Cenozoic

Mesozoic

Information provided by geoscience team at Ahmadu Bello University, Zaria, Nigeria --see About

Zeraf Formation

Zeraf Fm

Period:

Quaternary

Age Interval:

Calabrian – Recent

Province:
Sudan S

Type Locality and Naming

Muglad Basin -- SW Sudan and the northwestern part of South Sudan. Upper formation in the Kordofan Gr.

Reference: Schull 1988; Dou Lirong et al. 2013; Makeen et al., 2013

[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

Babikir (1997): The formation is primarily coarse-grained, partly conglomeratic, and consists of subangular to subrounded unconsolidated sands including clasts. There are some very thick laminae of clay, which are soft and light grey to yellow brown in colour. The sands are multicoloured and grey, yellowish orange or light brown in colour. Traces of pyrite are also present.

Lithology Pattern:

Coarse-grained sandstone

Relationships and Distribution

Lower contact

unconformably rests on the Adok Fm. Hiatus arbitrarily assigned as spanning the Gelasian.

Upper contact

Alluvium

Regional extent

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

GeoJSON

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Fossils

Diatom (Melisora granulata), Pollen (Gramineae - Chenopodipollis microporatus)

Age

Quaternary

Age Span:

Beginning stage:

Calabrian

Fraction up in beginning stage:

0.00

Beginning date (Ma):

1.80

Ending stage:

Holocene

Fraction up in the ending stage:

1.0

Ending date (Ma):

0.00

Depositional setting

The nature of the lithology suggests a relatively high energy regime of fluviatile depositional environments and flood plains as represented by the minor clay content (Babikir, 1997). The Zeraf Fm probably represents fluvial reworking of deposits from deposits of the other formations within the Kordofan Gr – Adok, Tendi, and Nayil Formations (as interpreted by Schull 1988; Dou Lirong et al. 2013) (Makeen et al., 2013).

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