John R. Beckett

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Introduction: The partitioning of elements between olivine and liquid is key to understanding igneous processes in mafic and ultramafic systems [1]. The landmark study of Roeder and Emslie [2] concluded that the olivine (ol)-liquid (liq) exchange coefficient, KD;Fe2þ Mg = (FeO/MgO) ol / (FeO/MgO) (by weight), is 0.30 ± 0.03, independent of temperature (T)(More)
We measured Ni partitioning between olivine and melt, D Ni , in experiments on mid-ocean ridge basalt (MORB) encapsulated in olivine at pressures from 1atm to 3·0 GPa and temperatures from 1400 to 15508C.We present a series of experiments where the temperature (T) at each pressure (P) was selected so that the liquid composition remained approximately(More)
Meteorites exposed to high pressures and temperatures during impact-induced shock often contain minerals whose occurrence and stability normally confine them to the deeper portions of Earth's mantle. One exception has been MgSiO3 in the perovskite structure, which is the most abundant solid phase in Earth. Here we report the discovery of this important(More)
A calibration procedure is presented for the use of a Y2O3-stabilized zirconia (YSZ) oxygen sensor in 1 atm gas-mixing furnaces in the temperature range 1200–1500°C and 0–8 orders of magnitude below the iron-wüstite (IW) buffer. Corrections to the Nernst equation were obtained by measuring apparent oxygen fugacities of gases in equilibrium with graphite(More)
FORMATION CONDITIONS. S.R. Sutton, S. Simon, L. Grossman, J.S. Delaney, J. Beckett, M. Newville, P. Eng, and M. Rivers. Department of Geophysical Sciences and Consortium for Advanced Radiation Sources, University of Chicago, Chicago, IL 60637 (; Geology Department, Rutgers University, New Brunswick, NJ; Division of Geological &(More)
Chi Ma*, Oliver Tschauner, John R. Beckett, Boris Kiefer, George R. Rossman, Wenjun Liu; Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena CA 91125; High Pressure Science and Engineering Center and Department of Geoscience, University of Nevada, Las Vegas, NV 89154; Department of Chemical and Nuclear Engineering,(More)
(Ca,Na,□)AlSi2O6, TWO HIGH PRESSURE PHASES FROM THE TISSINT MARTIAN METEORITE. Chi Ma, Oliver Tschauner, John R. Beckett, Yang Liu, George R. Rossman, Kirill Zuravlev, Vitali Prakapenka, Przemyslaw Dera, Stanislav Sinogeikin, Jesse Smith, Lawrence A. Taylor; California Institute of Technology, Pasadena, CA 91125, USA; University of Nevada, Las Vegas, NV(More)
Introduction: During a nano-mineralogy investigation of the Acfer 094 carbonaceous chondrite, lakargiite (CaZrO3) was identified as submicrometer inclusions in an isolated hibonite grain in section USNM 7233-1. The hibonite grain is described in Simon and Grossman [1]. Lakargiite is a recently found perovskite-group mineral from hightemperature skarns in(More)