R8：変成岩とテクトニクス

[R8-09] ローソン石青色片岩亜相における輝石-角閃石間のAl-Fe³⁺分配に対する速度論的制約

*薮田 渉¹、平島 崇男² (1. 無所属、2. 京都大学)

キーワード：青色片岩、Na輝石、Na角閃石、地質圧力計

Al-Fe³⁺ distribution between coexisting Na-Px and Na-Amp has been investigated in lawsonite blueschist facies rocks. It is suggested that Al is concentrated in Na-Amp from metabasalts preserving igneous texture, while Al is distributed equally in metacherts and veins, where the two minerals formed in simultaneous crystallization. These findings clearly show an limit of Jd-Qtz-Ab barometry and introduces a new point of view: rock texture, in interpreting chemical compositions of minerals.