A potential global chronostratigraphic boundary for the base of the middle Viséan A potential global chronostratigraphic boundary for the base of the middle Viséan
A potential global chronostratigraphic boundary for the base of the middle Viséan A potential global chronostratigraphic boundary for the base of the middle Viséan
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中维塞安底部的潜在全球年代地层边界 中维塞安底部的潜在全球年代地层边界
DOI：
10.1127/nos/2023/0746
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发表时间：
2023
影响因子：
2.2
通讯作者：
Cózar P
中科院分区：
文献类型：
--
作者：
Cózar P
南坎布里亚陆架三个部分霍尔克亚阶底部附近的高分辨率碳酸盐有孔虫生物地层学可以识别 Cf5α 和 Cf5β 亚带。格鲁宾斯森林 (Grubbins Wood) 最完整的部分几乎没有白云石化。在白疤采石场和巴克疤痕部分，在一个或两个分区的底部分别推断出较小的动物间隙。与 Barker Scar 相比，Grubbins Wood 部分的暴露程度最有限，而 White Scar Quarry 在此区间的暴露程度较大，尤其是子区域的基底层。 Grubbins Wood 剖面由于其特殊的有孔虫记录，更适合为 Ο’5β 亚带底部的中 Viséan 和 Holkerian 边界建立一致的边界层型。然而，巴克疤痕剖面应保留为英国的霍尔克单位层型，霍尔克剖面的底部重新定位在该剖面的较低位置，即 Ο'5β 亚带的底部。白色疤痕是一个合适的单位副层型，填补了巴克疤痕可能存在的动物区系空白和白云石化作用造成的数据空白。丰富的有孔虫组合使得全球与其他区域分区具有良好的相关性，如果在其他国家进行完善，将为中维塞恩地区提供更明确的全球年代地层基底边界。
High-resolution foraminiferal biostratigraphy of carbonates immediately below and near the base of the Holkerian Substage in three sections of the South Cumbria Shelf allows the recognition of the Cf5α and Cf5β subzones. The most complete section at Grubbins Wood is almost free of dolomitisation. At the White Scar Quarry and Barker Scar sections, minor faunal gaps are inferred at the base of one or both subzones, respectively. The Grubbins Wood section has the most limited exposure, whereas White Scar Quarry has extensive exposure of this interval, especially the basal horizons of the subzones, compared to Barker Scar. The Grubbins Wood section, because of its exceptional foraminiferal record is more suitable for the establishment of a coincident boundary stratotype for the mid Viséan and Holkerian boundary at the base of the Ο’5β subzone. However, the Barker Scar section should be retained as the Holkerian unit stratotype for Britain, with the base of the Holkerian repositioned lower in the section, at the base of the Ο’5β subzone. White Scar is a suitable unit-parastratotype, filling data gaps due to possible faunal gaps and dolomitisation at Barker Scar. The rich foraminiferal assemblages allow good global correlation with other regional zonations, which if refined in other countries, would allow a more affirmative global chronostratigraphic basal boundary for the middle Viséan.