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: 20
Data for food matrix reference materials for hydrogen, carbon, nitrogen, oxygen, and sulfur stable isotope-ratio measurements Data for food matrix reference materials for hydrogen, carbon, nitrogen, oxygen, and sulfur stable isotope-ratio measurements
An international project developed, quality-tested, and measured isotope-delta values of 10 new food matrix reference materials (RMs) for hydrogen, carbon, nitrogen, oxygen, and sulfur stable isotope-ratio measurements to support food authenticity testing and food provenance verification. These new RMs, USGS82 to USGS91, will enable users to normalize measurements of samples to isotope...
Supplemental Discrete Dissolved-Solids Data and Monthly Mean Dissolved-Solids Data for Lower Colorado River (1928-2016) Supplemental Discrete Dissolved-Solids Data and Monthly Mean Dissolved-Solids Data for Lower Colorado River (1928-2016)
Monthly Mean Dissolved-Solids Concentration and Monthly Mean Dissolved-Solids Load Data Flow weighted monthly mean dissolved-solids concentrations (mg/L) data and monthly mean dissolved-solids load data from 1928-2016 were computed by USGS using raw data from the Bureau of Reclamation. These data were computed by USGS for all of the seven sites (listed below). Colorado River above...
Tables and charts for isotope-abundance variations and atomic weights of selected elements: 2016 Tables and charts for isotope-abundance variations and atomic weights of selected elements: 2016
There are 63 chemical elements that have two or more isotopes that are used to determine their standard atomic weights. The isotopic abundances and atomic weights of these elements can vary in normal materials due to physical and chemical fractionation processes (not due to radioactive decay). These variations are well known for 12 elements (hydrogen, lithium, boron, carbon, nitrogen...
A multi-year record of chemical and isotopic composition of water from springs of the Shenandoah National Park, Virginia A multi-year record of chemical and isotopic composition of water from springs of the Shenandoah National Park, Virginia
From 1994 through 2017, the U.S. Geological Survey in cooperation with the National Park Service, Luray, Virginia Station collected and analyzed samples of selected springs, air and unsaturated-zone gases in Shenandoah National Park, Virginia. These data include field measurements of water temperature, specific conductance, concentrations of dissolved oxygen (O2), and pH. Laboratory...
Table of standard atomic weights of the elements 2015 Table of standard atomic weights of the elements 2015
Since 1985, the Commission on Isotopic Abundances and Atomic Weights of the International Union of Pure and Applied Chemistry (IUPAC) has disseminated value pairs of standard atomic weight and an associated uncertainty for elements, such that it can claim at a high level of confidence that any element in question in all known normal materials will have an atomic weight that will not...
Tables supporting improved EA-Cr_HTC hydrogen-isotope technique for halogen- and S-bearing organic compounds Tables supporting improved EA-Cr_HTC hydrogen-isotope technique for halogen- and S-bearing organic compounds
Accurate hydrogen isotopic analysis of halogen- and sulfur-bearing organics has not been possible with traditional high-temperature conversion (HTC) because the formation of hydrogen-bearing reaction products other than molecular hydrogen (H2) is responsible for non-quantitative H2-yields and possible hydrogen isotopic fractionation. The elemental analyzerchromium/high temperature...
Standard and conventional atomic weights 2016 abridged to four significant digits Standard and conventional atomic weights 2016 abridged to four significant digits
To indicate that atomic weights of many elements are not constants of nature, in 2009 and 2011 the Commission on Isotopic Abundances and Atomic Weights (CIAAW) of the International Union of Pure and Applied Chemistry (IUPAC) replaced single-value standard atomic weight values with atomic weight intervals for 12 elements (hydrogen, lithium, boron, carbon, nitrogen, oxygen, magnesium...
Four-place table of standard atomic weight values of hydrogen through uranium compared since 1961 Four-place table of standard atomic weight values of hydrogen through uranium compared since 1961
Four-figure standard atomic weights of the chemical elements are shown for 1961, 1975, 1983, 2007, 2009, 2011, 2013, 2015, and the current value for 2016. Values between 1975 and 2015 are only shown when there is a change in value with respect to the previous column.
Filter Total Items: 162
Minimum requirements for publishing hydrogen, carbon, nitrogen, oxygen and sulfur stable-isotope delta results (IUPAC Technical Report) Minimum requirements for publishing hydrogen, carbon, nitrogen, oxygen and sulfur stable-isotope delta results (IUPAC Technical Report)
Stable hydrogen, carbon, nitrogen, oxygen and sulfur (HCNOS) isotope compositions expressed as isotope-delta values are typically reported relative to international standards such as Vienna Standard Mean Ocean Water (VSMOW), Vienna Peedee belemnite (VPDB) or Vienna Cañon Diablo Troilite (VCDT). These international standards are chosen by convention and the calibration methods used to...
Authors
Grzegorz Skrzypek, Colin Allison, J.K. Bohlke, Luana Bontempo, Paul Brewer, Federica Camin, James F. Carter, Michelle M.G. Chartrand, Tyler B. Coplen, Manfred Groning, Jean-Francois Helie, Germain Esquivel-Hernandez, Rebecca Kraft, Dana A. Magdas, Jacqueline L. Mann, Juris Meija, Harro A. J. Meijer, Heiko Moossen, Nives Ogrinc, Matteo Perini, Antonio Possolo, Karyne Rogers, Arndt Schimmelmann, Aldo Shemesh, David X. Soto, Freddy Thomas, Robert Wielgosz, Michael R. Winchester, Zhao Yan, Philip J. H. Dunn
TSAW — An exercise in consensus TSAW — An exercise in consensus
No abstract available.
Authors
Tyler B. Coplen
Standard atomic weights of the elements 2021 (IUPAC Technical Report) Standard atomic weights of the elements 2021 (IUPAC Technical Report)
Following the reviews of atomic-weight determinations and other cognate data in 2015, 2017, 2019 and 2021, the IUPAC (International Union of Pure and Applied Chemistry) Commission on Isotopic Abundances and Atomic Weights (CIAAW) reports changes of standard atomic weights. The symbol A r°(E) was selected for standard atomic weight of an element to distinguish it from the atomic weight of...
Authors
Thomas Prohaska, Johanna Irrgeher, Jacqueline Benefield, J.K. Bohlke, Lesley Chesson, Tyler B. Coplen, Tiping Ding, Philip J.H. Dunn, Manfred Groning, Norman E. Holden, Harro A. J. Meijer, Heiko Moossen, Antonio Possolo, Yoshio Takahashi, Jochen Vogl, Thomas Walczyk, Jun Wang, Michael E. Wieser, Shigekazu Yoneda, Xiang-Kun Zhu, Juris Meija
Insights on geochemical, isotopic, and volumetric compositions of produced water from hydraulically fractured Williston Basin oil wells Insights on geochemical, isotopic, and volumetric compositions of produced water from hydraulically fractured Williston Basin oil wells
Tracing produced water origins from wells hydraulically fractured with freshwater-based fluids is sometimes predicated on assumptions that (1) each geological formation contains compositionally unique brine and (2) produced water from recently hydraulically fractured wells resembles fresher meteoric water more so than produced water from older wells. These assumptions are not valid in...
Authors
Tanya J. Gallegos, Colin A. Doolan, Rodney R. Caldwell, Mark A Engle, Matthew S. Varonka, Justin E. Birdwell, Glenn D. Jolly, Tyler B. Coplen, Thomas A. Oliver
By
Devils Hole calcite was precipitated at ±1°C stable aquifer temperatures during the last half million years Devils Hole calcite was precipitated at ±1°C stable aquifer temperatures during the last half million years
Subaqueous carbonates from the Devils Hole caves (southwestern USA) provide a continuous Holocene to Pleistocene North American paleoclimate record. The accuracy of this record relies on two assumptions: That carbonates precipitated close to isotope equilibrium and that groundwater temperature did not change significantly in the last 570 thousand years. Here, we investigate these...
Authors
David Bajnai, Tyler B. Coplen, Katharina Methner, Niklas Loffler, Emilija Krsnik, Jens Fiebig
USGS44, a new high-purity calcium carbonate reference material for δ13C measurements USGS44, a new high-purity calcium carbonate reference material for δ13C measurements
Rationale
Authors
Haiping Qi, Heiko Moossen, Harro A.J. Meijer, Tyler B. Coplen, Anita T Aerts-Bijma, Lauren T Reid, Heiko Geilmann, Jurgen Richter, Michael Rothe, Willi A. Brand, Blaza Toman, Jacqueline Benefield, Jean-Francois Helie
Variation of lead isotopic composition and atomic weight in terrestrial materials (IUPAC Technical Report) Variation of lead isotopic composition and atomic weight in terrestrial materials (IUPAC Technical Report)
The isotopic composition and atomic weight of lead are variable in terrestrial materials because its three heaviest stable isotopes are stable end-products of the radioactive decay of uranium (238U to 206Pb; 235U to 207Pb) and thorium (232Th to 208Pb). The lightest stable isotope, 204Pb, is primordial. These variations in isotope ratios and atomic weights provide useful information in...
Authors
Xiang-Kun Zhu, Jacqueline Benefield, Tyler B. Coplen, Zhaofu Gao, Norman E. Holden
Calibration of carbonate-water triple oxygen isotope fractionation: Seeing through diagenesis in ancient carbonates Calibration of carbonate-water triple oxygen isotope fractionation: Seeing through diagenesis in ancient carbonates
High precision triple oxygen isotope measurements of carbonates can better constrain temperatures and oxygen isotope compositions of seawater through geologic time than 18O/16O measurements alone, but lack of a definitive calibration has hindered progress. In this study, we fluorinated both carbonate and water samples to measure quantitatively the triple oxygen isotope composition of...
Authors
Jordan A. G. Wostbrock, Uwe Brand, Tyler B. Coplen, Peter K. Swart, Sandra J. Carlson, Adrian J. Brearley, Zachary D. Sharp
Food matrix reference materials for hydrogen, carbon, nitrogen, oxygen, and sulfur stable isotope-ratio measurements: Collagens, flours, honeys, and vegetable oils Food matrix reference materials for hydrogen, carbon, nitrogen, oxygen, and sulfur stable isotope-ratio measurements: Collagens, flours, honeys, and vegetable oils
An international project developed, quality-tested, and measured isotope–delta values of 10 new food matrix reference materials (RMs) for hydrogen, carbon, nitrogen, oxygen, and sulfur stable isotope-ratio measurements to support food authenticity testing and food provenance verification. These new RMs, USGS82 to USGS91, will enable users to normalize measurements of samples to isotope...
Authors
Arndt Schimmelmann, Haiping Qi, Philip J.H. Dunn, Federica Camin, Luana Bontempo, Doris Potocnik, Nives Ogrinc, Simon Kelly, James Carter, Aiman Abrahim, Lauren T Reid, Tyler B. Coplen
Dual clumped isotope thermometry resolves kinetic biases in carbonate formation temperatures Dual clumped isotope thermometry resolves kinetic biases in carbonate formation temperatures
Surface temperature is a fundamental parameter of Earth’s climate. Its evolution through time is commonly reconstructed using the oxygen isotope and the clumped isotope compositions of carbonate archives. However, reaction kinetics involved in the precipitation of carbonates can introduce inaccuracies in the derived temperatures. Here, we show that dual clumped isotope analyses, i.e...
Authors
David Bajnai, Weifu Guo, Christoph Spotl, Tyler B. Coplen, Katharina Methner, Niklas Loffler, Emilija Krsnik, Eberhard Gischler, Maximilian Hansen, Daniela Henkel, Gregory D. Price, Jacek Raddatz, Denis Scholz, Jens Fiebig
Investigation of recent decadal-scale cyclical fluctuations in salinity in the lower Colorado river Investigation of recent decadal-scale cyclical fluctuations in salinity in the lower Colorado river
Beginning in the late 1970s, 10- to 15-year cyclical oscillations in salinity were observed at lower Colorado River monitoring sites, moving upstream from the international border with Mexico, above Imperial Dam, below Hoover Dam, and at Lees Ferry. The cause of these cyclical trends in salinity was unknown. These salinity cycles complicate the U.S. Bureau of Reclamation's (Reclamation)
Authors
Fred D. Tillman, Alissa L. Coes, David W. Anning, Jon P. Mason, Tyler B. Coplen
Most Earth-surface calcites precipitate out of isotopic equilibrium Most Earth-surface calcites precipitate out of isotopic equilibrium
Oxygen-isotope thermometry played a critical role in the rise of modern geochemistry and remains extensively used in (bio-)geoscience. Its theoretical foundations rest on the assumption that 18O/16O partitioning among water and carbonate minerals primarily reflects thermodynamic equilibrium. However, after decades of research, there is no consensus on the true equilibrium 18O/16O...
Authors
Mathieu Daeron, Russell N Drysdale, Marion Peral, Damien Huyghe, Dominique Blamart, Tyler B. Coplen, Franck Lartaud, Giovanni Zanchetta
Science and Products
Filter Total Items: 20
Data for food matrix reference materials for hydrogen, carbon, nitrogen, oxygen, and sulfur stable isotope-ratio measurements Data for food matrix reference materials for hydrogen, carbon, nitrogen, oxygen, and sulfur stable isotope-ratio measurements
An international project developed, quality-tested, and measured isotope-delta values of 10 new food matrix reference materials (RMs) for hydrogen, carbon, nitrogen, oxygen, and sulfur stable isotope-ratio measurements to support food authenticity testing and food provenance verification. These new RMs, USGS82 to USGS91, will enable users to normalize measurements of samples to isotope...
Supplemental Discrete Dissolved-Solids Data and Monthly Mean Dissolved-Solids Data for Lower Colorado River (1928-2016) Supplemental Discrete Dissolved-Solids Data and Monthly Mean Dissolved-Solids Data for Lower Colorado River (1928-2016)
Monthly Mean Dissolved-Solids Concentration and Monthly Mean Dissolved-Solids Load Data Flow weighted monthly mean dissolved-solids concentrations (mg/L) data and monthly mean dissolved-solids load data from 1928-2016 were computed by USGS using raw data from the Bureau of Reclamation. These data were computed by USGS for all of the seven sites (listed below). Colorado River above...
Tables and charts for isotope-abundance variations and atomic weights of selected elements: 2016 Tables and charts for isotope-abundance variations and atomic weights of selected elements: 2016
There are 63 chemical elements that have two or more isotopes that are used to determine their standard atomic weights. The isotopic abundances and atomic weights of these elements can vary in normal materials due to physical and chemical fractionation processes (not due to radioactive decay). These variations are well known for 12 elements (hydrogen, lithium, boron, carbon, nitrogen...
A multi-year record of chemical and isotopic composition of water from springs of the Shenandoah National Park, Virginia A multi-year record of chemical and isotopic composition of water from springs of the Shenandoah National Park, Virginia
From 1994 through 2017, the U.S. Geological Survey in cooperation with the National Park Service, Luray, Virginia Station collected and analyzed samples of selected springs, air and unsaturated-zone gases in Shenandoah National Park, Virginia. These data include field measurements of water temperature, specific conductance, concentrations of dissolved oxygen (O2), and pH. Laboratory...
Table of standard atomic weights of the elements 2015 Table of standard atomic weights of the elements 2015
Since 1985, the Commission on Isotopic Abundances and Atomic Weights of the International Union of Pure and Applied Chemistry (IUPAC) has disseminated value pairs of standard atomic weight and an associated uncertainty for elements, such that it can claim at a high level of confidence that any element in question in all known normal materials will have an atomic weight that will not...
Tables supporting improved EA-Cr_HTC hydrogen-isotope technique for halogen- and S-bearing organic compounds Tables supporting improved EA-Cr_HTC hydrogen-isotope technique for halogen- and S-bearing organic compounds
Accurate hydrogen isotopic analysis of halogen- and sulfur-bearing organics has not been possible with traditional high-temperature conversion (HTC) because the formation of hydrogen-bearing reaction products other than molecular hydrogen (H2) is responsible for non-quantitative H2-yields and possible hydrogen isotopic fractionation. The elemental analyzerchromium/high temperature...
Standard and conventional atomic weights 2016 abridged to four significant digits Standard and conventional atomic weights 2016 abridged to four significant digits
To indicate that atomic weights of many elements are not constants of nature, in 2009 and 2011 the Commission on Isotopic Abundances and Atomic Weights (CIAAW) of the International Union of Pure and Applied Chemistry (IUPAC) replaced single-value standard atomic weight values with atomic weight intervals for 12 elements (hydrogen, lithium, boron, carbon, nitrogen, oxygen, magnesium...
Four-place table of standard atomic weight values of hydrogen through uranium compared since 1961 Four-place table of standard atomic weight values of hydrogen through uranium compared since 1961
Four-figure standard atomic weights of the chemical elements are shown for 1961, 1975, 1983, 2007, 2009, 2011, 2013, 2015, and the current value for 2016. Values between 1975 and 2015 are only shown when there is a change in value with respect to the previous column.
Filter Total Items: 162
Minimum requirements for publishing hydrogen, carbon, nitrogen, oxygen and sulfur stable-isotope delta results (IUPAC Technical Report) Minimum requirements for publishing hydrogen, carbon, nitrogen, oxygen and sulfur stable-isotope delta results (IUPAC Technical Report)
Stable hydrogen, carbon, nitrogen, oxygen and sulfur (HCNOS) isotope compositions expressed as isotope-delta values are typically reported relative to international standards such as Vienna Standard Mean Ocean Water (VSMOW), Vienna Peedee belemnite (VPDB) or Vienna Cañon Diablo Troilite (VCDT). These international standards are chosen by convention and the calibration methods used to...
Authors
Grzegorz Skrzypek, Colin Allison, J.K. Bohlke, Luana Bontempo, Paul Brewer, Federica Camin, James F. Carter, Michelle M.G. Chartrand, Tyler B. Coplen, Manfred Groning, Jean-Francois Helie, Germain Esquivel-Hernandez, Rebecca Kraft, Dana A. Magdas, Jacqueline L. Mann, Juris Meija, Harro A. J. Meijer, Heiko Moossen, Nives Ogrinc, Matteo Perini, Antonio Possolo, Karyne Rogers, Arndt Schimmelmann, Aldo Shemesh, David X. Soto, Freddy Thomas, Robert Wielgosz, Michael R. Winchester, Zhao Yan, Philip J. H. Dunn
TSAW — An exercise in consensus TSAW — An exercise in consensus
No abstract available.
Authors
Tyler B. Coplen
Standard atomic weights of the elements 2021 (IUPAC Technical Report) Standard atomic weights of the elements 2021 (IUPAC Technical Report)
Following the reviews of atomic-weight determinations and other cognate data in 2015, 2017, 2019 and 2021, the IUPAC (International Union of Pure and Applied Chemistry) Commission on Isotopic Abundances and Atomic Weights (CIAAW) reports changes of standard atomic weights. The symbol A r°(E) was selected for standard atomic weight of an element to distinguish it from the atomic weight of...
Authors
Thomas Prohaska, Johanna Irrgeher, Jacqueline Benefield, J.K. Bohlke, Lesley Chesson, Tyler B. Coplen, Tiping Ding, Philip J.H. Dunn, Manfred Groning, Norman E. Holden, Harro A. J. Meijer, Heiko Moossen, Antonio Possolo, Yoshio Takahashi, Jochen Vogl, Thomas Walczyk, Jun Wang, Michael E. Wieser, Shigekazu Yoneda, Xiang-Kun Zhu, Juris Meija
Insights on geochemical, isotopic, and volumetric compositions of produced water from hydraulically fractured Williston Basin oil wells Insights on geochemical, isotopic, and volumetric compositions of produced water from hydraulically fractured Williston Basin oil wells
Tracing produced water origins from wells hydraulically fractured with freshwater-based fluids is sometimes predicated on assumptions that (1) each geological formation contains compositionally unique brine and (2) produced water from recently hydraulically fractured wells resembles fresher meteoric water more so than produced water from older wells. These assumptions are not valid in...
Authors
Tanya J. Gallegos, Colin A. Doolan, Rodney R. Caldwell, Mark A Engle, Matthew S. Varonka, Justin E. Birdwell, Glenn D. Jolly, Tyler B. Coplen, Thomas A. Oliver
By
Devils Hole calcite was precipitated at ±1°C stable aquifer temperatures during the last half million years Devils Hole calcite was precipitated at ±1°C stable aquifer temperatures during the last half million years
Subaqueous carbonates from the Devils Hole caves (southwestern USA) provide a continuous Holocene to Pleistocene North American paleoclimate record. The accuracy of this record relies on two assumptions: That carbonates precipitated close to isotope equilibrium and that groundwater temperature did not change significantly in the last 570 thousand years. Here, we investigate these...
Authors
David Bajnai, Tyler B. Coplen, Katharina Methner, Niklas Loffler, Emilija Krsnik, Jens Fiebig
USGS44, a new high-purity calcium carbonate reference material for δ13C measurements USGS44, a new high-purity calcium carbonate reference material for δ13C measurements
Rationale
Authors
Haiping Qi, Heiko Moossen, Harro A.J. Meijer, Tyler B. Coplen, Anita T Aerts-Bijma, Lauren T Reid, Heiko Geilmann, Jurgen Richter, Michael Rothe, Willi A. Brand, Blaza Toman, Jacqueline Benefield, Jean-Francois Helie
Variation of lead isotopic composition and atomic weight in terrestrial materials (IUPAC Technical Report) Variation of lead isotopic composition and atomic weight in terrestrial materials (IUPAC Technical Report)
The isotopic composition and atomic weight of lead are variable in terrestrial materials because its three heaviest stable isotopes are stable end-products of the radioactive decay of uranium (238U to 206Pb; 235U to 207Pb) and thorium (232Th to 208Pb). The lightest stable isotope, 204Pb, is primordial. These variations in isotope ratios and atomic weights provide useful information in...
Authors
Xiang-Kun Zhu, Jacqueline Benefield, Tyler B. Coplen, Zhaofu Gao, Norman E. Holden
Calibration of carbonate-water triple oxygen isotope fractionation: Seeing through diagenesis in ancient carbonates Calibration of carbonate-water triple oxygen isotope fractionation: Seeing through diagenesis in ancient carbonates
High precision triple oxygen isotope measurements of carbonates can better constrain temperatures and oxygen isotope compositions of seawater through geologic time than 18O/16O measurements alone, but lack of a definitive calibration has hindered progress. In this study, we fluorinated both carbonate and water samples to measure quantitatively the triple oxygen isotope composition of...
Authors
Jordan A. G. Wostbrock, Uwe Brand, Tyler B. Coplen, Peter K. Swart, Sandra J. Carlson, Adrian J. Brearley, Zachary D. Sharp
Food matrix reference materials for hydrogen, carbon, nitrogen, oxygen, and sulfur stable isotope-ratio measurements: Collagens, flours, honeys, and vegetable oils Food matrix reference materials for hydrogen, carbon, nitrogen, oxygen, and sulfur stable isotope-ratio measurements: Collagens, flours, honeys, and vegetable oils
An international project developed, quality-tested, and measured isotope–delta values of 10 new food matrix reference materials (RMs) for hydrogen, carbon, nitrogen, oxygen, and sulfur stable isotope-ratio measurements to support food authenticity testing and food provenance verification. These new RMs, USGS82 to USGS91, will enable users to normalize measurements of samples to isotope...
Authors
Arndt Schimmelmann, Haiping Qi, Philip J.H. Dunn, Federica Camin, Luana Bontempo, Doris Potocnik, Nives Ogrinc, Simon Kelly, James Carter, Aiman Abrahim, Lauren T Reid, Tyler B. Coplen
Dual clumped isotope thermometry resolves kinetic biases in carbonate formation temperatures Dual clumped isotope thermometry resolves kinetic biases in carbonate formation temperatures
Surface temperature is a fundamental parameter of Earth’s climate. Its evolution through time is commonly reconstructed using the oxygen isotope and the clumped isotope compositions of carbonate archives. However, reaction kinetics involved in the precipitation of carbonates can introduce inaccuracies in the derived temperatures. Here, we show that dual clumped isotope analyses, i.e...
Authors
David Bajnai, Weifu Guo, Christoph Spotl, Tyler B. Coplen, Katharina Methner, Niklas Loffler, Emilija Krsnik, Eberhard Gischler, Maximilian Hansen, Daniela Henkel, Gregory D. Price, Jacek Raddatz, Denis Scholz, Jens Fiebig
Investigation of recent decadal-scale cyclical fluctuations in salinity in the lower Colorado river Investigation of recent decadal-scale cyclical fluctuations in salinity in the lower Colorado river
Beginning in the late 1970s, 10- to 15-year cyclical oscillations in salinity were observed at lower Colorado River monitoring sites, moving upstream from the international border with Mexico, above Imperial Dam, below Hoover Dam, and at Lees Ferry. The cause of these cyclical trends in salinity was unknown. These salinity cycles complicate the U.S. Bureau of Reclamation's (Reclamation)
Authors
Fred D. Tillman, Alissa L. Coes, David W. Anning, Jon P. Mason, Tyler B. Coplen
Most Earth-surface calcites precipitate out of isotopic equilibrium Most Earth-surface calcites precipitate out of isotopic equilibrium
Oxygen-isotope thermometry played a critical role in the rise of modern geochemistry and remains extensively used in (bio-)geoscience. Its theoretical foundations rest on the assumption that 18O/16O partitioning among water and carbonate minerals primarily reflects thermodynamic equilibrium. However, after decades of research, there is no consensus on the true equilibrium 18O/16O...
Authors
Mathieu Daeron, Russell N Drysdale, Marion Peral, Damien Huyghe, Dominique Blamart, Tyler B. Coplen, Franck Lartaud, Giovanni Zanchetta
*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