Cenozoic • Paleogene formation In GSP lexicon

Kohat Formation

Middle Eocene (Lutetian-Bartonian; ~46.66-38.54 Ma)

Cited in 9 sources Last reviewed Aug 20, 2026

Unit summary

Rank: formation
Status: Published
Age: Cenozoic · Paleogene · Middle EoceneMiddle Eocene (Lutetian-Bartonian; ~46.66-38.54 Ma)
Named by: Not recorded
Type locality: Kohat-Khushalgarh Highway section
Thickness: 37-170 m in western Ko-MP, and only as thin slivers in Kalachitta area m
Lithology: Limestone and Claystone. It consists of interbedded nummulitic limestone and shale, and is subdivided into two members:Kaladhand Member: It is composed predominantly of limestone, which is light grey, hard, compact and thin bedded with shale intercalations, particularly in the lower part. It contains abundant diagnostic Early Eocene forams, such as Orbitolites complanatus, Alveolina oblonga, Lind…
Synonyms: Not recorded

Limestone and Claystone. It consists of interbedded nummulitic limestone and shale, and is subdivided into two members:Kaladhand Member: It is composed predominantly of limestone, which is light grey, hard, compact and thin bedded with shale intercalations, particularly in the lower part. It contains abundant diagnostic Early Eocene forams, such as Orbitolites complanatus, Alveolina oblonga, Linderina burgesi and Assilina pustulosa. It is essentially a cliff-forming sequence, but in places becomes more shaly and forms steep slopes.Sadkal Member: It is mainly comprised of greenish grey, calcar…

Fossils

Assilina exponens Nummulites beaumonti Assilina cancellata Assilina papillata Assilina laminosa

Contacts

In the Kohat Basin column

Shale / mudGypsum / evaporiteLimestoneFossils recordedContact not recordedConformable

Band colour = period; texture = dominant rock type. Lines between bands mark the contact type; dotted = no contact recorded in the sources (not a claim of conformity). True scale makes height ∝ recorded thickness; hatched = thickness not recorded. Ages approximate, for ordering.

This unit (highlighted) within its province column; faded ends continue above and below. Line style marks the contact type.

Distribution & setting

Kohat Basin

Basin: Not recorded
Region: Not recorded
Depositional environment: shallow marine
Coordinates: Not recorded

Correlation

Not recorded. Compare this unit against other basins on the correlation panel →

Economic significance

Not recorded

Remarks

Not recorded

Research notes (9)

Field-by-field findings drawn from the cited literature. Every statement is traced to a registered source — follow a citation for the full reference.

Name & nomenclature (1)

Attested in Shah (2009), Geological Survey of Pakistan Memoir 22 - the Stratigraphic Committee's compiled lexicon. Adds the definitional GSP/SCP lexicon citation.

Shah, S.M.I. (2009)

Age & correlation (4)

Afzal, Williams & Aldridge (2009) assign the Kohat Formation to shallow benthonic Zones SBZ14-SBZ16 (Lutetian-Bartonian, Middle Eocene), on Assilina exponens (Akhtar & Butt 2001) and foraminifera of intermediate age between SBZ10 and SBZ17 (Weiss 1993). It marks the last episode of marine sedimentation in the Kohat area, Kala Chitta and Hazara ranges, overlain by non-marine Miocene Murree molasse. Consistent with the curated Middle Eocene (Lutetian-Bartonian) age.

Afzal, J., Williams, M. & Aldridge, R.J. (2009)
Kazmi & Jan (1997): the Kohat Formation (Eocene) is 50–170 m of grey-to-cream massive nodular limestone and olive shale with a lower Kaladhand Limestone, middle Sadkal Shale and upper Habib Rahi Limestone member; it rests conformably on the Kuldana Formation and is overlain unconformably by the Neogene; foraminifera include Assilina spp., Lockhartia hunti and Nummulites mammilla.

Kazmi, A.H. & Jan, M.Q. (1997)
In the Kohat Basin the top of the Kohat Formation (BFZ 6, Upper Lutetian ~ SBZ 16 / Assilina gigantea Zone of Schaub 1981) records the final cessation of marine sedimentation and closure of the eastern Tethys seaway at ~41.2 Ma, per Ahmad et al. (2016).

Ahmad, S., Kroon, D., Rigby, S. & Khan, S. (2016)
Biostratigraphy at Shekhan Nala (Mirza et al., 2006): larger benthic foraminifera (Nummulites mamillatus/atacicus/globulus/subirregularis, Assilina exponens/granulosa/spinosa/dandotica, Operculina, Discocyclina, Dictyoconoides, Alveolina) confirm an early Middle Eocene (Lutetian) age. Three members — Kaladhand Limestone, Sadkal Shale (a foraminiferal biolithite) and Habib Rahi Limestone (karstified top); a shallow-marine inner-neritic carbonate bank marking the terminal Eocene marine phase, capped unconformably by the Murree Formation.

Mirza, K., Sameeni, S.J., Munir, M.H. & Yasin, A. (2006)

Fossils & biostratigraphy (2)

Yaseen et al. (2007), Middle Eocene Kohat Formation at Shekhan Nala (Kohat Basin): larger foraminifera Nummulites beaumonti, N. mamillatus, Assilina exponens and Alveolina elliptica confirm a Middle Eocene age. Expands the recorded fauna beyond the single Assilina exponens.

Yaseen, A., Munir, M., Rehman, O. & Mirza, K. (2007)
Ahmad, Kroon, Rigby & Khan (2016, Stratigraphy 13(4)) document the Kohat Formation in the Sheikhan Nala section (Kohat Basin) as hosting their upper three nummulitid Benthic Foraminiferal Zones - BFZ 4 (FO Assilina exponens; 32 m), BFZ 5 (FO Nummulites beaumonti; 9 m) and BFZ 6 (range of Assilina cancellata; 28 m) - with a figured LBF assemblage of Assilina exponens, A. laminosa, A. papillata, A. cancellata, Nummulites beaumonti, N. acutus, Alveolina elliptica and A. spinosa. This constrains the formation to the Middle-Upper Lutetian (middle Eocene), consistent with the curated age.

Ahmad, S., Kroon, D., Rigby, S. & Khan, S. (2016)

Depositional environment (1)

Yaseen et al. (2007): the Kohat Formation at Shekhan Nala comprises three microfacies (bioclastic wackestone, bioclastic packstone, bioclastic grainstone) and four lithofacies from base to top - TS-1 calcareous shale interbedded with fossiliferous limestone, TS-2 nummulitic shale and limestone, TS-3 highly fossiliferous limestone, TS-4 massive nodular limestone - indicating deposition in shallow-marine settings. The formation is divided (Meissner et al. 1974) into the Kaladhand, Sadkal (= Nummulitic Shales of Pinfold 1918) and Habib Rahi members.

Yaseen, A., Munir, M., Rehman, O. & Mirza, K. (2007)

Geological significance (1)

Craig et al. (2018): in the Kohat-area Eocene succession the Middle Eocene Kohat Limestone marks the culmination of a second Kohat transgression (restricted to NW Pakistan), overlain by the Upper Eocene Kohat Formation shales (Chharat Group); the underlying Middle Eocene Mami Khel red beds prograded over the deepest part of the Kohat basin before that second transgression.

Craig, J., Hakhoo, N., Bhat, G.M., Hafiz, M., Khan, M.R., Misra, R., Pandita, S.K., Raina, B.K., Thurow, J., Thusu, B., Ahmed, W. & Khullar, S. (2018)

Sources (7)

Indian Plate Lexicon (indplex.geolex.org), Geological Society of India and international compilation.
Afzal, J., Williams, M. & Aldridge, R.J. (2009). Revised stratigraphy of the lower Cenozoic succession of the Greater Indus Basin in Pakistan. Journal of Micropalaeontology, 28(1): 7-23.
Shah, S.M.I. (2009). Stratigraphy of Pakistan. Geological Survey of Pakistan, Memoir Vol. 22.
Kazmi, A.H. & Jan, M.Q. (1997). Geology and Tectonics of Pakistan. Graphic Publishers, Karachi.
Kazmi, A.H. & Abbasi, I.A. (2008). Stratigraphy and Historical Geology of Pakistan. Department & National Centre of Excellence in Geology, University of Peshawar, Peshawar. 524 pp. ISBN 978-969-9119.
Yaseen, A., Munir, M., Rehman, O. & Mirza, K. (2007). Microfacies Analysis of the Middle Eocene Kohat Formation, Shekhan Nala, Kohat Basin, Pakistan. Geological Bulletin of the Punjab University, 42, 15-24.
Craig, J., Hakhoo, N., Bhat, G.M., Hafiz, M., Khan, M.R., Misra, R., Pandita, S.K., Raina, B.K., Thurow, J., Thusu, B., Ahmed, W. & Khullar, S. (2018). Petroleum systems and hydrocarbon potential of the North-West Himalaya of India and Pakistan. Earth-Science Reviews, 187, 109-185.

Reviewer confidence: high

Every fact on this page is source-cited. This entry is part of the peer-archived Pakistan Stratigraphy Dataset (doi.org/10.5281/zenodo.21363991, CC‑BY‑4.0).

Lexicon status: Name attested in the Shah (1977/2009) Geological Survey of Pakistan compilation — the national stratigraphic lexicon. This records where the name is documented; it is not an endorsement of the unit’s definition, age or figures.

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Cite this unit

APA

Qudsi, L. (2026). Kohat Formation. In Pakistan Stratigraphy Dataset [Data set]. Zenodo. https://doi.org/10.5281/zenodo.21363991

BibTeX

@misc{stratigraphypk_kohatformation,
  author    = {Qudsi, Lareb},
  title     = {{Kohat Formation} --- Pakistan Stratigraphy Dataset},
  year      = {2026},
  publisher = {Zenodo},
  doi       = {10.5281/zenodo.21363991},
  url       = {https://doi.org/10.5281/zenodo.21363991}
}

Archived dataset: doi.org/10.5281/zenodo.21363991 (CC‑BY‑4.0) · Direct link to this entry: https://stratigraphy.pk/formation/kohat-formation (accessed October 29, 2026).

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