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Recent discoveries of at least two types of volcanogenic massive sulphide (VMS) deposits hosted in varying terranes have greatly expanded the mineral potential of the Yukon Territory. Kuroko style deposits at Kudz Ze Kayah and Wolverine are hosted by an Early Mississippian felsic metavolcanic and carbonaceous sedimentary package within the Yukon-Tanana Terrane in the Finlayson Lake area. The massive sulphide lenses at Wolverine have spectacular grades and constitute a geological resources, as of November 1996, of 5,311,000 tonnes with 1.81 g/t Au, 359.1 g/t Ag, 1.41% Cu, 1.53% Pb and 12.96% Zn. New discoveries at the Fyre Lake and Ice properties continue to expand the volcanic hosted massive sulphide potential of the Finlayson Lake area. Fyre Lake is a copper-cobalt-gold Besshi-type deposit hosted by chlorite schist. Towards the end of the season DDH 65 at Fyre Lake intersected 31.3 m of 2.29% Cu, 0.53 gpt Au and 0.07% Co. The enigmatic, ""Cyprus-type"", Ice occurrence has copper-cobalt mineralization in mafic volcanic rocks that are interpreted to belong to the Slide Mountain Terrane. The last hole of the season, DDH IC96-34 intersected 20.56 m of massive pyrite, chalcopyrite and bornite with grades of 5.2% Cu, 0.6 gpt Au, 25 gpt Ag and 0.6% Co. Prior to discovery of Ice, volcanic hosted massive sulphide mineralization was unknown in the Slide Mountain Terrane in the Yukon. The Yukon-Tanana and Slide Mountain Terranes are not restricted to the Finlayson Lake area but cover a considerable portion of the Yukon Territory. West of Dawson the Yukon-Tanana Terrane contains several exhalite occurrences in the Devono-Missisippian Nasina Assemblage and the Permian Klondike Schist. Devono-Mississippian strata in the Yukon-Tanana Terrane may correlate with similar aged units in the Pelly-Cassiar Platform and Selwyn Basin where there are several massive sulphide occurrences. The Marg Deposit occurs at the northern edge of the Selwyn Basin; the MM, Bnob and Chzerpnough properties are hosted by extension related, pyritic, brecciated, felsic metavolcanic rocks within the Pelly-Cassiar Platform. The Yukon-Tanana Terrane extends westward into the Delta District of Alaska where there are at least 26 stratiform and replacement massive sulphide deposits and occurrences. Strata potentially correlative with the Yukon-Tanana Terrane hosts several volcanogenic massive sulphide deposits and occurrences in northern British Columbia.

Discovery of the volcanic-associated massive sulphide (VMS) Kudz Ze Kayah (KZK) deposit in 1994, closelyfollowed by the discovery of the Wolverine VMS deposit, resulted in a period of intense exploration activity in Yukon. This led to the discovery of additional VMS mineralization that includes GP4F, Ice and significant new reserves at Fyre Lake. Numerous VMS prospects were identified. The Fyre Lake, KZK, GP4F, Wolverine, and Ice VMS deposits are hosted by the Yukon-Tanana Terrane (YTT) in the Finlayson Lake district of southeastern Yukon. The Fyre Lake deposit (8 200 000 tonnes of 2.1% Cu and 0.73 g/t Au) is stratigraphically lowest and occurs in mafic metavolcanic rocks of the Devonian to Mississippian Grass Lakes succession. The KZK and GP4F deposits (13 000 000 tonnes of 5.5% Zn, 1% Cu, 1.3% Pb, 125 g/t Ag and 1.2 g/t Au and 1 500 000 tonnes of 6.4% Zn, 3.1% Pb, 0.1% Cu, 89.7 g/t Ag and 2.0 g/t Au, respectively) are within the Devonian to Mississippian succession but lie stratigraphically above Fyre Lake in felsic metavolcanic rocks. The Wolverine deposit (6 237 000 tonnes of 12.66% Zn, 1.33% Cu, 1.55% Pb, 370.9 g/t Ag and 1.76 g/t Au) is hosted by Carboniferous rhyolitic metavolcanic rocks and carbonaceous argillite of the Wolverine succession. The Ice deposit (4 561 863 tonnes of 1.48% Cu ) occurs highest in the stratigraphy and is hosted within late Palaeozoic mafic metavolcanic and associated metasedimentary rocks of the Campbell Range succession. The YTT underlies a large part of Yukon, east-central Alaska and parts of British Columbia. VMS mineralization occurs within rocks of the YTT in the Dawson and Glenlyon areas of Yukon, in the Teslin-Rancheria area in Yukon and adjacent British Columbia, and in several areas within Alaska, as well as in the Finlayson Lake area of the Yukon. In the Dawson area, which lays adjacent to the massive-sulphide-rich Finlayson Lake district (before approximately 425 km of right lateral movement on the Tintina Fault), VMS prospects are hosted in Late Devonian to mid-Mississippian Nasina Assemblage and Permian Klondike Schist. In the Glenlyon area, massive sulphide mineralization and chert horizons occur within a belt of rocks that is at least 20 km long. In the Teslin-Rancheria area and adjacent northern British Columbia, several VMS prospects have been identified. The Alaskan VMS occurrences are in the Delta, Bonnifield and Trident Glacier districts. Exploration during this period was not confined to the YTT but extended into rocks of the North American miogeocline that are coeval, and possibly correlative, with Devono-Mississippian strata of the YTT. This led to the discovery of additional resources at the Marg and Wolf VMS deposits. The Marg deposit (5 527 002 tonnes of 1.76% Cu, 2.46% Pb, 4.60% Zn, 62.7 g/t Ag and 1.0 g/t Au) occurs in the Selwyn Basin within a Devonian to Mississippian sequence of carbonaceous siliceous phyllite, quartz-muscovite and quartz-chlorite phyllite and massive quartzite. These strata also host the Jane prospect. The Wolf deposit (4.1 million tonnes of 6.2% Zn, 1.8% Pb and 84 g/t Ag) occurs in the Pelly-Cassiar Platform within the Devono-Mississippian Pelly Mountains volcanic belt and is hosted by felsic metavolcanic and associated metasedimentary rocks. Numerous other VMS prospects, including MM, occur throughout the length of this 80-km-long volcanic belt. The newly defined VMS deposits are comparable in size to the average Canadian VMS deposit indicating the discoveries are significant. Mineralization in the YTT occurs in Late Devonian to Permian strata thus there are several prospective horizons and the potential for additional discoveries is significant.

The Wolverine polymetallic volcanic-hosted massive sulphide deposit occurs in a highly deformed but coherent stratigraphic succession of early Mississippian to early Permian metavolcanic and metasedimentary rocks of the Yukon-Tanana Terrane. The deposit is part of the emerging Finlayson Lake volcanic-hosted massive sulphide district and contains a geological resource of 6,237,000 tonnes grading 12.66% zinc, 1.33% copper, 1.55% lead, 370.9 g/t silver and 1.76 g/t gold. Local stratigraphy consists of four major units including (from oldest to youngest): (1) quartz-and feldspar-phyric volcaniclastic, carbonaceous sedimentary and porphyritic intrusive rocks; (2) interbedded argillite, aphyric rhyolite and magnetite-carbonate-pyrite exhalite; (3) fragmental rhyolite; and (4) interbedded carbonaceous argillite, greywacke, basalt and rhyolite. The mineralization consists of pyrite and sphalerite, with lesser pyrrhotite, chalcopyrite, galena, tetrahedrite-tennantite and arsenopyrite. Mineralization occurs as massive stratiform, massive replacement and sulphide stringer veins. Sulphides are typically massive, fine-grained, layered and locally brecciated. Styles of hydrothermal alteration identified in the host rocks include proximal silicification and more distal chloritization, sericitization and, in places, carbonatization. Future research will be focussed on identifying the salient physico-chemical controls on the mineralization process and their implications for volcanic-hosted massive sulphide exploration in the district and elsewhere.

Coal was discovered in the Rock River Basin by Sulpetro Minerals Ltd. In July 1980, and five holes sunk to delimit coal occurrences in September 1981. Samples were collected from all five holes for palynologic analysis and the undisrupted core from three holes examined in the field to determine the depositional setting of the coal and provide a basis for evaluation of the coal potential of this area.

Upper Devonian and Lower Mississippian metavolcanic rocks of Yukon-Tanana Terrane in southern Finlayson Lake and Frances Lake map areas occur in three thrust sheets, locally modified by a Cretaceous normal fault. The lower thrust sheet, the Big Campbell sheet, comprises the Upper Devonian to Lower Mississippian metavolcanic stratigraphy that hosts the main volcanichosted massive sulphide (VHMS) deposits of the district. Metavolcanic rocks in the middle thrust sheet, the Money Creek sheet, include the Upper Devonian Waters Creek and Early Mississippian Tuchitua River formations. The former comprises primarily felsic metavolcanic rocks and carbonaceous phyllite and is extensively intruded by sheets of comagmatic porphyry. The latter comprises primarily intermediate metavolcanic, volcaniclastic and epiclastic rocks. The upper thrust sheet, the Cleaver Lake sheet, is in part made up of Late Devonian calc-alkaline basalt and rhyolite, the Cleaver Lake formation, and comagmatic felsic to ultramafic plutonic rocks. Of these, the Waters Creek formation and the formations in the Big Campbell sheet have the highest potential to host VHMS deposits.

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The Fyre Lake volcanic-hosted massive sulphide (VMS) deposit is located about 160 km northwest of Watson Lake in the Finlayson Lake district of southeastern Yukon. The deposit is hosted by Devonian (?) and Mississippian rocks of the Yukon-Tanana Terrane and occurs close to the contact between chlorite schist and overlying carbonaceous phyllite. Copper-cobalt-gold mineralization occurs in two parallel zones: West Kona and East Kona. The chemical composition and rare earth element (REE) pattern of chlorite schist which hosts the Kona zones is unique in the Fire Lake area. The data indicate that the protolith of these meta-volcanic rocks has a boninitic affinity and was likely derived from a depleted source region. Mafic meta-volcanic rocks (chlorite schist) elsewhere in this area are tholeiitic and may have developed in an arc or rift-related setting. Analyses of psammitic schists in the hanging wall of the West Kona zone indicate the rocks are felsic in composition and were likely deposited in a mature arc or continental-margin setting.

The definition of regionally extensive stratigraphy in deformed and metamorphosed rocks of the Yukon-Tanana Terrane in the Finlayson Lake district allows the recognition of at least three mineralized horizons. They are:: a Lower horizon in chlorite schist of unit 2 close to the contact with overlying carbonaceous phyllite of unit 3; a Middle horizon in felsic meta-volcanic rocks of unit 3; and an Upper horizon in pillowed mafic volcanic rocks of the Campbell Range belt. The lower horizon hosts the Fyre Lake deposit. The Kudz Ze Kayah deposit and probably the deposits near Wolverine Lake are in the Middle horizon. The Upper horizon hosts the Money deposit.