 form d, in the latest part of Zone N. 13 (Globigerinoides ruber Zone). In the second zone (7,133 - 5,007 feet), specimens of Gds. ruber form d were recovered in only three samples and in very low numbers, representing the "pseudoextinction interval" of the species as described in the Caribbean, Atlantic, and Mediterranean in the lower part of Zone N.14. A transition between the second and third zone is characterised by the reappearance of Gds. ruber form c in the uppermost part of Zone N.14, at the top of a subzone characterized by abundant Globigerinoides obliquus obliquus. The third zone (4,787 - 4,504 feet) is the acme of Gds. ruber in this core, in association with Globigerinoides obliquus extremus and Globigerinoides ruber seigliei, suggesting Zones N.16-N.18. In this interval, forms c and b are both common. The fourth zone (4,476-4,034 feet), dominated by Gds. ruber form a, is above the last appearance of Gds. o. extremus and Gds. r. seigliei, and is interpreted as Pliocene (=N18-21), consistent with the occurrence of Pliocene palynomorphs in these samples.
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content type line 23
ISSN:0026-2803
1937-2795
DOI:10.2307/1486069