Bostan Formation
Middle Pleistocene to present (Chibanian-Holocene; ~0.77-0 Ma)
Balochistan Basin · Kakar-Khurasan Basin
Quaternary in the time scale →Cited in 8 sources Last reviewed Aug 2, 2026
- Rank
- formation
- Status
- Published
- Age
- Cenozoic · Quaternary · Middle Pleistocene to HoloceneMiddle Pleistocene to present (Chibanian-Holocene; ~0.77-0 Ma)
- Named by
- Malkani (2012)
- Type locality
- Kamroud village, Siahan Range (Makran)30.4325°N, 67.0061°E
- Thickness
- 600-750 m
- Lithology
- Gypsiferous claystone to sandstone; lacustrine to playa deposits.
- Synonyms
- Sakhi Sarwar Group (in part)
A very young (Pleistocene–Holocene) gravel-and-mud molasse of northern Balochistan.
The Bostan Formation is named after the village of Bostan, 20 km east of Kuchlak (HSC 1961). It consists of clay, silt, sandstone and conglomerate; the clay and silt are red to maroon and brown, and the sandstone and conglomerate are medium to thick bedded and mostly friable, indicating uplift of the area. It is assigned to the Pleistocene-Holocene Sakhi Sarwar Group (Malkani 2012k, 2014c) - first used after the Sakhi Sarwar area of D.G. Khan and treated as synonymous with the Bostan Formation - which comprises the Dada Formation (mainly conglomerate) and the Sakhi Sarwar Formation (mud and sandstone with poorly developed conglomerate, mud-dominant in valley centres), concealed at places in valleys and plains by Subrecent and Recent fluvial, eolian and colluvial deposits.
Fossils
Not recorded
Contacts
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
- Basin
- Balochistan Basin
- Region
- Kakar-Khurasan Basin
- Depositional environment
- lacustrine, playa
- Coordinates
- 30.4325°N, 67.0061°E
Correlation
Not recorded. Compare this unit against other basins on the correlation panel →
Economic significance
Not recorded
Remarks
A Pleistocene–Holocene molasse of the Kakar-Khurasan/Pishin region, equivalent to the Sakhi Sarwar Group (Boston Formation), capping the basin fill.
Sources (8)
- Malkani, M.S. & Mahmood, Z. (2017). Stratigraphy of Pakistan. Geological Survey of Pakistan, Memoir Vol. 24.
- 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. & Jan, M.Q. (1997). Geology and Tectonics of Pakistan. Graphic Publishers, Karachi.
- 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.
- Kasi, A.K., Kassi, A.M., Umar, M., Manan, R.A. & Kakar, M.I. (2012). Revised lithostratigraphy of the Pishin Belt, northwestern Pakistan. Journal of Himalayan Earth Sciences, 45(1), 53-65.
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
Qudsi, L. (2026). Bostan Formation. In Pakistan Stratigraphy Dataset [Data set]. Zenodo. https://doi.org/10.5281/zenodo.21363991
@misc{stratigraphypk_bostanformation,
author = {Qudsi, Lareb},
title = {{Bostan 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/bostan-formation (accessed September 5, 2026).
To cite the unit's original definition instead, see: Malkani (2012).
Related units
Referenced in other successions
Underlain by Haro Conglomerate Formation· Malthanai Formation
Saved on this device only.