Peel Plateau and the contiguous east flank of the Richardson Mountains, northeastern Yukon, comprise a relatively unexplored but prospective petroleum basin. Within the Devonian succession of this basin, shale rocks of unit ‘Cf’ are little known, but may have the potential to form an important conventional source and/or unconventional reservoir target. Unit ‘Cf’ is dominated by thick intervals of dark grey to black, siliceous, organic-rich marine shale, together with intercalated siltstone and very fine grained sandstone beds. Although unit ‘Cf’ has been mapped at surface on the eastern flank of the Richardson Mountains, it is not known whether it occurs to the east in the Peel Plateau and Plain subsurface. A correlation of this unit to the Ford Lake Shale (‘CF’ map unit), which occurs to the west in Eagle Plain and Kandik basins, has been implied. In this study, unit ‘Cf’ was assessed for lithology, mineralogy, age and hydrocarbon source and reservoir rock potential, including type and quantity of organic matter and thermal maturity. Common organic geochemical analytical techniques were utilized (including Rock-Eval pyrolysis and optical microscopy), together with X-ray diffraction (XRD) to determine shale mineralogy and age determination by palynology. Outcrop characteristics were then utilized to identify unit ‘Cf’ in four subsurface Yukon wells: H-37, N-25, I-21 and A-42.

Extensive conglomeratic strata in the Late Jurassic to Early Cretaceous Tantalus Formation were deposited in both shallow gravel-bed braided rivers, and deeper meandering gravel bed rivers. Overbank, marsh and swamp deposits, with potential to contain abundant terrestrial organic materials, are restricted to recessive intervals associated with small sandy and gravelly highconstructive river systems. Medium- to high-volatile bituminous and anthracitic coals in these intervals have limited potential as a source of additional gaseous hydrocarbons. Most of the conglomerates have a high fracture density, which would make them good reservoirs for coal-bed methane in settings where the Tantalus Formation lies beneath a seal of younger volcanic strata. Strata of the Late Norian Mandanna member of the Aksala formation near Takhini Hotsprings do not contain fluvial strata: laminated, bioturbated, intraclast-bearing red sandstones were deposited in an intertidal setting, and may have lost most of their organic material prior to burial.

Northwestern Lansing map area, 120 km east of Mayo, lacks known mineral occurrences yet contains upper Paleozoic stratigraphic units similar to those at volcanic-hosted and sedimentary exhalative deposits such as Marg and Macmillan Pass. Pyritic and locally baritic Earn Group and (previously unmapped) younger strata underlie most of the area. The sedimentary rocks are cleaved and folded but less strained than equivalent rocks in adjacent Mayo map area, and most contain abundant iron sulphide laminae, nodules, and replacements. A muscovite granite intrudes the grey-green phyllite. The Robert Service Thrust at the southern boundary of the Upper Paleozoic units, appears offset by steep, northwest-trending faults.

The Eagle Plain basin, having proven hydrocarbon potential, is a relatively underexplored intermontane basin located in northern Yukon . Previous studies of the middle Albian-Cenomanian Parkin Formation and the Turonian Fishing Branch Formation are based on broad lithostratigraphic correlations. The primary goal of the study is to refine the sequence stratigraphic framework of the middle to Upper Cretaceous succession based on sedimentological observations. New findings from this study require subdivision of the stratigraphic nomenclature by defining new informal lithological members. Facies transitions, paleoflow indicators and isopach maps indicate overall westward deepening of the basin. Large-scale, sand-prone mass transport deposits observed in the upper part of the lower Parkin shale member in western Eagle Plain indicate the presence of shelf-to-basin floor relief of at least 100 m. Recognition of significant shelf-to-basin floor topography greatly increases the potential for hydrocarbon reservoirs (gas-dominated) in stratigraphic traps associated with the shelf edge.

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.

Precambrian-Cambrian boundary strata of the Wernecke Mountains east-central Yukon comprise a succession of alternating carbonate and siliciclastic units. To date only minor showings of economic mineral deposits have been described from carbonate strata. Most of these deposits are hosted by an unnamed Upper Proterozoic dolostone unit, or by Lower Cambrian carbonates of the Sekwi Formation. Lithostratigraphic, biostratigraphic and sedimentological studies of the entire Precambrian-Cambrian boundary succession were carried out in order to determine the depositional history and mineral potential.

A copy of this thesis is available at the EMR library – QE187 H35. This thesis is available online at https://archive.org/details/Hamilton1981_0/

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.

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A copy of this thesis is available at the EMR library – QE195 L56 1988. This thesis is available online at http://hdl.handle.net/2429/27980.