Krol Sandstone-black shale association of the Lesser Himalayan Neoproterozoic succession, Himachal Pradesh, India: An unexplored record of the hothouse aftermath
Krol Sandstone-black shale association of the Lesser Himalayan Neoproterozoic succession, Himachal Pradesh, India: An unexplored record of the hothouse aftermath
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印度喜马偕尔邦小喜马拉雅新元古代系列的克罗尔砂岩-黑色页岩组合：温室后果的未勘探记录
DOI：
10.1016/j.marpetgeo.2022.105723
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发表时间：
2022
影响因子：
4.2
通讯作者：
Kubota Masahiro
中科院分区：
文献类型：
--
作者：
Dey Sumit;Dasgupta Prabir;Das Kaushik;Goto Kosuke T.;Matin Abdul;Suzuki Katsuhiko;Kubota Masahiro
引用推断的冰川混积岩-盖碳酸盐组合作为雪球地球假说的明确证据，无法解释融化开始和碳酸盐沉积最佳温度恢复之间中间时期沉积记录的缺失。小喜马拉雅新元古代序列的克罗尔砂岩-黑色页岩组合代表了温室后果的初始阶段。黑色页岩是成冰期晚期冰川初始融化阶段形成的海洋缺氧的产物。随着融化过程的继续，一些先前存在的风沙沉积物（位于上陆架区域融化的冰盖上）重新流动，导致更深的陆架扇（克罗尔砂岩）在这片黑色页岩上堆积。岩石学成分、碎屑锆石年龄和古水流方向，结合现有的重建古地理，表明克罗尔砂岩的组成砂粒可能源自南澳大利亚新元古代晚期的风成砂片，该砂片形成于晚成冰期埃拉蒂纳冰川作用的最冷阶段。这些发现不仅记录了温室后果初始阶段的沉积记录，而且为古地理重建开辟了新的证据。
Citation of the inferred glacial diamictite-cap carbonate association, as the unequivocal evidence of the Snowball Earth hypothesis, fails to explain the absence of the sedimentary record of the intermediate period between the onset of thawing and the restoration of the optimum temperature for carbonate deposition. The Krol Sandstone-black shale association of the Lesser Himalayan Neoproterozoic succession, represents the initial phase of that hothouse aftermath. The black shale is the product of oceanic anoxia developed during the initial thawing phase of late Cryogenian glaciation. As the melting process continued, remobilization of some pre-existing aeolian sand sheet deposit, lying on the melting ice sheet in the upper shelf region, led to the accumulation of deeper shelf fans, the Krol Sandstone, over this black shale. The petrographic composition, detrital zircon age, and the palaeoflow directions, in conjunction with the available reconstructed paleogeography, suggest that the constituent sand particles of Krol Sandstone were possibly derived from a Late Neoproterozoic aeolian sand sheet of South Australia formed during the coldest phase of the late Cryogenian Elatina glaciation. These findings not only document the sedimentary record of the initial phase of the hothouse aftermath, but also open up a new line of evidence for paleogeographic reconstruction.