Mesozoic • Triassic formation In GSP lexicon

Ailak Formation

Late Permian–Late Triassic

Karakoram-Hindukush Basin · Central Karakoram Batholith

Cited in 9 sources Last reviewed Aug 20, 2026

Unit summary

Rank: formation
Status: Published
Age: Mesozoic · Triassic · Late TriassicLate Permian–Late Triassic
Named by: Gaetani et al. (1995)
Type locality: Baroghil Alak by Gaetani et al36.8500°N, 73.3800°E
Thickness: about 1000 m
Lithology: Massive dolomite and limestone.
Synonyms: Not recorded

A thick Late Permian to Late Triassic dolomite-and-limestone unit of the Baroghil divide.

Named by Gaetani et al. (1995) after Baroghil Alak, the Ailak Formation comprises dolomite and limestone of Late Permian to Late Triassic age in the Karakoram of the upper Hunza–Chitral region.

Fossils

Fusulinid foraminifera (Nankinella, Sphaerulina)Dasyclad alga (Permocalculus)Tubiphytes

Contacts

In the Karakoram column

LimestoneShale / mudFossils 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

Karakoram

Basin: Karakoram-Hindukush Basin
Region: Central Karakoram Batholith
Depositional environment: marine
Coordinates: 36.8500°N, 73.3800°E

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Correlation

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

Economic significance

Not recorded

Remarks

A roughly 1000 m carbonate-platform succession exposed along the continental divide in the Baroghil region, overlying the Gharil Formation; it may be the lateral equivalent of the Kundil and Wirokhun formations of the Chapursan area.

Sources (9)

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.
Zanchi, A. & Gaetani, M. (2011). The geology of the Karakoram range, Pakistan: the new 1:100,000 geological map of Central-Western Karakoram. Italian Journal of Geosciences, 130(2), 161-262.
Shah, S.M.I. (2009). Stratigraphy of Pakistan. Geological Survey of Pakistan, Memoir Vol. 22.
Gaetani, M., Nicora, A., Henderson, C., Cirilli, S., Gale, L., Rettori, R., Vuolo, I. & Atudorei, V. (2013). Refinements in the Upper Permian to Lower Jurassic stratigraphy of Karakorum, Pakistan. Facies, 59, 915-948.
Perri, M.C., Molloy, P.D. & Talent, J.A. (2004). Earliest Triassic conodonts from Chitral, northernmost Pakistan. Rivista Italiana di Paleontologia e Stratigrafia, 110(1), 467-478.
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.
Gaetani, M., Angiolini, L., Garzanti, E., Jadoul, F., Leven, E.Ya., Nicora, A. & Sciunnach, D. (1995). Permian stratigraphy in the Northern Karakorum, Pakistan. Rivista Italiana di Paleontologia e Stratigrafia, 101(2), 107-152.

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

BibTeX

@misc{stratigraphypk_ailakformation,
  author    = {Qudsi, Lareb},
  title     = {{Ailak 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/ailak-formation (accessed September 5, 2026).

To cite the unit's original definition instead, see: Gaetani et al. (1995).

Below · older

Gharil Formation

Permian

Referenced in other successions

Overlain by Darwaz An Formation

Underlain by Ini Sar Formation