Cenozoic

Mesozoic

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Samma Formation

Samma Fm

Period:

Paleogene

Age Interval:

Early Paleocene

Province:
SouthSudan

Type Locality and Naming

Melut Basin (NE South Sudan - W Ethiopia), which is the southeastern basin of the greater White Nile rift basin. This interval seems to be a hiatus in the Rawat Basin.

Reference: Dou et al., 2007; Dou et al., 2023 (Melut Basin); Mohammed et al, 2017 (Rawat Basin)

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

[Fig. 3: Rawat Basin- Block 25 in southern Sudan (after Ministry of Petroleum & Gas-OEPA, 2015, Extracted from Mohammed et al., 2017).]

[Fig. 4: Summary of Tectono-stratigraphy of the Rawat Basin (from Mohammed, 2016).]

Lithology and Thickness

Composed of thick coarse- to medium-grained sandstones with interbedded thin claystones which were deposited in progressive braided delta, marginal and shallow lacustrine environments (Dou et al., 2007).

Lithology Pattern:

Sandstone

Relationships and Distribution

Lower contact

unconformably overlies the Melut Fm

Upper contact

Yabus Fm conformably rests on the Samma Fm in the Melut Basin.

Regional extent

Only in the Melut Basin (NE South Sudan - W Ethiopia), which is the southeastern basin of the greater White Nile rift basin.

GeoJSON

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Fossils

Age

Early PaleoceneNOTE: Age span as estimated for the Melut Basin used here for graphic and paleogeographic display purposes.

Age Span:

Beginning stage:

Danian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

66.04

Ending stage:

Selandian

Fraction up in the ending stage:

0.5

Ending date (Ma):

60.45

Depositional setting

Progressive braided delta depositional setting (Dou et al., 2007).

Depositional pattern:

Additional Information

Compiler:

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

Dou L., Xiao K., Cheng D., Shi B., Li Z. (2007): Petroleum Geology of the Melut Basin and the Great Palogue Field, Sudan. Marine and Petroleum Geology, 24, pp.129-144

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

Mohammed H. Z. A., Awad M. Z., Eisawi (2017): Upper Cretaceous to Neogene Palynology of the Rawat Basin, White Nile State, Sudan. Journal of Earth Science & Climatic Change. 08 (04)

Robertson Research International “RRI”, Geological Research Authority of Sudan “GRAS” (2016): The Geology and Petroleum Potential of Southern, Central, and Eastern Sudan. Unpublished Report. Vol. 1-4