Mesozoic • Jurassic formation GSP memoir

Dilband Formation

Jurassic

Kirthar Basin · Western Kirthar (Balochistan)

Part of Sulaiman Group

Jurassic in the time scale →

Cited in 6 sources Last reviewed Aug 2, 2026

Unit summary

Rank: formation
Status: Published
Age: Mesozoic · Jurassic · Early CretaceousJurassic
Named by: Abbas et al. (1998)
Type locality: Dilband area, Kalat District
Thickness: about 20m
Lithology: Oolitic hematite ironstone with sandstone and shale.
Synonyms: Mazar Drik Formation

An Early Cretaceous ironstone unit in Kalat District — the home of Pakistan's biggest iron-ore deposit.

Named by Abbas et al. (1998) in the northern Kirthar Range (synonym Mazar Drik Formation), the Dilband Formation is a thin unit (about 20–30 m) with three members — a lower jarositic clay, a middle reddish ironstone and an upper green glauconitic shale — straddling the Jurassic–Cretaceous boundary. Its lower contact with the Chiltan (Takatu/Zidi) Limestone and upper contact with the Sembar Formation are disconformable to locally conformable. Ammonites (e.g. Macrocephalites; Bullatimorphites bullatus of Arkell, 1956; Fatmi, 1977) indicate a Late Bathonian age for the Mazar Drik unit, and Malkani (2003) reported the dinosaur Brohisaurus kirthari.

Fossils

Choffatia Bullatimorphites bullatus Clydoniceras Brohisaurus kirthari

Contacts

In the Kirthar Range column

Shale / mudLimestoneSandstoneFossils 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

Basin: Kirthar Basin
Region: Western Kirthar (Balochistan)
Depositional environment: shallow marine
Coordinates: Not recorded

Correlation

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

Economic significance

Metals & minerals

Hosts the Dilband iron-ore deposit — Pakistan's largest — oolitic hematite at the top-Chiltan unconformity grading about 52–62% iron oxide.

Remarks

An Early Cretaceous ironstone-bearing unit resting on the top-Chiltan unconformity in the Kalat region, the host of Pakistan's principal iron-ore resource.

Research notes (3)

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 (1)

Umar et al. (2024, after Malkani 2021): the Dilband ironstone member carries Phylloceras and Lyticeras ammonites, giving a Neocomian–Valanginian age along the Jurassic–Cretaceous boundary; it lies disconformably on the Chiltan Limestone and at the base of the Sembar Formation. Deposited in a small, sediment-starved, tectonically unstable shallow-marine sub-basin during extensional normal faulting.

Umar, M., Kassi, A.M., Jamil, M., Kasi, A.K. & Khan, A.S. (2024)

Economic significance (1)

Umar et al. (2024, after Abro et al. 2011; Malkani 2020b): the Dilband oolitic-hematite iron deposits of the Mastung district (south of Quetta) run up to 60% iron (average ~35%), with ~200 million tonnes of reserves discovered along the Jurassic–Cretaceous boundary — Pakistan's principal sedimentary iron resource.

Umar, M., Kassi, A.M., Jamil, M., Kasi, A.K. & Khan, A.S. (2024)

Geological significance (1)

Malkani et al. (2017, Kirthar): the Dilband Formation (Late Bathonian, spanning the Jurassic–Cretaceous boundary; up to ~30 m; three members — lower jarositic clay, middle reddish ironstone, upper green glauconitic shale) hosts the Dilband iron ore at the J/K boundary and yields the titanosauriform/early-titanosaurian sauropod Brohisaurus kirthari (Sun Chaku, Karkh; Charoh, Zidi, Khuzdar) plus ammonites (Macrocephalites, Indocephalites, Indosphinctes, Choffatia, Bullatimorphites bullatus, Clydoniceras). It is treated as a synonym of the Mazar Drik Formation in this corpus. Attributed corroboration of the already-listed Brohisaurus; Brohisaurus is a Malkani-corpus taxon.

Malkani, M.S., Khosa, M.H., Alyani, M.I., Somro, N., Zafar, T., Arif, J. & Aleem, M.Z. (2017)

Sources (6)

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.
Malkani, M.S., Khosa, M.H., Alyani, M.I., Somro, N., Zafar, T., Arif, J. & Aleem, M.Z. (2017). Revised Stratigraphic Setup and Mineral Deposits of Kirthar Basin (Lower Indus Basin), Pakistan. Lasbela University Journal of Science and Technology, VI, 54-84.
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.
Malkani, M.S., Mahmood, Z., Somro, N. & Shaikh, S.I. (2017). Revised Stratigraphy and Mineral Resources of Kirthar Basin, Pakistan. Geological Survey of Pakistan, Information Release No. 1010.
Umar, M., Kassi, A.M., Jamil, M., Kasi, A.K. & Khan, A.S. (2024). Cretaceous stratigraphic framework and sedimentary architecture, Pakistan: signatures of rift-drift tectonics and submarine volcanism along the western continental margin of the Indian Plate. In: Hart, M.B. et al. (eds) Cretaceous Project 200 Volume 2: Regional Studies. Geological Society, London, Special Publications, 545.

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: Appears in a single-author Geological Survey of Pakistan memoir (Malkani & Mahmood 2017), not cross-confirmed against the Shah lexicon. The Stratigraphic Committee of Pakistan is largely inactive, so documented provenance — not formal ratification — is the available signal.

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Cite this unit

APA

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

BibTeX

@misc{stratigraphypk_dilbandformation,
  author    = {Qudsi, Lareb},
  title     = {{Dilband 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/dilband-formation (accessed October 29, 2026).

To cite the unit's original definition instead, see: Abbas et al. (1998).

Below · older

Chiltan Limestone