Cenozoic • Paleogene formation In GSP lexicon

Baska Formation

Eocene

Sulaiman Basin

Part of Ghazij Group, Chamalang (=Ghazij) Group

Paleogene in the time scale →

Cited in 7 sources Last reviewed Aug 10, 2026

Unit summary

Rank: formation
Status: Published
Age: Cenozoic · Paleogene · Early EoceneEocene
Named by: Hemphill et al. (1973)
Type locality: 2 km east-northeast of Baska village31.4833°N, 70.1333°E
Thickness: 100m
Lithology: Green to grey shale and claystone interbedded with alabaster (gypsum), gypsiferous limestone and marl.
Synonyms: Not recorded

A gypsum-bearing Early Eocene shale, the top of the Ghazij Group, marking a restricted, salty phase.

Proposed by Hemphill and Kidwai (1973) to replace Eames' (1952) descriptive term 'shale with alabaster', with its type section near Baska village, the Baska Formation consists of gypsum, shale, limestone, marl and rare siltstone and is roughly 30–100 m thick. Its lower contact with the Drug Formation and upper contact with the Habib Rahi Formation are conformable. Fossiliferous rubbly limestone beds have yielded foraminifera (e.g. Lockhartia hunti, Dictyoconoides vredenburgi), bivalves and gastropods with an Early Eocene aspect (Iqbal, 1969).

Fossils

Barbatia drougensis Gosavia humberti

Contacts

In the Sulaiman Fold Belt column

LimestoneShale / 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

Sulaiman Fold Belt

Basin: Sulaiman Basin
Region: Not recorded
Depositional environment: restricted marine, evaporitic
Coordinates: 31.4833°N, 70.1333°E

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Correlation

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

Economic significance

Salt & evaporites

Contains alabaster (gypsum) beds.

Remarks

The uppermost, gypsum-bearing unit of the Ghazij Group in the Sulaiman Range, recording restricted, evaporitic conditions at the close of Ghazij deposition.

Research notes (4)

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 of Pakistan's compiled lexicon (listed in the memoir's contents). Adds the definitional GSP/SCP lexicon citation.

Shah, S.M.I. (2009)

Age & correlation (1)

Jones (1997): latest Early–earliest Middle Eocene, from the nummulitid Assilina maior punctulata (Cuisian Supérieur–Lutetian Basal of Schaub 1981; NP14–NP15) and planktonic foraminifera 'Globigerina' lozanoi (P8–P10) and Globorotalia (Acarinina) ex gr. pentacamerata (P8–?P9).

Jones, R.W. (1997)

Depositional environment (1)

Jones (1997): a low-energy back-bank lagoon characterised by Miliolida, with sea-grasses (epiphytic discorbids) and rare globigerinids indicating open-ocean influence; deposited during the regressive third-order sequence TA3.1 of Haq et al. (1987).

Jones, R.W. (1997)

Geological significance (1)

Hemphill & Kidwai (1973, USGS PP 716-B) NAMED the Baska Shale (replacing the informal 'shales with alabaster' of Eames 1952), type section 1.5 mi ENE of Baska village (D.I. Khan area). Early Eocene (Cuisian?); green to greenish-grey claystone with alabaster (gypsum) nodules, veins and beds, gypsiferous limestone and marl bearing larger foraminifera (Cuneolina, Lockhartia hunti, Dictyoconoides vredenburgi); ~607-620 m [ft] thick near Domanda/Baska, thinning northward.

Hemphill, W.R. & Kidwai, A.H. (1973)

Sources (7)

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.
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.
Hemphill, W.R. & Kidwai, A.H. (1973). Stratigraphy of the Bannu and Dera Ismail Khan Areas, Pakistan. U.S. Geological Survey Professional Paper 716-B (Geological Investigations in Pakistan), 36 p.

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

BibTeX

@misc{stratigraphypk_baskaformation,
  author    = {Qudsi, Lareb},
  title     = {{Baska 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/baska-formation (accessed October 29, 2026).

To cite the unit's original definition instead, see: Hemphill et al. (1973).

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