Upper Triassic Mid-Latitude Cool-Water Carbonate Deposit: Sedimentology and Stratigraphy of the Gore Point Member, Roche Point Formation, Arctic Islands, Canada

• Main Author: Hay, Chelsey
• Other Authors: Beauchamp, Benoît, Grasby, Stephen E., Meyer, Rudi, Dutchak, Alex
• Format: Master Thesis
• Language: English
• Published: Science 2021
• Subjects: Education > Sciences; Geology; Arctic; Canada; Ellesmere Island; King Island; Mackenzie King Island; Roche Point; sverdrup basin
• Online Access: http://hdl.handle.net/1880/113068; https://doi.org/10.11575/PRISM/38630

The Gore Point Member is a mixed carbonate-siliciclastic unit deposited in the Sverdup Basin (Canadian Arctic Islands) during the Carnian (Late Triassic). While mixed carbonate-siliciclastic deposits are not rare within the global rock record, the Gore Point Member is unique in that it is the only unit with meaningful amounts of carbonate material within the Mesozoic succession of the Sverdrup Basin. However, as detailed sedimentological or sequence stratigraphic studies of the Gore Point Member have been yet to be undertaken, the existence of this anomalous unit remains unexplained. This study applies thin section microscopy and microfacies analysis of 285 samples from 12 sites across western Ellesmere Island, and lithofacies analysis of one core on Mackenzie King Island, to interpret the depositional setting of the Gore Point Member. These observations reveal fine-grained quartz-dominated siliciclastics and heterozoan carbonate material deposited in a ramp setting in an arid, cool-temperate environment. Integration of sedimentological trends with subsurface wireline well logs throughout the Sverdrup Basin reveals deposition across three fourth-order transgressive-regressive sequences. It is postulated that the arid climate along with tectonic quiescence reduced siliciclastic input, providing a window of opportunity for heterozoan biota to propagate. The Gore Point Member is significant as it is one of very few examples globally of a ramp-type carbonate deposit from the Triassic, and the highest latitude and most cool-water example recognized thus far.