Three-dimensional cooling pattern of a granitic pluton II : The study of deuteric sub-solidus reactions in the Toki granite , Central Japan
Three-dimensional cooling pattern of a granitic pluton II : The study of deuteric sub-solidus reactions in the Toki granite , Central Japan
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花岗岩体的三维冷却模式II：日本中部土岐花岗岩的重氢亚固相线反应研究
DOI：
10.2465/jmps.100129b
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发表时间：
2011
影响因子：
5
通讯作者：
N. Tadao
中科院分区：
文献类型：
--
作者：
T. Yuguchi;T. Tsuruta;T. Nishiyama;Y. Takashi;N. Tadao
通过岩石学研究，揭示了日本中部托木花岗岩亚固体反应的发育和变化，揭示了该分带岩体的三维冷却模式。从托木花岗岩的19个钻孔中采集的样品显示出亚固相反应程度的空间变化特征。在该岩体中，出溶粗化产生了微透长石，包括富含钠长石的片层，而氘粗化则形成了斑透长石、金缕石和反应边缘。氘粗化反应的程度可由斑长岩中钠长石斑的宽度和间距、金金属矿和反应边缘的厚度来评价。这些纹理特征的宽度、间距和厚度随着海拔高度的增加而系统地增加；它们在水平向内的方向上也逐渐增加，在岩体的西部，而在岩体的东部则没有增加。构造发育的系统变化表明，托木花岗岩在深水粗化阶段从顶部和西缘开始有效冷却。三元长石测温表明，氘粗化可能发生在低于500℃的温度下。
Petrographical studies examining the development and variations of sub-solidus reactions recorded in the Toki granite represent the three-dimensional cooling pattern of this zoned pluton in Central Japan. Samples collected from 19 boreholes in the Toki granite show characteristics indicative of spatial variations in the extent of the sub-solidus reactions. Exsolution coarsening has produced microperthite, including albite-rich lamellae, in this pluton, while deuteric coarsening has resulted in the formation of patchperthite, myrmekite, and the reaction rim. The extent of the deuteric coarsening reactions can be evaluated from the width and spacing of the albiterich patch in patchperthite and from the thickness of myrmekite and the reaction rim. The width, spacing, and thickness of these textural features increase systematically with elevation; they also increase gradually in the horizontal inward direction in the western part of the pluton but not in the eastern part of the pluton. The systematic variations in textural development indicate that the Toki granite cooled effectively from the roof and from the western margin during the deuteric coarsening stage. The deuteric coarsening may have occurred at temperatures below 500 °C, as indicated by ternary feldspar thermometry.