Richard Lee Armstrong (August 4, 1937 – August 9, 1991) was an American/Canadian scientist who was an expert in the fields of radiogenic

isotope geochemistry Isotope geochemistry is an aspect of geology based upon the study of natural variations in the relative abundances of isotopes of various elements. Variations in isotopic abundance are measured by isotope ratio mass spectrometry, and can reveal ...

and

geochronology Geochronology is the science of determining the age of rocks, fossils, and sediments using signatures inherent in the rocks themselves. Absolute geochronology can be accomplished through radioactive isotopes, whereas relative geochronology is p ...

geochemical Geochemistry is the science that uses the tools and principles of chemistry to explain the mechanisms behind major geological systems such as the Earth's crust and its oceans. The realm of geochemistry extends beyond the Earth, encompassing the ...

evolution of the earth,

geology Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Ea ...

of the

American Cordillera The American Cordillera is a chain of mountain ranges ( cordilleras) that consists of an almost continuous sequence of mountain ranges that form the western "backbone" of North America, Central America and South America, with Aconcagua as ...

, and large-magnitude crustal extension. He published over 170 scientific papers. Armstrong was born in

Seattle, Washington Seattle ( ) is a port, seaport city on the West Coast of the United States. It is the county seat, seat of King County, Washington, King County, Washington (state), Washington. With a 2020 population of 737,015, it is the largest city in bo ...

Education

In 1955, he moved to

New Haven, Connecticut New Haven is a city in the U.S. state of Connecticut. It is located on New Haven Harbor on the northern shore of Long Island Sound in New Haven County, Connecticut and is part of the New York City metropolitan area. With a population of 134,023 ...

to attend

Yale University Yale University is a Private university, private research university in New Haven, Connecticut. Established in 1701 as the Collegiate School, it is the List of Colonial Colleges, third-oldest institution of higher education in the United Sta ...

. He obtained his BSc in 1959 and a PhD in 1964. He stayed at Yale as assistant and associate professor in the geology department until 1973. While he was a Yale professor, he took two leaves, the first in 1963–1964 on a National Science Foundation Postdoctoral Fellowship at the

University of Berne The University of Bern (german: Universität Bern, french: Université de Berne, la, Universitas Bernensis) is a university in the Swiss capital of Bern and was founded in 1834. It is regulated and financed by the Canton of Bern. It is a compre ...

, and in 1968-1969 as a Morse and Guggenheim Fellow at the

Australian National University The Australian National University (ANU) is a public research university located in Canberra, the capital of Australia. Its main campus in Acton encompasses seven teaching and research colleges, in addition to several national academies and ...

and

California Institute of Technology The California Institute of Technology (branded as Caltech or CIT)The university itself only spells its short form as "Caltech"; the institution considers other spellings such a"Cal Tech" and "CalTech" incorrect. The institute is also occasional ...

Career

In 1973, Armstrong moved to

Vancouver Vancouver ( ) is a major city in western Canada, located in the Lower Mainland region of British Columbia. As the most populous city in the province, the 2021 Canadian census recorded 662,248 people in the city, up from 631,486 in 2016. Th ...

, British Columbia, Canada to be an associate professor at the

University of British Columbia The University of British Columbia (UBC) is a public university, public research university with campuses near Vancouver and in Kelowna, British Columbia. Established in 1908, it is British Columbia's oldest university. The university ranks a ...

. He was eventually made a full professor. In 1979, he became a Canadian citizen. Armstrong studied the

chronology Chronology (from Latin ''chronologia'', from Ancient Greek , ''chrónos'', "time"; and , '' -logia'') is the science of arranging events in their order of occurrence in time. Consider, for example, the use of a timeline or sequence of events. ...

of magmatism,

metamorphism Metamorphism is the transformation of existing rock (the protolith) to rock with a different mineral composition or texture. Metamorphism takes place at temperatures in excess of , and often also at elevated pressure or in the presence of ...

, and

tectonics Tectonics (; ) are the processes that control the structure and properties of the Earth's crust and its evolution through time. These include the processes of mountain building, the growth and behavior of the strong, old cores of continents ...

of western North America. He utilized several methodologies, including

Potassium Potassium is the chemical element with the symbol K (from Neo-Latin '' kalium'') and atomic number19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmosp ...

Argon Argon is a chemical element with the symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. Argon is the third-most abundant gas in Earth's atmosphere, at 0.934% (9340 ppmv). It is more than twice as a ...

Rubidium Rubidium is the chemical element with the symbol Rb and atomic number 37. It is a very soft, whitish-grey solid in the alkali metal group, similar to potassium and caesium. Rubidium is the first alkali metal in the group to have a density hig ...

Strontium Strontium is the chemical element with the symbol Sr and atomic number 38. An alkaline earth metal, strontium is a soft silver-white yellowish metallic element that is highly chemically reactive. The metal forms a dark oxide layer when it is ...

Uranium Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weakly ...

Lead Lead is a chemical element with the Symbol (chemistry), symbol Pb (from the Latin ) and atomic number 82. It is a heavy metals, heavy metal that is density, denser than most common materials. Lead is Mohs scale of mineral hardness#Intermediate ...

and

Neodymium Neodymium is a chemical element with the symbol Nd and atomic number 60. It is the fourth member of the lanthanide series and is considered to be one of the rare-earth metals. It is a hard, slightly malleable, silvery metal that quickly tarnishes ...

Samarium Samarium is a chemical element with symbol Sm and atomic number 62. It is a moderately hard silvery metal that slowly oxidizes in air. Being a typical member of the lanthanide series, samarium usually has the oxidation state +3. Compounds of samar ...

to obtain isotopic data. Armstrong's early theories guided research for a generation. His views were controversial and contested by many prominent isotope geochemists. It took decades for other scientists to accept his ideas. Before he died, Armstrong was vindicated through the recognition he received for his model of crustal recycling at the 1990 ICOG meeting in Canberra after presenting a paper on "The Persistent Myth of Crustal Growth". 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. Armstrong was an active member of the

Geological Society of America The Geological Society of America (GSA) is a nonprofit organization dedicated to the advancement of the geosciences. History The society was founded in Ithaca, New York, in 1888 by Alexander Winchell, John J. Stevenson, Charles H. Hitch ...

and editorial boards for several journals. He participated in the peer review process of the

National Science Foundation The National Science Foundation (NSF) is an independent agency of the United States government that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National ...

and Canada's

Natural Sciences and Engineering Research Council The Natural Sciences and Engineering Research Council of Canada (NSERC; french: Conseil de recherches en sciences naturelles et en génie du Canada, CRSNG) is the major federal agency responsible for funding natural sciences and engineering rese ...

. He also participated in Canada's

Lithoprobe Lithoprobe was a Canadian national geoscience research project funded by the Natural Sciences and Engineering Research Council from 1984 to 2005, and one of the largest geoscientific research programs in Canadian history. The project aimed to resea ...

program a national geoscience research project and contributed to the development of the geological timescale, particularly the Triassic. On August 9, 1991, Armstrong died of liver cancer, five days after his 54th birthday.

Accolades

*1981, made a fellow of the Royal Society of Canada *1986, awarded a

Killam Prize The Izaak Walton Killam Memorial Prize was established according to the will of Dorothy J. Killam to honour the memory of her husband Izaak Walton Killam. Five Killam Prizes, each having a value of $100,000, are annually awarded by the Canada Co ...

by the University of British Columbia *1990, awarded the Logan Medal by the

Geological Association of Canada The Geological Association of Canada (GAC) is a learned society that promotes and develops the geological sciences in Canada. The organization holds conferences, meetings and exhibitions for the discussion of geological problems and the exchange ...

*The Richard Lee Armstrong Endowment Fund, an endowed scholarship, was established at the Department of Earth Sciences, University of British Columbia after his death *A new radiogenic isotope laboratory was dedicated to his memory by the University of British Columbia * The

asteroid An asteroid is a minor planet of the Solar System#Inner solar system, inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic o ...

21362 Dickarmstrong 136 may refer to: *136 (number) * AD 136 *136 BC *136 (MBTA bus) The Massachusetts Bay Transportation Authority MBTA bus, bus division operates bus routes in the Boston, Massachusetts metropolitan area. All routes connect to Massachusetts Bay Tr ...

Often cited and recognized papers

*Armstrong, R.L.. 1966. K-ar dating of plutonic and volcanic rocks in orogenic belts: Age determination by potassium argon: ''Heidelberg, Springer-Verlag'', pp. 117–133. *Armstrong, R.L.. 1968. A model for Pb and Sr isotope evolution in a dynamic earth: ''Reviews of Geophysics'', v. 6, pp. 175–199. *Armstrong, R.L.. 1972. Low-angle faults, hinterland of the Sevier orogenic belt, eastern Nevada and western Utah: ''Geological Society of America Bulletin'', v. 83, pp. 1729–1754. *Armstrong, R.L.. 1981. Radiogenic isotopes; The case for crustal recycling on a near-steady-state no-continental-growth Earth: ''Royal Society of London Philosophical Transactions'', v. 301, pp. 443–472. *Armstrong, R.L., 1988. Mesozoic and Early Cenozoic Magmatism of the Canadian Cordillera. doi: 10.1130/SPE218-p55 GSA Special Papers 1988, v. 218, pp. 55–92 *Armstrong, R.L, Parrish, R.. 1990. A geologic excursion across the Canadian Cordillera near 49°N (Highways 1 and 3 from Vancouver to southwestern Alberta and on to Calgary, Alberta): ''Geological Association of Canada Meeting, Vancouver, May, Field Trip Guidebook'', 71 p. *Harland, W.B.; Armstrong, R.L.; Cox, A.V.; Craig, L.E.; Smith, A.G.; Smith, D.G., 1990. ''A Geologic Time Scale'', 1989 edition. Cambridge University Press: Cambridge, pp. 1–263. *Armstrong, R.L., 1991. The Persistent Myth of Crustal Growth. ''Austral. J. Earth Sci.'', Vol: 38:613–63

References

Geosociety Newsletter- March 1993Geolog- Spring 2003Mineralogical Association of Canada- Dr Edward Dale Ghent

External links

Isotope Geochemistry
{{DEFAULTSORT:Armstrong, Richard Lee 1937 births 1991 deaths 20th-century Canadian geologists Fellows of the Royal Society of Canada Yale University alumni Deaths from cancer in British Columbia California Institute of Technology faculty University of British Columbia Faculty of Science faculty Scientists from Seattle Scientists from Vancouver American emigrants to Canada Yale University faculty Logan Medal recipients Deaths from liver cancer Presidents of the Canadian Association of Physicists