The continental shelf and slope, with upwelling systems, are usually accompanied by the formation of oxygen minimum zones, thereby stimulating marine paleoproductivity and promoting organic matter (OM) enrichment. However, due to a more oxygen-enriched environment, a distinct paleoecological characteristic, and the uncertainty of upwelling effects, it remains ambiguous whether a similar mechanism of OM preservation occurs in the adjacent carbonate platform. Here, limestone–marl alternations (LMAs) that developed in the Yangtze Carbonate Platform (YCP) during the Middle Permian were selected as the research object and compared with the chert–mudstone alternations developed on the Lower Yangtze continental shelf (LYCS). Both sets of rhythmites belong to the contemporaneous products of the Permian Chert Event in South China.

Considering that the Middle Permian rhythmites in South China contain the Milankovitch record and that upwelling was controlled by astronomically forced monsoons, this study investigated the impact of upwelling on the carbonate platform by adopting astronomical cycle research. Based on GR data, a framework of astronomical cycles was established. The suboxic to anoxic conditions of the YCP are supported by evidence from syngenetic pyrite framboids, Ce/Ce* ranges, and U_EF–Mo_EF covariation. Upwelling geochemical indicators and the detection of a pivotal (∼210-kyr) astronomical cycle regarding upwelling indicate that the YCP was affected by upwelling. The paleoproductivity/OM/fossil-related data exhibit this ∼210-kyr astronomical cycle, and the correspondence between the converted AMs determines that upwelling enhanced marine primary paleoproductivity and OM preservation. However, the intensities of short eccentricity cycles exceed those of the ∼210 kyr cycle in the time series analyses of data from the nearshore YCP. Additionally, the covariations between the upwelling proxy and total fossil content confirm the impact of upwelling on biomass of benthic organisms. Therefore, the (monsoon-driven) upwelling system in the continental shelf can extend to the carbonate platform. After reaching the platform, under the control of a (an) (astronomically forced) climatic–oceanic system, limited upwelling can stimulate primary productivity and marine OM preservation; however, upwelling reduces biomass in the bottom water. In the nearshore side of the platform, detrital dilution likely replaces upwelling as the primary stimulus for productivity. Moreover, this study reveals and explains the ∼200-kyr cycles in the Permian strata of South China for the first time.

具有上升流系统的大陆架和陆坡通常伴随着含氧最低区的形成，从而刺激海洋古生产力并促进有机质（OM）富集。然而，由于更富氧的环境、独特的古生态特征以及上升流效应的不确定性，邻近碳酸盐台地是否存在类似的有机质保存机制仍不清楚。本文以中二叠世扬子碳酸盐台地（YCP）发育的石灰岩-泥灰岩交替（LMA）为研究对象，并与下扬子大陆架（LYCS）发育的燧石-泥岩交替（LMA）进行对比。两组韵律岩均属于华南二叠系燧石事件的同期产物。

考虑到华南中二叠世韵律岩含有米兰科维奇记录，且上升流受天文强迫季风控制，本研究采用天文循环研究，探讨上升流对碳酸盐岩台地的影响。基于GR数据，建立了天文周期的框架。YCP 的低氧到缺氧条件得到了同生黄铁矿 framboid、Ce/Ce* 范围和 U _EF –Mo _EF共变的证据的支持。上升流地球化学指标和有关上升流的关键天文周期（∼210-kyr）的检测表明，YCP 受到上升流的影响。古生产力/OM/化石相关数据显示了这个约210-kyr的天文周期，并且转换后的AM之间的对应关系确定了上升流增强了海洋初级古生产力和OM保存。然而，在近岸 YCP 数据的时间序列分析中，短偏心率周期的强度超过了~210 kyr 周期的强度。此外，上升流代理和总化石含量之间的协变证实了上升流对底栖生物生物量的影响。因此，大陆架（季风驱动的）上升流系统可以延伸到碳酸盐台地。到达平台后，在（天文强迫）气候海洋系统的控制下，有限的上升流可以刺激初级生产力和海洋有机质保护；然而，上升流会减少底层水中的生物量。在平台的近岸一侧，碎屑稀释可能取代上升流成为生产力的主要刺激因素。此外，这项研究首次揭示并解释了华南二叠纪地层的~200 kyr旋回。