Kamila Amphibolite Belt
Early to mid-Cretaceous (transition from oceanic to arc magmatism inferred); hornblende Ar-Ar cooling ages c. 80-83 Ma record suturing-related deformation
Kohistan Arc · Kohistan Batholith
Cretaceous in the time scale →Cited in 5 sources Last reviewed Aug 20, 2026
- Rank
- complex
- Status
- Published
- Age
- Mesozoic · CretaceousEarly to mid-Cretaceous (transition from oceanic to arc magmatism inferred); hornblende Ar-Ar cooling ages c. 80-83 Ma record suturing-related deformation
- Named by
- Treloar et al. (1989, 1996)
- Type locality
- Kamila area, Indus valley, Kohistan; forms the southern part of the arc (Kamila Shear Zone).
- Thickness
- Not recorded
- Lithology
- Amphibolite-facies basic lavas (some pillowed), hyaloclastite and breccias intruded by gabbros and diorites; two suites — a Ti-rich, HFSE/HREE-enriched high-Ti oceanic-type MORB suite and a Ti-poor, calc-alkaline low-Ti arc suite with a negative Nb anomaly.
- Synonyms
- Not recorded
The Kamila Amphibolite Belt is the oldest part of the Kohistan island arc — a variably sheared, amphibolite-facies mixture of basic lavas (some pillowed), hyaloclastite and intrusive gabbros/diorites. It comprises two geochemical suites: an older high-Ti suite of transitional oceanic-type basalts (MORB-like, interpreted as magmatically thickened, possibly ocean-plateau, pre-arc crust) forming the basement, intruded by a low-Ti calc-alkaline suite marking the earliest true arc magmatism. Its southern part is the c. 20 km-wide, SW-vergent Kamila Shear Zone.
Fossils
Not recorded
Contacts
Lower contact — not recorded; upper contact — intrusive.
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
- Basin
- Kohistan Arc
- Region
- Kohistan Batholith
- Depositional environment
- volcanic-arc, oceanic, marine
- Coordinates
- Not recorded
Correlation
Not recorded. Compare this unit against other basins on the correlation panel →
Economic significance
Not recorded
Remarks
Demonstrates that the earliest part of Kohistan is oceanic basement, not subduction-related — the high-Ti basalts are pre-arc oceanic crust intruded by the first arc-type magmas. Amphibolitised Chilas Complex gabbronorites occur in its northern part.
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.
Lithology (2)
-
Coward et al. (1984): the amphibolite belt (between the Chilas and Jijal complexes) contains banded amphibolites with or without garnet, hornblendites, hornblende schists, garnet and anorthositic gabbros, anorthosites, diorites, tonalites and granites, and thin garnet-quartzite and calc-silicate lenses; the proportion of true amphibolite is commonly low, and most intrusive rocks are concordant, parallel to the regional trend and intensely deformed, the coarser leucocratic types becoming augen gneisses.
Coward, M.P., Jan, M.Q., Rex, D., Tarney, J., Thirlwall, M. & Windley, B.F. (1984)
-
Ahmad et al. (2025), from new 1:50,000 mapping of central Kohistan, describe the Kamila Amphibolite Belt as amphibolite-facies metagabbros, metadiorites, metatonalites and metavolcanics with minor metasediments (after Jan 1979b, 1988; Treloar et al. 1990), forming the southern part of the arc between the Chilas Complex and the Jijal-Sapat complexes.
Geological significance (1)
-
Anczkiewicz et al. (1998): in Lower Swat the Kamila unit (gabbro and gabbro-norite with cumulate textures) forms the base of the Kohistan Island Arc in the hanging wall of the Indus Suture / Main Mantle Thrust (Kohistan Thrust), recording southward thrusting; the arc accreted to Asia at ~102-75 Ma and was obducted onto the Indian plate at ~65-55 Ma.
Anczkiewicz, R., Burg, J.-P., Hussain, S.S., Dawood, H., Ghazanfar, M. & Chaudhry, M.N. (1998)
Sources (5)
- 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. Journal of the Geological Society, London, 153, 681-693.
- 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.
- Anczkiewicz, R., Burg, J.-P., Hussain, S.S., Dawood, H., Ghazanfar, M. & Chaudhry, M.N. (1998). Stratigraphy and structure of the Indus Suture in the Lower Swat, Pakistan, NW Himalaya. Journal of Asian Earth Sciences, 16(2-3), 225-238.
- 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.
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: Defined in journal or other literature; not found in a GSP memoir. There is no body currently ratifying unit status, so provenance is shown in place of a formal ruling.
Cite this unit
Qudsi, L. (2026). Kamila Amphibolite Belt. In Pakistan Stratigraphy Dataset [Data set]. Zenodo. https://doi.org/10.5281/zenodo.21363991
@misc{stratigraphypk_kamilaamphibolitebelt,
author = {Qudsi, Lareb},
title = {{Kamila Amphibolite Belt} --- 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/kamila-amphibolite-belt (accessed October 29, 2026).
To cite the unit's original definition instead, see: Treloar et al. (1989, 1996).
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