Cenozoic • Paleogene formation In GSP lexicon

Toi Formation

Eocene

Sulaiman Basin

Part of Ghazij Group, Chamalang (=Ghazij) Group

Paleogene in the time scale →

Cited in 5 sources Last reviewed Jul 18, 2026

Unit summary

Rank: formation
Status: Published
Age: Cenozoic · Paleogene · Early EoceneEocene
Named by: Shah (1987)
Type locality: Toi Nala, Sulaiman Range31.4833°N, 70.1167°E
Thickness: up to ~1,196 m (Moghal Kot)
Lithology: Interbedded coarse, pebbly, cross-bedded sandstone and brown mudstone, siltstone, shale and conglomerate, with locally developed coal seams.
Synonyms: Not recorded

A thick Early Eocene sandstone-and-mudstone with coal, recording rivers and deltas building into the Eocene sea.

Formalized by Shah (2002) and named after the Toi River near Mughal Kot, the Toi Formation is sandstone with greenish-grey shale and rubbly marl/limestone plus some sub-bituminous coal, about 600 m thick at the type section and up to about 1200 m at Kingri, Bahlol and Chamalang. Its lower contact with the Shaheed Ghat Formation is conformable and its upper contact with the Kingri Formation is disconformable. As part of the Eocene Chamalang Group, it is not correlated with the Vihowa/Siwalik molasse.

Fossils

Freshwater bivalves Gastropods Plant remains

Contacts

In the Sulaiman Fold Belt column

SandstoneShale / mudLimestoneFossils 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

Sulaiman Fold Belt

Basin: Sulaiman Basin
Region: Not recorded
Depositional environment: fluvial, deltaic
Coordinates: 31.4833°N, 70.1167°E

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Correlation

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

Economic significance

Coal & lignite

Contains locally developed coal seams.

Remarks

A thick, coal-bearing fluvio-deltaic clastic unit of the Ghazij Group, recording terrestrial influx into the Eocene Sulaiman basin between marine units.

Sources (4)

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.

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

BibTeX

@misc{stratigraphypk_toiformation,
  author    = {Qudsi, Lareb},
  title     = {{Toi 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/toi-formation (accessed August 30, 2026).

To cite the unit's original definition instead, see: Shah (1987).

Below · older

Drug Formation

Paleogene

Above · younger

Baska Formation

Paleogene

Referenced in other successions

Overlain by Kingri Formation