Cenozoic

Mesozoic

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Sharaf Formation

Sharaf Fm

Period:

Cretaceous

Age Interval:

Barremian

Province:
Sudan S

Type Locality and Naming

Muglad Basin -- SW Sudan and the northwestern part of South Sudan.

Synonym: Sharaf Fm and the overlying Abu Gebra Fm are often combined into a single Abu Gebra Fm (Lenhard et al., 2025)

Reference: Ramses, 1997; Lenhard et al., 2025

[Fig. 1: Western and Central African rift system. West African rift subsystem and Central African]

[Fig. 2: General stratigraphic column - Muglad Basin, Sudan, showing three geological cycles – Neocomian to Barremian, Aptian to Maastrichtian, and Paleocene to Pliocene - Miocene, or Quaternary and Petroleum Systems (from Ahmed and Ozumba, 2017)]

[Fig. 3: Comprehensive stratigraphic columns in the Muglad Basin (from Dou et al., 2023)]

[Fig. 4: Regional stratigraphy of the Muglad basin, SW Sudan (after Schull 1988; Dou Lirong et al. 2013 – extracted from Makeen et al., 2013)]

[Fig. 5: Location map of the Fula sub-basin in the Muglad basin including oilfields (study area) (after Dou Lirong et al. 2013 – extracted from Makeen et al., 2013)]

Lithology and Thickness

The Sharaf Formation is one of the early first cycle graben-fill clastics derived from basement complex, and it is made up of claystones, siltstones, and fine-grained sandstones that grade into coarse alluvial clastics toward the basin edges (Ramses, 1997).

Lithology Pattern:

Sandy claystone

Relationships and Distribution

Lower contact

Pre-Cambrian Basement Complex, non-conformably

Upper contact

Abu Gabra Fm rests conformably on the Sharaf Fm. Sandstone increases in frequency upwards from Sharaf Fm through the Abu Gebra Fm.

Regional extent

Muglad Basin -- SW Sudan and the northwestern part of South Sudan

GeoJSON

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Fossils

Age

Barremian (assuming lower half of Sharaf-AbuGabra merged interval in strat column of Lenhard et al., 2025)

Age Span:

Beginning stage:

Barremian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

126.50

Ending stage:

Barremian

Fraction up in the ending stage:

1.0

Ending date (Ma):

121.40

Depositional setting

Fluvial floodplain – lacustrine (Ramses, 1997). "In the first rift cycle (Barremian-Aptian), the Sharaf Fm and Abu Gabra Fm consist mainly of lacustrine shales and clays with thin intervals of sandstone. … The shales are interpreted to have formed in stratified lakes as distal dysoxic to anoxic facies." (Lenhardt et al., 2025)

Depositional pattern:

Additional Information

Compiler:

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

Dou D., Dingsheng C., Zhi L., Zhiwei Z., Jingchun W. (2013): Petroleum Geology of the Fula Sub-Basin, Muglad Basin, Sudan. Journal of Petroleum Geology, 36(1): pp.43-60

Jingyao W. (2015): The Study of Sequence Stratigraphy and Sedimentary System in Muglad Basin. IOSR Journal of Applied Geology and Geophysics (IOSR-JAGG), 3(6): pp.37-40

Makeen Y. M., Abdullah W. H., Hakimi M. H. (2013): Biological markers and organic petrology study of organic matter in the Lower Cretaceous Abu Gabra sediments (Muglad Basin, Sudan): origin, type and palaeoenvironmental conditions. Arabian Journal of Geosciences. DOI 10.1007/s12517-013-1203-z

Lenhardt, N., Omietimi, E. J., Edegbai, A. J., Schwark, L., Catuneanu, O., Fairhead, J. D., Gotz, A. E. (2025): Traversing the rift: A review of the evolution of the West and Central African Rift System and its economic potential. Earth-Science Reviews, 261: pp. 1-39