Muslim Bagh Ophiolite

USGS OFR 94-689 gives the Muslim Bagh Ophiolite Complex a Late Cretaceous age based on K-Ar ages of 82-67 Ma (Sawada et al. 1992); emplacement onto the continental margin of the Indo-Pakistan block is now placed in the Late Cretaceous to early Paleocene (Kojima et al. 1994), revising the earlier middle Paleocene-early Eocene emplacement estimate (Allemann 1979; Otsuki et al. 1989). The complex hosts chromite, magnesite and magnetite deposits.

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

Petrology of the mantle section: foliated peridotite (mainly harzburgite with minor dunite) passing up through a transition zone of residual dunite with wehrlite/pyroxenite impregnations into layered/cumulate ultramafics — a supra-subduction-zone ophiolite (Kakar et al. 2013).

Kakar, M.I., Mahmood, K., Kerr, A.C. & Khan, M. (2013)

Ashraf, Qureshi & Faruqi (1972): serpentinite of the Tleri Muhammad Jan area (north of Hindubagh/Muslim Bagh, Zhob) - part of the Muslim Bagh ophiolite - consists of chrysotile, antigorite and lizardite with accessory chromite, carbonates, talc and magnetite (chemical, optical, DTA and XRD analysis).

Ashraf, M., Qureshi, M.W. & Faruqi, F.A. (1972)

Siddiqui, Ashraf & Qureshi (1974) mapped ~120 sq mi of the serpentinite belt north of Hindubagh (Muslimbagh), Zhob Valley: serpentinized dunite (dominant) with concordant layered harzburgite (bastite after bronzite) and minor relict peridotite, cut by pyroxenite dykes; dolerite blocks caught in the serpentinite are metasomatised to rodingite (grossular, idocrase/vesuvianite, prehnite, prochlorite).

Siddiqui, F.A., Ashraf, M. & Qureshi, M.W. (1974)

The serpentinite was emplaced tectonically along two sub-parallel E-W thrusts ~2.5 mi apart, with Palaeocene-Eocene strata thrust over Siwalik/Oligo-Miocene clastics; no contact metamorphism accompanies the serpentinites, and the Nisai-Shaigalu contact was found to be conformable rather than a thrust (Siddiqui et al. 1974).

Siddiqui, F.A., Ashraf, M. & Qureshi, M.W. (1974)

Chromite in the belt is largely refractory grade (Cr2O3 ~50-55%, Cr/Fe 2.3-2.7 at Tor Tangi) with metallurgical-grade occurrences in the east (Surghund, Gat: Cr2O3 ~58%, Cr/Fe >3.4) (Siddiqui et al. 1974). Weathering of the serpentinite produced a silica-rich 'birbirite' residual cap (up to 79.8% SiO2), previously mis-identified as laterite.

Siddiqui, F.A., Ashraf, M. & Qureshi, M.W. (1974)

Kazmi & Jan (1997): the Muslimbagh (Zhob Valley) Ophiolite comprises ultramafic tectonites (~70% lherzolite/harzburgite peridotite + dunite), ultramafic-mafic cumulates, a 1,000 m sheeted-dyke complex, a dolerite dyke swarm and pillow lavas, with a ~300 m metamorphic sole (hornblendite, garnet schists, marble) and an associated mélange. Formed ~81–82 Ma (K-Ar) and obducted during the Paleocene (emplacement ~65–70 Ma; Ar-Ar), it tectonically overlies Maastrichtian and older rocks and is unconformably overlain by Eocene shallow-marine limestone; origin debated (spreading centre / back-arc / slow-spreading Neo-Tethys branch). Corroborates the curated Late Cretaceous age.

Kazmi, A.H. & Jan, M.Q. (1997)

Yaseen et al. (2019) and Waliullah et al. (GSP): the Muslim Bagh–Zhob ophiolite forms the base of the Pishin–Katawaz sedimentary succession — a Neo-Tethyan remnant obducted onto the western passive margin of the Indian plate in the Late Cretaceous, unconformably overlain by the Eocene Nisai Formation. Its podiform chromite is actively mined around Khanozai and Muslim Bagh (Karezat quadrangle), where it makes up roughly a third of the Khanozai–Torkhula ophiolite segment.

Khan, J.A., Waliullah & Akhtar, W. (2024)

Kasi et al. (2012): the Muslim Bagh Ophiolite forms the base (Zone I) of the Pishin Belt and is part of the Bela–Muslim Bagh–Zhob–Waziristan ophiolite belt along the NW margin of the Indian Plate — a relic of Neo-Tethyan oceanic floor obducted at/after the Cretaceous–Tertiary boundary, emplaced at ~65–70 Ma (⁴⁰Ar/³⁹Ar; Mahmood et al. 1995). It consists of an upper nappe of ultramafic rocks intruded by gabbro plutons and dolerite dykes over a lower nappe of pillow basalts and sediments underlain by ophiolitic mélange, and is non-conformably overlain by the Eocene Nisai Formation.

Kasi, A.K., Kassi, A.M., Umar, M., Manan, R.A. & Kakar, M.I. (2012)

Maldonado et al. (2011, USGS): the Muslim Bagh Ophiolite Complex (Late Cretaceous), together with the associated Bagh Ophiolite Complex (Late Cretaceous to Late Triassic) and Late Cretaceous dolerite dikes, is a central element of the plate-convergence assemblage of the Quetta-Muslim Bagh-Sibi region.

Maldonado, F., Mengal, J.M., Khan, S.H. & Warwick, P.D. (2011)