The Marinoan glaciation represents the pinnacle of glacial severity in Earth’s geological history. Deep-water glacial deposits have revealed a complex interplay of at least two glacial advance-retreat cycles. However, the extent to which these glacial episodes are mirrored in shallow-water settings has received less attention. To shed light on this, we undertook an exhaustive lithofacies analysis of three shallow-water sections within the Nantuo Formation in South China. Our findings delineate six distinct lithofacies within the Nantuo Formation: massive diamictite, crudely stratified diamictite, pebbly sandstone, massive sandstone, dropstone-bearing laminated siltstone/mudstone, and laminated mudstone/siltstone. The vertical successions of these lithofacies have allowed us to identify two facies associations indicative of glacial dynamics; they are the ice-grounding line fan facies association and the ice-distal facies association. By juxtaposing our findings with the facies analysis of three deep-water sections, we have established a lateral correlation, confirming the presence of at least two glacial advance and retreat cycles in shallow-water environments. Each glacial advance is marked by the presence of inversely graded massive diamictite, indicative of ice-proximal, glaciomarine conditions. In contrast, each retreat phase is characterized by a fining-upward sequence from siltstone to mudstone, interspersed with dropstones, signifying ice-distal, glaciomarine settings. This study not only underscores the dynamic character of the Marinoan snowball Earth glaciation but also suggests that the glacial oscillations observed in deep-water environments have counterparts in shallow waters. It provides evidence that the scale of the Marinoan glacial fluctuations was not confined to the deep ocean but extended to encompass the entire basin, offering a more comprehensive understanding of the Earth’s climatic and glacial history during this critical period.

中文翻译：

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低温马里诺雪球地球的冰川波动


马里诺冰川作用代表了地球地质史上冰川严重程度的顶峰。深水冰川沉积物揭示了至少两个冰川前进-后退周期的复杂相互作用。然而，这些冰川事件在浅水环境中的反映程度却受到较少的关注。为了阐明这一点，我们对华南南沱组内的三个浅水剖面进行了详尽的岩相分析。我们的研究结果描绘了南陀组内的六个不同的岩相：块状杂岩、粗略分层杂岩、卵石砂岩、块状砂岩、含滴石的层状粉砂岩/泥岩和层状泥岩/粉砂岩。这些岩相的垂直连续使我们能够确定两个表明冰川动力学的相关联;它们是 ICE-GROUNDING Line 扇形相协会和 ICE-远端相协会。通过将我们的发现与三个深水剖面的相分析并置，我们建立了横向相关性，证实了浅水环境中至少存在两个冰川前进和后退循环。每次冰川前进都以存在逆梯度的块状杂岩为标志，这表明冰邻近的冰川海洋条件。相比之下，每个退缩阶段的特点是从粉砂岩到泥岩的向上细化序列，点缀着水滴石，表示冰远端的冰川海洋环境。这项研究不仅强调了马里诺雪球地球冰川作用的动态特征，还表明在深水环境中观察到的冰川振荡在浅水环境中也有对应的。 它提供了证据，证明马里诺冰川波动的规模并不局限于深海，而是扩展到包括整个盆地，从而更全面地了解地球在这个关键时期的气候和冰川历史。