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