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Toshiko K. Mayeda

Bio: Toshiko K. Mayeda is an academic researcher from University of Chicago. The author has contributed to research in topics: Chondrite & Meteorite. The author has an hindex of 63, co-authored 158 publications receiving 21182 citations. Previous affiliations of Toshiko K. Mayeda include University of California, Los Angeles.
Topics: Chondrite, Meteorite, Chondrule, Olivine, Parent body


Papers
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Journal ArticleDOI
TL;DR: A number of marine water and fresh water samples were examined for the relative O18O16 ratio, and the variation of this ratio was determined to a precision of ± 1% as mentioned in this paper.

3,113 citations

Journal ArticleDOI
TL;DR: In this paper, a technique was developed in which bromine pentafluoride was used as a reagent for quantitative liberation of oxygen from oxides and silicates, and the results of isotopic analyses were compared with measurements made in other laboratories by other procedures.

2,636 citations

Journal ArticleDOI
TL;DR: In this article, the fractionation factors for the distribution of 18O between alkaline-earth carbonates and water have been measured over the temperature range 0 −500°C.
Abstract: Equilibrium fractionation factors for the distribution of 18O between alkaline‐earth carbonates and water have been measured over the temperature range 0–500°C. The fractionation factors α can be represented by the equationsCaCO3–H2O, 1000 lnα = 2.78(106 T−2)− 3.39,SrCO3–H2O, 1000 lnα = 2.69(106 T−2)− 3.74,BaCO3–H2O, 1000 lnα = 2.57(106 T−2)− 4.73.Measurements on MnCO3, CdCO3, and PbCO3 were made at isolated temperatures. A statistical‐mechanical calculation of the isotopic partition function ratios gives reasonably good agreement with experiment. Both cationic size and mass are important in isotopic fractionation, the former predominantly in its effect on the internal vibrations of the anion, the latter in its effect on the lattice vibrations.

2,397 citations

Journal ArticleDOI
TL;DR: In this article, the authors measured the equilibrium constants for oxygen isotope exchange between quartz and water and showed that the behavior of fractionation with temperature can be approximated by 1000 ln α = 3.38 (106 T−2) − 3.40 for 200°-500°C and by 2.51 (1.96) − 1.96 for 500°-750°C.
Abstract: Equilibrium constants for oxygen isotope exchange between quartz and water have been measured from 195°C (1000 ln α = 12.0) to 750°C (1000 ln α = 0.4). Over limited temperature ranges the behavior of fractionation with temperature can be approximated by 1000 ln α = 3.38 (106 T−2) − 3.40 for 200°–500°C and by 1000 ln α = 2.51 (106 T−2) − 1.96 for 500°–750°C. The results of measurements in the quartz-water system can be combined with analogous results from other mineral systems to make mineral-pair isotopic thermometers for application to problems of petrogenesis.

1,309 citations

Journal ArticleDOI
02 Nov 1973-Science
TL;DR: The oxygen of anhydrous, high-temperature minerals in carbonaceous meteorites is strongly depleted in the heavy stable isotopes 17O and 18O and probably results from the admixture of a component of almost pure 16O.
Abstract: Oxygen isotope analysis of anhydrous high-temperature phases from carbonaceous meteorite chondrites indicates a high degree of O(17) and O(18) isotope depletion. The isotope decay is believed to be a result of nuclear rather than chemical processes caused by the admixture of a component consisting of almost pure O(16). It is theorized that this component may predate the solar system and may represent interstellar dust with a separate history of nucleosynthesis.

735 citations


Cited by
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Journal ArticleDOI
01 Nov 1964-Tellus A
TL;DR: In this paper, the isotopic fractionation of water in simple condensation-evaporation processes is considered quantitatively on the basis of the fractionation factors given in section 1.2.
Abstract: In chapter 2 the isotopic fractionation of water in some simple condensation-evaporation processes are considered quantitatively on the basis of the fractionation factors given in section 1.2. The condensation temperature is an important parameter, which has got some glaciological applications. The temperature effect (the δ's decreasing with temperature) together with varying evaporation and exchange appear in the “amount effect” as high δ's in sparse rain. The relative deuterium-oxygen-18 fractionation is not quite simple. If the relative deviations from the standard water (S.M.O.W.) are called δ D and δ 18 , the best linear approximation is δ D = 8 δ 18 . Chapter 3 gives some qualitative considerations on non-equilibrium (fast) processes. Kinetic effects have heavy bearings upon the effective fractionation factors. Such effects have only been demonstrated clearly in evaporation processes, but may also influence condensation processes. The quantity d = δ D −8 δ 18 is used as an index for non-equilibrium conditions. The stable isotope data from the world wide I.A.E.A.-W.M.O. precipitation survey are discussed in chapter 4. The unweighted mean annual composition of rain at tropical island stations fits the line δ D = 4.6 δ 18 indicating a first stage equilibrium condensation from vapour evaporated in a non-equilibrium process. Regional characteristics appear in the weighted means. The Northern hemisphere continental stations, except African and Near East, fit the line δ D = 8.0 δ 18 + 10 as far as the weighted means are concerned (δ D = 8.1 δ 18 + 11 for the unweighted) corresponding to an equilibrium Rayleigh condensation from vapour, evaporated in a non-equilibrium process from S.M.O.W. The departure from equilibrium vapour seems even higher in the rest of the investigated part of the world. At most stations the δ D and varies linearily with δ 18 with a slope close to 8, only at two stations higher than 8, at several lower than 8 (mainly connected with relatively dry climates). Considerable variations in the isotopic composition of monthly precipitation occur at most stations. At low latitudes the amount effect accounts for the variations, whereas seasonal variation at high latitudes is ascribed to the temperature effect. Tokyo is an example of a mid latitude station influenced by both effects. Some possible hydrological applications are outlined in chapter 5. DOI: 10.1111/j.2153-3490.1964.tb00181.x

7,081 citations

Journal ArticleDOI
26 May 1961-Science
TL;DR: The relationship between deuterium and oxygen-18 concentrations in natural meteoric waters from many parts of the world has been determined with a mass spectrometer and shows a linear correlation over the entire range for waters which have not undergone excessive evaporation.
Abstract: The relationship between deuterium and oxygen-18 concentrations in natural meteoric waters from many parts of the world has been determined with a mass spectrometer. The isotopic enrichments, relative to ocean water, display a linear correlation over the entire range for waters which have not undergone excessive evaporation.

6,721 citations

Book
01 Jun 1989
TL;DR: The chemical composition of natural water is derived from many different sources of solutes, including gases and aerosols from the atmosphere, weathering and erosion of rocks and soil, solution or precipitation reactions occurring below the land surface, and cultural effects resulting from human activities.
Abstract: The chemical composition of natural water is derived from many different sources of solutes, including gases and aerosols from the atmosphere, weathering and erosion of rocks and soil, solution or precipitation reactions occurring below the land surface, and cultural effects resulting from human activities. Broad interrelationships among these processes and their effects can be discerned by application of principles of chemical thermodynamics. Some of the processes of solution or precipitation of minerals can be closely evaluated by means of principles of chemical equilibrium, including the law of mass action and the Nernst equation. Other processes are irreversible and require consideration of reaction mechanisms and rates. The chemical composition of the crustal rocks of the Earth and the composition of the ocean and the atmosphere are significant in evaluating sources of solutes in natural freshwater. The ways in which solutes are taken up or precipitated and the amounts present in solution are influenced by many environmental factors, especially climate, structure and position of rock strata, and biochemical effects associated with life cycles of plants and animals, both microscopic and macroscopic. Taken together and in application with the further influence of the general circulation of all water in the hydrologic cycle, the chemical principles and environmental factors form a basis for the developing science of natural-water chemistry. Fundamental data used in the determination of water quality are obtained by the chemical analysis of water samples in the laboratory or onsite sensing of chemical properties in the field. Sampling is complicated by changes in the composition of moving water and by the effects of particulate suspended material. Some constituents are unstable and require onsite determination or sample preservation. Most of the constituents determined are reported in gravimetric units, usually milligrams per liter or milliequivalents

6,271 citations

Journal ArticleDOI
TL;DR: In this paper, Niee's and Solenhofen standards were compared to the Chicago PDB standard for carbon and oxygen isotope ratios, and the correction factors for instrumental effects and for the nature of the mass spectra were derived.

4,071 citations

Book ChapterDOI
01 Jan 1984

3,213 citations