Tansulukh Formation

Tansulukh Fm

Period:

Quaternary

Age Interval:

Calabrian

Province:
Cyrenaica Basin

Type Locality and Naming

Synonym:

References: Shaltami, O.R., et al. (2020), and Google Gemina (Aug’26)

Lithology and Thickness

“It is predominantly composed of well-indurated marine calcarenites, skeletal grainstones, and packstones. Highly oolitic in portions. Due to its uniform texture, hardness, and coastal accessibility, exposures of this marine calcarenite have historically been utilized for local infrastructure, engineering evaluations, and industrial cement” (Google Gemini overview)

Lithology Pattern:

Oolitic limestone

Relationships and Distribution

Lower contact

Unconformable onto the Wadi Al Maqar Fm of the Qarat Weddah Gr according to Shaltami et al. (2020).

Upper contact

Unconformably overlain by the Al Hammah Fm according to Shaltami et al. (2020).

Regional extent

Found within the coastal zone of the Cyrenaica Basin in northeastern Libya

GeoJSON

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Fossils

The Tansulukh Fm features an abundance of intact or poorly transported marine macrofossils. These include thick-shelled bivalves, gastropods, coralline algae, bryozoans, and distinct shallow-water benthic foraminifera. (Google Gemini overview)

Age

Calabrian according to Shaltami et al. (2020). [For graphic purposes, the extent of the upper and lower unconformities, which are equivalent to nearly the same time span of the known preserved deposits, have been omitted here.]

Age Span:

Beginning stage:

Calabrian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

1.80

Ending stage:

Calabrian

Fraction up in the ending stage:

1.0

Ending date (Ma):

0.77

Depositional setting

The formation represents an in-situ shallow marine shelf to beach-shoreface environment. The Tansulukh represents the marine "highstand" or transitional phases when rising sea levels flooded the northern Cyrenaica shelf, allowing marine life to thrive and deposit thick carbonate blankets before subsequent regressions pushed aeolian dunes over them. (Google Gemini overview)

Depositional pattern:

Additional Information

“In the regional stratigraphic framework of northern Libya, the vast coastal deposits are broadly generalized under the "Gargaresh Fm" or "Gargaresh Gr". However, localized high-resolution studies in the Al Watiyate and adjacent coastal districts of Al Jabal Al Akhdar split these packages based strictly on depositional genesis: Tansulukh Fm -- Established to explicitly designate the true marine calcarenites. Al Hamamah Fm / Al Haniyah Fm -- Restricted to the aeolian (wind-blown) calcarenites and subaerial dunes that migrated landward.” (Google Gemini overview)

Compiler:

Shaltami, O.R., et al. (2020). Petroleum system of the Cyrenaica Basin – A review. In: 1^st International Symposium on Geosciences (ISG2020), 21th March 2020, Proceeding Book: published by BR Petrobras. P. 64-71.

Tawadros, E.E. (2011). Geology of North Africa. CRC Press (Taylor & Francis Group), 931 pp.

Google Gemini (Aug 2026) – assembled synthesis of Cyrenaica Basin units from various web-accessible publications.

El Oshebi, F.M., Fares, F.F. (2026). Stratigraphy, facies, and depositional environments of the Eocene sequence in the Ras Al Hilal area, Cyrenaica, Libya. Arabian Jour. Geosciences, 19:79. https://doi.org/10.1007/s12517-026-12488-2.

El-Hawat, A.S., Abdulsamad, E.O. (2004) Geology and Archeology of Cyrenaica, Northeastern Libya. Field trip guide B01, 32^nd International Geological Congress. 36 pp.