Structure and isotopic composition of carbonate rocks.

1.通过CL-图像方法识别碳酸盐胶结物类型：在最石灰岩中，已识别出海洋成因的不发光边缘胶结物和淡水成因的暗淡至明亮发光、亮晶晶、晶簇状胶结物，如：哥得兰岛的志留纪石灰岩、尼泊尔-喜马拉雅和相马-福岛的侏罗纪石灰岩以及Kikai岛的第四纪琉球石灰岩。屋顶悬垂型，渗流胶结物的特征分区模式也已被确认为志留纪石灰岩的哥特兰岛，这表明胶结作用发生在波动的条件下的Eh和Mn浓度。因此，CL-图像方法已被证明是一个强大的和有用的技术，用于识别各种水泥类型。2.发光度和碳酸盐化学之间的比较：对选定样品的SEM-EDS分析表明，明亮发光的碳酸盐比暗淡到不发光的碳酸盐含有更多的Mn。含锰碳酸盐被认为是在相对还原的环境中形成的。这意味着明亮发光的碳酸盐是在缺氧条件下形成的。3.微量样品的氧、碳和锶同位素组成测定：碳同位素特征（大多数在3 permil以内）表明，碳酸盐胶结作用的主要阶段发生在对海水和大气开放的近地表环境中。在假定近地表成岩作用的前提下，根据氧、锶同位素组成估算了降水温度和海水与地下水的混合比。4.只有在进行了显微结构分析和胶结物类型表征的基础上，化学和同位素分析才能提供有关碳酸盐岩成岩和沉积环境的关键数据。因此，CL成像技术在碳酸盐岩沉积学中具有重要意义。

1. Recognition of types of carbonate cement by means of CL-image method: Non-luminescent rim-cement of marine origin and dull to bright luminescent, sparry, drusy cement of freshwater origin have been recognized in such limest ones as; Silurian limestones of Gotland, Jurassic limestones of Nepal-Himalaya and Soma-Fukushima, and Quaternary Ryukyu Limestone of Kikai Island. Roof-pendant type, vadose cements with characteristic zoned patterns have also been recognized for the Silurian Limestone of Gotland, suggesting that the cementation took place under the fluctuating conditions in terms of Eh and Mn concentration. Thus, CL-image method has been proved to be a powerful and useful technique for identification of various cement types. 2. Comparison between luminosity and carbonate chemistry: SEM-EDS analyses on selected samples have revealed that bright-luminescent carbonate contains more Mn than dull to non-luminescent carbonates. Mn-bearing carbonates are considered to have been formed in relatively reduced environments. This implies that bright-luminescent carbonates were formed under oxygen-deficient conditions. 3. Determination of oxygen, carbon, and strontium isotope compositions for micro-samples: Carbon isotopic signatures, mostly within *3 permil, suggest that major phase of carbonate cementation occurred near-surface environments which were open to sea-water and atmosphere. Supposing the near-surface diagenesis, the temperature of precipitaion and/or mixing ratio of sea- water and ground water are estimated from oxygen and strontium isotopic compositions. 4. Chemical and isotoipic analyses would provide critical data concerning diagenetic and sedimentary environments of carbonates only when the micro-textural analyses and the characterization of cement- types had been done. In this sense, CL-image tecnique is very important in carbonate sedimentology.