The Faro - Anvil district deposits are located in central Yukon, 200 km northeast of Whitehorse in north-western Canada.
The deposits are located along the western margin of Selwyn Basin, occurring within a thick prism of complexly deformed and variably metamorphosed, late Proterozoic to Silurian metasediments and lesser mafic volcanic/plutonic rocks along the southern flank of the mid-Cretaceous granitic plutonic Anvil Batholith.
The host sequence comprises the lower monotonous, 5000 m thick Neoproterozoic to Lower Cambrian Mt Mye Formation (correlated with the Gull Lake Formation in the main Selwyn Basin), and the overlying, 1000 m thick Cambrian to Ordovician Vangorda Formation (Rabbitkettle Formation equivalent).
The Mt Mye Formation is composed of non-calcareous amphibolite and greenschist facies schists, with lesser, but important carbonaceous phyllite, limestone, marble, thinly banded calc-silicates and amphibolites. Rocks types vary from non-calcareous muscovite, chlorite, quartz and plagioclase phyllite at low metamorphic grade to non-calcareous biotite, muscovite, quartz, plagioclase (garnet, staurolite, andalusite, fibrolite) schist in areas of amphibolite-grade metamorphism, with minor marble and calc-silicate schist. Metabasic sills occur mostly in the uppermost part of the formation.
The Vangorda Formation comprises a thick sequence of recessive, generally calcareous, phyllitic, probable meta-turbidites (locally metamorphosed to resistant calc-silicate rock), intercalated with lesser mafic meta-igneous (basaltic extrusive and intrusive) rocks, which are represented by calc-silicates around the orebodies, with an important basal carbonaceous phyllite member.
The Anvil Range district contains a string of 7 deposits distributed over a strike interval of 35 km, roughly parallel to, and 3 to 6 km to the north-east of the major Vangorda fault zone.
The massive sulphide deposits are stratabound, distributed over a 150 m stratigraphic interval straddling the Mt Mye and Vangorda Formation boundary, and are associated with a regionally distributed, but laterally discontinuous graphitic phyllite unit. The galena and sphalerite bearing massive sulphide ore includes pyritic, barytic, carbonatic and pyrrhotitic variants, with common post depositional breccia textures. The massive sulphides are fringed laterally and below by quartzose and graphitic disseminated sulphide mineralisation, which may be banded and/or spectacularly brecciated. The ore lenses are typically elongated.
The combined pre-mining mineral resource of the main deposits Faro, Vangorda, Grum, Dy (Grizzly) and Swim has been quoted at: 120Mt of 3.7% Pb, 5.6% Zn, 45-50 g/t Ag (Yukon Geol. Surv. Minfile)
The principal members of the Faro Group of deposits are:
Faro - 63 Mt @ 5.5% Zn, 5.5% Pb, 41 g/t Ag. Vangorda - 6 Mt @ 4.6% Zn, 3.5% Pb, 50 g/t Ag. Grum - 30 Mt @ 5% Zn, 3.5% Pb, 50 g/t Ag. DY - 21 Mt @ 6.7% Zn, 5.5% Pb, 48 g/t Ag. Swim - 4.5 Mt @ 5.5% Zn, 4% Pb, 51 g/t Ag, 0.27% Cu, 0.7 g/t Au.
(Porter GeoConsultancy, http://www.portergeo.com.au/, 1997)
