The sedimentary rocks of Devon island, canadian arctic archipelago

Abstract

The present study deals mainly with the stratigraphy, structural geology and environment of deposition of the strata of the Arctic Platform, comprising mainly a structurally concordant succession of lower Paleozoic strata in the western three quarters of the island. The Paleozoic strata comprise, for the most part, a westerly dipping homocline. The greater part of the sedimentary column, in terms of age span and volume of sediments, is made up of Lower Cambrian to Lower Devonian strata. However, strata of Proterozoic, Mesozoic and Cenozoic ages are represented also. The column is divisible into three structurally conformable successions that are separated from one another by regional unconformities, and a fourth succession that includes two unnamed formations in the Haughton impact crater: 1. The Proterozoic is represer1ted by a single formation consisting mainly of sandstone and siltstone. Outcrops are limited to a small area on the south coast where the formation lies nonconformably on Precambrian crystalline rocks, and is overlain unconformably by Cambrian strata. 2. The Paleozoic sediments consist mainly of shelf-type carbonate strata. They are divisible into fifteen formations with a total exposed thickness of about 3700 m. Most formations maintain relatively uniform charac1 eristics throughout the report area. However, the three youngest formations, which outcrop in extreme western parts of the island, exhibit noteworthy facies relationships, with two shelf-type carbonate formations in southern parts of the island giving place laterally to graptolitic rocks in the north. Unconformities occur within the Paleozoic succession: between Lower and Middle Cambrian rocks; and probably between rocks of Late Ordovician and Early Silurian ages. 3. Three easily weathered formations are preserved in a series of grabens developed in the Paleozoic terrane of western Devon Island. They are: 1. the Hassel Formation, nonmarine sandstone, Albian to Cenomanian; 2. the Kanguk Formation, marine shale, Turonian to Campanian; 3. the Eureka Sound Formation, mainly neomarine sandstone, Maastrichtian. 4. The older of two formatior1s within the limits of the Haughton crater consists of impact breccia. The younger consists of lake sediments. Devon Island is cut by numerous, steeply-dipping, normal faults. Key words: Stratigraphy, structurC!l geology, environment of deposition, Phanerozoic rocks, Devon Island, Arctic Canada.

Organic geochemistry of impactites from the Haughton impact structure, Devon Island, Nunavut, Canada

“…7). This level of maturity is also indicated by regional graptolite reflectance values of less than 1.0% (Gentzis et al, 1996), and conodont alteration indices of less than 1.5 (Thorsteinsson and Mayr, 1987).…”

Pedogenesis in the sorted patterned ground of Devon Plateau, Devon Island, Nunavut, Canada

“…The rocks consist of dolomite, schist, sandstone, and conglomerates with scarce amounts of gypsum (Thorsteinsson and Mayr, 1987). According to Krupicka (1977), the upper part of the Plateau is mostly dolomite with a thin layer of orthoquartzite on top of the dolomitic beds.…”

Subglacial drainage patterns of Devon Island, Canada: detailed comparison of rivers and subglacial meltwater channels

“…The location provides access to both exposed subglacial channels and river networks, allowing for systematic comparisons of their geometry and longitudinal profiles. Geologically, the study area lies entirely within carbonate strata of the Upper Ordovician Allen Bay Formation, specifically the lower member, which comprises a uniform succession of medium bedded to massive limestone with dolomitic labyrinthine mottling (e.g., Osinski and Spray, 2005;Thorsteinsson and Mayr, 1987), and is overlain by quaternary glacial till (e.g., Dyke, 1999;Osinski and Spray, 2005). Depositional landforms such as eskers, and glacial deposits including glacier moraines and striations are rare on the plateau surface of Devon Island (Fortier et al, 1963) and only occur sporadically within the Haughton impact structure (Osinski and Spray, 2005).…”