Gir Formation

Gir Fm

Period:

Paleogene

Age Interval:

Eocene (Ypresian).

Province:
Sirte Basin

Type Locality and Naming

Synonym:

References: Selley, 1997; Ahlbrandt, 2001; Abugares, 2007

Lithology and Thickness

The Gir Formation is subdivided into three members; the lower Facha Dolomite, Hun Evaporite and the upper Mesdar Limestone members (Abugares, 2007). It consists of limestones, dolomites and evaporites, often arranged in a regular cyclic motif. The evaporites include gypsum (near the surface), anhydrite, and halite in the south western part of the basin (Selley, 1997).

Lithology Pattern:

Dolomitic limestone

Relationships and Distribution

Lower contact

It conformably (transitionally?) overlies the Kheir Fm. (see Fig. 7 of Ahlbrandt, 2001).

Upper contact

It is conformably(?) overlain by the Gialo Fm. (see Fig. 7 of Ahlbrandt, 2001)

Regional extent

GeoJSON

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Fossils

Age

Ypresian, but onset of the lower dolomite-member is transitional onto the Kheir Fm limestone.

Age Span:

Beginning stage:

Ypresian

Fraction up in beginning stage:

0.1

Beginning date (Ma):

55.21

Ending stage:

Ypresian

Fraction up in the ending stage:

1.0

Ending date (Ma):

48.07

Depositional setting

Shallow-marine to restricted carbonate platform (Abugares, 2007).

Depositional pattern:

Additional Information

Compiler:

T. S. Ahlbrandt (2001): The Sirte Basin Province of Libya—Sirte-Zelten Total Petroleum System, U.S. Geological Survey Bulletin 2202–F

R.C. Selley (1997): The Sirte Basin of Libya. In: African Basins. Sedimentary Basins of the World, 3, edited by R.C. Selley (Series Editor: K.J. Hsu), Elsevier Science B.V., Amsterdam, pp. 27-37.

Abugares, Miloud M. (2007): Deposition, Diagenesis, and Reservoir Development of the Cretaceous Lidam Formation, SE Sirt Basin, Libya. Durham e-Theses. http://etheses.dur.ac.uk/2599/

Elkanouni, I. E. D. (2014). Sedimentology, Sequence stratigraphyand Spatial-temporal Patterns of the late Paleocene Succession, western Sirt Basin, Libya, Durham e Theses. http://etheses.dur.ac.uk/10538/