Date: Saturday 22 April 2017
Time: One day from 9.00 am
Venue: To be advised
Prof. Lyal Harris, Institut national de la recherche scientifique — Centre Eau Terre Environnement, Quebec
This one day workshop aims to show how structural geological information at different depths in the crust and upper mantle can be best extracted and interpreted from geophysical data in diverse geological environments for use in regional mineral exploration programs.
Who should attend?
The workshop is primarily intended for exploration and survey geologists, students and researchers with a limited knowledge of geophysics. It is descriptive and practical, so if you were confused by all the maths in a geophysical course but want to know what types of geophysical treatments are available and how to use them, then this is a course for you. The structural interpretation aspects and geological applications would, however, also benefit geophysicists who wish to learn what geophysical treatments geologists require in different settings.
The workshop will present an overview of aeromagnetic, gravity and seismic tomographic data treatment and enhancement techniques for mapping and interpreting geological structures, including:
- Gradient filters and their combinations (ternary images, image enhancement etc.)
- Edge detection techniques (including worming)
- Spectral analysis and “depth slicing” to map structures at different depths (including applications to deep crustal to SCLM structural controls on mineralisation)
- Visualisation of seismic tomographic data to map upper mantle discontinuities.
Examples will be shown from Archaean granite-greenstone, Proterozoic high-grade gneiss, Palaeozoic volcano-sedimentary terrains and present-day subduction systems. Group exercises will provide participants with practical experience in structural interpretation of aeromagnetic and gravity data.
About the presenter
Lyal Harris is an Australian-Canadian geoscientist, professor of structural geology at INRS-ETE, an applied research, postgraduate-only university in Quebec City, Canada
His research integrates enhancement and interpretation of gravity, aeromagnetic and seismic tomographic data with field studies and analogue modelling for regional structural and tectonic syntheses, with applications to mineral exploration targeting. He is especially interested in the link between deep crustal and upper mantle structures and mineral deposits.
Projects with mineral and petroleum exploration companies, and the Geological Survey of Canada (GSC) and the Quebec geological survey (MERN), include fieldwork and structural interpretation of geophysical data in Australia, Canada, France, Indonesia, India, and the USA; additional geophysics-only studies have been carried out in the Canadian arctic, New Guinea, western USA, North Africa to Middle East, Spain, Portugal, Japan, South America and the Himalayas-Tibetan Plateau.
Recent research on developing non-plate tectonic models for the Archaean Earth with GSC colleague Jean Bédard has included comparative studies of the planet Venus using radar and gravity data (research that received an award as one of the top 10 scientific discoveries for 2014 by Quebec Science and the 2015 GSC team research award).
He is a member of the Australian Institute of Geoscientists and the Ordre des géologues du Québec and a fellow of the Society of Economic Geologists; he is also adjunct professor at Laval University and sessional lecturer at the Université du Québec à Chicoutimi.
Participants are required to bring their own laptop running either Windows or Mac OS with GIS software installed, i.e. software can both display multiple geotiff image layers and enable on-screen annotation and line drawing (bring a mouse to make this easier). If you do not already have GIS software installed or if you use an old version of QGIS:
- Install a recent version of the free QGIS software which runs on several operating systems. For Mac users, installation is straightforward but make sure you install software and dependency frameworks in the order given.
- Install a QGIS line drawing plugin from the plugins menu: e.g. ‘Smart editing tools’.
Please download any required software and images to be used (a link and instructions in using QGIS will be sent to participants beforehand) and import images into a GIS before the workshop. Make sure the line drawing capabilities function and you are familiar with using them.