Sequence stratigraphic study of the Late Oligocene to Early-Middle Miocene in Niger Delta, Nigeria: application of palaeobathymetry analysis and biostratigraphy

Author(s):  
Usman Abubakar ◽  
Musa Bappah Usman ◽  
Enam Okon Obiosio ◽  
Aniediobong Jonah Ukpong
Author(s):  
Dairo VA

Biostratigraphic studies of foraminifera were carried out on two exploratory wells drilled in the Eastern Niger Delta to establish the age, biozonation and paleoenvironment of the foraminifera present in the strata penetrated by the wells. A total of 80 ditch cutting samples retrieved at 60ft intervals from AX-1 and AX-2 Wells at the depth of 3,600ft to 6,000ft and 4,200ft to 6500ft. respectively were subjected to micropaleontological analysis which involves picking and identification of the foraminifera present. The resulting data were loaded into the Stratabug software and interpreted. The foraminifera recovered and identified from the two wells are made up of both benthic and planktic species. The marker species, whose stratigraphic range are well established were used to describe the biozonation and these includes Heterostegina sp, Catapsydrax stainforthi, Chiloguembelina victoriana, Orbulina universa/suturalis, Praeorbulina sicana,Buliminella subfusiformis, Nonion centrosulcatum, Catapsydrax dissimilis, Globigerinoides bisphericus and Globigerinoides sicanus. Four biozones of foraminifera made up of N8, N7-N8, N6-N7 and N5-N6 were recognised based on the zonation scheme of Grandstein; with their stratigraphic age ranging from early Miocene to middle Miocene. Furthermore, the environment of deposition prevailing in the Formations penetrated by the two wells are predominantly middle neritic with similarity in their ages as observed from the correlation of the biozones from the two wells


2020 ◽  
Vol 218 ◽  
pp. 103366 ◽  
Author(s):  
Ali Ihsan Karayigit ◽  
Mustafa Atalay ◽  
Rıza Görkem Oskay ◽  
Patricia Córdoba ◽  
Xavier Querol ◽  
...  

1984 ◽  
Vol 3 (2) ◽  
pp. 73-94 ◽  
Author(s):  
William A. S. Sarjeant

Abstract. The type material of six dinoflagellate cyst species from the Late Oligocene to Middle Miocene of northwest Germany, described originally by Gerlach (1961), is reillustrated and redescribed. It is shown to include representatives of nine species. Areosphaeridium (ex: Baltisphaeridium) pectiniforme is found to be a senior synonym of Areosphaeridium multicornutum Eaton. Systematophora placacantha is considered to be a senior synonym of Cleistosphaeridium (ex: Baltisphaeridium) panniforme (Gerlach). The new combination Rhynchodiniopsis tenuitabulata (Gerlarch) is proposed. Revised diagnoses for these three species and for Leptodinium membranigerum (Gerlach), Achomosphaera triangulata (Gerlach) and Lejeunecysta hyalina (Gerlach) are proposed. The morphology of a form described here for the first time, and tentatively attributed to Phthanoperidinium, is considered perhaps to imply a separate origin for the Phthanoperidiniaceae: for that reason familial, rather than tribal, rank is preferred for that group. The stratigraphical ranges of the nine species here recognised and of two others of Gerlach’s species redescribed in earlier papers are detailed; elimination of misattributed forms means that these ranges are shorter than the published literature suggests.


The general geology of the New Hebrides is summarized in terms of three volcanic and two main sedimentary episodes. Calc-alkaline volcanics ol the first episode occur on the western islands and accumulated mainly on the submarine slopes below small reef-fringed volcanic islands in Late Oligocene to Middle Miocene times. During the Late Miocene and Early Pliocene wholly submarine tholeiitic or high-Al volcanics accumulated in the eastern and southern part of the New Hebrides while calcareous sediments were forming in the western islands. During the third volcanic phase, of Pliocene to Recent age, regional uplift has led to most of the volcanics being subaerial while extensive flights of limestone terraces occur round the older islands. In consequence the land area of the New Hebrides has increased rapidly during Quaternary times. The landforms produced are briefly described.


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