Age of the basal 'Lower Old Red Sandstone' Stonehaven Group of Scotland: The oldest reported air-breathing land animal is Silurian (late Wenlock) in age
Age of the basal 'Lower Old Red Sandstone' Stonehaven Group of Scotland: The oldest reported air-breathing land animal is Silurian (late Wenlock) in age
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苏格兰斯通黑文群的基底“下老红砂岩”的年龄：报道的最古老的呼吸空气的陆地动物的年龄是志留纪（文洛克晚期）
DOI：
10.1144/jgs2023-138
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发表时间：
2023
影响因子：
2.7
通讯作者：
Wellman C
中科院分区：
文献类型：
--
作者：
Wellman C
苏格兰米德兰山谷的基底上志留统-下泥盆统“下老红砂岩”矿床含有几个重要的化石生物群，包括来自考伊港鱼床的化石生物群。该生物群具有重要意义，因为它代表了已知最古老的化石陆地生态系统之一，并且包括报道的最古老的呼吸空气的陆地动物（多足类纽马尼肺藻）。根据分散孢子的生物地层证据，该生物群的年龄可追溯到文洛克晚期（志留纪晚期）。然而，最近，基于锆石的 238U-206Pb 辐射分析，这一年龄限制受到了挑战，并提出这些矿床要年轻得多（早泥盆世：洛赫科阶）。该提议对于（1）早期陆地生态系统的组成和性质以及（2）与地体增生时间和“下部老红砂岩”沉积开始的地质环境具有严重影响。我们报告了新发现的分散孢子组合和额外的锆石数据，证实了文洛克晚期（志留纪晚期）年龄。这一年龄指定确立了考伊港鱼床生物群的重要性，并且更符合其生物组成和区域地质环境。
The basal upper Silurian–Lower Devonian ‘Lower Old Red Sandstone’ deposits of the Midland Valley of Scotland contain several important fossil biotas, including that from the Cowie Harbour Fish Bed. This biota is of great significance because it represents one of the oldest known examples of a fossilized terrestrial ecosystem and includes the oldest reported air-breathing land animal (the myriapodPneumodesmus newmani). Based on biostratigraphical evidence from dispersed spores this biota is dated as late Wenlock (late Silurian) in age. Recently, however, this age constraint was challenged, based on238U–206Pb radiometric analysis of zircons, and it was proposed that these deposits are much younger (Early Devonian: Lochkovian). This proposal has serious implications regarding (1) the composition and nature of early terrestrial ecosystems and (2) the geological setting with respect to the timing of terrane accretion and the onset of ‘Lower Old Red Sandstone’ sedimentation. We report on newly discovered dispersed spore assemblages and additional zircon data that confirm a late Wenlock (late Silurian) age. This age designation establishes the importance of the biota of the Cowie Harbour Fish Bed and is more compatible with both its biotic composition and the regional geological setting.