Prograde and retrograde metamorphism of hematitebearing basic schists in the Sanbagawa belt in central Shikoku
Prograde and retrograde metamorphism of hematitebearing basic schists in the Sanbagawa belt in central Shikoku
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四国中部三波川带含赤铁矿基性片岩的顺变质作用和逆变质作用
DOI：
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发表时间：
1990
期刊：
影响因子：
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通讯作者：
S. Banno
中科院分区：
文献类型：
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作者：
M. Otsuki;S. Banno
中高压变质作用中含赤铁矿基性片岩的矿物组合与温度有关。对于富含赤铁矿、钠长石、白云母和石英的组合，可以用四组分系统处理共生关系，而不遗漏或分组主要组分。
在四国中部的三百川带，含赤铁矿基性片岩中的主要角闪石由温石型、交叉型和斜晶石型转变为角闪石型。闪石的稳定性是在含有另一个过剩相--绿帘石的伪三元体系中用化学方法描述的。由于逆行反应在前进角闪石周围产生低T/P角闪石，许多角闪石在化学性质上是异相的。通过对角闪石分带的检验，可以绘制出一条从前向压力侧通过的逆行P-T轨迹。
The mineral assemblages of hematite-bearing basic schists in intermediate high-pressure metamorphism are temperature dependent. For assemblages with excess hematite, albite, muscovite and quartz, the paragenetic relations can be dealt with in terms of a four-component system, without omitting or grouping major components.
In the Sanbagawa belt in central Shikoku, the dominant amphibole in the hematite-bearing basic schists changes from winchite, via crossite and barroisite to hornblende. The stability of amphibole is described chemographically within a pseudoternary system with another excess phase, epidote. Many amphiboles are chemically heterogeneous owing to retrograde reactions which produced low-T/P amphibole around the prograde amphibole. The examination of amphibole zoning makes it possible to draw a retrograde P-T trajectory which passes on the lower pressure side of the prograde one.