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TitleInterpreting regional 3D fault networks from integrated geological and geophysical data sets: an example from the Guichon Creek batholith, British Columbia
AuthorLesage, G; Byrne, K; Morris, W A; Enkin, R JORCID logo; Lee, R GORCID logo; Mir, RORCID logo; Hart, C J R
SourceJournal of Structural Geology vol. 119, 2019 p. 93-106,
Alt SeriesNatural Resources Canada, Contribution Series 20200246
PublisherPergamon-Elsevier Science Ltd
Mediapaper; on-line; digital
File formatpdf
ProvinceBritish Columbia
NTS92I/02; 92I/03; 92I/06; 92I/07; 92I/10; 92I/11; 92I/14; 92I/15
Lat/Long WENS-121.4167 -120.6667 50.9167 50.0000
Subjectsgeophysics; general geology; Science and Technology; mathematical and computational geology; faults; anomalies; magnetic anomalies; Modelling
Illustrationslocation maps; tables; magnetic anomaly maps; sketch maps; 3-D models; models; magnetic profiles; plots; photographs; photomicrographs; tables
Released2018 12 26
AbstractThe effects of fault processes on rocks commonly include a lowered magnetic susceptibility and an increased predisposition to erosion. We present a workflow that uses these characteristics of faults and geological observations to interpret a 3D fault network. The location of faults on the topographic surface is first interpreted by a multi-layer lineament mapping method that includes geological and geophysical data sets. We then demonstrate how magnetic intensity data can be used to estimate the dip of fault-related magnetic anomalies by performing 2D inverse modeling along profiles extracted from a magnetic intensity grid. The accuracy of the method is assessed by modeling the dip of low magnetic anomalies of known geometry created in a synthetic 3D magnetic susceptibility model. Modeled dips are consistently accurate to better than 5 degrees for input dips > 60 degrees. A requirement of the method, however, is that the magnetic susceptibility contrast between the background field and the magnetic anomaly must be > 75% for the anomaly to be accurately modeled. Comparison between fault orientations modeled from magnetic data and measured in the field in the Guichon Creek batholith confirms that the methodology can be successfully applied to brittle faults in real, albeit relatively simple geological environments.
Summary(Plain Language Summary, not published)
This research focuses on how faults in the Earth's crust can affect the magnetic properties of rocks. When rocks are near faults, they often have lower magnetic properties and become more prone to erosion. The goal of this study is to develop a method to understand the location and characteristics of these faults in a 3D network.
Researchers used various geological and geophysical data to identify the locations of these faults on the Earth's surface. They also employed magnetic intensity data to estimate the angle (dip) of magnetic anomalies associated with the faults. By modeling these anomalies, they can determine the angle of the fault.
The study found that this method is quite accurate, especially when dealing with steeply inclined faults. However, it requires that the magnetic differences between the background and the anomalies are significant. The results were validated by comparing the modeled fault angles with real field measurements in the Guichon Creek batholith.
Understanding how to detect and map these faults can be valuable for geological studies and has implications for various fields such as earthquake research and resource exploration.

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