Organic petrography and trace element geochemistry of organic black shales in the Kribi Campo sub-Basin, West Africa: Implication for petroleum source rock evaluation and depositional environment

The aim of this study was to characterise the maceral properties, depositional environment and petroleum source rock properties of black shales deposits of the lower Mundeck Formation of the Douala Kribi Campo sub-basin from organic petrography and trace element geochemical studies. The study showed...

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Main Authors: Kah Odilia Sih, Bokanda Ekoko Eric, Florence Njinto Kwankam, Cortland F. Eble, Yugyè Jules Alex, Ashukem Ethel Nkongo, Mokake Fidelis Esue, Agyingi Christopher
Format: Article
Language:English
Published: Elsevier 2023-07-01
Series:Scientific African
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S2468227623000686
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author Kah Odilia Sih
Bokanda Ekoko Eric
Florence Njinto Kwankam
Cortland F. Eble
Yugyè Jules Alex
Ashukem Ethel Nkongo
Mokake Fidelis Esue
Agyingi Christopher
author_facet Kah Odilia Sih
Bokanda Ekoko Eric
Florence Njinto Kwankam
Cortland F. Eble
Yugyè Jules Alex
Ashukem Ethel Nkongo
Mokake Fidelis Esue
Agyingi Christopher
author_sort Kah Odilia Sih
collection DOAJ
description The aim of this study was to characterise the maceral properties, depositional environment and petroleum source rock properties of black shales deposits of the lower Mundeck Formation of the Douala Kribi Campo sub-basin from organic petrography and trace element geochemical studies. The study showed that the Kribi Campo shales are typically dominated by the liptinite group of macerals, followed by vitrinite and the inertinite group respectively. The liptinite group is primarily represented by lamalginite, bituminite and solid bitumen, while vitrinite consists primarily of collotelinite, vitrodetrinite, and corpogelinite. The inertinite maceral group is the least abundant and is represented by fusinite, semifusinite, pyrolytic carbon, funginite and inertodetrinite. The constituents of the maceral in the shales point to a type II and III kerogen which are proficient of generating oil and gas. Based on vitrinite reflectance, the shales may be classified as being subbituminous A/B to subbituminous and A/high volatile bituminous C in rank. In terms of petroleum production, these shales are regarded as thermally immature with an indicated Tmax temperature (from programmed pyrolysis) of 421 °C.Trace element ratios of Sr/Ba for the studied shales shows values between 0.18 to 0.34 indicating that the shales were deposited in both fresh water and estuary environment. The estuary environment may have resulted from marine contamination to fresh water environment as this is seen only in one shale sample. The V/Ni and V/V+Ni ratio of the studied shales is >1 and ranges from 0.60–0.94 respectively, revealing their deposition in an anoxic environment.
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spelling doaj.art-5ab68b23ac5547a496024869b0e637d82023-06-17T05:19:41ZengElsevierScientific African2468-22762023-07-0120e01611Organic petrography and trace element geochemistry of organic black shales in the Kribi Campo sub-Basin, West Africa: Implication for petroleum source rock evaluation and depositional environmentKah Odilia Sih0Bokanda Ekoko Eric1Florence Njinto Kwankam2Cortland F. Eble3Yugyè Jules Alex4Ashukem Ethel Nkongo5Mokake Fidelis Esue6Agyingi Christopher7Department of Geology, University of Buea, CameroonDepartment of Geology, University of Buea, Cameroon; Corresponding author.National higher polytechnic institute, University of Bamenda, P.O.BOX 039, Bambili, CameroonKentucky Geological Survey, University of Kentucky, Lexington, KY, USANational Hydrocarbon Corperation (SNH) Yaoundé, CameroonDepartment of Earth Sciences, University of Yaoundé I, CameroonDepartment of Geology, University of Buea, CameroonDepartment of Geology, University of Buea, CameroonThe aim of this study was to characterise the maceral properties, depositional environment and petroleum source rock properties of black shales deposits of the lower Mundeck Formation of the Douala Kribi Campo sub-basin from organic petrography and trace element geochemical studies. The study showed that the Kribi Campo shales are typically dominated by the liptinite group of macerals, followed by vitrinite and the inertinite group respectively. The liptinite group is primarily represented by lamalginite, bituminite and solid bitumen, while vitrinite consists primarily of collotelinite, vitrodetrinite, and corpogelinite. The inertinite maceral group is the least abundant and is represented by fusinite, semifusinite, pyrolytic carbon, funginite and inertodetrinite. The constituents of the maceral in the shales point to a type II and III kerogen which are proficient of generating oil and gas. Based on vitrinite reflectance, the shales may be classified as being subbituminous A/B to subbituminous and A/high volatile bituminous C in rank. In terms of petroleum production, these shales are regarded as thermally immature with an indicated Tmax temperature (from programmed pyrolysis) of 421 °C.Trace element ratios of Sr/Ba for the studied shales shows values between 0.18 to 0.34 indicating that the shales were deposited in both fresh water and estuary environment. The estuary environment may have resulted from marine contamination to fresh water environment as this is seen only in one shale sample. The V/Ni and V/V+Ni ratio of the studied shales is >1 and ranges from 0.60–0.94 respectively, revealing their deposition in an anoxic environment.http://www.sciencedirect.com/science/article/pii/S2468227623000686Depositional environmentKribi Campo sub basinKerogen typeMaceral propertiesPetrographyTrace element geochemistry
spellingShingle Kah Odilia Sih
Bokanda Ekoko Eric
Florence Njinto Kwankam
Cortland F. Eble
Yugyè Jules Alex
Ashukem Ethel Nkongo
Mokake Fidelis Esue
Agyingi Christopher
Organic petrography and trace element geochemistry of organic black shales in the Kribi Campo sub-Basin, West Africa: Implication for petroleum source rock evaluation and depositional environment
Scientific African
Depositional environment
Kribi Campo sub basin
Kerogen type
Maceral properties
Petrography
Trace element geochemistry
title Organic petrography and trace element geochemistry of organic black shales in the Kribi Campo sub-Basin, West Africa: Implication for petroleum source rock evaluation and depositional environment
title_full Organic petrography and trace element geochemistry of organic black shales in the Kribi Campo sub-Basin, West Africa: Implication for petroleum source rock evaluation and depositional environment
title_fullStr Organic petrography and trace element geochemistry of organic black shales in the Kribi Campo sub-Basin, West Africa: Implication for petroleum source rock evaluation and depositional environment
title_full_unstemmed Organic petrography and trace element geochemistry of organic black shales in the Kribi Campo sub-Basin, West Africa: Implication for petroleum source rock evaluation and depositional environment
title_short Organic petrography and trace element geochemistry of organic black shales in the Kribi Campo sub-Basin, West Africa: Implication for petroleum source rock evaluation and depositional environment
title_sort organic petrography and trace element geochemistry of organic black shales in the kribi campo sub basin west africa implication for petroleum source rock evaluation and depositional environment
topic Depositional environment
Kribi Campo sub basin
Kerogen type
Maceral properties
Petrography
Trace element geochemistry
url http://www.sciencedirect.com/science/article/pii/S2468227623000686
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