Porphyry and Hydrothermal Cu-Au Deposits: A Global Perspective

The Jeeroy deposit is located in the South Tien Shan belt in north western Krygyzstan. It is 160 km west-southwest of the capital, Bishkek, in the Ala-Tau Range of the Northern Tien Shan Mountains, on a north-western regional fault within the Tien Shan gold belt.
The Ala Tau Range is predominantly underlain by Lower to Upper Proterozoic sediments, essentially sandstones, shales, phyllites and limestones with hypabyssal intrusives and effusives of liparites, dacites and porphyries. These sediments and volcanics are tectonically juxtaposed against Cambrian-Ordovician thinly bedded limestones and dolomite and Ordovician-Devonian volcanogenic suites (andesites, dacite flows and tuffs) grading up to terrigenous red polymict and arkosic sandstones, agglomerates and shales of Devonian to Permian age.
The regional sequence is intruded by late Riphean and Vendian granodiorites, tonalites and quartz monzonites and larger Cambrian - Ordovician "granitoid" batholiths which vary in composition from diorite and quartz diorite to granodiorite and granite.
The Jerooy deposit is hosted by a large lower Palaeozoic quartz diorite and quartz syenite complex with later porphyritic and aplitic intrusives with metasediments and volcanogenic sediments occurring as inliers within the intrusive complex. Jerooy is a low sulphide, gold-quartz mesothermal deposit generally associated with silica in which the sulphide content is less than 1%. Major sulphides are pyrite, bismuthinite and tetradymite. Most of the gold occurs as free gold less than 0.01 mm in size, with minor telluride minerals (calaverite and krennerite). An estimation at the pre-feasibility stage gave a resource of 11.218 Mt @ 5.92 g/t Au for 66 t (2.14 Moz) of gold.

Note: No abstract accompanied the paper. The above is an editors resumé.