Tanzuft Shale Fm
Period:
Silurian
Age Interval:
Rhuddanian – Gorstian, Lb2
Province:
Libya
Type Locality and Naming
Column: Fezzan Basin
Synonym: Tannezuft Shale Fm
Lithology and Thickness
Important unit for petroleum exploration. One of the major source rocks in North Africa. Dark gray marine, graptolitic shales with thin siltstone and sandstone stringers in the lower part. The lower part contains hot shales (radioactive), with Uranium levels probably deposited as aeolian volcanic ash.
Lithology Pattern:
Claystone
Relationships and Distribution
Lower contact
Regionally, the schematic strat column indicates the next older unit as Memouiat Fm
Upper contact
Regionally, the schematic strat column indicates the next younger unit as Akakus Sandstone Fm
Regional extent
GeoJSON
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Fossils
Age
USGS chart places this formation in the Llandoverian stage, at the base of the Silurian. Rhuddanian - Gorstian
Age Span:
Beginning stage:
Rhuddanian
Fraction up in beginning stage:
0.0
Beginning date (Ma):
443.07
Ending stage:
Gorstian
Fraction up in the ending stage:
1.0
Ending date (Ma):
425.01
Depositional setting
Deposited in a turbiditic environment, with the top of the unit is hummocky and cross-stratified.
Depositional pattern:
Additional Information
Compiler:
Chart derived from: USGS Correlation Chart and Columnar Section for Rocks in Libya, 1963. Descriptions from: Hallet, Don: Petroleum Geology of Libya, 2002.