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Magnetotelluric Study of the Saskatchewan Elbow Impact Structure and Applications of Finite-Element Modeling

Date

2020-07-14

Authors

Journal Title

Journal ISSN

Volume Title

Publisher

ORCID

0000-0002-5144-5961

Type

Thesis

Degree Level

Masters

Abstract

The Elbow structure (50°59’N, 106°43’W) is located in south-central Saskatchewan on an elbow of the South Saskatchewan River. It was initially discovered using seismic methods by Carter Oil in 1943, and was then verified through drilling by Imperial Oil in 1945. Initially, the structure was interpreted to be formed by either anticlinal or salt tectonism but was later confirmed to be a crater impact. The Elbow structure is 8 km in diameter and circular in plan, with a central structurally uplifted area of fractured and brecciated target rocks surrounded by a ring depression. The impact occurred between 370 to 420 million years ago during the Devonian Period. Although seismic and gravity studies had been carried out by oil and gas companies in the last century, which lead to the discovery and verification of the Elbow structure, no electromagnetics studies (in particular magnetotellurics) have been used for Elbow crater exploration since then. In September 2019, a magnetotellurics (MT) survey was carried out at the Elbow site to study any subsurface geoelectric disturbance caused by the impact. All aspects of a magnetotellurics study including survey planning, field operation, data acquisition, processing and analysis, and inverse and forward model ing are discussed in the thesis. Additionally, applications of finite-element modeling on the magnetotellurics method using numerical modeling software COMSOL Multiphysics are dis cussed. The first application of numerical modeling focuses on the general magnetotellurics layered Earth problem. The second application of finite-element modeling focuses on the effect of geomagnetically induced current (GIC) flow in overhead conducting skywires on the magnetotellurics signal, particularly the vertical component of the magnetic field.

Description

Keywords

Magnetotellurics, Saskatchewan Elbow Impact, Finite-Element Modeling

Citation

Degree

Master of Science (M.Sc.)

Department

Geological Sciences

Program

Geology

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DOI

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