<p>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 <i>in situ</i> 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, <i>in situ</i> 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.</p>