Abstract

Chemical analyses for 21 elements together with physical data are presented for 38 amphiboles (34 of them new) from garnet granulites, pyroxene granulites, amphibolites, and quartz diorites constituting the sourhtern half of the Kohistan Cretaceous-early Tertiary arc. The metamorphic hornblendes are rich in alumina and some of them have high Al vi /Al iv ratios. The influence of metamorphic conditions is not important except on A-site occupancy and, possibly, on Ti and Mn contents. Refractive indices, birefringence, and density display a systematic increase (and 2V a decrease) with decrease in the ratio (Mg + Al vi )(Mg + Al iv + Al vi + Ti + Fe3+) + Fe (super 2+) + Mn). Pleochroic colors and amount of absorption are controlled by Fe (super 3+) , Ti, Fe (super 3+) /Ti, and Mg/Fe (super 2+) , while Z:c appears to increase with Fe.3+) + Ca.--Modified journal abstract.

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