Paleozoic • Devonian–Carboniferous formation In GSP lexicon

Ali Masjid Formation

Late Devonian to Early Carboniferous (early Frasnian to mid-Tournaisian)

Northern Indus Suture

Devonian–Carboniferous in the time scale →

Cited in 7 sources Last reviewed Aug 10, 2026

Unit summary

Rank: formation
Status: Published
Age: Paleozoic · Devonian–Carboniferous · Late Devonian–Early Mississippian (Tournaisian)Late Devonian to Early Carboniferous (early Frasnian to mid-Tournaisian)
Named by: Stauffer (1968)
Type locality: Ali Masjid village, Khyber Pass34.0800°N, 71.2900°E
Thickness: 220 m
Lithology: Red shale alternating with siltstone, sandstone, quartzite and limestone, with thin conglomerates and lateritic beds marking repeated breaks in sedimentation.
Synonyms: Ali Masjid Group

A Late Devonian red-shale-and-sandstone unit of the Khyber Pass, between the Shagai and Khyber limestones.

The Ali Masjid Formation is a Late Devonian to Early Carboniferous (early Frasnian to mid-Tournaisian) unit of the Khyber Pass area, named after Ali Masjid village and extending across the Khyber Agency (Kazmi & Jan 1997). It consists of red shale alternating with siltstone, sandstone, quartzite and limestone, with thin conglomerates and lateritic beds marking repeated breaks in sedimentation; its age is tightly constrained by conodont faunas (Molloy, Talent & Mawson 1997). Khan et al. (1989) had earlier grouped it, with the Landikotal Slates, in the Shagai Formation.

Fossils

Brachiopods CoralsConodonts (Famennian–Tournaisian zonal fauna)

Contacts

In the Khyber–Nowshera Belt column

Shale / mudMetamorphicLimestoneFossils 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

Khyber–Nowshera Belt

Basin: Northern Indus Suture
Region: Not recorded
Depositional environment: marine, marginal marine
Coordinates: 34.0800°N, 71.2900°E

Google Maps ↗ OpenStreetMap ↗

Correlation

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

Economic significance

Not recorded

Remarks

A red-bed unit extending across the Khyber Agency; thin conglomerates and laterites record repeated breaks in sedimentation, and fossiliferous beds west of the type section yield a Late Devonian brachiopod-and-coral fauna. It is correlated with the Haji Gak Formation of Afghanistan.

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.
OpenStreetMap contributors and GEOnet Names Server (public geographic gazetteers), used to geolocate named GSP type localities to approximate decimal coordinates.
Shah, S.M.I. (2009). Stratigraphy of Pakistan. Geological Survey of Pakistan, Memoir Vol. 22.
Molloy, P.D., Talent, J.A. & Mawson, R. (1997). Late Devonian-Tournaisian conodonts from the eastern Khyber region, north-west Pakistan. Rivista Italiana di Paleontologia e Stratigrafia, 103(2), 123-148.
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.
Pogue, K.R., Harris, A.G. & Hussain, A. (1992). Paleozoic and Mesozoic stratigraphy of the Peshawar basin, Pakistan: Correlations and implications. Geological Society of America Bulletin, 104(8), 915-927.

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.

Cite this unit

APA

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

BibTeX

@misc{stratigraphypk_alimasjidformation,
  author    = {Qudsi, Lareb},
  title     = {{Ali Masjid 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/ali-masjid-formation (accessed September 5, 2026).

To cite the unit's original definition instead, see: Stauffer (1968).

Below · older

Shagai Limestone

Silurian–Devonian

Above · younger

Khyber Limestone

Carboniferous–Permian