Well-preserved skeletons of Paleocene and Eocene scleractinians and octocorals (Polytremacis sp.) from Poland and Ukraine were studied to reveal microborings produced in vivo by coral-associated microendoliths. Microborings (mostly < 5 μm in diameter) are hardly visible, if at all, under a petrographic microscope. Their resin casts are obtained, however, through the epoxy vacuum cast-embedding technique and observed under a scanning electron microscope (SEM). Three-dimensional resin-filled (cast) microborings are also clearly visible under SEM in acid-etched petrographic thin-sections. Backscattered scanning electron microscopy imaging (BSE) is useful for visualization of the microborings during SEM study of both etched and non-etched thin-sections. A simple but very effective method to reveal the dense network of resin casts of microborings is observations of etched thin-sections under the petrographic microscope. Fluorescence microscopy (FL), especially with application of blue and green filters (Nikon’s B-1A and G-2A filter cubes), is recommended if etching thin-sections or polished samples is not possible. However, color contrast between the resin casts and the calcium carbonate of the coral skeleton was strong enough only in some examined thin-sections. The cathodoluminescence microscopy, the other method, does not require the etching of the thin-sections and is potentially useful for detection of microborings filled with calcite cement, although this technique was not applicable for the samples studied. Symbiotic coral-microendolith association (in broad meaning of the term symbiosis) is a common phenomenon in modern corals, but its fossil record is very sparse. This study shows that empty microborings can be common in fossil corals, allowing preparation of the resin casts. Some of the tested methods permit rapid detection of resin-filled microborings in thin-sections even by non-specialists, and selection of samples for SEM studies. Corals from claystones and mudstones, usually less affected by diagenesis, have higher taphonomic potential for preservation of empty microborings than corals from reef facies. The methods discussed here can be also applied for rapid detection of post-mortem microborings occurring in other substrates.

中文翻译：

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检测珊瑚相关微内石产生的微孔的简单方法

对波兰和乌克兰保存完好的古新世和始新世石珊瑚和八珊瑚（Polytremacis sp.）的骨骼进行了研究，以揭示珊瑚相关微内石在体内产生的微孔。在岩相显微镜下，微孔（直径大多< 5 μm）几乎不可见，如果有的话。然而，它们的树脂铸件是通过环氧树脂真空铸件嵌入技术获得的，并在扫描电子显微镜 (SEM) 下观察。在 SEM 下，酸蚀岩相薄片中的三维树脂填充（铸造）微孔也清晰可见。背散射扫描电子显微镜成像 (BSE) 可用于在蚀刻和非蚀刻薄片的 SEM 研究期间可视化微孔。揭示微孔树脂铸件的致密网络的一种简单但非常有效的方法是在岩相显微镜下观察蚀刻薄片。如果无法蚀刻薄片或抛光样品，建议使用荧光显微镜 (FL)，尤其是应用蓝色和绿色滤光片（尼康的 B-1A 和 G-2A 滤光片立方体）。然而，树脂铸件和珊瑚骨架的碳酸钙之间的颜色对比仅在一些检查的薄片中足够强烈。阴极发光显微镜是另一种方法，不需要蚀刻薄片，可用于检测充满方解石水泥的微孔，尽管该技术不适用于所研究的样品。共生珊瑚-微内石组合（共生一词的广义含义）是现代珊瑚中的普遍现象，但其化石记录非常稀少。这项研究表明，空的微孔在化石珊瑚中很常见，可以制备树脂铸件。一些经过测试的方法允许即使是非专家也可以快速检测薄截面中树脂填充的微孔，并选择用于 SEM 研究的样品。来自粘土岩和泥岩的珊瑚通常受成岩作用的影响较小，与来自礁岩相的珊瑚相比，它们在保存空微孔方面具有更高的埋藏潜力。此处讨论的方法也可用于快速检测其他基材中发生的死后微孔。这项研究表明，空的微孔在化石珊瑚中很常见，可以制备树脂铸件。一些经过测试的方法允许即使是非专家也可以快速检测薄截面中树脂填充的微孔，并选择用于 SEM 研究的样品。来自粘土岩和泥岩的珊瑚通常受成岩作用的影响较小，与来自礁岩相的珊瑚相比，它们在保存空微孔方面具有更高的埋藏潜力。此处讨论的方法也可用于快速检测其他基材中发生的死后微孔。这项研究表明，空的微孔在化石珊瑚中很常见，可以制备树脂铸件。一些经过测试的方法允许即使是非专家也可以快速检测薄截面中树脂填充的微孔，并选择用于 SEM 研究的样品。来自粘土岩和泥岩的珊瑚通常受成岩作用的影响较小，与来自礁岩相的珊瑚相比，它们在保存空微孔方面具有更高的埋藏潜力。此处讨论的方法也可用于快速检测其他基材中发生的死后微孔。通常受成岩作用的影响较小，与来自珊瑚礁相的珊瑚相比，它们在保存空微孔方面具有更高的埋藏潜力。此处讨论的方法也可用于快速检测其他基材中发生的死后微孔。通常受成岩作用的影响较小，与来自珊瑚礁相的珊瑚相比，它们在保存空微孔方面具有更高的埋藏潜力。此处讨论的方法也可用于快速检测其他基材中发生的死后微孔。