Richard Lee Armstrong FRSC (August 4, 1937 – August 9, 1991) was an American-Canadian scientist who was an expert in the fields of radiogenic isotope geochemistry and geochronology, geochemical evolution of the earth, geology of the American Cordillera, and large-magnitude crustal extension.
He utilized several methodologies, including Potassium-Argon, Rubidium-Strontium, Uranium-Lead and Neodymium-Samarium to obtain isotopic data.
Most of Armstrong's effort was spent systematically building an enormous database on the geochronology of the North American Cordillera.
This database highlighted the magmatic evolution of the region and continues to provide a wealth of information to the scientific community.
He also participated in Canada's Lithoprobe program a national geoscience research project and contributed to the development of the geological timescale, particularly the Triassic.