Quaternary • Quaternary In GSP lexicon

Soan Formation

Pliocene to Pleistocene

Cited in 10 sources Last reviewed Jul 30, 2026

Unit summary

Rank: Not recorded
Status: Published
Age: Quaternary · Quaternary · Pliocene-PleistocenePliocene to Pleistocene
Named by: Cheema et al. (1977)
Type locality: Not recorded
Thickness: 120-450 m in Trans Indus-Potwar Province (TrI-PP) m
Lithology: Boulder conglomerate, sandstone, silt
Synonyms: Suan

A capping layer of coarse Plio-Pleistocene boulder gravel — the youngest Siwalik deposit, shed from the rising Himalaya.

Coarse alluvial fan deposits from rapidly rising Himalaya. Contains famous Soan Culture Paleolithic tools. Upper unit of the Soan Group.

Fossils

Stegodon rathiansis

Contacts

In the Potwar Basin column

ConglomerateSandstoneFossils 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

Potwar Basin Kohat Basin

Basin: Not recorded
Region: Not recorded
Depositional environment: fluvial, continental
Coordinates: Not recorded

Correlation

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

Economic significance

Not recorded

Remarks

The youngest, boulder-conglomerate-dominated unit of the Siwalik molasse (the Urak Boulder Conglomerate of the Sibi region), capping the foreland succession; its coarse Plio-Pleistocene gravels record the final, high-energy unroofing of the rising Himalaya.

Research notes (6)

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 (2)

Rendell et al. (1987): palaeomagnetic study of a 68 m Upper Siwalik (Soan) section in the Soan syncline at Riwat. A palaeolithic artefact-bearing gritstone/conglomerate horizon near the base of the section is dated to 2.0 ± 0.2 Ma — one of the oldest reported traces of early human occupance in Asia and a numeric anchor for the lower Upper Siwalik / Soan interval.

Rendell, H.M., Hailwood, E.A. & Dennell, R.W. (1987)
Opdyke et al. (1979): magnetostratigraphy of eight Upper Siwalik sections on the Potwar Plateau (calibrated by fission-track tuff ages of 2.3 ± 0.4 and 2.5 ± 0.4 Ma at the Gauss/Matuyama boundary) shows the Upper Siwalik subgroup spans from the middle Gauss to the middle Brunhes — one section (1.87 km thick) covers ~5.5 to 0.6 Ma. The Tatrot-to-Pinjor faunal change occurs at about 2.47 Ma at the Gauss/Matuyama boundary (marked by the first appearance of Equus and Elephas), placing the Tatrot (Pliocene) and Pinjor (Pleistocene) faunal levels of the Soan/Upper Siwalik in a numeric framework consistent with the curated Pliocene–Pleistocene age.

Opdyke, N.D., Lindsay, E., Johnson, G.D., Johnson, N., Tahirkheli, R.A.K. & Mirza, M.A. (1979)

Lithology (2)

Iqbal et al. (2018): in the Rumbli–Panjar area the Soan Formation is dominantly grey, fine- to medium-grained, medium- to thick-bedded sandstone with siltstone and clays; assigned a Pliocene age with a local section thickness ~600 m (Kashmir Basin, after Islam 2006).

Iqbal, O., Baig, M.S., Pervez, S. & Siddiqi, M.I. (2018)
Gill (1951): the Upper Siwalik of the Northern Potwar (Soan syncline) comprises, in ascending order, the Tatrot Stage (clay, sandstone, conglomerate), the Pinjor Stage (pink silt, sandstone, gravel and conglomerate) and the Boulder Conglomerate Stage (coarse conglomerate and sand) — the historical stages of the Upper Siwalik succession represented in the Soan Formation.

Gill, W.D. (1951)

Fossils & biostratigraphy (1)

Stegodon rathiansis Sarwar, Akram & Saeed (1985) — an advanced stegodont (~18½ ridge-plates in the lower M3; holotype PUPC 69/364) — from the uppermost Tatrotian (Upper Siwaliks) near Rathian, District Jhelum. In the Pakistani scheme the Soan Formation comprises the Tatrot and Pinjor (Chaudhry et al., 1985).

Sarwar, M., Akram, H. & Saeed, M. (1985)

Geological significance (1)

Gill (1951): in the Soan syncline the complete Siwalik succession from the Kamlial to the Pinjor Stage (Villafranchian) is free of marked unconformities and is overlain with strong unconformity by the post-Siwalik Pleistocene Lei Conglomerate — differing from de Terra (1936, 1939), who placed the first great unconformity at the base of the Tatrot Stage.

Gill, W.D. (1951)

Sources (8)

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.
Shah, S.M.I. (1977). Stratigraphy of Pakistan. Geological Survey of Pakistan, Memoir Vol. 12.
Indian Plate Lexicon (indplex.geolex.org), Geological Society of India and international compilation.
Rendell, H.M., Hailwood, E.A. & Dennell, R.W. (1987). Magnetic polarity stratigraphy of Upper Siwalik Sub-Group, Soan Valley, Pakistan: implications for early human occupance of Asia. Earth and Planetary Science Letters, 85, 488-496.
Iqbal, O., Baig, M.S., Pervez, S. & Siddiqi, M.I. (2018). Structure and Stratigraphy of Rumbli and Panjar Areas of Kashmir and Pakistan with the Aid of GIS. Journal of the Geological Society of India, 91, 57-66.
Opdyke, N.D., Lindsay, E., Johnson, G.D., Johnson, N., Tahirkheli, R.A.K. & Mirza, M.A. (1979). Magnetic polarity stratigraphy and vertebrate paleontology of the Upper Siwalik subgroup of northern Pakistan. Palaeogeography, Palaeoclimatology, Palaeoecology, 27, 1-34.
Gill, W.D. (1951). The stratigraphy of the Siwalik Series in the Northern Potwar, Punjab, Pakistan. Quarterly Journal of the Geological Society of London, 107, 375-394.

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

BibTeX

@misc{stratigraphypk_soanformation,
  author    = {Qudsi, Lareb},
  title     = {{Soan 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/soan-formation (accessed October 29, 2026).

To cite the unit's original definition instead, see: Cheema et al. (1977).

Referenced in other successions

Underlain by Lei Conglomerate