Antarctica and Australia were sutured together at the equator during the major pulse of animal biodiversification associated with the Cambrian radiation. However, the lack of detailed systematic chemostratigraphic and biostratigraphic sampling of lower Cambrian sedimentary successions from Antarctica has significantly impeded precise age determination and correlation with Cambrian strata on other palaeocontinents. This study is the first to present integrated, simultaneously sampled biostratigraphic and chemostratigraphic (δ13C isotopes) data from the same measured stratigraphic sections through the lower Cambrian Byrd Group in the Transantarctic Mountains. Shelly fossil assemblages (brachiopods, tommotiids, molluscs, bradoriids, trilobites) from the Holyoake Range and Churchill Mountains facilitate direct correlation with the Dailyatia odyssei Zone of South Australia (Cambrian Stages 3–4), and trilobites provide strong correlation between the Starshot Formation and the Cymbric Vale Formation in western New South Wales. A new ID-TIMS radiometric date of 514.96 ± 0.16 Ma from a tuff in the lower Cymbric Vale Formation is similar to dates from tuff beds in the Third Plain Creek Member of the Mernmerna Formation in the Flinders Ranges, providing an important absolute-age tie point between these lower Cambrian successions. Chemostratigraphic data from the upper Shackleton Limestone in the Holyoake Range capture a negative δ13C excursion that can be correlated to negative values within the multi-peaked MICE (cycles V–VIII in Siberia). Integrated faunal and chemostratigraphic data indicate a Cambrian Stages 3–4 age, giving robust chronostratigraphic context for the upper Shackleton Limestone–Holyoake Formation–Starshot Formation succession for the first time, permitting reconstruction of the depositional history of the lower Cambrian of Antarctica and global correlation of Byrd Group strata.

中文翻译：

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首次对下寒武统伯德群、跨南极山脉和东冈瓦纳内部的相关性进行多代理年代地层学


南极洲和澳大利亚在赤道上被缝合在一起，这是与寒武纪辐射相关的动物生物多样性的主要脉冲。然而，缺乏对南极洲下寒武纪沉积演替的详细系统化学地层学和生物地层学采样，严重阻碍了精确的年龄确定和与其他古大陆寒武纪地层的相关性。这项研究首次提出了来自跨南极山脉下寒武纪伯德群的相同测量地层剖面的综合、同步采样的生物地层学和化学地层学（δ13C 同位素）数据。来自霍利奥克山脉和丘吉尔山脉的贝壳化石组合（腕足类、雄蚜类、软体动物、鹦鹉类、三叶虫）与南澳大利亚的 Dailyatia odyssei 区（寒武纪第 3-4 阶段）有直接关联，而三叶虫在星射组和新南威尔士州西部的 Cymbric Vale 组之间提供了很强的相关性。新的ID-TIMS辐射测年为514.96 ± 0.16 马，距离下镲布里克山谷组的凝灰岩，与弗林德斯山脉Mernmerna组第三平原溪段凝灰岩层的测年相似，为这些下寒武统演替提供了一个重要的绝对年龄联系点。来自 Holyoake 山脉上 Shackleton 石灰岩的化学地层学数据捕获了负 δ13C 偏移，该偏移可以与多峰 MICE 中的负值相关（西伯利亚的周期 V-VIII）。 综合的动物群和化学地层学数据表明寒武纪 3-4 阶段的年龄，首次为上沙克尔顿石灰岩-霍利奥克组-星际射击组演替提供了强有力的年代地层背景，从而可以重建南极洲下寒武统的沉积历史和伯德群地层的全球相关性。