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Correcting airborne gravity data for overburden thickness; a case study from the Nechako interior plateau, British Columbia

Raymond M. Caron, Claire Samson, Martin Bates and Michel Chouteau
Correcting airborne gravity data for overburden thickness; a case study from the Nechako interior plateau, British Columbia (in Geophysics applied to mineral exploration, Nicolas Pinet (editor), Erwan Gloaguen (editor) and Bernard Giroux (editor))
Canadian Journal of Earth Sciences = Revue Canadienne des Sciences de la Terre (May 2019) 56 (5): 483-492

Abstract

Large areas of bedrock in Canada, such as in the interior plateau of British Columbia, are covered by a thick glacial overburden. Lateral variations in overburden thickness can create spurious anomalies in gravity data. These anomalies can be of a size and amplitude similar to those associated with mineral bodies and can be mistaken for them. A methodology is introduced that corrects gravity data for changes in overburden thickness through the use of a bedrock topography map created by integrating information from a helicopter transient electromagnetic survey with geological survey data, well water data, and gravel pit locations. The approach is tested for a 68 km X 38 km area in the prospective Nechako interior plateau of British Columbia, Canada. The methodology extends the traditional Bouguer corrections by taking into account the gravitational contribution of the overburden. Results show that the capability of an airborne survey to detect a change in overburden thickness depends primarily on survey line spacing and to a lesser extent on the level of random noise in the gravity data. The bedrock topography correction has the capability of removing the gravitational attraction of overburden for the purpose of revealing, through interpretation, geological structures in the gravity data that originate from the bedrock and are otherwise concealed.


ISSN: 0008-4077
EISSN: 1480-3313
Coden: CJESAP
Serial Title: Canadian Journal of Earth Sciences = Revue Canadienne des Sciences de la Terre
Serial Volume: 56
Serial Issue: 5
Title: Correcting airborne gravity data for overburden thickness; a case study from the Nechako interior plateau, British Columbia
Title: Geophysics applied to mineral exploration
Author(s): Caron, Raymond M.Samson, ClaireBates, MartinChouteau, Michel
Author(s): Pinet, Nicolaseditor
Author(s): Gloaguen, Erwaneditor
Author(s): Giroux, Bernardeditor
Affiliation: Carleton University, Ottawa, ON, Canada
Affiliation: Geological Survey of Canada, Quebec City, QC, Canada
Pages: 483-492
Published: 201905
Text Language: English
Summary Language: French
Publisher: National Research Council of Canada, Ottawa, ON, Canada
References: 36
Accession Number: 2019-067093
Categories: Applied geophysics
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. geol. sketch maps
N53°58'00" - N53°58'00", W125°34'00" - W125°34'00"
Secondary Affiliation: Sander Geophysics, CAN, CanadaPolytechnique Montreal, CAN, Canada
Country of Publication: Canada
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute. Reference includes data from Canadian Science Publishing, NRC Research Press, Ottawa, ON, Canada. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 201935
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