Marble has a great potential to understand a history of various geological events occurring during tectonic processes. In order to decode metamorphic–metasomatic records on C–O isotope compositions of marble at mid‐crustal conditions, we conducted a C–O–Sr isotope study on upper amphibolite‐facies marbles and a carbonate–silicate rock from the Hida Belt, which was once a part of the crustal basement of the East Asian continental margin. Carbon and oxygen isotope analyses of calcite from marbles (Kamioka area) and a carbonate–silicate rock (Wadagawa area) show a large variation of δ¹³C [VPDB] and δ¹⁸O [VSMOW] values (from −4.4 to +4.2 ‰ and +1.6 to +20.8 ‰, respectively). The low δ¹³C values of calcites from the carbonate–silicate rock (from −4.4 to −2.9 ‰) can be explained by decarbonation (CO₂ releasing) reactions; carbon–oxygen isotope modeling suggests that a decrease of δ¹³C strongly depends on the amount of silicate reacting with carbonates. The occurrence of metamorphic clinopyroxene in marbles indicates that all samples have been affected by decarbonation reactions. All δ¹⁸O values of calcites are remarkably lower than the marine‐carbonate values. The large δ¹⁸O variation can be explained by the isotope exchange via interactions between marble, external fluids, and/or silicates. Remarkably low δ¹⁸O values of marbles that are lower than mantle value (~+5 ‰) suggest the interaction with meteoric water at a later stage. Sr isotope ratios (⁸⁷Sr/⁸⁶Sr = 0.707255–0.708220) might be close to their protolith values. One zircon associated with wollastonite in a marble thin‐section yields a U–Pb age of 222 ± 3 Ma, which represents the timing of the recrystallization of marble, triggered by H₂O‐rich fluid infiltration at a relatively high‐temperature condition. Our isotope study implies that the upper amphibolite‐facies condition, like the Hida Belt, might be appropriate to cause decarbonation reactions which can modify original isotope compositions of marble if carbonates react with silicates.

中文翻译：

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日本飞ida带大理石中的δ13C–δ18O变化

大理石具有了解构造过程中发生的各种地质​​事件的历史的巨大潜力。为了解码中地壳条件下大理石的C-O同位素组成的变质-变质记录，我们对飞ida山地带的上斜角岩相大理石和碳酸盐-硅酸盐岩进行了C-O-Sr同位素研究。曾经是东亚大陆边缘地壳的一部分。从弹子（冈区域）和碳酸酯-硅酸盐岩（Wadagawa区域）示出δ的大的变化方解石碳和氧的同位素分析¹³ C [VPDB]和δ ¹⁸ -O [VSMOW]值（从-4.4至4.2‰和+1.6至+20.8‰）。低Δ ¹³碳酸盐-硅酸盐岩中方解石的C值（从-4.4到-2.9‰）可以通过脱碳（释放CO ₂）反应来解释。碳-氧同位素模型表明，δ的减少¹³ Ç强烈地依赖于硅酸盐与碳酸盐反应的量。大理石中变质的clinopyroxene的出现表明所有样品都受到脱碳反应的影响。所有δ ¹⁸方解石的O值比所述海洋碳酸盐值显着降低。大δ ¹⁸ ö变化可以通过经由外部流体硅酸盐大理石之间的相互作用，和/或同位素交换进行说明。值得注意的是低δ ¹⁸大理石的O值低于地幔值（〜+ 5‰），表明在稍后阶段与流星水的相互作用。Sr同位素比（⁸⁷ Sr / ⁸⁶ Sr = 0.707255–0.708220）可能接近其原石值。在大理石薄片中，与硅灰石相关的一个锆石产生的U–Pb年龄为222±3 Ma，这代表了在相对高温条件下富H ₂ O流体渗透触发大理石再结晶的时间。我们的同位素研究表明，像飞ida地带这样的上部闪石相条件可能适合引起脱碳反应，如果碳酸盐与硅酸盐反应，则可以改变大理石的原始同位素组成。