Previously unrecognized glacial erosional landforms (i.e. cirques, u-shaped troughs, truncated spurs and arêtes, in order of increasing doubt), and glacial depositional landforms (i.e. end moraine and possibly ground moraine) occur in the Fifty Mile Creek area, west of the pre-Reid Cordilleran glacial limit. The cirques and end moraine, representing the best evidence of glaciation, are similar to landforms in the adjacent Yukon-Tanana uplands of Alaska and formed during the Eagle glaciation (>40 ka, or Reid in age). Glaciation caused climate-controlled variations in runoff and cycles of aggradation and incision in the Fifty Mile Creek drainage. This resulted in the formation of upper- and lower-level terraces along Fifty Mile Creek and its tributaries. The terraces are composed of slightly muddy, sandy gravel of locally derived lithologies, and are fluvial in origin. Placer gold occurs along Fifty Mile Creek and several of its tributaries, as well as in the lower-level terraces. The upper-level terraces are potentially placer-gold bearing.

Ice accumulations in the Coast Mountains of southwestern Yukon and the Cassiar Mountains of south-central Yukon during the late Wisconsinan were responsible for glaciation of the Whitehorse area. Cirques in the Coast Mountains likely supported the first glaciers that advanced out of the mountain valleys ahead of the more distal Cassiar accumulation. Glacial maximum is characterized by topographically unconstrained ice flow trending northwesterly over most of the map area. Ice thickness over the city of Whitehorse exceeded 1350 m during full glacial conditions. Deglaciation is characterized by frontal retreat punctuated by periods of dynamic equilibrium and readvances. Differential retreat of the Cassiar and Coast Mountain ice lobes enabled the Cassiar lobe to penetrate, and at times readvance, up-gradient into Coast Mountain valleys. This pattern of deglaciation created ice dams and a series of proglacial lakes that submerged valleys under as much as 300 m of meltwater.

Includes glacial limits, glacial deposits, ice-flow direction and descriptive notes on placer gold and glaciation in the Dawson area.

Preliminary investigation of surficial geology in northern Kluane Range has resulted in new interpretations of Pleistocene ice cover including extensive unglaciated terrain and restricted glaciation during the Last Glacial Maximum. Two glacial limits are identified: a higher limit recording the most extensive glaciation of the area; and a lower limit that records younger, less extensive glaciation. This paper describes Pleistocene limits of the Donjek Glacier and the distribution of surficial materials in the upper Quill, Maple, and Wade creek drainages. The source and transport mechanism of surface materials has particular significance for surficial geochemistry sampling programs and implications for mineral exploration are addressed.

Late Wisconsinan McConnell glaciation (ca. 24-11 ka) occurred in four phases in the Pelly Mountains of southern Yukon. Phase 1 marked the onset of ice accumulation in cirques above 1524 m above sea level (a.s.l.). These local glaciers expanded and fed valley glaciers that extended into the surrounding lowlands (after 26.3 ka). At glacial maximum or phase 2, the development of ice-divides to the east and south of the Pelly Mountains permitted Cordilleran ice lobes to invade the lesser glaciated Pelly Mountains, which resulted in up-valley ice-flow. This ice-flow arrangement continued into early deglaciation (phase 3), a period characterized by re-advances of the invading ice lobes. Following retreat of the ice lobes from the Pelly Mountains, some local cirque glaciers above 1600 m a.s.l. resumed limited down-valley flow (phase 4). For drift prospecting purposes, the dominant glacial dispersion trajectory in these high relief areas is controlled by the last phases of ice-flow (either phase 3 or 4).

The late Cenozoic history of McQuesten map area is characterized by progressively less extensive glaciations and deteriorating interglacial climates. The glaciations, from oldest to youngest, are the pre-Reid (a minimum of two early to mid Pleistocene glaciations), Reid (>200 ka), and McConnell (<29.6 ka BP). Pre-Reid interglacial reconstructions suggest a much warmer and more humid climate than today. The Koy-Yukon interglacial (200 ka) is considered to have a climate similar to a southern boreal forest and the first intact Diversion Creek paleosol, from this period, is documented in the McQuesten River valley. The Stewart neosol (Holocene) is widespread and poorly developed in comparison to past interglacial soils. The distribution of surficial deposits, related to multiple glaciations, physiography, and fluvial order contrasts, may govern the distribution of placer gold occurrences in the study area. Placer deposits occur anomalously in areas outside the pre-Reid limit on Klondike Plateau, and on Stewart Plateau. A copy of this thesis is available at the EMR library – QE195.B65 1997. This thesis is available online at https://www.collectionscanada.gc.ca/obj/s4/f2/dsk2/ftp04/mq21154.pdf

The central Yukon Territory has a number of favourable placer deposit settings due to its unique history of multiple glaciations, active stream sedimentation in association with proglacial outwash settings and terrain which has remained unglaciated. Placer gold was found along the Stewart River on point bars in 1884 prior to the discovery of gold in the Klondike area. This was the first indication that the Yukon Territory contained important economic concentrations of placer gold. This study is concerned with the late Tertiary and Quaternary geology in the Lower Stewart River and adjacent Yukon River above Dawson. Previous systematic surficial geological mapping and testing for placer gold on the high-level terraces along these rivers has been limited. This report describes the sedimentology and stratigraphy of key gravelly exposures in this area because similar high-level terraces in the Fortymile River drainage in Alaska had been mined for gold for many years. Work of this type also provides information on the physical characteristics of gravelly deposits (e.g., grain size distribution) which may assist regulatory decisions on placer mining in the lower Stewart and Yukon drainages. Accompanying this report are two 1:50 000-scale surficial geology maps including marginal notes (Garner Creek, NTS 115O/13 and Matson Creek and Ogilvie NTS 115N/9 (east half) and 115O/12), as well as one 1:250 000-scale topographic map (Stewart River - NTS 115N/O) including field study site locations, heavy mineral sample sites and hardrock mineral occurrences.

The nature and extent of past glaciations are depicted on the glacial limits map of Yukon.

A copy of this thesis is available at the EMR library – GB581.15.Y8 G72. This thesis is available online at https://central.bac-lac.gc.ca/.item?id=TC-QMM-67745&op=pdf&app=Library&oclc_number=895199473.

The Hart River area (maps 116 A/10 and 11) of the southeastern Ogilvie Mountains is underlain by two varied and widespread successions which offer the most potential for discovery of sediment-hosted base metal deposits in the northern Canadian Cordillera. A 'shelf sequence', north of the Dawson fault, includes:: Middle Proterozoic Wernecke Supergroup; Middle and (?) Late Proterozoic Fifteenmile group; the Late Proterozoic Windermere Supergroup; Ordovician and Silurian carbonate; Ordovician to Devonian (?) Road River Group; Devonian Ogilvie Formation; and Devono-Mississippian Earn Group. The 'offshelf sequence' includes:: Late Proterozoic Hyland Group; Cambrian volcanic rocks; Lower Cambrian Vampire Formation equivalent; Cambrian Gull Lake Formation equivalent; Cambro-Ordovicain Rabbitkettle Formation equivalent; Ordovician and younger(?) Road River Group; Mississippian Keno Hill quartzite; and Devonian(?) to Jurassic(?) Lower Schist. The most promising exploration targets are:: 1) massive sulphide deposits associated with the Hart River volcanic rocks in the Gillespie Lake Group (upper part of the Wernecke Supergroup); 2) sedimentary copper deposits in the Fifteenmile Group; 3) 'Anvil-type' pyritic massive sulphide deposits in the transition zone between the Gull Lake and Rabbitkettle Formations; 4) 'Howard's Pass-type' zinc-lead deposits in previously unmapped black shales and chert of the Road River Group; 5) sulphide deposits associated with Cambrian, Ordovician(?) and Devonian(?) mafic volcanic and intrusive rocks; 6) covered areas at the base of the Lower Schist which may overlie the Earn Group, with potential for 'Macmillan Pass-type' zinc, lead, silver, barite deposits; 7) volcanogenic massive sulphide deposits associated with felsic volcanic rocks in the Keno Hill quartzite.