Albite-biotite zone of the Sanbagawa metamorphic belt in the northwestern part of the Kii Peninsula, Japan
Albite-biotite zone of the Sanbagawa metamorphic belt in the northwestern part of the Kii Peninsula, Japan
复制标题
日本纪伊半岛西北部三波川变质带钠长石-黑云母带
DOI：
10.2465/ganko.92.43
复制
发表时间：
1997
期刊：
影响因子：
--
通讯作者：
H. Maekawa
中科院分区：
文献类型：
--
作者：
Changle Wang;H. Maekawa
在纪伊半岛西北部的三八川变质带中发现了黑云母及其蚀变产物。在先前接受的石榴石带内的区域中的泥质片岩偶尔含有黑云母和/或一种矿物，其在光学上几乎与黑云母相同。后者矿物具有小于6wt%的可变K2 O含量，并且除了低K含量之外具有与生物质相似的化学计量。电子探针和X射线衍射分析表明，该矿物为风化黑云母，其中含有层间蛭石。考虑到这种蚀变含黑云母泥质片岩的位置，黑云母带是新建立的，沿着大日向斜的东西走向轴的狭窄区域。黑云母带泥质片岩中石榴子石对的Fe-Mg分配系数表明纪伊半岛的黑云母带对应于四国中部钠长石-黑云母带的低品位部分。
In the Sanbagawa metamorphic belt in the northwestern part of the Kii Peninsula, occurrences of biotite and its altered products are newly recognized. Pelitic schists in the area within the previously accepted garnet zone occasionally contain biotite and/or a mineral, which is optically almost identical to biotite. The latter mineral has variable K2O contents less than 6 wt%, and has similar stoichiometry to biofite except low-K content. EPMA and XRD analyses suggest that the mineral is weathered biotite, which contains interlayered vermiculite. Taking the localities of such altered biotite-bearing pelitic schists into consideration, the biotite zone is newly established as a narrow region along the east-west trending axis of the Dainichi synform. The Fe-Mg partition coefficients for garnet-chlorite pairs in the pelitic schists of biotite zone indicate that the biotite zone in the Kii Peninsula corresponds to the lower-grade part of the albite-biotite zone in central Shikoku.