Tourmaline as an evidence of exhalative origin for Besham base metal deposits in northern Pakistan
Abstract
Tourmaline occurs as an accessory phase in the metaquartzite/meta-arkose unit of the Pazang group in Besham area. The Chemistry of different tourmaline grains varies within the same sample but there is no change in composition within a single grain. These tourmalines have an intermediate composition between schorl and dravite. This composition along with FeO/FeO+MgO ratio for the studied tourmaline grains is unlike those of granitic terrain and can be comparable to that of the tourmalinites found in association with submarine exhalative massive sulfide deposits.
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