Tyler B. Coplen, Ph.D.
Dr. Tyler Coplen is the Director of the Reston Stable Isotope Laboratory of the USGS Water Resources Mission Area.
Tyler B. Coplen is an ST scientist in geochemistry. His research focuses on isotope hydrology, development of innovative analytical techniques for isotopic analysis of light elements, provides forensic-quality analytical services to USGS programs, and creates isotopic reference materials for calibration of mass spectrometers and laser absorption spectrometers in isotope laboratories worldwide. In 1974, he joined the U.S. Geological Survey, and in 1978, he set up the Reston Stable Isotope Laboratory, please visit the Reston Stable Isotope Laboratory website. He set up and led the Subcommittee on Natural Isotopic Fractionation (1985–2002) of the International Union of Pure and Applied Chemistry (IUPAC) that resulted in a dozen elements being assigned standard atomic-weight values that are intervals, instead of single values, to indicate that atomic-weight values of many elements are not constants of nature.
Professional Experience
Assistant Research Geochemist, University of California, Riverside 1970–1974
Education and Certifications
Ph.D. 1970, University of Chicago, Department of Geophysical Sciences, Advisor: Prof. Robert N. Clayton
M.S. 1968, University of Chicago, Department of Geophysical Sciences
B.S. 1966, Pacific Lutheran University, Major: Physics
Affiliations and Memberships*
Honorary Member, Commission on Isotopic Abundances and Atomic Weights of the International Union of Pure and Applied Chemistry
Science and Products
Filter Total Items: 18
No Result Found
Filter Total Items: 153
Comparison of stable isotope reference samples Comparison of stable isotope reference samples
Use of light stable isotope ratio measurements has proliferated in the past decade. The need for procuring additional stable isotope reference materials was recognized at an International Atomic Energy Agency (IAEA) consultants' meeting convened in 19761. This group recommended acquisition of two carbonates, two carbon dioxide samples, a biotite, a sulphate, and other reference materials...
Authors
Tyler B. Coplen, Carol Kendall, Jessica A. Hopple
Comment on “Two New Carbonate Stable Isotope Standards” Comment on “Two New Carbonate Stable Isotope Standards”
Friedman et al (1) propose that NBS 19 calcium carbonate substitute for PDB. This is in apparent conflict with the recommendation of the September 1976 consultants’ meeting convened by the International Atomic Energy Agency on stable isotope standards. Furthermore, Friedman et al suggest ɛ‐values be adopted for NBS 19 that do not take into account the ɛ‐values of NBS 20 (Solenhofen...
Authors
T. B. Coplen, C. Kendall, I. L. Barnes
Tracing ground-water movement by using the stable isotopes of oxygen and hydrogen, upper Penitencia Creek alluvial fan, Santa Clara Valley, California Tracing ground-water movement by using the stable isotopes of oxygen and hydrogen, upper Penitencia Creek alluvial fan, Santa Clara Valley, California
Starting in 1965 the Santa Clara Valley Water District began importing about i00,000 acre-feet per year of northern California water. About one-half of this water was used to artificially recharge the Upper Penitencia Creek alluvial fan in Santa Clara Valley. In order to determine the relative amounts of local ground water and recharged imported water being pumped from the wells, stable...
Authors
K. S. Muir, Tyler B. Coplen
Pressure control of a gas by a calculator-operated mercury piston Pressure control of a gas by a calculator-operated mercury piston
No abstract available.
Authors
Tyler B. Coplen
The origin of the Cerro Prieto geothermal brine The origin of the Cerro Prieto geothermal brine
The Cerro Prieto geothermal brine may have originated from mixing of Colorado River water with seawater evaporated to about six times its normal salinity. This mixture circulated deeply and was heated by magmatic processes. During deep circulation, Li, K, Ca, B, SiO2 and rare alkalis were transferred from rock minerals to the water, and Mg, SO4, and a minor quantity of Na were...
Authors
A.H. Truesdell, J. M. Thompson, T.B. Coplen, N.L. Nehring, C. J. Janik
Preliminary isotopic studies of fluids from the Cerro Prieto geothermal field Preliminary isotopic studies of fluids from the Cerro Prieto geothermal field
Preliminary isotopic studies of Cerro Prieto geothermal fluids and earlier studies of Mexicali Valley ground waters suggest local recharge of the geothermal system from the area immediately to the west. Oxygen isotope exchange of water with reservoir rock minerals at temperatures increasing with depth has produced fluids with oxygen-18 contents increasing with depth, and pressure...
Authors
A.H. Truesdell, R. O. Rye, F. J. Pearson, E.R. Olson, N.L. Nehring, J. F. Whelan, M.A. Huebner, T.B. Coplen
Ultrafiltration by a compacted clay membrane-I. Oxygen and hydrogen isotopic fractionation Ultrafiltration by a compacted clay membrane-I. Oxygen and hydrogen isotopic fractionation
Laboratory experiments were carried out to determine the magnitude of the isotopic fractionation of distilled water and of 0.01 N NaCl forced to flow at ambient temperature under a hydraulic pressure drop of 100 bars across a montmorillonite disc compacted to a porosity of 35 per cent by a pressure of 330 bars. The ultrafiltrates in both experiments were depleted in D by 2.5%. and in O18...
Authors
T.B. Coplen, B.B. Hanshaw
Ultrafiltration by a compacted clay membrane-II. Sodium ion exclusion at various ionic strengths Ultrafiltration by a compacted clay membrane-II. Sodium ion exclusion at various ionic strengths
Several recent laboratory studies and field investigations have indicated that shales and compacted clay minerals behave as semipermeable membranes. One of the properties of semipermeable membranes is to retard or prevent the passage of charged ionic species through the membrane pores while allowing relatively free movement of uncharged species. This phenomenon is termed salt filtering...
Authors
B.B. Hanshaw, T.B. Coplen
Science and Products
Filter Total Items: 18
No Result Found
Filter Total Items: 153
Comparison of stable isotope reference samples Comparison of stable isotope reference samples
Use of light stable isotope ratio measurements has proliferated in the past decade. The need for procuring additional stable isotope reference materials was recognized at an International Atomic Energy Agency (IAEA) consultants' meeting convened in 19761. This group recommended acquisition of two carbonates, two carbon dioxide samples, a biotite, a sulphate, and other reference materials...
Authors
Tyler B. Coplen, Carol Kendall, Jessica A. Hopple
Comment on “Two New Carbonate Stable Isotope Standards” Comment on “Two New Carbonate Stable Isotope Standards”
Friedman et al (1) propose that NBS 19 calcium carbonate substitute for PDB. This is in apparent conflict with the recommendation of the September 1976 consultants’ meeting convened by the International Atomic Energy Agency on stable isotope standards. Furthermore, Friedman et al suggest ɛ‐values be adopted for NBS 19 that do not take into account the ɛ‐values of NBS 20 (Solenhofen...
Authors
T. B. Coplen, C. Kendall, I. L. Barnes
Tracing ground-water movement by using the stable isotopes of oxygen and hydrogen, upper Penitencia Creek alluvial fan, Santa Clara Valley, California Tracing ground-water movement by using the stable isotopes of oxygen and hydrogen, upper Penitencia Creek alluvial fan, Santa Clara Valley, California
Starting in 1965 the Santa Clara Valley Water District began importing about i00,000 acre-feet per year of northern California water. About one-half of this water was used to artificially recharge the Upper Penitencia Creek alluvial fan in Santa Clara Valley. In order to determine the relative amounts of local ground water and recharged imported water being pumped from the wells, stable...
Authors
K. S. Muir, Tyler B. Coplen
Pressure control of a gas by a calculator-operated mercury piston Pressure control of a gas by a calculator-operated mercury piston
No abstract available.
Authors
Tyler B. Coplen
The origin of the Cerro Prieto geothermal brine The origin of the Cerro Prieto geothermal brine
The Cerro Prieto geothermal brine may have originated from mixing of Colorado River water with seawater evaporated to about six times its normal salinity. This mixture circulated deeply and was heated by magmatic processes. During deep circulation, Li, K, Ca, B, SiO2 and rare alkalis were transferred from rock minerals to the water, and Mg, SO4, and a minor quantity of Na were...
Authors
A.H. Truesdell, J. M. Thompson, T.B. Coplen, N.L. Nehring, C. J. Janik
Preliminary isotopic studies of fluids from the Cerro Prieto geothermal field Preliminary isotopic studies of fluids from the Cerro Prieto geothermal field
Preliminary isotopic studies of Cerro Prieto geothermal fluids and earlier studies of Mexicali Valley ground waters suggest local recharge of the geothermal system from the area immediately to the west. Oxygen isotope exchange of water with reservoir rock minerals at temperatures increasing with depth has produced fluids with oxygen-18 contents increasing with depth, and pressure...
Authors
A.H. Truesdell, R. O. Rye, F. J. Pearson, E.R. Olson, N.L. Nehring, J. F. Whelan, M.A. Huebner, T.B. Coplen
Ultrafiltration by a compacted clay membrane-I. Oxygen and hydrogen isotopic fractionation Ultrafiltration by a compacted clay membrane-I. Oxygen and hydrogen isotopic fractionation
Laboratory experiments were carried out to determine the magnitude of the isotopic fractionation of distilled water and of 0.01 N NaCl forced to flow at ambient temperature under a hydraulic pressure drop of 100 bars across a montmorillonite disc compacted to a porosity of 35 per cent by a pressure of 330 bars. The ultrafiltrates in both experiments were depleted in D by 2.5%. and in O18...
Authors
T.B. Coplen, B.B. Hanshaw
Ultrafiltration by a compacted clay membrane-II. Sodium ion exclusion at various ionic strengths Ultrafiltration by a compacted clay membrane-II. Sodium ion exclusion at various ionic strengths
Several recent laboratory studies and field investigations have indicated that shales and compacted clay minerals behave as semipermeable membranes. One of the properties of semipermeable membranes is to retard or prevent the passage of charged ionic species through the membrane pores while allowing relatively free movement of uncharged species. This phenomenon is termed salt filtering...
Authors
B.B. Hanshaw, T.B. Coplen
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government