Cenozoic • Neogene In GSP lexicon

Gaj Formation

Early Miocene

Neogene in the time scale →

Cited in 9 sources Last reviewed Jul 31, 2026

Unit summary

Rank: Not recorded
Status: Published
Age: Cenozoic · Neogene · Early–Middle MioceneEarly Miocene
Named by: Blanford (1876)
Type locality: Gaj River, Kirthar Range26.8750°N, 67.3200°E
Thickness: 200-400 m
Lithology: Variegated grey gypsiferous shale interbedded with calcareous, ferruginous, cross-bedded sandstone and fossiliferous argillaceous limestone.
Synonyms: Not recorded

A Miocene shale-and-sandstone of the Kirthar Range, marking the shift from sea to land deposition.

Last marine sequence in Kirthar region before complete Tethys closure. Transition to continental conditions.

Fossils

Foraminifera Molluscs Marine vertebrates

Contacts

In the Kirthar Range column

ConglomerateShale / mudSandstoneFossils 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

Kirthar Range Sindh Province

Basin: Not recorded
Region: Not recorded
Depositional environment: marginal marine, deltaic
Coordinates: 26.8750°N, 67.3200°E

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Correlation

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

Economic significance

Not recorded

Remarks

A Miocene shale-sandstone-limestone unit resting conformably on the Nari Formation; the Kirthar equivalent of the lower Sulaiman molasse and a marker of the Miocene marine-to-continental transition.

Research notes (4)

Field-by-field findings drawn from the cited literature. Every statement is traced to a registered source — follow a citation for the full reference.

Name & nomenclature (1)

Attested in Shah (2009), Geological Survey of Pakistan Memoir 22 - the Stratigraphic Committee's compiled lexicon. Adds the definitional GSP/SCP lexicon citation.

Shah, S.M.I. (2009)

Age & correlation (1)

Biozonation near Karachi (Khan, 1968): the Gaj Formation is Late Aquitanian to Burdigalian, carrying the Miogypsina globulina Zone — Miogypsina globulina/intermedia/tani/gunteri/cushmani, Miogypsinoides dehaarti, Austrotrillina howchini and Taberina malabarica — with lepidocyclinids disappearing in its upper half.

Khan, M.H. (1968)

Lithology (1)

Corroborated by USGS OFR 94-689: greenish-gray, variegated, gypsiferous shale with subordinate calcareous ferruginous crossbedded sandstone and argillaceous fossiliferous limestone (Miocene? to Oligocene?).

Maldonado, F., Khan, S.H. & Mengal, J.M. (1994)

Geological significance (1)

Brohi et al. (2009): the Miocene Gaj Formation is reported for the first time from the Khorwari section of the Surjan Anticline (Thano Bula Khan, Jamshoro) — mixed clastic/non-clastic shallow-marine to non-marine shale, clay, sandstone and limestone; part of the Eocene–Pleistocene Surjan Tertiary succession studied for economic (dimension-stone, mineral and hydrogeological) potential.

Brohi, I.A., Bablani, S.A. & Solangi, S.H. (2009)

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.
OpenStreetMap contributors and GEOnet Names Server (public geographic gazetteers), used to geolocate named GSP type localities to approximate decimal coordinates.
Indian Plate Lexicon (indplex.geolex.org), Geological Society of India and international compilation.
Maldonado, F., Khan, S.H. & Mengal, J.M. (1994). Preliminary Geologic Map of Parts of Loralai, Sibi, Quetta, and Khuzdar Divisions, Balochistan Province, West-Central Pakistan. U.S. Geological Survey Open-File Report 94-689, 20 p., 1 sheet.
Shah, S.M.I. (2009). Stratigraphy of Pakistan. Geological Survey of Pakistan, Memoir Vol. 22.
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.
Brohi, I.A., Bablani, S.A. & Solangi, S.H. (2009). Geology and Economic Significance of Tertiary Rocks, Khorwari Section, Surjan Anticline, Thano Bula Khan, Sindh. Sindh University Research Journal (Science Series), 41(1), 95-106.

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

BibTeX

@misc{stratigraphypk_gajformation,
  author    = {Qudsi, Lareb},
  title     = {{Gaj 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/gaj-formation (accessed October 29, 2026).

To cite the unit's original definition instead, see: Blanford (1876).

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