2019 Annual Meeting of Japan Association of Mineralogical Sciences (JAMS)
Sep 19 - Sep 23, 2019Kyushu University Ito Campus
2019 Annual Meeting of Japan Association of Mineralogical Sciences (JAMS)
Sep 19 - Sep 23, 2019Kyushu University Ito Campus
[R8-03]Excess Argon behavior in Dora Maila
*Tetsumaru Itaya1, Hironobu Hyodo2, Takeshi Imayama2(1. HIGC, 2. IFST, Okayama Univ. of Sci.)
Keywords:
Dora-Maira,UHP unit,Excess argon behavior,,Muscovite & K-feldspar Ar-Ar ages
Biotites in the undeformed meta-granites from UHP unit of Dora-Maira record “Excess Argon Wave” (EAW) derived from the deformed white micas in the eclogite and the blueschist units during the exhumation. White micas and K-feldspar in the granite give 70~150 Ma and 20~50 Ma of Ar-Ar age fractions, respectively. These data suggest that white micas, biotites and K-feldspar have trapped successively the EAW during the exhumation of the UHP unit. We will propose a model of the EAW behavior.