Mesozoic • Cretaceous formation In GSP lexicon

Chashmai Kharsai Formation

Early Cretaceous

Cited in 2 sources Last reviewed Jul 18, 2026

Unit summary

Rank: formation
Status: Published
Age: Mesozoic · Cretaceous · Early CretaceousEarly Cretaceous
Named by: Ahmad et al. (2000)
Type locality: Chashmai Kharsai, along the Mirali–Miran Shah road, North Waziristan Agency (32°58′36″N, 70°05′30″E).32.9767°N, 70.0917°E
Thickness: 30 m at the type locality (disconformable contact above the Isha Formation).
Lithology: Belemnite-bearing shale.
Synonyms: Not recorded

An Early Cretaceous belemnite-bearing shale of the North Waziristan area, introduced by Ahmed et al. (2000) and recorded in Shah (2009). It is a distinct unit from the Eocene Chashmai Formation, with which the name "Chashmai Kharsai" has been confused in the baseline data.

Fossils

Belemnites

Contacts

In the Sulaiman Fold Belt column

LimestoneIgneousShale / 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: Not recorded
Region: Not recorded
Depositional environment: marine
Coordinates: 32.9767°N, 70.0917°E

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Correlation

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

Economic significance

Not recorded

Remarks

Not recorded

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)

CONFIRMED by Ahmad et al. (2000): the Chashmai Kharsai Formation is the basal Cretaceous unit of the North Waziristan succession, disconformable on the Jurassic Isha Formation and overlain by the Marsi Khel and Zerghar formations.

Ahmad, S., Ali, F., Rehman, N. & Gul, J. (2000)

Thickness (1)

Ahmad et al. (2000): the Chashmai Kharsai Formation is a belemnite-rich shale (dark green-grey, weathering rusty brown with a purple tint; alternating harder/softer shale with phosphatic nodules and glauconitic sandy layers) 30 m thick at its type locality (Chashmai Kharsai, 32°58′36″N, 70°05′30″E, along the Mirali–Miran Shah road), disconformably overlying the Isha Formation.

Ahmad, S., Ali, F., Rehman, N. & Gul, J. (2000)

Stratigraphic contacts (1)

Ahmad et al. (2000): the Chashmai Kharsai Formation disconformably overlies the Jurassic Isha Formation and grades conformably up into the Marsikhel Formation. (introducedBy attribution corrected 'Ahmed' -> 'Ahmad' per the paper's authorship.)

Ahmad, S., Ali, F., Rehman, N. & Gul, J. (2000)

Sources (2)

Shah, S.M.I. (2009). Stratigraphy of Pakistan. Geological Survey of Pakistan, Memoir Vol. 22.
Ahmad, S., Ali, F., Rehman, N. & Gul, J. (2000). Lithostratigraphy of the Kurram Group along the Mirali-Miran Shah Road, North Waziristan Agency, NWFP, Pakistan. Geological Bulletin, University of Peshawar, 33, 79-86.

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

BibTeX

@misc{stratigraphypk_chashmaikharsaiformation,
  author    = {Qudsi, Lareb},
  title     = {{Chashmai Kharsai 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/chashmai-kharsai-formation (accessed October 29, 2026).

To cite the unit's original definition instead, see: Ahmad et al. (2000).

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