| 松嫩平原东南缘罗家窝棚组陆相红层的致色机理 |
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| 引用本文：刘晓萌,孟 杰,谢远云,李本仙,迟云平,康春国,孙 磊,魏振宇,刘海金,汪烨辉,吴 鹏.2025.松嫩平原东南缘罗家窝棚组陆相红层的致色机理[J].地球学报,46(4):815-826. |
| DOI：10.3975/cagsb.2024.112001 |
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| 作者 | 单位 | E-mail | | 刘晓萌 | 哈尔滨师范大学地理科学学院, 黑龙江哈尔滨 150025 | 2811997948@qq.com | | 孟 杰 | 哈尔滨师范大学地理科学学院, 黑龙江哈尔滨 150025；哈尔滨师范大学寒区地理环境监测与空间信息服务黑龙江省重点实验室, 黑龙江哈尔滨 150025 | mengjie26@126.com | | 谢远云 | 哈尔滨师范大学地理科学学院, 黑龙江哈尔滨 150025
哈尔滨师范大学寒区地理环境监测与空间信息服务黑龙江省重点实验室, 黑龙江哈尔滨 150025 | | | 李本仙 | 吉林大学地球科学学院, 吉林长春 130012 | | | 迟云平 | 哈尔滨师范大学地理科学学院, 黑龙江哈尔滨 150025
哈尔滨师范大学寒区地理环境监测与空间信息服务黑龙江省重点实验室, 黑龙江哈尔滨 150025 | | | 康春国 | 哈尔滨学院地理系, 黑龙江哈尔滨 150086 | | | 孙 磊 | 哈尔滨师范大学地理科学学院, 黑龙江哈尔滨 150025
哈尔滨师范大学寒区地理环境监测与空间信息服务黑龙江省重点实验室, 黑龙江哈尔滨 150025 | | | 魏振宇 | 哈尔滨师范大学地理科学学院, 黑龙江哈尔滨 150025 | | | 刘海金 | 哈尔滨师范大学地理科学学院, 黑龙江哈尔滨 150025 | | | 汪烨辉 | 哈尔滨师范大学地理科学学院, 黑龙江哈尔滨 150025 | | | 吴 鹏 | 湖南科技大学地球科学与空间信息工程学院, 湖南湘潭 411201 | |
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| 基金项目:国家自然科学基金项目(编号: 42171006); 黑龙江省自然科学基金项目(编号: ZD2023D003) |
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| 中文摘要:陆相红层在全球分布广泛, 被认为是特殊环境的产物, 而关于松嫩平原陆相红层的致色机理研究较为薄弱。本文以松嫩平原东南缘的罗家窝棚组陆相红层为研究对象, 对采集的样品进行元素地球化学、岩石学、矿物学分析, 探讨红层的致色机制以及所指示的环境背景。通过对样品的地球化学分析, 显示罗家窝棚组陆相红层样品的Fe2O3即全铁平均含量较高(6.76%); 全岩X射线衍射分析、岩石薄片鉴定以及漫反射光谱(DRS)分析显示样品中的赤铁矿含量较高, 显示出赤铁矿为红层的致色矿物; 岩石薄片分析中赤铁矿在颗粒间的不完全填充以及潜在红层物源区的缺失, 指示赤铁矿为自生成因; 高分辨率透射电镜(HRTEM)分析显示赤铁矿附着于黏土矿物高岭石表面, 而高岭石在迁移过程中可作为铁氧化物的运输媒介, 因此认为部分赤铁矿是由其他黏土矿物转化, 最终在形成高岭石的过程中晶格中铁淋失并在高岭石表层吸附氧化而成; 样品Fe2O3含量较其他红层剖面偏高, 而黏土矿物晶格内的铁是有限的, 结合CIA、A-CN-K三元图解以及主量元素UCC标准化图解认为罗家窝棚红层处于化学风化的最终阶段, 而另一部分铁作为不易迁移元素逐渐累积。综上, 罗家窝棚组陆相红层的致色矿物为自生赤铁矿, 而形成赤铁矿的铁离子来源有两种, 一种为黏土矿物转化过程中结构铁的淋失, 另一种为其他含铁矿物化学风化过程中铁的逐渐累积。依据赤铁矿以及高岭石的气候指示意义、年均温MAT、年降水量MAP以及主量元素的强烈淋溶, 推测罗家窝棚组红层剖面可能为东亚夏季风增强暖湿背景下干湿交替的产物。 |
| 中文关键词:陆相红层 罗家窝棚组 致色矿物 赤铁矿 高岭石 |
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| Coloration Mechanism of Continental Red Bed in the Luojiawopeng Formation on the Southeastern Edge of the Songnen Plain |
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| Abstract:Continental red beds are widely distributed worldwide and are considered to be the product of a special environment. However, research on the coloration of continental red beds in the Songnen Plain is insufficient. In this study, we considered the red bed of the Luojiawopeng Formation on the southeastern edge of the Songnen Plain as the research object; analyzed the geochemistry, petrology, and mineralogy of the collected samples; and explored the coloration mechanism and environmental background. Geochemical analysis of these samples showed that the Fe2O3 content of the Luojiawopeng Formation red bed was relatively high (6.76%), and whole-rock X-ray diffraction analysis, thin section identification, and diffuse reflection spectrum (DRS) analysis indicated that the content of hematite was extremely high, indicating that hematite is a red bed coloring mineral. The incomplete filling of hematite between grains in the thin-section analysis and the absence of local red bed provenance indicates that the hematite is of authigenic origin. High-resolution transmission electron microscopy (HRTEM) analysis showed that hematite adheres to the surface of the clay mineral kaolinite, which can serve as a transportation medium for iron oxides during migration. Therefore, it is believed that some hematite was transformed from other clay minerals, and the iron in the crystal lattice was leached, adsorbed, and oxidized on the surface of the kaolinite during its formation. The Fe2O3 content of this sample was higher than that of the other red beds, whereas the iron in the clay mineral lattice was limited. Combining CIA, A-CN-K ternary diagram, and UCC standardization, we concluded that the Luojiawopeng red bed is in the final stage of chemical weathering, while besides clay mineral source another part of iron is gradually accumulated as an immobile element. Luojiawopeng continental red bed of the coloration mineral is authigenic hematite, and the iron comes from the gradual accumulation of secondary clay mineral transformation, leaching, and chemical weathering. Based on the climatic significance of hematite and kaolinite, MAT, MAP, and the strong leaching of major elements, we infer that the Luojiawopeng red bed tends to be the product of alternating dry and wet weather under the warm and wet background of the East Asian summer monsoon. |
| keywords:continental red bed Luojiawopeng Formation chromogenic mineral hematite kaolinite |
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