Original scientific paper
https://doi.org/10.17794/rgn.2026.3.9
GEOCHEMISTRY AND GENESIS OF THE MANGANESE ORES IN THE NAWAGAI OPHIOLITIC MELANGE, MOHMAND DISTRICT, KHYBER PAKHTUNKHWA, PAKISTAN
Irfan Ullah
; National Center of Excellence in Geology, University of Peshawar, Peshawar 25130, Pakistan.
Aamir Khan
; State Key Laboratory for Critical Mineral Research and Exploration, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China.,University of Chinese Academy of Sciences, Beijing, 100049, China.,National Center of Excellence in Geology, University of Peshawar, Peshawar 25130, Pakistan.
*
Mohammad Tahir Shah
; National Center of Excellence in Geology, University of Peshawar, Peshawar 25130, Pakistan.
Liaqat Ali
; National Center of Excellence in Geology, University of Peshawar, Peshawar 25130, Pakistan.
Asad Khan
; Department of Earth Sciences, FATA University, FR Kohat 26100, Pakistan.,State Key Laboratory of Critical Mineral Research and Exploration, School of Geosciences and Info-Physics, Central South University, Changsha 410083, China.
Muhammad Mustafa
; College of Geosciences, China University of Petroleum (Beijing), Beijing 102249, China.
* Corresponding author.
Abstract
The Nawagai ophiolitic melange is present in the western part of the Main Mantle Thrust /Indus Suture Zone (MMT/ISZ) in northern Pakistan and is considered as a part of the fold belt that contains ophiolitic sequences. The studied manganese ore bodies are present in the Nawagai ophiolitic melange in the Mohmand District of Khyber Pakhtunkhwa, Pakistan. These ores are dislocated lenticular bodies of various size and are generally associated with the cryptocrystalline meta-chert. Both Mn-ores and the host meta-cherts are highly tectonized and are, therefore, subjected to metamorphism/ deformation. Mineralogically, the studied Mn-ores are dominantly composed of braunite with a lesser amount of pyrolusite and piemontite as Mn bearing phases while the gangue minerals are mainly cryptocrystalline quartz with a lesser amount of calcite. The Mn-phases are interlocked within the cryptocrystalline quartz; however, the cross cutting micro-veins of quartz and calcite are also noticed. At places the pyrolusite and piemontite are replacing braunite. Geochemically, the studied Mn-ores are highly variable in their grade. These are generally high-grade to low-grade but as a whole, from an economic perspective, these ores can be considered as low-grade ores on the basis of MnO, Fe2O3 and SiO2 contents. No correlation among the major elements has been found, however, significant positive correlation between SiO2 and MnO has been noted. The fractionation behaviour of Mn and Fe and the concentration of various major and trace elements suggest that the studied Mohmand area Mn-ores have been formed from the hydrothermal fluid distal to the source (vent) with the input from the pelagic sediments along the mid-ocean ridges within the Neo Tethys-Ocean. These have been obducted, as exotic bodies within ophiolitic sequences, on the Indian Plate due to the subduction of Indian Plate underneath the Kohistan Island Arc along the MMT/ISZ. These Mn-ores and the meta-cherts have attained severe metamorphism and deformation during and after the emplacement of the ophiolitic bodies in the existing position.
Keywords
manganese; petrography; mineralogy; geochemistry; ore genesis
Hrčak ID:
347417
URI
Publication date:
26.5.2026.
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