Dr. Michael Lesher
Mineral Exploration - University Chair
Field, laboratory, and mathematical studies of the volcanological, geological, mineralogical, geochemical, and petrological controls on the formation and localization of magmatic chrome and nickel – copper – cobalt – platinum-group element deposits
Contributes to the exploration for chrome and nickel – copper – cobalt – platinum-group elements in Canada and elsewhere in the world. Chrome is used to strengthen steel and to make superalloys; nickel is used in stainless steel and a vast array of other products, including mobile phones, medical imaging equipment, power generators, and batteries; copper is used mainly in electrical equipment; cobalt is used in alloys for aircraft engine parts, in alloys with corrosion/wear resistant uses, and in batteries and in electroplating; platinum-group elements are used as catalysts, in laboratory, electrical, and dental equipment, and in jewelry.
Magmatic Chromite and Sulfide Melts
Chrome, nickel, copper, cobalt, and platinum-group elements (platinum, palladium, rhodium, rhenium, ruthenium, iridium, osmium) are not abundant in the Earth’s crust, and must be concentrated (up to 1 million times their normal abundances) into chromite crystals or molten iron-nickel-copper sulfides in high temperature (up to 1640oC) magmas that erupted from volcanoes or intruded below the Earth’s surface. These processes occurred on such a large scale that they resurfaced large parts of the Earth, setting the stage for the oxygenation of the atmosphere, and – after life developed – resulted in some of the most devastating mass extinctions in the history of the Earth. Despite decades of study, the mechanisms by which large amounts of very dense chromite or molten sulfides formed and were transported by less dense silicate magmas (like the ones currently erupting on Hawaii) through even less dense upper and middle crustal rocks (like the banded white-grey-pink rocks exposed along many roads in northern Canada) are poorly understood. Professor Lesher’s research group maps the rocks that contain the mineralization in the field, underground, and in diamond drill cores; studies their mineralogy and geochemistry using state-of-the-art analytical methods to extract information regarding how they formed; and mathematically models the physical and chemical processes responsible for their concentration to develop mantle- to crustal-scale geological, genetic, and exploration models. Their research is being done in Sudbury (where the ores formed as a result of one of the world’s largest and oldest preserved meteorite impacts) and the recently-discovered “Ring of Fire” area of northern Ontario, the Thompson area of Manitoba, the Raglan area of northernmost Québec, Brazil, China, and Western Australia (where the ores formed from magmas derived from deep within the Earth).