Cenozoic

Mesozoic

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Baobab Formation

Baobab Fm

Period:

Cretaceous

Age Interval:

Albian

Province:
Chad S

Type Locality and Naming

Bongor Basin (SW Chad). Outcrops in the northern of the basin, with the lower part of the section outcropping in the southern part of the basin

Synonym:

Reference: Chen et al., 2018; Wang et al., 2022; Dou et al., 2023

[Fig. 1: Simplified map of the West and Central African Rift System (WCARS) showing the major features discussed in the text and the location of the Melut Basin in South Sudan (modified from Genik, 1993)]

[Fig. 2: Stratigraphic chart for the Bongor Basin showing the positions of producing reservoirs, source rocks and seals (from Dou et al., 2020)]

Lithology and Thickness

Greyish yellow coarse-grained sandstones interbedded with thin bedded mudstones (Chen et al., 2018; Wang et al., 2022). The residual thickness of the Baobab Formation is 200–1200 m. In the northern part of the basin, it is mainly composed of fine sandstone to gritstone. The lower section in the southern part contains a large set of mudstone intercalated with thin siltstone (Dou et al., 2023).

Lithology Pattern:

Clayey sandstone

Relationships and Distribution

Lower contact

conformably rests on the Ronier Fm,

Upper contact

Alluvium unconformably overlies the Baobab Fm

Regional extent

Bongor Basin (SW Chad)

GeoJSON

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Fossils

Pollens (Classopollis, Ephedripites, Jugella, Cicatricosisporites, Tricolporopollenites, Tricolpollenites)

Age

Albian

Age Span:

Beginning stage:

Albian

Fraction up in beginning stage:

0.00

Beginning date (Ma):

113.20

Ending stage:

Albian

Fraction up in the ending stage:

1.0

Ending date (Ma):

100.50

Depositional setting

Alluvial plain (Chen et al., 2018; Wang et al., 2022).

Depositional pattern:

Additional Information

Compiler:

Enam O. Obiosio, Solomon Joshua Avong and Henry Nasir Suleiman (2024) - Stratigraphic Lexicon compiled from the following books:

Chen L., Ji H., Dou L., Du Y., Xu Z., Zhang L. (2018): The Characteristics of Source Rock and Hydrocarbon Changing Time of Precambrian Granite Reservoirs in the Bongor Basin, Chad. Mar. Petroleum Geol. 97, pp. 323-338

Wang Y., Xu G., Zhou W., Liang J., He S. (2022): Predicting Granitic Buried-Hill Reservoirs Using Seismic Reflection Data – A Case Study From the Bongor Basin, Southwestern Chad. Frontiers in Earth Science, pp. 1-13

Dou L., Xiao K., Wang J. (2023): Petroleum Geology and Exploration of the Bongor Basin. Petroleum Industry Press.