Title: Tectonic studies of the Laurentian craton using magnetotelluric data and the implications for diamond resources
Abstract: Cratons are the oldest continental landmasses, have a thick lithosphere, preserve important records on the formation and evolution of the continents, and are key repositories of economic mineralization and volatile storage. The longevity of cratons means they are often structurally complex features formed by protracted and multi-phased episodes of tectonic formation, destruction, and modification. The magnetotelluric (MT) method is a useful tool in studying cratons as it can readily image to the base of the lithosphere. Additionally, the resistivity measurements are sensitive to a number of conductive phases in the lithosphere that reflect modification related to various tectonic processes. As a result, MT data can be used to image the structure of cratons and investigate their tectonic evolution. Here, the MT method is used to investigate three regions of the Laurentian craton, a composite craton that makes up much of the continental plate beneath North America and Canada. The first area is the Southern Oklahoma Aulacogen, which is located along the southern margin of the continent, which developed as a failed rift in the Cambrian and later deformed as part of the Ancestral Rocky Mountain orogeny. The second area is the Trans-Hudson Orogen, arguably the key tectonic feature responsible for the assembly of Laurentia. The final area is northern Alberta, which was added to Laurentia during the Proterozoic, but has seen tectonic modification during the Cenozoic formation of the Canadian Cordillera. MT data were collected in each study area, and resistivity anomalies are discussed in relation to the tectonic modification and evolution of Laurentia. Resistivity anomalies are also discussed for how they relate to diamond potential in the Trans-Hudson Orogen and in northern Alberta.
Biography: I am a PhD student at the University of Alberta. My research interests focus on using MT and potential field methods to investigate plate tectonics and mineral potential. I have been primarily focused on determining the lithosphere structure in stable and tectonically inactive regions of the North American continent. Due to their age, these regions have often experienced multi-phases of tectonic activity over geologic history, leading to a complex lithosphere structure. I quantitatively interpret resistivity anomalies in the deep lithosphere in order to understand how they relate to the regional tectonic history. I am further interested in how these deep resistivity anomalies relate to mineralization in the crust and placing these observations within the mineral systems framework.
To join virtually: Zoom
Contact: bchase1@ualberta.ca
Recording: Zoom Recording (will be available within a week after the seminar)