Electromagnetic and magnetic imaging of the Stillwater Complex, Montana, USA

Exploration Geophysics
By: , and 

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Abstract

Modelling and analysis of helicopter electromagnetic data result in resistivity and susceptibility models and derivatives of magnetic data that characterise shallow parts of the Stillwater Complex, critical for aiding exploration and expansion of globally scarce critical and battery mineral resources that include platinum group elements, nickel, copper and chromium. The magnetic susceptibly models derived from the electromagnetic data and the tilt derivative of the magnetic data image layering, mafic dikes, banded iron formation, and serpentinised peridotite. Known areas with contact-type mineralisation are generally characterised by low resistivities and susceptibilities where the volume of mineralised rock is large and/or the depth is shallow. We use iso-cluster and edge detection analysis of both resistivities and susceptibilities to identify potential mineralisation in poorly characterised regions as well as faults. Low resistivity layers beneath large landslides reflect water saturated porous slip surfaces which can interfere with drilling. This uncommon approach of tightly linking the resistivity and susceptibility models and magnetic anomaly data to rock property, surficial geologic, drill hole and soil geochemistry data to image the geology in the upper ∼100 m, aids identification of prospective mineralised regions as well landslides and faults that can impact mineral exploration and local hazards.

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Publication type Article
Publication Subtype Journal Article
Title Electromagnetic and magnetic imaging of the Stillwater Complex, Montana, USA
Series title Exploration Geophysics
DOI 10.1080/08123985.2023.2214166
Volume 54
Issue 6
Year Published 2023
Language English
Publisher Taylor and Francis
Contributing office(s) Geology, Geophysics, and Geochemistry Science Center
Description 18 p.
First page 553
Last page 570
Country United States
State Montana
Other Geospatial Stillwater Complex
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