Gold mineralization at the Mt. Skukum deposit occurs in nearly vertical quartz-carbonate veins which crosscut flat-lying andesites with a NNE trend. The mineralized veins represent the second stage of a two stage hydrothermal system, the first of which resulted in emplacement of thin chalcedonic veinlets. These two stages of veins are probably indicative of an evolving hydrothermal fluid rather than being representative of two separate events. Vein emplacement is one of the latest of a series of events which began with volcanism, producing felsic and andesitic volcanic rocks which overlie basement in this area. Subsequent periods of tectonism produced large faults along which rhyolitic dykes were emplaced. Continued tectonism resulted in reactivation of old faults along which andesitic and dacitic dykes were injected, crosscutting rhyolite dykes in many cases. As volcanic activity waned, the faults remained active, leaving zones of high permeability which acted as conduits for the still active hydrothermal circulation. Veins appear to have been emplaced at low temperature in a circulating hydrothermal system driven by a heat source at depth associated with dykes present in the area. Circulating hydrothermal fluids may have leached gold from the surrounding andesitic volcanics during propylitization. Permeability may have been controlled by faulting, brecciated flow tops and bottoms, and lapilli tuff horizons. Gold was precipitated in highly permeable conduits, such as the Main Fault Zone and breccia bodies.

The upper Sixtymile River area is located approximately 128 km west of Dawson City, Yukon. Lithology in this area consists of Precambrian to Paleozoic metamorphic rocks, Paleozoic ultramafic rocks, Middle Jurassic pegmatitic and aplitic dikes, Upper Cretaceous porphyritic dikes and volcanic rocks with intercalated sedimentary rocks, Quaternary alkaline basaltic dikes and Quaternary alluvial sediments. Precious metal occurrences in these volcanic rocks are divided into two types, based on differences in local distribution, petrology and wall rock alteration: a gold-bearing pyrite-arsenopyrite type and a silver-bearing galena-sphalerite type. Both types are characterized by four stages of mineralization.

The Eocene Skukum volcanic complex, 60 km south-southwest of Whitehorse, is elliptical in plan, covers an area of about 140 km², and unconformably overlies Cretaceous granitic rocks and Precambrian metasedimentary rocks. The complex is fault-bounded and in places has been intruded by felsic dykes and stocks. A major north-trending fault divides the area into two parts: a western part which includes a lower interlayered sedimentary-volcanic sequence and an upper unit, approximately 500 m thick, characterized by andesite lava flows, pyroclastic flows and sedimentary units; and an eastern part which comprises about 800 m of altered felsic pyroclastic flows and brecciated, flow layered and spherulitic felsic lava flows. Study of the interlayered sedimentary-volcanic formation provides a control on the paleotopography of the Skukum area, and the depositional environment and provenance of the formation..

Geologic understanding of the richly mineralized Dawson Range gold belt (DRGB) in the central Yukon, Canada is hindered by: (1) limited outcrop exposure due to thick soil cover; and (2) low resolution age-constraints despite a long history of porphyry Cu–Au–Mo deposit (PCD) exploration. Here, the well-preserved Klaza Au–Ag–Pb–Zn porphyry–epithermal deposit is used as a type-example of Late Cretaceous magmatic–hydrothermal mineralization to address the complex metallogeny of the DRGB. U–Pb zircon dating defines four magmatic pulses of Late Triassic to Late Cretaceous ages with the latter consisting of the Casino (80–72 Ma) and Prospector Mt. (72–65 Ma) suites. The Casino suite has five phases of intermediate-to-felsic calc-alkaline composition, correspond with older (77 Ma) porphyry mineralization, and displays evidence of magma mingling. The intermediate-to-mafic, slightly alkalic Prospector Mt. suite shows evidence of mingling with the youngest Casino suite phases, correlates with younger (71 Ma), intermediate-sulfidation epithermal and porphyry-type mineralization, and shoshonitic basalts of the Carmacks Group. Zircon trace element data suggest a common melt source for these suites; however, the younger suite records features (e.g., high La/Yb) that indicate a higher pressure melt source. The results from this study highlight the Prospector Mt. suite as a historically overlooked causative magma event linked to Au-rich PCDs in the DRGB and extends the temporal window of PCD prospectivity in this area. The transition from mid-Cretaceous Whitehorse suite magmas to Late Cretaceous Casino-Prospector Mt. suite magmas is proposed to reflect a transition from subduction to localized extension, which is becoming more recognized as a common characteristic of productive porphyry belts globally.

The Dromedary property consists of 344 claims on Dromedary Mountain, Kalzas Mountain, and the intervening Macmillan River valley, all immediately northeast of Tintina Trench and 240 km northeast of Whitehorse. The property lies within Selwyn Basin geological terrane, and the following rock units are present: Proterozoic-Cambrian Hyland Group, Kechika phyllite and limestone, minor Road River shale and siltstone, Earn Group conglomerate, limestone, black silty shale and baritic chert, and overlying Permian shelf sediments. South Fork subvolcanic intrusions and Cretaceous granitic plugs have induced local biotite and calc-silicate hornfels and skarn. The area was staked by Anaconda in 1980 and four areas of interest identified: Dromedary Creek, Dromedary Mountain, François and Kal-Cave. Blackstone Resources Inc. optioned the property in 1996 and has drilled the Dromedary Creek and François areas, encountering massive sulphide mineralization in all five holes. Economic grade Pb-Zn and massive pyrrhotite with significant gold occur on the François grid. In 1997 the magnetic signature of the pyrrhotite on the François grid was traced 5 km, and soil anomalies were detected further to the west. In the Kal-Cave area a 7.5 km long lead-zinc soil anomaly was refined and numerous new occurrences of iron-sulphide mineralization, carbonate porphyroblasts, manganese and iron oxide were detected. Best samples from this area contain 5.53% Pb and 5.83% Zn.

Whitehorse Trough is a frontier basin in south-central Yukon that is thought to contain gas and possibly oil. It formed in the early Triassic as an arc-marginal basin between the ancient North American margin to the east and the volcano-plutonic Stikine Terrane to the west. Three stratigraphic units, termed the Lewes River Group (Upper Triassic), the Laberge Group (Lower-Middle Jurassic) and the Tantalus Formation (Upper Jurassic-Lower Cretaceous), are recognized in the Whitehorse Trough. The Laberge Group is informally subdivided into four units, which, from the base upwards includes the Richthofen, Conglomerate, Nordenskiold and Tanglefoot formations. The Richthofen formation in the Laberge map area (NTS 105E) is characterized by thin- to mediumbedded turbidites, massive sandstone, matrix- and clast-supported conglomerate, scarce ammonites and belemnites, and abundant trace fossils, particularly Chondrites. No comprehensive stratigraphic section exists for the Richthofen formation, but it is estimated to be at least 500 m thick and appears to consist of a lower clast-supported conglomerate unit, a middle unit dominated by thin- to-medium bedded turbidites with minor amounts of massive sandstone and clast- and matrix-supported conglomerate, and an upper clast-supported conglomerate unit. The Richthofen formation unconformably overlies the Lewes River Group and was deposited by a southeast-prograding submarine fan (or fans) during the Early Jurassic. It is correlative with the Inklin Formation in northwestern British Columbia. Programmed pyrolysis using Rock-Eval 6 analysis of 63 samples from the Richthofen formation indicates that it is a poor to fair source rock and is gas-prone.

The Mount Skukum Volcanic Complex (MSVC) is the northernmost extension of the Sloko volcanic province in western British Columbia, a broad northwest-trending volcanic belt along the northeast margin of the Coast Plutonic Belt. Rocks of the Sloko volcanic province are preserved as downfaulted blocks and as erosional remnants on higher upland surfaces. They comprise an assemblage of intermediate to felsic volcanic rocks and derived sedimentary rocks that lie unconformably on Cretaceous granitic rocks, folded Jurassic rocks and Precambrian (?) metasedimentary rocks. The MSVC is Paleocene-Eocene in age, and elliptical in plan; it covers an area of about 140 km squared. It is a downfaulted volcanic block, deposited on Cretaceous granitic rocks of the Ruby Range Batholith and older metasedimentary rocks of the Yukon Group. The complex is surrounded peripherally by several high-level rhyolite intrusions which have recently been dated at 53 ±1.1 Ma using rubidium-strontium geochronology. The MSVC has a maximum vertical thickness of 850 m. It includes:: 1) a downfaulted part of an andesitic stratovolcano which forms the western and southern parts of the complex and comprises the distal and medial facies assemblage of Formations 1 and 2, and the more proximal facies assemblage of Formation 3 a small felsic cauldron subsidence structure in the northeast corner of the area represented by the felsic cauldron-fill deposits of Formation 4; 3) an andesitic vent facies environment located in a small area in the midwestern part of the complex and comprising the deposits of Formation 5; and 4) a central quartz-feldspar-phyric rhyolite intrusion along the western boundary of the small felsic cauldron. A NNE-trending fracture system is the dominant and perhaps the latest structural feature in the MSVC. Economic epigenetic gold veins are found in three major subparallel NNE-trending fault zones. The veins consist of quartz and calcite and are unusual in that they contain no sulphides and have poorly developed wall rock alteration. As of February 1984, the average grade was 27 g/t gold and 22.63 g/t silver with proven reserves of 149,114 tonnes.

Whitehorse trough is a northwestward-tapering belt of Upper Triassic to Lower Cretaceous volcanic and sedimentary rocks extending ~650 km from the British Columbia–Yukon border, north to the vicinity of Carmacks in south-central Yukon. It consists of three main stratigraphic units (i.e., the Lewes River Group, Laberge Group and Tantalus Formation) representing three sedimentary basins, partially overlapping in space and time. The Laberge Group (Lower-Middle Jurassic), informally subdivided into the Richthofen, Tanglefoot and Nordenskiold formations, was deposited in the Laberge basin, a collapsing fore-arc basin in which the arc was undergoing uplift and erosion. The Richthofen formation consists of conglomerate, massive sandstone, sandstone-mudstone couplets, volcaniclastic rocks and minor limestone interpreted as submarine fan systems. The Tanglefoot formation consists of coal-bearing sandstone, mudstone, conglomerate, volcaniclastic rocks and minor limestone interpreted as delta systems and shallow marine deposits. The Richthofen and Tanglefoot formations are the same age (i.e., Sinemurian to Bajocian), but the Richthofen formation is restricted to the southern half of the basin, whereas the Tanglefoot formation occurs in the northern half. The Nordenskiold formation consists of subaerially erupted, resedimented volcaniclastics deposited mainly during Pliensbachian time. The Richthofen formation is interpreted as a spent source rock and the Nordenskiold formation is not a source rock. The Tanglefoot formation is interpreted as a potential source rock and possibly an effective source rock. It contains petroleum fluid inclusions (mainly 23°- 32° and 40°- 44° API gravity) indicating a minimum trapping temperature of 110-115°C. The Tanglefoot formation is also a potential reservoir rock.

Detailed exploration conducted during 2006 in the western part of the Skukum Creek deposit has revealed new structural, mineralogical and geochemical features. The deposit incorporates a number of (at least six or seven) sub- parallel narrow mineralized zones, coincident with andesite-dacite-rhyolite dyke swarms extending for at least 1 km along strike and for hundreds of metres down-dip. Various mineralized zones differ in size, structural setting, intensity and composition of mineralization, and, in total, form a large mineralized package more than 200 m wide, corresponding to a property- to district-scale fault zone extending for over 10 km and traced by a dyke belt. Significant potential exists for the exploration of these structures along strike and down-dip. The diamond drilling intersected numerous high-grade intercepts of gold and silver mineralization corresponding to the low-sulphidation sub-type of epithermal gold-silver deposits. However, strong enrichment in base metals (up to 25% of combined Zn+Pb+Cu) and arsenic suggests essential differences from typical epithermal mineralized systems.

The Kluane Ranges, located in southwest Yukon, are underlain by Late Paleozoic to Late Triassic volcanic and sedimentary rocks assigned to Wrangellia. Bedrock mapping completed within the White River area indicates Wrangellian rocks underwent several phases of deformation between Late Triassic and Miocene time. Middle Triassic marine, fine-grained sedimentary rocks are preserved in grabens where they are overlain by basal conglomerates and breccias of the Nikolai formation. The grabens are related to uplift associated with the deposition of Nikolai formation flood basalts and intrusion of ultramafic bodies. Late Jurassic to Early Cretaceous compression resulted in structural stacking of older rocks and northeast- and southwest-verging overturned folds. Latest (?) Cretaceous to Miocene dextral strike-slip along the Denali fault system led to the formation of steeply dipping faults, extensional and compressional basins and refolding of older regional scale folds. Reactivation of Jura-Cretaceous faults also occurred at this time. An enigmatic pre-Middle Triassic deformation event is believed to be preserved locally in rocks of the Hasen Creek Formation.