The Nonacho Group Sedimentary Rocks

Regions: South Slave Region

Tags: physical sciences, sedimentology, Nonacho, rock

Principal Investigator: Fischer, Beth J (3)
Licence Number: 17010
Organization: NWT Geological Survey
Licensed Year(s): 2022
Issued: Apr 27, 2022
Project Team: Jade Lockie, Alessandro Lelpi

Objective(s): To know the age of each formation of the Nonacho sedimentary rocks, to know more about the sources of the Nonacho sediments and to determine what processes deposited the sediments at each place and time.

Project Description: This licence has been issued for the scientific research application No.5098.

The research team would like to know the age of each formation of the Nonacho sedimentary rocks. Is the oldest formation a lot older than the youngest, or only a bit older? The team would like to know more about the sources of the Nonacho sediments. What types of bedrock were eroded to make those sediments? Did rivers carry sediments from high areas in the south and the west into the Nonacho basin, or only from the south? Did the sediments come the south at first, then from the north later? The team would like to determine what processes deposited the sediments at each place and time. Were sediments dropped out of a flowing river, did they settle onto a lake bottom, were they blown onto a windy plain?

Knowing the processes, the research team can infer what the ancient Nonacho landscape was like. Maybe it was a desert in one place and a lake somewhere else. Maybe it was a mountain lake with rivers running into it. Maybe the basin was land-locked at first and then became flooded by an ocean. The team can infer how the ancient Nonacho landscape differed from place to place, and how it changed with time. Knowing the ancient landscapes, the team hope to understand the tectonic forces and climate that affected that part of the world around 2 billion years ago.

The research team will spend 5 weeks in the field, in three different camps. The team will look for good exposures of rock where beds can be measured, and there the team will measure a section of rock and study it in detail. The team will walk through the bush in various places, mapping the rocks the team see. The team will collect a few buckets of rock samples. The research team will move to campsites using float planes. The team will access field areas from camp by boat, except for four days when the team hope to have a helicopter. The helicopter will allow the team to work at sites that can’t be reached in one workday by boat and walking.

In the lab, the research team will separate out the zircon grains and measure isotopes in them to get information about where the grains came from, including the ages of the rocks they were eroded from. The team will do other chemical analyses to help us understand where the sediments came from. The field observations and the lab data will be interpreted mainly by the one of the team who is a university student. This student is working toward a graduate degree as a Master of Science (MSc). This team member will be the lead author who writes reports and makes maps of the geology.

The proposed work will be described on the website of the Northwest Territories Geological Survey (NTGS) at www.nwtgeoscience.ca. A description of the work and location maps will be sent to the Deninu K'ue First Nation Environment and Conservation Committee in Fort Resolution, the NWT Métis Nation Lands and Resources Manager in Fort Smith, the Salt River First Nation Chief in Fort Smith, the Smith’s Landing First Nation in Fort Smith, and the Wildlife, Land and Environment Committee of the Lutselk’e Dene First Nation in Lutselk’e. Results of the work will be available as an MSc thesis from Laurentian University, and as downloadable publications by NTGS.

The fieldwork for this study will be conducted from July 08, 2022 to August 10, 2022