Abstract For sample mounting, organic petrology laboratories typically use cold-setting epoxy-resin (e.g., 40 °C, used by Oklahoma Geological Survey, OGS) or heat-setting thermoplastic (e.g., 180 °C, used by U.S. Geological Survey, USGS). Previous workers have suggested a systematic huminite/vitrinite reflectance (VRo) increase was associated with the thermoplastic preparation process, relative to epoxy mounting, which was possibly attributed to moisture loss from organic matter due to the transient high temperatures of plastic mounting. In this study, we evaluated thermal effects to low thermal maturity organic matter from transient exposure to elevated temperatures. A subbituminous coal sample was subjected to long-term (4 to 38 weeks) exposure to temperatures of 85 to 120 °C and afterward evaluated by multiple approaches to test thermal advance [elemental analyses, Rock-Eval pyrolysis, Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), pyrolysis gas chromatography, and petrographic analyses, including huminite/vitrinite reflectance and spectral fluorescence], all of which showed no detectable systematic (statistically insignificant) changes between the original sample and its heat-treated products. We also compared huminite/vitrinite reflectance of six low thermal maturity samples (those most likely to react to transient heating) mounted via both cold-setting epoxy-resin and heat-setting thermoplastic. Results indicate measured VRo of a sample prepared by one mounting process was within the standard deviation of reflectance for the same sample prepared via the other process. Moreover, VRo results were not systematically higher in thermoplastic mounts. Contrary to previous work, these results suggest thermoplastic mounting or other transient exposure to elevated temperatures does not impact thermal maturity estimates from reflectance measurement for low thermal maturity organic samples. Furthermore, the average interlaboratory difference in measured VRo (between OGS and USGS) for the same sample prepared by either epoxy-resin or thermoplastic mounting was 0.038%, about double the average difference between VRo for the same sample prepared via epoxy-resin versus thermoplastic in a single laboratory (0.024%). This result indicates interlaboratory variability impacts VRo measurement reproducibility to the extent that systematic differences could not be observed between thermoplastic and cold-setting sample preparation approaches, even if such differences were present.

中文翻译：

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有机岩石学样品安装：瞬态暴露于高温不会产生热效应

摘要 对于样品安装，有机岩石学实验室通常使用冷固化环氧树脂（例如，40 °C，俄克拉荷马州地质调查局 (OGS) 使用）或热固性热塑性塑料（例如，180 °C，美国地质调查局 (USGS) 使用） ）。以前的工作人员认为，相对于环氧树脂镶嵌而言，系统性腐殖质/镜质体反射率 (VRo) 增加与热塑性制备过程有关，这可能是由于塑料镶嵌的瞬态高温导致有机物质的水分流失。在这项研究中，我们评估了瞬态暴露于高温对低热成熟有机物质的热效应。将亚烟煤样品长期（4 至 38 周）暴露在 85 至 120 °C 的温度下，然后通过多种方法进行评估以测试热进展 [元素分析、Rock-Eval 热解、傅里叶变换红外光谱 (FTIR) )、核磁共振 (NMR)、热解气相色谱和岩相分析，包括腐殖质/镜质体反射率和光谱荧光]，所有这些都显示原始样品与其热处理产品之间没有可检测到的系统性（统计上无关紧要的）变化。我们还比较了通过冷固化环氧树脂和热固化热塑性塑料安装的六个低热成熟度样品（最有可能对瞬态加热做出反应的样品）的腐殖质/镜质体反射率。结果表明，通过一种安装工艺制备的样品的测量 VRo 在通过另一种工艺制备的相同样品的反射率标准偏差内。此外，VRo 结果在热塑性安装件中并没有系统性地更高。与之前的工作相反，这些结果表明热塑性塑料安装或其他瞬态暴露于高温不会影响低热成熟度有机样品的反射率测量的热成熟度估计。此外，对于通过环氧树脂或热塑性塑料镶嵌制备的相同样品，测量的 VRo 的平均实验室间差异（OGS 和 USGS 之间）为 0.038%，大约是通过环氧树脂与热塑性塑料制备的相同样品的 VRo 平均差异的两倍在单个实验室 (0.024%)。