近日，中国石油大学葸克来团队报道了深湖盆地高频氧化还原波动及其对有机碳埋藏的影响——鄂尔多斯盆地三叠系延长组页岩微米级纹层记录。相关论文发表在2026年7月21日出版的《中国科学：地球科学》杂志上。

传统上，还原条件被认为是有利于深湖相环境中有机碳埋藏的因素。然而，这类环境中的沉积事件可引发高频氧化还原波动，显著影响有机质的产率和保存。然而，在页岩中识别此类高频事件信号仍颇具挑战性。

研究组聚焦鄂尔多斯盆地三叠系延长组长7?亚段富有机质页岩。通过对微米级纹层组成和结构的详细表征，发现莓状黄铁矿的周期性产出忠实记录了深湖相环境中高频氧化还原变化的过程。研究组提出了一种利用莓状黄铁矿原位显微拉曼光谱参数（峰位移和半高宽）指示湖盆环境变化的新方法。结合莓状黄铁矿粒径、原位δ³⁴S同位素和微量元素地球化学，研究组成功解码了深湖相环境中的高频氧化还原波动及其对高效有机碳埋藏的控制作用。

研究组的数据表明，受间歇性物源供给和波动的湿度影响，周期性发育的异重流形成了由“粉砂级长英质矿物”和“富有机质黏土”组成的二元纹层。在洪水期，粉砂级长英质矿物的输入带来了营养物质和氧气，从而提高了初级生产力。在间洪水期，黏土沉积和还原条件有利于有机质的保存。这种“生产-保存”耦合机制促进了有机碳的高效积累。研究组建立的分析方法将古环境记录的分辨率提高到微米级别，为理解控制有机碳埋藏的基本过程提供了新见解。

附：英文原文

Title: High-frequency redox fluctuations in deep-lacustrine basin <A3B2 pi6>and their impact on organic carbon burial: Records from micrometer-scale laminae in the Triassic Yanchang <A3B2 pi6>Formation Shale, Ordos Basin

Author: Ke LI, Kelai XI, Yingchang CAO, Zhe ZHAO, Xiujuan WANG, Miruo LIN, Keyu LIU, Fang HAO

Issue&Volume: 2026/07/21

Abstract: Traditionally, the reducing conditions were regarded as favorable factors for the organic carbon burial in deep-lacustrine environments. However, sedimentary events in these settings can trigger high-frequency redox fluctuations, significantly influencing the productivity and preservation of organic matter. Yet, identifying such high-frequency event signals in shale remains challenging. This study focuses on the organic-rich shale of the Chang 73 sub-member, Triassic Yanchang Formation, in the Ordos Basin. Through detailed characterization of micrometer-scale laminae composition and texture, we discovered that the cyclic occurrence of framboidal pyrite faithfully records the processes of high-frequency redox variations in the deep-lacustrine environment. A new approach utilizing in situ micro-Raman spectral parameters (peak shift and full width at half maximum) of framboidal pyrite was proposed to indicate the environmental changes of lacustrine basins. Combined with framboidal pyrite size, in situ δ34S isotope, and trace element geochemistry, high-frequency redox fluctuations were decoded successfully in the deep-lacustrine environments and their control on efficient organic carbon burial. Our data indicate that, influenced by intermittent material supply and fluctuating humidity, periodically developed hyperpycnal flows led to the formation of binary laminae composed of “silt-grained felsic minerals” and “organic-rich clay”. During flood episodes, silt-graded felsic minerals input delivered nutrients and oxygen, thereby enhancing primary productivity. In the inter-flood periods, clay deposition and reducing conditions facilitated organic matter preservation. This coupled “production-preservation” mechanism facilitated efficient organic carbon accumulation. The analytical methods established in this study enhance the resolution of paleoenvironmental records to the micrometer level, offering new insights into the fundamental processes controlling organic carbon burial.

DOI: 10.1007/s11430-025-1987-9

Source: https://www.sciengine.com/SCES/doi/10.1007/s11430-025-1987-9