Geochemistry and paleoecology of shales from the Cenomanian-Turonian Afowo formation Dahomey Basin, Nigeria: Implication for provenance and paleoenvironments

Simple item page
dc.contributor.authorAdeoye, James A.
dc.contributor.authorSamuel, O Akande
dc.contributor.authorAdekeye, Olabisi
dc.contributor.authorVictor, Abikoye
dc.date.accessioned2023-07-06T08:17:38Z
dc.date.available2023-07-06T08:17:38Z
dc.date.issued2020
dc.description.abstractCenomanian - Turonian (CT) Afowo shales selected from offshore X, and coastline Orimedu-1 and Ise-2 exploratory wells in the Dahomey Basin, southwestern Nigeria, were analyzed for foraminifera, major oxide and trace elements to evaluate their provenance and paleoenvironments. The hydrocarbon rich calcareous CT shale is about 100m thick in the coastline area and 300m thick in offshore area with abundant of marine planktonic and benthonic foraminifera. Benthonic species were significantly present in the coastline wells suggesting a shallow marine condition probably a neritic to inner shelf environments while abundant deep water Rotaliporid sp. and shallow water fauna heterohelix sp. in X well suggest inner shelf to bathyal (ca. >350 m) depositional environments. SiO2 and Al2O3 are the most abundant oxides of CT shale with average value of 46.4% and 12.7% in X, 57.1% and 15.65% in Orimedu-1 and 55.3% and 13.1% in Ise-2 respectively suggesting high influx of terrigenous and argillaceous sediments at the coastal area. Average Al2O3/TiO2 of 19.2 in X, 17.8 in Orimedu-1 and 19.3 in Ise-2 indicates that the sediments were sourced from intermediate igneous rock. Favorable oxic conditions for chemical weathering is more pronounce in the manganese concentration of 658–937 ppm in Orimedu-1 and 829–838 ppm in Ise-2 than 364–604 ppm in the shales from X well. Their degree of weathering estimated from chemical index of alteration (CIA) averaging 97 in the coastline wells is higher than 61 in X well, thus indicating high degree of oxidation in the depositional environments. Vanadium to nickel ratio ranging from 2.88 to 5.0 in X well suggest mixed marine and terrigenous source under dysoxic to oxic conditions for the shales while 0.48–1.2 values in Orimedu-1 further indicates a prevailing oxidizing condition at the time of deposition. Dysoxic-oxic and moderate deep-water conditions were more favorable in the offshore area and probably a significant paleo-factor for organic matter preservation of CT shales in the basin.en_US
dc.identifier.urihttps://uilspace.unilorin.edu.ng/handle/20.500.12484/11413
dc.language.isoenen_US
dc.subjectGeochemistry, paleoecology and Dahomey basinen_US
dc.titleGeochemistry and paleoecology of shales from the Cenomanian-Turonian Afowo formation Dahomey Basin, Nigeria: Implication for provenance and paleoenvironmentsen_US
dc.typeArticleen_US

Files

Original bundle
Now showing 1 - 1 of 1
No Thumbnail Available
Name:
Geochemistry and paleoecology of shales from the Cenomanian-Turonian Afowo formation Dahomey Basin, Nigeria_ Implication for provenance and paleoenvironments - ScienceDirect.pdf
Size:
308.97 KB
Format:
Adobe Portable Document Format
Description:
Download
License bundle
Now showing 1 - 1 of 1
No Thumbnail Available
Name:
license.txt
Size:
1.71 KB
Format:
Item-specific license agreed upon to submission
Description:
Download

Collections