University of California, Berkeley, California, United States
Entering the University of California in 1902, Larsen came under the influence of A. C. Lawson and A. S. Eakle while an undergraduate. This led to his taking advanced courses in mathematics and chemistry and contributed to his ultimate decision to make geology and petrology his lifework. After receiving the Bachelor of Science degree in 1906, Larsen remained at the university to teach. He left in 1908 but returned to take his doctorate in 1918.
Career
Achievements
A mineral, discovered in 1828, received the name Larsenit in his honor.
Membership
American Academy of Arts and Sciences
1925 - 1961
American Academy of Arts and Sciences, Cambridge, Massachusetts, United States
Larsen was a member of the American Academy of Arts and Sciences.
National Academy of Sciences
1944 - 1961
National Academy of Sciences, Washington, District of Columbia, United States
Larsen was a member of the National Academy of Sciences.
University of California, Berkeley, California, United States
Entering the University of California in 1902, Larsen came under the influence of A. C. Lawson and A. S. Eakle while an undergraduate. This led to his taking advanced courses in mathematics and chemistry and contributed to his ultimate decision to make geology and petrology his lifework. After receiving the Bachelor of Science degree in 1906, Larsen remained at the university to teach. He left in 1908 but returned to take his doctorate in 1918.
Esper Signius Larsen Jr. was an American geologist who specialized in petrology and mineralogy. He also served as a professor of petrography at Harvard University.
Background
Esper Signius Larsen Jr. was born on March 14, 1879, in Astoria, Oregon, United States. He was the son of Esper Signius Larsen, the first Danish consul in Portland, and his wife Louisa Pauly. When Larsen was young, the family moved to Portland, where his father became a wholesale and retail grocer.
Education
Larsen attended public schools in Portland. Upon graduation from high school, he did not enter college immediately but worked to ease the financial pressures on the family. Entering the University of California in 1902, Larsen came under the influence of Andrew Cowper Lawson and Arthur Starr Eakle while an undergraduate. This led to his taking advanced courses in mathematics and chemistry and contributed to his ultimate decision to make geology and petrology his lifework. After receiving the Bachelor of Science degree in 1906, Larsen remained at the university to teach. He left in 1908 but returned to take his doctorate in 1918.
Larsen conducted advanced research first as an assistant petrologist in the geophysical laboratory of the Carnegie Institution in Washington. With H. E. Marwin he developed petrographic techniques, making investigations in optical crystallography and the immersion method of mineral analysis.
In 1909 Larsen was appointed assistant geologist for the United States Geological Survey, an association that was one of the most important in his entire professional life. He joined Charles Whitman Cross, who had been studying the volcanic province of the San Juan Mountains of Colorado and New Mexico for fifteen years. Their final report appeared forty-seven years later, in 1956. In Washington, Larsen was associated with Frederick Eugene Wright, who pioneered in the development of optical mineralogy. Their joint paper in 1909 was one of the earliest systematic efforts to establish criteria for geological thermometry.
In 1914 Larsen became a full geologist with the United States Geological Survey and served until 1923; for the last five years of this period, he headed the petrology section. Upon leaving the Survey, he became professor of petrography at Harvard University, where he remained until 1949. He then returned to the Survey until failing health forced him to reduce his activities in 1958.
Larsen’s concern with optical mineralogy led him to assemble and tabulate the optical characteristics of more than 600 nonopaque minerals. Microscopy had been applied intensely to the study of rocks and minerals as early as 1850, with Sorby’s development of the thin section technique. It was developed by Zirkel and Rosenbusch in the following years. Larsen extended and refined these early techniques, developing a hollow prism to measure directly the index of refraction of immersion liquids. These methods were refined for the measurement of mineral refraction indexes to three decimal places - until very recently this instrument served as the principal guide to mineral chemistry. Larsen’s systematic methods of petrographic microscopy and his catalog-tables of the optical properties of minerals and the interrelationships of their properties with their chemistry were published in 1921. A revised handbook written with H. Berman, The Microscopic Determination of the Nonopaque Minerals, appeared in 1934 and remains the single indispensable handbook of optical crystallography.
Larsen’s extensive field studies of the San Juans, the southern California batholith, the Idaho batholith, and later the Highwood Mountains of Montana made him a confirmed magmatist. His extensive microscopic studies of the specimens collected during the annual field seasons of nearly half a century reinforced the conclusions he drew in the field.
Larsen’s other major contributions were his development of the concepts of the petrographic province and the variation diagram. He studied the theory of thermal diffusion and applied it to the problem of the cooling of a batholith. He also developed a method of determining the age of igneous rocks using the lead in accessory minerals. His researches in California’s San Diego County batholithic intrusive rocks had led him to examine the radioactivity of zircon. His retirement from Harvard in 1949 enabled him to devote full time in Washington to applying his methods for determining the age of rocks.
Larsen strongly supported the laboratory investigations of minerals under pressures and high temperatures associated with T. Vogt and N. L. Bowen.
Membership
Larsen was a member of the American Academy of Arts and Sciences (1925) and the National Academy of Sciences (1944). In 1928 he was president of the Mineralogical Society of America.
American Academy of Arts and Sciences
,
United States
1925 - 1961
National Academy of Sciences
,
United States
1944 - 1961
Personality
Larsen's early studies developed in him the habit of extensive and detailed examination of specimens. His single-minded concentration on geology led to extreme absentmindedness; nonetheless his kindness and the grave consideration that he infallibly extended to those around him made him the object of an affectionate veneration on the part of his students.
Connections
Larsen was married to Eva A. Smith. The couple had two sons; one of them, Esper Larsen III, was also a geologist at the United States Geological Survey.