Chemical mass balance in a reaction zone between serpentinite and metapelites in the Nishisonogi metamorphic rocks, Kyushu, Japan: Implications for devolatilization
Chemical mass balance in a reaction zone between serpentinite and metapelites in the Nishisonogi metamorphic rocks, Kyushu, Japan: Implications for devolatilization
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DOI：
10.1111/j.1440-1738.2007.00556.x
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发表时间：
2007-03
期刊：
影响因子：
1.5
通讯作者：
Y. Mori;T. Nishiyama;T. Yanagi
中科院分区：
文献类型：
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作者：
Y. Mori;T. Nishiyama;T. Yanagi
在日本九州西曾木变质岩中，在蛇纹岩和泥质片岩之间常发现厚度为0.5- 10.0m的反应带。从蛇纹岩到泥质片岩，每个反应带几乎由滑石+碳酸盐、阳起石（或碳酸盐+石英）、滑石、白云母和钠长石的单矿物或双矿物层组成。菱镁矿+石英脉从滑石+碳酸盐岩层延伸到蛇纹岩中，而白云石脉从白云母层延伸到泥质片岩中。这些矿脉被具有定向生长特征的半自形矿物充填。原生流体包裹体在反应带和矿脉中产生相同的均一化温度（145-150°C），表明它们是同时形成的。使用等离子体方法进行的质量平衡计算表明，相对于原岩，反应区中的SiO2、MgO、H2O和K2 O被耗尽。这些组分可能是在反应区形成过程中作为流体从反应区中提取出来的。
Abstract Reaction zones of 0.5–10.0 m thick are commonly observed between serpentinite and pelitic schist in the Nishisonogi metamorphic rocks, Kyushu, Japan. Each reaction zone consists of almost monomineralic or bimineralic layers of talc + carbonates, actinolite (or carbonates + quartz), chlorite, muscovite and albite from serpentinite to pelitic schist. Magnesite + quartz veins extend into the serpentinite from the talc + carbonates layer, while dolomite veins extend into the pelitic schist from the muscovite layer. These veins are filled by subhedral minerals with oriented growth features. Primary fluid inclusions yield the same homogenization temperatures (145–150°C) both in the reaction zone and in the veins, suggesting their simultaneous formation. Mass‐balance calculations using the isocon method indicate that SiO2, MgO, H2O and K2O are depleted in the reaction zone relative to the protoliths. These components were probably extracted from the reaction zone as fluids during the formation of the reaction zone.