图8. 偏光显微镜下有机质纹层特征
a—龙马溪组灰黑色含硅质泥岩,采样深度3 084.09 m,电阻率为0.1 Ω·m,多个纹层相互堆叠,形成界面不明显的富有机质层;b—龙马溪组黑色页岩,采样深度3 931.72 m,电阻率为10 Ω·m,部分纹层有机质呈块状分布,多个纹层相互堆叠,形成界面不明显的含有机质层;c—龙马溪组黑色页岩,采样深度4 039.3 m,电阻率为15.42 Ω·m,富有机质纹层和含有机质纹层相互堆叠,形成递变层

Fig.8. Characteristics of organic lamination under polarizing microscope
a—a gray-black siliceous mudstone of the Longmaxi Formation with a sampling depth of 3 084.09 m and a measured resistivity of 0.1 Ω·m. Multiple laminas stack each other to form an organic-rich layer with no obvious interface; b—black shale of Longmaxi Formation with a sampling depth of 3 931.72 m and a measured resistivity of 10 Ω·m. Some laminar organic matter is distributed in blocks, and multiple laminates stack each other to form organic matter bearing layers with no obvious interface; c—black shale of Longmaxi Formation with a sampling depth of 4 039.3 m and a measured resistivity of 15.42 Ω·m. The organic-rich laminae and organic-containing laminae stack each other to form graded layers