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https://hdl.handle.net/2440/77892
Type: | Journal article |
Title: | Geochemistry and petrogenesis of the volcanic rocks from Bagh complex, northern Balochistan, Pakistan |
Author: | Kahar, M. Mahmood, K. Kerr, A. Collins, A. Khan, M. Kasi, A. |
Citation: | Journal of Himalayan Earth Sciences, 2012; 45(1):17-29 |
Publisher: | University of Peshawar |
Issue Date: | 2012 |
ISSN: | 1994-3237 |
Statement of Responsibility: | M. Ishaq Kakar, Khalid Mahmood, Andrew C. Kerr, Alan S. Collins, Mehrab Khan and Aimal Khan Kasi |
Abstract: | The Bagh complex is an assemblage of igneous and sedimentary rocks containing many lithologic units which are bounded by layered parallel thrusts. The volcanic rocks from basalt-chert unit (Bbc) and hyaloclastite-mudstone unit (Bhm) are comprised of pillowed and bedded basalt, hyaloclastite and reworked sediments. Petrography and geochemistry of the basalt from Bbc shows that these rocks are basaltic trachy-andesite, trachy-andesite and foidite with tholeiitic charecter. While those from Bhm are tephrite-basanite, basalt and picro-basalt having alkaline nature. N-MORB-normalized diagram of the tholeiitic rocks have flat pattern of HFS-elements. In contrast enrichment of LIL-elements with the REE having almost flat pattern between 10X and 20X chondritic which are typical of N-MORB. The enrichment of LIL-elements, especially Th and depletion of Nb relative to other incompatible elements are depicting the addition of subduction zone component to a depleted mantle source. The multi element normalised plots of the volcanic rocks from Bhm show a similar pattern to that of OIB. Theese show a marked enrichment in the LIL-elements, depletion in some of the HFS-elements enrichments in LREEs and a marked depletion in the HREEs as compared to NMORB. The geochemical features on tectonic discrimination diagram of tholiiete from Bbc and alkaline rocks from Bhm suggest supra-subduction zone and oceanic-island arc tectonic settings respectively. These rocks were possibly erupted during Cretaceous period in the area which extends from the continental margin of the Indian subcontinent over the Neo-Tethys Ocean floor, and then were obducted with the Muslim Bagh ophiolite over the Indian subcontinent. |
Keywords: | Bagh complex Melange volcanic rocks Tholeiite Alkaline Petrogenesis |
Rights: | Copyright status unknown |
Description (link): | http://nceg.upesh.edu.pk/gb-45(1)-2012.html |
Published version: | http://nceg.upesh.edu.pk/GeologicalBulletin/Vol-45(1)-2012/Vol-45(1)-2012-Paper2.pdf |
Appears in Collections: | Aurora harvest Earth and Environmental Sciences publications |
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