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Compiled by: Jacques LeBlanc (2022), Stratigraphic Lexicon: The Sedimentary Formations of The Republic of Niger, Africa. Colnes Publishing (Tallin, Estonia), 365 pp. For more information see "About"

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Ash Shabiyat Formation

Ash Shabiyat Fm

Period:

Ordovician

Age Interval:

Early Ordovician (Tremadocian) (9)

Province:
Djado Basin

Type Locality and Naming

Al Qarqaf Arch (Libya) (Fig. 1). Jabal Ash Shabiyat in the eastern Murzuq Basin. Gargaf Gr.

[Figure 1: Stratigraphic column of the Ash Shabiyat Formation at the Type Locality in Libya (Shalbak, 2015)]

References: Havlicek et al., 1973; Mergl et al., 2001; Shalbak, 2015; Hallet, 2016.

Synonym: Achebyat/Achabiyat Fm (both misspelling) (Mergl et al., 2001); “Oblique supérieure” Fm; The spelling was modified to its current form by Hallet (2002) after verifying the official name records of localities in Libya.

Lithology and Thickness

Built-up of non-fossiliferous (except for common trace fossils), cross-bedded, mainly coarse-grained sandstones. Its thickness is ~ 70 m.

Lithology Pattern:

Relationships and Distribution

Lower contact

Underlying unit is the Hasawnah Fm

Upper contact

Overlying unit is the Hawaz Fm

Regional extent

Djado Basin

GeoJSON

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Fossils

Common trace fossils (contains abundant Tigillites, Cruziana and Harlania trace fossils.)

Age

Early Ordovician (Tremadocian) (Havlicek et al., 1973)

Age Span:

Beginning stage:

Tremadocian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

486.85

Ending stage:

Tremadocian

Fraction up in the ending stage:

1.0

Ending date (Ma):

477.08

Depositional setting

Fluvio-deltaic. It represents a maximum flooding interval and is essentially a silty marine sandstone.

Depositional pattern:

Additional Information

Compiler:

Jacques LeBlanc (2022), Stratigraphic Lexicon: The Sedimentary Formations of The Republic of Niger, Africa. Colnes Publishing (Tallin, Estonia), 365 pp. https://doi.org/10.47909/978-9916-9760-6-7 (or via https://sites.google.com/site/leblancjacques)