Abstract:
The Buner Gah is a N-S trending stream that traverses the Kohistan Island Arc rocks
in the Diamir District of Gilgit-Baltistan province of Pakistan. The area of investigation in
the Buner Gah lies between latitudes of 35° 17` to 35° 28` N and longitudes 74° 16` to 74°
19` E. The purpose of this study was to investigate economic minerals in rocks and stream
sediments and to find out their origin and make the tectonic model for mineralization. The
study area represents Chilas complex and the Niat amphibolites of the Kohistan Island arc.
The Chilas complex rocks exposed in the area belong to the main gabbronorite association
and here only pyroxene-quartz diorite and tonalites are exposed. The rocks of Niat
amphibolites contain diorites, tonalites and quartz monzonite. There are marble bodies too
which are intruded by felsic aplite dykes. Skarn is formed in the Niat amphibolite belt. The
skarn contains apart from carbonate matrix, quartz and diopside. Sulphide mineralization
is noticed at one place in altered rock within the Niat amphibolite belt which through atomic
absorption spectrometry analysis yield 0.01 ppm gold and 74.25 ppm silver. In the stream
samples only a few chalcopyrite and pyrite grains could be observed. The skarn is also
devoid of any economic mineralization. There are reports of gold occurrences in the placer
sands of the Indus River near Buner Gah, which may indicate that the gold source may not
be from the Buner Gah as this valley does not host much hydrothermal mineralization
within the rocks.
