Discussion on palaeoecology of the Late Triassic extinction event in the SW UKJournal, Vol. 165, 2008, pp. 319–332
Discussion on palaeoecology of the Late Triassic extinction event in the SW UKJournal, Vol. 165, 2008, pp. 319–332
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《SW UKJournal》中三叠纪晚期灭绝事件的古生态学讨论，第 165 卷，2008 年，第 319-332 页
DOI：
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发表时间：
2008
影响因子：
2.7
通讯作者：
J. Cope
中科院分区：
文献类型：
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作者：
J. Radley;R. Twitchett;L. Mander;J. Cope
乔纳森·拉德利写道：英国南部的Penarth群（晚三叠世，可能在早侏罗世）标志着一次海侵和一条浅的陆表海航道的建立（Hallam & El Shaarawy 1982; Warrington & Ivimey-Cook 1992），受海退-海侵脉冲的影响，以快速相变为特征（Hallam & Wignall 2004; Hesselbo et al . 2004年）。一种有据可查的大型无脊椎动物包括珊瑚、腕足动物、软体动物和棘皮动物（Swift和Martill，1999年）。相发育范围从受风暴影响的浅海泥岩（韦斯特伯里组）向上到钙质泥岩、粉砂岩和基本上为细粒的碳酸盐岩（Lilstock组），显示出极浅的水域条件：波浪涟漪、风暴床、干燥和遗漏表面（Swift 1999 a ; Wignall 2001; Hallam & Wignall 2004）。Lilstock组的大型动物多样性低，通常被归因于浅水中的盐度偏离正常海水，部分内陆环境，与公海隔离（Hallam & El Shaarawy 1982; Swift 1995; Allison & Wright 2005）。然而，广泛出现的狭盐海洋大型化石，如珊瑚和棘皮动物（Swift & Martill 1999）表明盐度波动最轻微（Wignall 2001）。
Mander等人（2008年）提供了高分辨率底栖大型动物数据，主要来自软体动物的大型化石，在英国西南部的两个关键部分的Penarth群内发生了重大的古生态变化。他们详细的研究结果表明，在最上面的韦斯特伯里组-下Lilstock组（科瑟姆段）区间（最新的Rhaetian）内，分类丰富性丧失，其次是一个以最新的Rhaetian或早期Hettangian上Lilstock组（上科瑟姆段-下Langport段）为代表的低丰度区间。他们将这种模式归因于灭绝事件，随后是灭绝后的“死亡区”;后者与负有机碳同位素漂移的开始相吻合，并且在陆地孢粉植物中记录了灭绝事件。相对多样化的贝壳。。
Jonathan Radley writes: The Penarth Group (of Late Triassic and possibly ranging to Early Jurassic age) of the southern UK marks a marine transgression and the establishment of a shallow epicontinental seaway (Hallam & El Shaarawy 1982; Warrington & Ivimey-Cook 1992), influenced by regressive–transgressive pulses and characterized by rapid facies changes (Hallam & Wignall 2004; Hesselbo et al . 2004). A well-documented invertebrate macrofauna includes corals, brachiopods, molluscs and echinoderms (Swift & Martill 1999). Facies developments range from storm-influenced, shallow-marine mudrocks (Westbury Formation) upwards into calcareous mudstones, siltstones and essentially fine-grained carbonates (Lilstock Formation) demonstrating extremely shallow-water conditions: wave ripples, storm beds, desiccation and omission surfaces (Swift 1999 a ; Wignall 2001; Hallam & Wignall 2004). The low-diversity macrofauna of the Lilstock Formation has frequently been attributed to salinities deviating from that of normal seawater within shallow-water, partly landlocked settings, isolated from the open sea (Hallam & El Shaarawy 1982; Swift 1995; Allison & Wright 2005). However, widespread occurrences of stenohaline marine macrofossils such as corals and echinoderms (Swift & Martill 1999) suggest that salinity fluctuations were at most slight (Wignall 2001).
Mander et al . (2008) have presented high-resolution benthic macrofaunal data, principally from molluscan macrofossils, for significant palaeoecological change within the Penarth Group of two key sections in the SW UK. Their detailed results demonstrate loss of taxonomic richness within the uppermost Westbury Formation–lower Lilstock Formation (Cotham Member) interval (latest Rhaetian), followed by a poorly fossiliferous interval represented by the latest Rhaetian or early Hettangian upper Lilstock Formation (upper Cotham Member–lower Langport Member). They attributed this pattern to an extinction event followed by a post-extinction ‘Dead Zone’; the latter coinciding with the onset of a negative organic carbon-isotope excursion, and an extinction event recorded in the terrestrial palynoflora. The relatively diverse shelly …