Cenozoic • Paleogene In GSP lexicon

Habib Rahi Formation

Middle Eocene

Part of Early-Middle Eocene Kahan Group, Kahan Group, Kirthar Group

Cited in 6 sources Last reviewed Jul 30, 2026

Unit summary

Rank: Not recorded
Status: Published
Age: Cenozoic · Paleogene · Middle EoceneMiddle Eocene
Named by: Tainsh (1959)
Type locality: North of Zampost, Zhob–Dera Ismail Khan road
Thickness: 15–150 m
Lithology: Greyish-brown, thin- to thick-bedded or massive, hard argillaceous fossiliferous limestone with nodules and cherty beds.
Synonyms: Not recorded

A hard Middle Eocene limestone, the base of the Kirthar Group, and a gas reservoir in the Sulaiman fields.

Named after Habib Rahi area. Includes Kohat Formation and related members. Marine limestone sequence in Kohat Sub-Basin. Part of the Kahan Group.

Fossils

Larger foraminifera (Nummulites, Assilina)Gastropods Echinoids

Contacts

In the Kohat Basin column

Gypsum / evaporiteLimestoneShale / mudFossils recordedContact not recorded

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

Reservoir

An Eocene limestone reservoir unit of the Sulaiman gas province.

Remarks

The basal limestone of the Kirthar Group in the Sulaiman Range, conformably overlying the Ghazij Group and forming a regional Eocene marker and gas reservoir.

Research notes (3)

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

Age & correlation (1)

Jones (1997), Habib Rahi Limestone (Kirthar Formation member): early Middle Eocene, from the larger benthonic nummulitid Assilina maior punctulata (Cuisian Supérieur–Lutetian Basal of Schaub 1981; NP14–NP15) and calcareous nannofossils Discoaster saipanensis, Nannotetrina spp. and Sphenolithus pseudoradians.

Jones, R.W. (1997)

Thickness (1)

Type-section thickness (Shah, 2009): 15–60 m. Type locality: reference section: Fort Sandeman–D.I. Khan road, N of Zam Post. Recorded from the GSP lexicon (Memoir 22); the existing thickness field is retained.

Shah, S.M.I. (2009)

Geological significance (1)

Jones (1997): the Habib Rahi Member is associated with the transgressive third-order sequences TA3.2–TA3.3 of Haq et al. (1987); its nummulitic/nummulithoclastic grainstones (Rotaliida) grade to laminated basinal shales, and A-form-dominated nummulitid populations plot in the 'toe of slope' field.

Jones, R.W. (1997)

Sources (5)

Malkani, M.S. & Mahmood, Z. (2017). Stratigraphy of Pakistan. Geological Survey of Pakistan, Memoir Vol. 24.
Kazmi, A.H. & Jan, M.Q. (1997). Geology and Tectonics of Pakistan. Graphic Publishers, Karachi.
Indian Plate Lexicon (indplex.geolex.org), Geological Society of India and international compilation.
Shah, S.M.I. (2009). Stratigraphy of Pakistan. Geological Survey of Pakistan, Memoir Vol. 22.
Jones, R.W. (1997). Aspects of the Cenozoic stratigraphy of the Northern Sulaiman Ranges, Pakistan. Journal of Micropalaeontology, 16(1), 51-58.

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). Habib Rahi Formation. In Pakistan Stratigraphy Dataset [Data set]. Zenodo. https://doi.org/10.5281/zenodo.21363991

BibTeX

@misc{stratigraphypk_habibrahiformation,
  author    = {Qudsi, Lareb},
  title     = {{Habib Rahi 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/habib-rahi-formation (accessed October 29, 2026).

To cite the unit's original definition instead, see: Tainsh (1959).

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