NWT RESEARCH DATABASE

Regions: North Slave Region

Tags: physical sciences, geology, sedimentary rocks, rock outcrops, heat transfer, geothermal engery

Objective(s): To determine sediment provenance of the Cambrian and Cretaceous sandstones of the Southern Northwest Territories that represent Cambrian continental margin deposits and Cordilleran foreland basin deposits, respectively.

Project Description: This licence has been issued for the scientific research application No.4817. The overarching goal of this project is to define the basin evolution of the Southern Northwest Territories (SNWT) to assess the potential for geothermal energy production from the SNWT sedimentary basin. The underlying hypothesis of the project is that a better-understanding of the basin history of the SNWT will provide key insights to explain the observed high geothermal gradient and heat flux. This temporal information on sediment burial/heating and erosion/cooling will allow for the evaluation of the geothermal energy potential in the SNWT. The research team will apply an analytical approach to samples collected along a 500 km long transect stretching from the eastern margin of the Canadian Cordillera near Fort Liard to the eastern end of the Western Canadian Sedimentary Basin west of Yellowknife. The research team will conduct fieldwork to collect rock samples at outcrops as well as subsurface core samples from mineral wells drilled across the SNWT. Our research objectives are to: 1) Determine sediment provenance of the Cambrian and Cretaceous sandstones of the SNWT that represent Cambrian continental margin deposits and Cordilleran foreland basin deposits, respectively; 2) Quantify the thermal evolution of the Phanerozoic rocks of the SNWT; 3) Assess if uplift and erosion can explain the elevated heat flow patterns for the SNWT; and, 4) Integrate and synthesize the new provenance and temperature-time data with stratigraphy and seismic data to develop a basin model. To address the above objectives, we will analyze the zircon U/Pb age distribution of Cambrian and Cretaceous sandstone to determine sediment provenance and conduct Petrographic analysis on thin sections from Cambrian and Cretaceous sandstone. The team will use low-temperature thermochronology including apatite and zircon fission track and (U-Th)/He analysis on clastic sedimentary rocks to quantify the maximum burial temperature (heating after deposition) and timing, and estimate the amount and timing of basin inversion and erosion that occurred (removal of overlying section). Spatial variations in sediment burial and basin inversion and erosion will be evaluated.. The team will conduct thermal history modeling of individual surface and borehole samples and build a new basin evolution model for the SNWT including a thermal evolution model that integrates phases of cooling and heating. The project includes two field seasons. Due to COVID 19 travel restrictions, only Northwest Territories Geological Survey (NTGS) will conduct the roadside and core facility sampling program for summer 2020. All analytical work will be conducted by the research group of Eva Enkelmann at the University of Calgary and will provide a variety of training opportunities for graduate and undergraduate students in laboratory, data analysis and thermal modeling skills. Annual technical presentations will be made each year at the Yellowknife Geoscience Forum. A plain-language annual research summary will be created and posted on the NTGS website. The research team will send a copy of the plain language reports to appropriate community representatives. The fieldwork for this study will be conducted from August 22, 2020 to December 31, 2020.