Implications of an integrated late Ediacaran to early Cambrian stratigraphy of the Siberian Platform, Russia
Implications of an integrated late Ediacaran to early Cambrian stratigraphy of the Siberian Platform, Russia
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DOI：
10.1130/b36534.1
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发表时间：
2023-09-01
影响因子：
4.9
通讯作者：
Zhu, Maoyan
中科院分区：
文献类型：
--
作者：
Bowyer, Fred T.;Zhuravlev, Andrey Yu;Zhu, Maoyan
从埃迪卡拉纪末期到寒武纪早期（约550-530 Ma）的过渡，见证了埃迪卡拉纪软体和骨骼生物群的衰落，以及寒武纪骨骼生物群的快速多样化，该生物群在泰伦纽阶（约538.8-521 Ma）化石记录中占主导地位。该区间存在全球广泛的正负δ C-13（碳水化合物）偏移，包括埃迪卡拉系寒武纪边界附近的负δ C-13（碳水化合物）偏移，称为1n/BACE。由于地层学的不完整性和缺乏限制 delta C-13（碳水化合物）化学地层学的辐射年龄，在该区间产生全球复合化学地层学和生物地层学相关性的工作变得复杂。西伯利亚地台广泛且富含化石的开放海洋碳酸盐沉积于埃迪卡拉纪末期至寒武系 2 以外，它们为完善化学地层和生物地层框架提供了独特的档案。在这里，我们提供了来自西伯利亚地台东南部两个部分的新的 delta C-13(carb) 数据，并将这些数据与来自整个西伯利亚地台多个部分的已发表的 delta C-13(carb) 数据进行了综合，这些数据记录了从最新的埃迪卡拉纪到寒武纪系列 2 的近连续碳酸盐沉积。该汇编允许构建两个可能的化学地层年龄模型，这些模型符合岩石地层相关性和平台范围地层堆积的连贯框架模式。然后，这些年龄模型被用来测试化石首次出现的替代校准以及西伯利亚平台上碳酸盐沉积的时空演化。两个模型都支持在最远端的开放海洋剖面中出现了前1n/BACE 假肢动物，并且它们证实了埃迪卡拉纪-寒武纪过渡生物组合，其中包括共存的云甲动物和假肢动物。西伯利亚地台的沉积学和层序地层分析也提供了强有力的证据，表明 1n/BACE 标志着相对海平面逐渐、脉冲式上升的开始，这种上升在整个泰伦纽阶和寒武纪系列 2 中持续存在。
The transition from the terminal Ediacaran to early Cambrian (ca. 550-530 Ma) witnessed both the decline of Ediacaran-type soft-bodied and skeletal biota and the rapid diversification of Cambrian-type skeletal biota, which dominate the Terreneuvian (ca. 538.8-521 Ma) fossil record. This interval hosts globally widespread positive and negative delta C-13(carb) excursions, including a negative delta C-13(carb) excursion near the EdiacaranCambrian boundary termed the 1n/BACE. Efforts to produce a global composite chemo-stratigraphic and biostratigraphic correlation through this interval are complicated by stratigraphic incompleteness and a dearth of radiometric ages with which to constrain delta C-13(carb) chemostratigraphy. Extensive and richly fossiliferous open-marine carbonates of the Siberian Platform were deposited from the terminal Ediacaran to beyond Cambrian Series 2, and they offer a unique archive to refine this chemostratigraphic and bio-stratigraphic framework. Here, we present new delta C-13(carb) data from two sections of the south-eastern Siberian Platform, and we synthesize these with published delta C-13(carb) data from multiple sections throughout the Siberian Platform that record near-continuous carbonate deposition from the latest Ediacaran to Cambrian Series 2. This compilation allowed the construction of two possible chemostratigraphic age models that conform to a coherent framework of lithostratigraphic correlation and platformwide stratal stacking patterns. These age models were then used to test alternative calibrations of fossil first appearances and the spatiotemporal evolution of carbonate deposition on the Siberian Platform. Both models support a pre1n/BACE appearance of anabaritids in the most distal open-marine sections, and they confirm a transitional Ediacaran-Cambrian biotic assemblage that consisted of co-occurring cloudinids and anabaritids. Sedimentologic and sequence stratigraphic analysis on the Siberian Platform also provides strong evidence to indicate that the 1n/BACE marks the onset of a gradual, pulsed rise in relative sea level that was sustained throughout the Terreneuvian and Series 2 of the Cambrian.