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Article

Episodes 2019; 42(4): 263-285

Published online December 1, 2019

https://doi.org/10.18814/epiiugs/2019/019022

Copyright © International Union of Geological Sciences.

Geochemical and petrological characteristics of xenoliths in Mansehra Granite, NW Himalaya, Pakistan: implications for petrogenesis and tectonic settings

Tehseen Zafar1,4*, Munazzam Ali Mahar2, Hafiz Ur Rehman3, Muhammad Riaz4, Khalid Latif 5, Abiola Oyebamiji1, and Mustansar Naeem4

1Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China; *Corresponding author, E-mail: tehseenabbas11@yahoo.com
2Department of Geological Sciences, University of Texas at El Paso, El Paso, TX 79968, United States
3Department of Earth and Environmental Sciences, Kagoshima University, Kagoshima, Japan
4Institute of Geology, University of the Punjab, Lahore, 54590, Pakistan
5National Centre of Excellence in Geology, University of Peshawar, Peshawar, 25130, Pakistan

Correspondence to:*E-mail: tehseenabbas11@yahoo.com

Received: April 17, 2019; Revised: September 16, 2019; Accepted: September 16, 2019

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Mansehra Granite (MG) is massive and sheared which contains light-gray to jet-black schistosed and light-gray micaceous quartzite restites. The later possess relatively higher quartz as compared with mica contents whereas the former has predominant quartz and feldspar. Enclosure of apatite and zircon in micas and absence of sillimanite in schistosed and non-foliated facies suggest that these rocks are restite in nature. Presence of abundant and larger mica flakes at contact of restites with MG indicates exposure of these flakes at relatively higher temperature of granitic melt (623.7−886.6 °C) particularly at their margins. However, central part of restites remained unaffected due lesser impact of elevated temperature. Schistose and surmicaceous restites show crenulation cleavage and preserve structural antiquity during amalgamation in felsic melt. Geochemically, restites and Tanawal Formation indicate calc-alkaline to high K calc-alkaline domain with orogenic syn-collisional settings. Geochemical characteristics and modal mineralogy of restites and Tanawal Formation are similar. This study suggests that former has been derived from the later and their field relationships and geochemical signatures provide credible evidence in favour of S-type trait of Mansehra Granite. In geochemical diagrams, MG portrayed calc-alkaline, peraluminous S-type nature and its magma was generated from heterogeneous Tanawal Formation via fractional crystallization.