Preliminary results from the Stewart River stratigraphy and surficial mapping suggest a minimum of four glaciations and two interglacial periods. Methods of stratigraphy, paleomagnetics, soil analysis, tephra chronology, and relative geomorphic preservation are employed to differentiate and describe Quaternary events. Glaciations, from oldest to youngest, are the pre-Reid (multiple early to mid Pleistocene glaciations), Reid (> 200 000 years), and McConnell (14 000 - 29 600 years). Interglacials are represented by organic deposits from Stirling Bend and Ash Bend, in addition to Wounded Moose and Diversion Creek paleosols preserved on pre-Reid and Reid surfaces. During their maximum extent, pre-Reid ice sheets inundated the study area leaving isolated nunataks on Klondike Plateau and the northern part of Stewart Plateau near Syenite Range. North trending intervalley channels on Stewart Plateau represent confined ice flow in Stewart and McQuesten River valleys from ice obstructions in Tintina Trench. Undifferentiated pre-Reid surficial materials are thick in the lowlands of Klondike Plateau and Tintina Trench, areas proximal to the terminus of multiple pre-Reid glaciations. Reid ice terminated at Reid Lakes in the Tintina Trench. The McConnell ice sheet impinged into the east boundary of the study area, terminating approximately 20 km northeast of Stewart Crossing. Petrographic analysis of woody material from the oldest pre-Reid deposit at Stirling Bend (unit A), suggests a late Tertiary age. Paleomagnetic measurements from overlying loess (unit B) and glaciofluvial sediments (unit C) have undetermined polarity. Remaining pre-Reid glacial and interglacial units from Stirling Bend have normal polarities and represent deposits from either a subchron within the Matuyama reversed chron or early Bruhnes normal chron. Reid deposits underlie Sheep creek tephra at Ash Bend suggesting a minimum age of 200 000 years. McConnell deposits are late Wisconsin age. The distribution of surficial materials, related to multiple glaciations, physiography, and fluvial order contrasts, may govern the distribution of placer occurrences in McQuesten map area. Placer deposits occur anomalously in areas around Klondike Plateau, coinciding with the terminus of pre-Reid glaciations, Further exploration in pre-Reid ice terminal environments may yield significant placers through a better understanding of sediment distribution and genesis.

These Quaternary research papers summarize the recent work of Quaternary scientists working in various areas of the Yukon. They are based on studies by government geologists, graduate theses and doctoral dissertations. This volume is the first in a series of publications which will document Quaternary research being done in Yukon in fields of surficial geology, placer geology, glacial history and geomorphology.

Stream sediment and water geochemistry for the Stewart River map area. The following stream sediments were analyzed: Ag, As, Au, Ba, Cd, Co, Cu, F, Fe, Hg, Loss-on-ignition, Mn, Mo, Ni, Pb, Sb, Sn, U, V, W, ,Zn. Stream waters were analyzed for pH, uranium, and fluoride.

A copy of this thesis is available at the EMR library – QE195.R53 1968. This thesis is available online at https://circle.ubc.ca/handle/2429/36000.

This bulletin describes the surficial geology and Quaternary history of the Stevenson Ridge and northern Kluane Lake map sheets, an area covering more than 12 000 square kilometres of southwestern Yukon. The map area straddles the Pleistocene glacial limits that formed the eastern margin of Beringia during glacial periods. As a result, the landforms of this region are diverse and reflect the contrasting geomorphology characteristic of glaciated versus unglaciated terrain. Importantly, work in this region filled a significant gap in our knowledge of central Yukon glacial limits and how adjacent landscapes were impacted by the Cordilleran Ice Sheet. Our goal was to produce an in depth description of the region’s surficial geology that is applicable for a wide range of purposes. While this region is remote, there is growing interest in its mineral endowment, specifically in the Dawson Range, east of the White River, and in the Ruby Range. Knowledge of the surficial geology can be employed in exploration geochemistry programs to improve sampling and can assist in placer exploration. Future development in the region will also benefit from this work by providing a framework on terrain hazards, such as permafrost and landslides, and construction materials like aggregate. From a land use planning perspective, the surficial sediments and associated soils are an important control on the region’s biogeography and therefore, habitat. Hundreds of soil pits were hand excavated during this program and this work is reflected in the detailed descriptions within the bulletin and on the maps.

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Twelve lithostratigraphic units, including ten autochthonous and two allochthonous units, are recognized, and most of these are divided into 27 subunits. They range from Cambrian to Quaternary in age and include a wide range of sedimentary, igneous and metamorphic rock types. Lower Cambrian siliciclastic and carbonate rocks of the Cassiar Batholith predominate. Three phases of structures are identified. First phase structures include bedding and slaty cleavage, of which the latter is attributed to late stage diagenetic recrystallization. Second phase structures trend northwest and include crenulation cleavage and related folds and lineations. They are attributed to northeast-southwest compression resulting from accretion and obduction of allochthonous rocks during arc-continent collision in Late Jurassic-Early Cretaceous time. Third phase structures are approximately 90° to the second phase structures and trend northeast. They include joints and related folds and lineations and are attributed to dextral transcurrent movement on Tintina, Kechika and Cassiar faults. Precious and base metal mineralization is found mostly within Paleozoic sedimentary rocks and Cretaceous plutonic rocks and forms predominantly veins and replacement lenses. The dominant sulphides include galena, sphalerite, pyrite and chalcopyrite. Arsenopyrite, freibergite, tetrahedrite, pyrrhotite, wolframite, cassiterite, stannite, fluorite and lepidolite are also present. Common gangue minerals include quartz, siderite and iron and manganese oxides. Mineralization appears to be structurally controlled by the northeast-southwest jointing and, to a lesser extent, lithologically controlled by limestone-phyllite contacts. It is attributed to hydrothermal solutions migrating along the joints and was probably deposited approximately 50 Ma ago. The most useful exploration guide to finding additional mineralization is iron and manganese gossans.

This data package contains results for parts of the Carmacks survey area (NTS 115I). This information has been provided in a variety of digital formats. PDF files include survey descriptions and details regarding methods, analytical data listings and summary statistics. Raw digital data of original field and analytical information plus new reanalysis results are included in Microsoft®Excel (XLS) format. NGR surveys were originally conducted in the Carmacks map area in 1985 and covered parts of NTS map sheet 115I (Geological Survey of Canada, 1986). Stream sediment and water samples were collected from a total of 951 sample sites. The work was undertaken by the GSC in conjunction with the Department of Indian Affairs and Northern Development, and the government of Yukon under the Canada-Yukon Mineral Development Agreement (1985-1989). As part of the 2014 Yukon Database Upgrade Project, original material collected from the 951 sample sites were selected for reanalysis. Representative 2 gram splits were successfully recovered from a total of 985 samples. Due to a deficiency of available material, 4 samples were not recovered. The samples were delivered to Bureau Veritas Commodities Canada Ltd. (Vancouver) and were analyzed by an ultra-trace aqua-regia digestion ICP-MS package for 53 elements.

This data package contains results for parts of the Dezadeash Range area (NTS 115A and 115B). This information has been provided in a variety of digital formats. PDF files include survey descriptions and details regarding methods, analytical data listings and summary statistics. Raw digital data of original field and analytical information plus new reanalysis results are included in Microsoft®Excel (XLS) format.

Sedimentary strata located within NTS map sheets 95C/5 and 95D/8, southeast Yukon, have a combined thickness ranging between 5000 and 15000 m and depositional ages ranging from Proterozoic to Paleocene. They can be grouped into eight successions with formations within each succession indicating either similar depositional environments or a horizontal or vertical lithological facies zonation. Early to middle Paleozoic successions are best exposed; Proterozoic, Late Paleozoic, Mesozoic and Cenozoic successions are only locally exposed. Many of the successions are bounded by unconformities; some also contain internal depositional hiatuses. The deposition and preservation of the successions reflect the regional tectonic framework of the Canadian Cordillera from Neoproterozoic to present.