caa a22 4500 445390077 CHVBK 20180317143044.0 cr unu---uuuuu 170323e20110301xx s 000 0 eng 10.1007/s00710-011-0145-y doi (NATIONALLICENCE)springer-10.1007/s00710-011-0145-y Topotaxic relationships between spinel and pyroxene in kelyphite after garnet in mantle-derived peridotites and their implications to reaction mechanism and kinetics [Elektronische Daten] [Masaaki Obata, Kazuhito Ozawa] Kelyphite is a reaction product between garnet and olivine, which was formed by subsolidus reactions upon decompression during the ascent of mantle peridotite. We studied crystallographic relationships among constituent (product) phases of kelyphite - orthopyroxene, clinopyroxene, spinel and reactant phases, garnet and olivine, using EBSD and found that, for a relatively high temperature sample (from Czech Moldanubian), spinel and pyroxenes are in a topotaxic relationship in such a way that spinel {111} coincides with pyroxene (100) and spinel {110} coincides with pyroxene (010); while the topotaxy is incomplete or non for a lower-temperature sample (from western Norway). On the basis of the observed microstructural and crystallographic relationships, we propose a hypothesis that the topotaxic relationship may be established at nucleation stages of the onset of the kelyphitization and that the degree of topotaxy may be related to the transformation temperature and the degree of supersaturation of the reaction. The lower the temperature, the higher the supersaturation and, therefore, more rapid the nucleation becomes, resulting in a more disordered state in topotaxic relationship. Springer-Verlag, 2011 Obata Masaaki Department of Geology and Mineralogy, Graduate school of Science, Kyoto University, 606-8502, Kyoto, Japan aut Ozawa Kazuhito Department of Earth and Planetary Science, Graduate school of Science, University of Tokyo, 7-3-1 Hongo, 113-0033, Tokyo, Bunkyo-ku, Japan aut Mineralogy and Petrology Springer Vienna 101/3-4(2011-03-01), 217-224 0930-0708 101:3-4<217 2011 101 710 https://doi.org/10.1007/s00710-011-0145-y text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00710-011-0145-y text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Obata Masaaki Department of Geology and Mineralogy, Graduate school of Science, Kyoto University, 606-8502, Kyoto, Japan aut NATIONALLICENCE 700 1- Ozawa Kazuhito Department of Earth and Planetary Science, Graduate school of Science, University of Tokyo, 7-3-1 Hongo, 113-0033, Tokyo, Bunkyo-ku, Japan aut NATIONALLICENCE 773 0- Mineralogy and Petrology Springer Vienna 101/3-4(2011-03-01), 217-224 0930-0708 101:3-4<217 2011 101 710 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer