TY - JOUR
T1 - Effect of NaCrSi2O6 component on Lindsley's pyroxene thermometer
T2 - An evaluation based on strongly metamorphosed LL chondrites
AU - Nakamuta, Y.
AU - Urata, K.
AU - Shibata, Y.
AU - Kuwahara, Y.
N1 - Funding Information:
The authors thank H. Y. McSween, Jr. and E. R. D. Scott for their constructive reviews and suggestions. This study was supported in part by the Grant-in-Aid for Scientific Research (No. 26400518) from the Japan Society for the Promotion of Science.
Publisher Copyright:
© The Meteoritical Society, 2016.
PY - 2017/3/1
Y1 - 2017/3/1
N2 - In Lindsley's thermometry, a revised sequence of calculation of components is proposed for clinopyroxene, in which kosmochlor component is added. Temperatures obtained for the components calculated by the revised method are about 50 °C lower than those obtained for the components calculated by the Lindsley's original method and agree well with temperatures obtained from orthopyroxenes. Ca-partitioning between clino- and orthopyroxenes is then thought to be equilibrated in types 5 to 7 ordinary chondrites. The temperatures for Tuxtuac (LL5), Dhurmsala (LL6), NWA 2092 (LL6/7), and Dho 011 (LL7) are 767–793°, 818–835°, 872–892°, and 917–936°C, respectively, suggesting that chondrites of higher petrographic types show higher equilibrium temperatures of pyroxenes. The regression equations which relate temperature and Wo and Fs contents in the temperature-contoured pyroxene quadrilateral of 1 atm of Lindsley (1983) are also determined by the least squares method. It is possible to reproduce temperatures with an error less than 20 °C (2SE) using the regression equations.
AB - In Lindsley's thermometry, a revised sequence of calculation of components is proposed for clinopyroxene, in which kosmochlor component is added. Temperatures obtained for the components calculated by the revised method are about 50 °C lower than those obtained for the components calculated by the Lindsley's original method and agree well with temperatures obtained from orthopyroxenes. Ca-partitioning between clino- and orthopyroxenes is then thought to be equilibrated in types 5 to 7 ordinary chondrites. The temperatures for Tuxtuac (LL5), Dhurmsala (LL6), NWA 2092 (LL6/7), and Dho 011 (LL7) are 767–793°, 818–835°, 872–892°, and 917–936°C, respectively, suggesting that chondrites of higher petrographic types show higher equilibrium temperatures of pyroxenes. The regression equations which relate temperature and Wo and Fs contents in the temperature-contoured pyroxene quadrilateral of 1 atm of Lindsley (1983) are also determined by the least squares method. It is possible to reproduce temperatures with an error less than 20 °C (2SE) using the regression equations.
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U2 - 10.1111/maps.12808
DO - 10.1111/maps.12808
M3 - Article
AN - SCOPUS:85008469173
SN - 1086-9379
VL - 52
SP - 511
EP - 521
JO - Meteoritics and Planetary Science
JF - Meteoritics and Planetary Science
IS - 3
ER -