Geochemical characteristics of Mansehra Granitic Complex in Northwestern
Himalayas, Pakistan: Implications for rare earth element mineralization
potential
Abstract
This study explores potential prospects of rare earth elements (REEs) in
Mansehra Granitic Complex (MGC), including Mansehra Granite, Hakale
Granite, microgranites and leucogranites in northwest Pakistan, as these
highly fractionated S-type peraluminous granites have potential for
hosting deposits of REEs. Petrographic and geochemical constraints
including concentration of mafic minerals, presence of microcline,
development of zoning in feldspar, strong negative Eu anomaly, negative
Ba, Sr, Nb, Ti and Zr anomalies, and positive Rb and Cs anomaly
advocates fractionation of MGC. Similarly, enriched Rb and Ba relative
to Sr, high K2O and low CaO, trace element ratios of
Rb/Sr, Rb/Ba, K/Ba, Nb/Ta and Zr/Hf, and strongly peraluminous nature
with A/CNK > 1.1 are highly indicative of the
differentiated nature of the studied granites. Despite of positive
response towards fractionation constraints, MGC is overall barren in
terms of REE and strategic metals mineralization. The elemental
concentrations and trace element ratios of MGC—upon comparison with
the recommended values given by different researchers for discrimination
between barren and mineralized granites—also fail to prove ore-hosting
potential of MGC. The composition of parent magma plays primary role in
development of ore deposits. The contradictory behavior of MGC on
fractionation graphs and mineralization potential diagrams indicates
that parent magma of MGC had low concentration of ore elements.