Samuel Epstein (geochemist)
Encyclopedia
Samuel Epstein was a Canadian
-American
geochemist who developed methods for reconstructing geologic temperature record
s using stable isotope geochemistry
. He was elected to the United States National Academy of Sciences
in 1977, and a fellow of the Royal Society of Canada
in 1997.
, Belarus
, then part of Poland
, and as a child his family emigrated to Winnipeg, Manitoba. After receiving a B.Sc. in Geology
and Chemistry
(1941) and a M.Sc. in Chemistry
(1942) from the University of Manitoba
, Epstein completed his Ph.D. at McGill University
under the supervision of Carl A. Winkler in 1944. His thesis focused on the synthesis and reaction kinetics of high explosives, including RDX
and HMX
. Epstein subsequently worked for the Canadian Atomic Energy Project for several years.
In 1947, Epstein moved to the United States
to begin a research fellowship with Harold Urey
's group at the University of Chicago
. While at Chicago, Epstein, along with Ralph Buchsbaum
, Heinz A. Lowenstam
, C. R. McKinney and others developed the carbonate-water isotopic temperature scale, allowing ancient ocean temperatures to be determined from precise measurements of 18O/16O
in geological samples of calcium carbonate. This method is still the most widely used geochemical climate proxy
for locations and times not sampled in ice core
records.
Epstein joined the faculty of the California Institute of Technology
in 1952, and continued to explore the new field of stable isotope geochemistry
. He and his students used mass spectrometry
to study natural variations in the isotopic abundances of hydrogen
, carbon, oxygen
and silicon
, with applications to archeology, biochemistry
, climatology
, and geology
. He was awarded the Wollaston Medal
of the Geological Society of London
in 1993.
Epstein remained at Caltech
as a Professor and Professor Emeritus until shortly before his death on September 17, 2001.
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
-American
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
geochemist who developed methods for reconstructing geologic temperature record
Geologic temperature record
The Geologic temperature record are changes in Earth's environment as determined from geologic evidence on multi-million to billion year time scales...
s using stable isotope geochemistry
Stable isotope
Stable isotopes are chemical isotopes that may or may not be radioactive, but if radioactive, have half-lives too long to be measured.Only 90 nuclides from the first 40 elements are energetically stable to any kind of decay save proton decay, in theory...
. He was elected to the United States National Academy of Sciences
United States National Academy of Sciences
The National Academy of Sciences is a corporation in the United States whose members serve pro bono as "advisers to the nation on science, engineering, and medicine." As a national academy, new members of the organization are elected annually by current members, based on their distinguished and...
in 1977, and a fellow of the Royal Society of Canada
Royal Society of Canada
The Royal Society of Canada , may also operate under the more descriptive name RSC: The Academies of Arts, Humanities and Sciences of Canada , is the oldest association of scientists and scholars in Canada...
in 1997.
Biography
Sam Epstein was born in KobrynKobryn
Kobryn or Kobrin is a city in the Brest voblast of Belarus and the center of the Kobryn Raion. The city is located in the southwestern corner of Belarus where the Mukhavets River and Dnepr-Bug Canal meet. The city lies about 52 km east of the city of Brest. Kobryn is located at Latitude...
, Belarus
Belarus
Belarus , officially the Republic of Belarus, is a landlocked country in Eastern Europe, bordered clockwise by Russia to the northeast, Ukraine to the south, Poland to the west, and Lithuania and Latvia to the northwest. Its capital is Minsk; other major cities include Brest, Grodno , Gomel ,...
, then part of Poland
Poland
Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...
, and as a child his family emigrated to Winnipeg, Manitoba. After receiving a B.Sc. in Geology
Geology
Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...
and Chemistry
Chemistry
Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....
(1941) and a M.Sc. in Chemistry
Chemistry
Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....
(1942) from the University of Manitoba
University of Manitoba
The University of Manitoba , in Winnipeg, Manitoba, Canada, is the largest university in the province of Manitoba. It is Manitoba's most comprehensive and only research-intensive post-secondary educational institution. It was founded in 1877, making it Western Canada’s first university. It placed...
, Epstein completed his Ph.D. at McGill University
McGill University
Mohammed Fathy is a public research university located in Montreal, Quebec, Canada. The university bears the name of James McGill, a prominent Montreal merchant from Glasgow, Scotland, whose bequest formed the beginning of the university...
under the supervision of Carl A. Winkler in 1944. His thesis focused on the synthesis and reaction kinetics of high explosives, including RDX
RDX
RDX, an initialism for Research Department Explosive, is an explosive nitroamine widely used in military and industrial applications. It was developed as an explosive which was more powerful than TNT, and it saw wide use in WWII. RDX is also known as cyclonite, hexogen , and T4...
and HMX
HMX
HMX, also called octogen, is a powerful and relatively insensitive nitroamine high explosive, chemically related to RDX. Like RDX, the name has been variously listed as High Melting eXplosive, Her Majesty's eXplosive, High-velocity Military eXplosive, or High-Molecular-weight rdX.The molecular...
. Epstein subsequently worked for the Canadian Atomic Energy Project for several years.
In 1947, Epstein moved to the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
to begin a research fellowship with Harold Urey
Harold Urey
Harold Clayton Urey was an American physical chemist whose pioneering work on isotopes earned him the Nobel Prize in Chemistry in 1934...
's group at the University of Chicago
University of Chicago
The University of Chicago is a private research university in Chicago, Illinois, USA. It was founded by the American Baptist Education Society with a donation from oil magnate and philanthropist John D. Rockefeller and incorporated in 1890...
. While at Chicago, Epstein, along with Ralph Buchsbaum
Ralph Buchsbaum
Ralph Morris Buchsbaum was an American zoologist, invertebrate biologist, and ecologist. His book Animals Without Backbones, written in 1938, was the first textbook in biology to be reviewed by Time and featured in Life, has gone through several revisions, is still in print, and has been widely...
, Heinz A. Lowenstam
Heinz A. Lowenstam
Heinz Adolf Lowenstam was German-born, Jewish-American paleoecologist celebrated for his discoveries in biomineralization: that living organisms manufacture substances such as the iron-containing mineral magnetite within their bodies...
, C. R. McKinney and others developed the carbonate-water isotopic temperature scale, allowing ancient ocean temperatures to be determined from precise measurements of 18O/16O
Isotopes of oxygen
There are three stable isotopes of oxygen that lead to oxygen having a standard atomic mass of 15.9994 u. 17 radioactive isotopes have also been characterized, with mass numbers from 12O to 28O, all short-lived, with the longest-lived being 15O with a half-life of 122.24 seconds...
in geological samples of calcium carbonate. This method is still the most widely used geochemical climate proxy
Proxy (climate)
In the study of past climates is known as paleoclimatology, climate proxies are preserved physical characteristics of the past that stand in for direct measurements , to enable scientists to reconstruct the climatic conditions that prevailed during much of the Earth's history...
for locations and times not sampled in ice core
Ice core
An ice core is a core sample that is typically removed from an ice sheet, most commonly from the polar ice caps of Antarctica, Greenland or from high mountain glaciers elsewhere. As the ice forms from the incremental build up of annual layers of snow, lower layers are older than upper, and an ice...
records.
Epstein joined the faculty of the California Institute of Technology
California Institute of Technology
The California Institute of Technology is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering...
in 1952, and continued to explore the new field of stable isotope geochemistry
Stable isotope
Stable isotopes are chemical isotopes that may or may not be radioactive, but if radioactive, have half-lives too long to be measured.Only 90 nuclides from the first 40 elements are energetically stable to any kind of decay save proton decay, in theory...
. He and his students used mass spectrometry
Mass spectrometry
Mass spectrometry is an analytical technique that measures the mass-to-charge ratio of charged particles.It is used for determining masses of particles, for determining the elemental composition of a sample or molecule, and for elucidating the chemical structures of molecules, such as peptides and...
to study natural variations in the isotopic abundances of hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
, carbon, oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
and silicon
Silicon
Silicon is a chemical element with the symbol Si and atomic number 14. A tetravalent metalloid, it is less reactive than its chemical analog carbon, the nonmetal directly above it in the periodic table, but more reactive than germanium, the metalloid directly below it in the table...
, with applications to archeology, biochemistry
Biochemistry
Biochemistry, sometimes called biological chemistry, is the study of chemical processes in living organisms, including, but not limited to, living matter. Biochemistry governs all living organisms and living processes...
, climatology
Climatology
Climatology is the study of climate, scientifically defined as weather conditions averaged over a period of time, and is a branch of the atmospheric sciences...
, and geology
Geology
Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...
. He was awarded the Wollaston Medal
Wollaston Medal
The Wollaston Medal is a scientific award for geology, the highest award granted by the Geological Society of London.The medal is named after William Hyde Wollaston, and was first awarded in 1831...
of the Geological Society of London
Geological Society of London
The Geological Society of London is a learned society based in the United Kingdom with the aim of "investigating the mineral structure of the Earth"...
in 1993.
Epstein remained at Caltech
California Institute of Technology
The California Institute of Technology is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering...
as a Professor and Professor Emeritus until shortly before his death on September 17, 2001.