R7: Petrology, Mineralogy and Economic geology (Joint Session with Society of Resource Geology)

[R7P-09] Exsolution texture of olivine in gabbroic rocks of oceanic core complexes

*Yunosuke Nishimura¹, Toshio Nozaka¹ (1. Okayama Univ.)

Keywords:olivine, exsolution, gabbro, Atlantis Bank, Atlantis Massif

Diopside + magnetite, magnetite, and ilmenite lamellae occur within olivine grains in gabbroic rocks from Atlantis Bank and Atlantis Massif, in parallel with (100) or occasionally (010) of host olivine. The crystallographic regularity between olivine and lamellae and the variation of Ca contents of host olivine suggest that the lamellae formed via exsolution of olivine. The lamella formation was not directly related to the degree of magmatic evolution but probably related to alteration processes such as fluid infiltration along dislocation walls of olivine.