Mesozoic • Cretaceous formation GSP memoir

Jabrai Formation

Cretaceous

Balochistan Basin · Kakar-Khurasan Basin

Cited in 3 sources Last reviewed Aug 9, 2026

Unit summary

Rank: formation
Status: Published
Age: Mesozoic · Cretaceous · CretaceousCretaceous
Named by: Aminullah & Kansi (2012)
Type locality: Qila Saifullah–Sharin Jogezai section30.7011°N, 68.3597°E
Thickness: 500–1,000 m
Lithology: Mudstone and shale with alternations of thin marl and limestone beds.
Synonyms: Not recorded

A Cretaceous mudstone-and-shale unit of the Nisai Group in northern Balochistan.

Jabrai Formation named by Aminullah and Kansi (2012). It consists of mudstone/shale with alternation of thin marl/limestone beds. Its thickness is 500-1000m exposed in the Qila Saifullah–Sharin Jogezai section. Malkani (2014c) assumed as Cretaceous by law of super position and also correlation with Parh and Fort Munro groups and Chamalang (Ghazij) Group of Sulaiman basin.

Fossils

Not recorded

Contacts

In the Zhob-Muslim Bagh column

IgneousLimestoneShale / mudMarlFossils recordedConformable

Band colour = period; texture = dominant rock type. Lines between bands mark the contact type. 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

Zhob-Muslim Bagh

Basin: Balochistan Basin
Region: Kakar-Khurasan Basin
Depositional environment: marine
Coordinates: 30.7011°N, 68.3597°E

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Correlation

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

Economic significance

Not recorded

Remarks

A Cretaceous mudstone-shale unit of the Nisai Group (Kakar-Khurasan basin), dated by superposition and regional correlation.

Sources (3)

Malkani, M.S. & Mahmood, Z. (2017). Stratigraphy of Pakistan. Geological Survey of Pakistan, Memoir Vol. 24.
OpenStreetMap contributors and GEOnet Names Server (public geographic gazetteers), used to geolocate named GSP type localities to approximate decimal coordinates.
Kakar, A., Kasi, A.M., Benedetti, A. & Kasi, A.K. Stratigraphy and depositional environment of a mixed siliciclastic-carbonate platform and slope succession of the Paleogene Nisai Group, Pakistan. (Venue per supplied manuscript.)

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: Appears in a single-author Geological Survey of Pakistan memoir (Malkani & Mahmood 2017), not cross-confirmed against the Shah lexicon. The Stratigraphic Committee of Pakistan is largely inactive, so documented provenance — not formal ratification — is the available signal.

Cite this unit

APA

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

BibTeX

@misc{stratigraphypk_jabraiformation,
  author    = {Qudsi, Lareb},
  title     = {{Jabrai 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/jabrai-formation (accessed August 30, 2026).

To cite the unit's original definition instead, see: Aminullah & Kansi (2012).