Nearly 90% of the Ediacaran Period (635–541 Ma) of the Neoproterozoic is represented by the Doushantuo Formation (DST Fm) in South China. Its lowest Member I is a 3.7 m-thick cap carbonate deposited at the termination of the Cryogenian Marinoan glaciation. The DST Fm consists of alternating organic-rich black shale and thinly bedded dolostone, and it contains some of the oldest records of multi-cellular life and three pronounced negative carbon isotope excursions. The Jiulongwan (JLW) section is a well-studied reference section for these Ediacaran events. Spectral analysis of geochemical data through the lower DST Fm (22.3 m) shows 27 predominant ∼90 cm sedimentary cycles that correspond to 405-ka long eccentricity cycles. The power spectra of the 405-ka tuned Ca and Fe/Ti series show significant peaks at ∼1.2-Ma, 405-ka, 133-ka, 128-ka, 100-ka, 82-ka, ∼31-ka and 29-ka periods, respectively. A 11.16 Ma-long astronomical time scale has been constructed for the lower DST Fm and provide a duration of 1.6 Ma for the cap carbonate (Member I) based on the 405-ka long eccentricity cycle tuning. Using the U-Pb age of 635.2 ± 0.6 Ma for the volcanic ash bed at the Member I/II boundary, we proposed a 636.8 Ma age for the base of the DST Fm. These ages and astronomical timescale provide important new constraints on the subdivision of Ediacaran strata, and have implications for understanding the character of the first negative δ¹³C excursion (EN1). Orbital forcing may have been played an important role for the climate changes and the evolution of Ediacaran multi-cellular life and the carbon cycle variations.

新元古代埃迪卡拉纪（635~541 Ma）近90%以华南陡山沱组（DST组）为代表。其最低的 I 段是一个 3.7 m 厚的碳酸盐帽，沉积在 Cryogenian Marinoan 冰川期的末端。DST Fm 由交替的富含有机物的黑色页岩和薄层白云岩组成，它包含一些最古老的多细胞生命记录和三个明显的负碳同位素偏移。九龙湾 (JLW) 剖面是这些埃迪卡拉纪事件的经过充分研究的参考剖面。通过较低的 DST Fm (22.3 m) 地球化学数据的光谱分析显示 27 个主要的 ∼90 cm 沉积旋回对应于 405-ka 长的偏心率旋回。405-ka 调谐 Ca 和 Fe/Ti 系列的功率谱在~1.2-Ma、405-ka、133-ka、128-ka、100-ka、分别为 82-ka、~31-ka 和 29-ka 时期。基于 405-ka 长偏心率周期调谐，为低 DST 组构建了 11.16 Ma 长的天文时间尺度，并为盖层碳酸盐岩（成员 I）提供了 1.6 Ma 的持续时间。使用 I/II 段边界火山灰层的 U-Pb 年龄 635.2 ± 0.6 Ma，我们提出 DST 组底部的年龄为 636.8 Ma。这些年龄和天文时间尺度为埃迪卡拉纪地层的细分提供了重要的新约束，并且对理解第一个负面的特征具有重要意义 6 Ma 为一、二段边界的火山灰层，我们提出 DST 组底部的年龄为 636.8 Ma。这些年龄和天文时间尺度为埃迪卡拉纪地层的细分提供了重要的新约束，并且对理解第一个负面的特征具有重要意义 6 Ma 为一、二段边界的火山灰层，我们提出 DST 组底部的年龄为 636.8 Ma。这些年龄和天文时间尺度为埃迪卡拉纪地层的细分提供了重要的新约束，并且对理解第一个负面的特征具有重要意义δ ¹³ C 偏移 (EN1)。轨道强迫可能对气候变化、埃迪卡拉纪多细胞生命演化和碳循环变化起到了重要作用。