Mesozoic • Cretaceous In GSP lexicon

Chilas Complex

Cretaceous (102-85 Ma)

Cited in 8 sources Last reviewed Aug 20, 2026

Unit summary

Rank: Not recorded
Status: Published
Age: Mesozoic · Cretaceous · mid-CretaceousCretaceous (102-85 Ma)
Named by: Jan et al.
Type locality: Chilas, Gilgit-Baltistan35.4200°N, 74.1000°E
Thickness: 8-10 km thick
Lithology: Large mafic–ultramafic body — gabbronorite with serpentinized ultramafic rocks (dunite, harzburgite, pyroxenite), dolerite and gabbro; associated with the Babusar Pass mélange.
Synonyms: Not recorded

The Chilas Complex — a giant layered gabbro body that was the mid-crustal magma chamber of the Kohistan arc.

Largest mafic-ultramafic plutonic body in Kohistan arc. Represents deep-level arc crust. Contains platinum group elements.

Fossils

Not recorded

Contacts

In the Kohistan Arc column

MetamorphicIgneousMixedShale / mudIntrusiveConformable

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

Kohistan Arc

Basin: Not recorded
Region: Not recorded
Depositional environment: volcanic-arc, plutonic
Coordinates: 35.4200°N, 74.1000°E

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Correlation

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

Economic significance

Other

Platinum group element potential

Remarks

The Chilas Complex — a huge mafic–ultramafic layered intrusion forming the mid-crustal level of the Kohistan arc, interpreted as a sub-arc magma-chamber complex; one of the world's classic exposures of arc mid-crust.

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.
Shah, S.M.I. (2009). Stratigraphy of Pakistan. Geological Survey of Pakistan, Memoir Vol. 22.
Treloar, P.J., Petterson, M.G., Jan, M.Q. & Sullivan, M.A. (1996). A re-evaluation of the stratigraphy and evolution of the Kohistan arc sequence, Pakistan Himalaya: implications for magmatic and tectonic arc-building processes. Journal of the Geological Society, London, 153, 681-693.
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.
Khan, M.A., Jan, M.Q., Windley, B.F., Tarney, J. & Thirlwall, M.F. (1989). The Chilas mafic-ultramafic igneous complex; the root of the Kohistan island arc in the Himalaya of northern Pakistan. In: Malinconico, L.L. & Lillie, R.J. (eds) Tectonics of the Western Himalayas. Geological Society of America Special Paper 232, 75-94.
Coward, M.P., Jan, M.Q., Rex, D., Tarney, J., Thirlwall, M. & Windley, B.F. (1984). Geology of the South Central Karakoram and Kohistan. In: Miller, K.J. (ed.), The International Karakoram Project, Vol. 2, 71-84. Cambridge University Press.

Reviewer confidence: medium

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

BibTeX

@misc{stratigraphypk_chilascomplex,
  author    = {Qudsi, Lareb},
  title     = {{Chilas Complex} --- 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/chilas-complex (accessed September 5, 2026).

To cite the unit's original definition instead, see: Jan et al..

Above · younger

Kohistan Batholith

Cretaceous-Paleogene