晚古生代冰期（LPIA）海平面波动的天文驱动力、环境和气候变化之间的联系增加了我们对当前全球海平面变化、气候转变和生物进化的复杂机制和模式的理解。然而，由于地球气候系统的复杂性，冰室时期百万年尺度的海洋和大陆水分传输模式以及碳循环过程尚未明确。本文联合地球物理测井、XRD、总有机碳（TOC）测试、热解，XRF等实验方法与时间序列分析、相关系数（COCO）、演化相关系数（eCOCO）、边缘海洋环境沉积噪音模型、能量拆解分析等数理统计学手段，证实了玛湖凹陷风城组层系保存了米兰科维奇旋回信号，采用时深转换方法建立了风城组“绝对”天文年代标尺，并结合岩性，有机地球化学和古环境特征，明确了风城组烃源岩有机质差异富集的天文主控因素。

结果表明：风城组（300.7~296.8 Ma）沉积时代属于石炭纪宾夕法尼亚亚纪格舍尔阶（Gzhelian）至二叠纪乌拉尔世阿瑟尔阶（Asselian），在地球地质历史中属于冰室时期，且总沉积时限为~3.9百万年（Myr）。通过时间序列分析，相关系数（COCO）和演化相关系数（eCOCO）分析得到风城组一段（F₁）、风城组二段（F₂）、风城组三段（F₃）的最优沉积速率分别为12.2~13.5 cm/kyr、8.7~9.2 cm/kyr，16.7 cm/kyr。基于边缘海洋环境沉积噪音模型（DYNOT和ρ1）揭指示晚石炭-早二叠冰室时期，玛湖凹陷地区相对湖平面经历先升高再逐渐降低最后再升高的过程，与微量元素Fe/Mn，Mn/Ti比值指示的古水深变化趋势相一致，进一步证明了沉积噪声模型在跟踪古湖泊水位变化方面的实用性和稳健性。滤波结果显示：相对湖平面变化、TOC变化、斜率能量变化共同存在~1.1 Myr周期。进一步比对发现，在斜率能量低值区间通常有利于水生浮游藻类的勃发，古生产力增大，在此基础上，升高的水深作为沉积有机质的关键保存条件，最终有机碳掩埋增加。这一结果表明，晚石炭—早二叠世玛湖凹陷的相对湖平面变化可能是由与相对湖平面反相的超长斜率旋回所驱动。研究结果加强了对晚古生代冰期湖面变化与天文诱发的气候变化之间关系的认识，并进一步阐明了在斜率能量周期下碳循环过程，为冰室时期有机质差异富集机质提供科学依据。

The relationship between astronomical driving force, environment and climate change of sea level fluctuation in the Late Paleozoic Ice Age (LPIA) has increased our understanding of the complex mechanism and model of global sea level change, climate change and biological evolution. However, due to the complexity of the earth's climate system, the ocean and continental water transport model and carbon cycle process in the million-year scale during the glacial period have not been clarified. In this paper, geophysical logging, XRD, total organic carbon (TOC) testing, pyrolysis, XRF and other experimental methods are combined with mathematical statistics such as time series analysis, correlation coefficient (COCO), evolution correlation coefficient (ECOCOC), sedimentary noise model of marginal marine environment, power decomposition analysis, etc., which proves that the Milankovic cycle signal is preserved in Fengcheng Formation in Mahu Sag, and the "absolute" astronomy of Fengcheng Formation is established by time-depth conversion method.

The results show that the sedimentary age of Fengcheng Formation (300.7~296.8Ma) belongs to Carboniferous Pennsylvanian sub-Gzhelian to Permian Uralician Asselian, and it belongs to the glacial period in the geological history of the earth, and the total sedimentary time is ~3.9 million years (Myr). Through the analysis of time series, correlation coefficient (eCOCO) and evolution correlation coefficient (ECOCOCO), the optimal sedimentation rates of the first member (F₁), the second member (F₂) and the third member (F₃) of Fengcheng Formation are 12.2~13.5cm/kyr, 8.7~9.2cm/kyr and 16.7cm/kyr respectively. Based on the sedimentary noise models of marginal marine environment (DYNOT and ρ1), it is revealed that the relative lake level in Mahu Sag experienced a process of first rising, then gradually decreasing and then rising, which is consistent with the change trend of paleo-water depths indicated by the ratios of trace elements Fe/Mn and Mn/Ti, which further proves the practicability and robustness of the sedimentary noise model in tracking the change of lake paleo-water level. The filtering results show that the relative lake level change, TOC change and obliquity power change coexist with a period of ~1.1Myr. Further comparison shows that the low obliquity power is usually conducive to the emergence of aquatic phytoplankton and the increase of paleoproductivity. On this basis, the rising water depth is the key preservation condition of sedimentary organic matter, and finally the organic carbon burial increases. This result shows that the change of relative lake level in Mahu Sag in late Carboniferous-early Permian may be driven by the ultra-long obliquity cycle opposite to the relative lake level. The research results strengthen the understanding of the relationship between lake level changes and astronomical-induced climate changes in the late Paleozoic ice age, and further clarify the carbon cycle process under the obliquity power cycle, which provides scientific basis for the differential enrichment of organic matter in the glacial period.