The Mount M'Clintock map area, northeast of Whitehorse, is dominated by Middle Triassic to Jurassic sedimentary and volcanic strata of Stikinia with small portions of the Cache Creek and Yukon-Tanana Terranes. These assemblages were deformed prior to the mid-Cretaceous intrusion of three plutonic suites and the deposition of two suites of volcanic rocks. Sedimentary rocks previously mapped as undifferentiated Lewes River and Laberge Group strata are separated into their respectve groups and further sub-divided into several members. Lewes River Group rocks form three units that are Carnian and older, Norian, and Upper Norian in age and are represented by siliceous siltstone and calcareous sandstone, conglomerate and limestone respectively. Laberge Group strata are divided according to lithology and dominated by siltstone-sandstone couplets and massive siltstone with lesser conglomerate and volcanogenic sandstone. Volcanic rocks previously mapped as Hutshi Group are divided into the dominantly mafic and submarine, MiddleTriassic Joe Mountain volcanic complex (JMVC) and the dominantly felsic and sub-aerial Mount Byng volcanic complex (BCVC). The volcanic and sedimentary rocks generally increase in age from Middle Triassic to Jurassic from west to east across the map area. Plutons cutting these strata belong to the M'Clintock Lakes (120 Ma), the Whitehorse (115 Ma), and the Mount McIntyre (109 Ma) plutonic suites. The predominantly felsic fragmental rocks of the BCVC are genetically associated with the Byng Creek pluton of the Mount McIntyre plutonic suite. The BCVC is nested into the country rocks and its eastern margin and is preserved as the rim of a tilted caldera. Strata of the Laberge and Lewes River groups are folded throughout. Wavelengths are on the order of approximately 1-2 km, but are much tigter in black siltstone units and adjacent to northwest-trending faults. Faults are ubiquitous throughout the map area and form three sets. North-trending faults are the most common. They are spaced a few kilometres from each other and dictate the physiography and drainage of the region. Northwest-trending faults, in the northeastern corner of the map area control the Teslin River valley and juxtapose Yukon-Tanana rocks with Stikinia. Older faults are dominantly east-trending but are terminated or reactivated by younger faults. Copper (gold-molybdenum-tungsten) skarns and gold-bearing quartz veins are the two mineral deposit types most likely to be discovered in the map area. The source of the placer gold in Sheldon Creek is unknown but may be related to gold veins in the JMVC, BCVC, Sheldon Creek volcanics or the surrounding sedimentary rocks. Hydrothermal activity in the JMVC is characterized by orange weathering alteration, breccias, and carbonate veins. Cache Creek rocks in the southern part of the map area are targets for listwaenite associated gold veins.

The Mount Pattison map area is situated near the southwest flank of the Dawson Range. This unglaciated landscape is highly dissected by summits on Britton Ridge and by the Klotassin River. Streams in the southern and western part of the map area drain into the Nisling River whereas streams in the eastern and northern part of the map area drain into the Klotassin River.

A two square mile stock of biotite quartz monzonite forms the core of Spearhead Mountain. The stock has intruded Ordovician and Silurian sediments and has thermalIy altered them for a distance of up to one quarter mile. Mineralizing fluids ascended near vertical cooling fractures in the quartz monzonite, creating a porphyry copper deposit of chalcopyrite and pyrrhotite. Trend surfaces from the first to the third order were established from plagioclase, orthoclase, quartz and total mafic minerals modal data and specific gravity values for the intrusive rock. Quartz, total mafic minerals and specific gravity vary systematically while orthoclase and plagioclase have erratic distributions. Contoured modal data and second degree trend surfaces for quartz, specific gravity and total mafic minerals show a circular distribution pattern. Linear trend surfaces indicate northwesterly and southeasterly gradients for quartz, plagioclase, orthoclase and specific gravity. The original homogeneous granitic magma was contaminated by silica assimilation of the intruded, highly siliceous sediments. Incomplete diffusion of the contaminating silica Iead to a circular outward increase in silica and a corresponding outward decrease in mafic minerals, but did not significantly affect the distribution of orthoclase or plagioclase. The circular zonation of the high specific gravity mafic minerals gave rise to a similar zonation of specific gravities. This thesis is available online at http://data.geology.gov.yk.ca/Reference/68112. A copy of this thesis is available at the EMR library – QE195 S26.

Geological map (1:50,000 scale) of Mount M'Clintock map area, southern Yukon (NTS 105D/16) including geological cross sections and mineral occurrences.

Preliminary geological map (1:50,000 scale) of Mount M'Clintock area, southern Yukon (NTS 105D/16) including geological cross sections and mineral occurrences.

Mineralized zones on the Jason property are stratifrom, sediment hosed Pb-Zn-barite deposits that occur in a Late Devonian age marine carbonaceous shale and turbidite sequence. The Jason Property is located 400 km northeast of Whitehorse near Macmillan Pass on the Canol Road. Since the discovery of mineralization in 1975, eighty-nine diamond drill holes have delineated three mineral deposits. In order of their discovery, they are known as the Main, South and End zones. Geological reserves indicated and inferred for the three zones total 14.1 million tonnes averaging 7.1% Pb, 6.6% Zn and 79.9 g/t Ag. The following questions are the focus of the study:: 1) What is the stratigraphic position and setting of the South zone? 2) What is the geological relationship of the South zone to the Main zone? 3) What is the geometry of the South zone? 4) How can the mineralization in the South zone be described in terms of mineralogical and textural facies? 5) What constraints on the processes of ore formation can be demonstrated by utilizing the above studies?

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Surficial geological map and till geochemistry (copper, lead and zinc) of Mount Mye area.

Surficial geological map and till geochemistry (copper, lead and zinc) of Mount Mye area.

Galena and pyrrhotite occur in manganese-stained quartz-carbonate breccia beneath rusty limestone. Surface geology of the area suggests that the mineralization is a replacement of brecciated limestone in the footwall of a low-angle fault. Results from previous exploration have proved disappointing but the host structure is probably regional in extent and larger deposits may exist along strike.