A Giant Boring in a Silurian Stromatoporoid Analysed by Computer Tomography
A Giant Boring in a Silurian Stromatoporoid Analysed by Computer Tomography
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通过计算机断层扫描分析志留纪层孔体中的巨大钻孔
DOI：
10.4202/app.2008.0111
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发表时间：
2008
影响因子：
1.8
通讯作者：
A. Freiwald
中科院分区：
文献类型：
--
作者：
L. Beuck;M. Wisshak;A. Munnecke;A. Freiwald
这项研究描述了最大的已知古生代钻孔痕迹，Osprioneides kampto igen，et isp。十一月，发现于瑞典哥特兰岛上志留纪下部文洛克组（维斯比组）的层孔虫密生层（Densastroma pexisum）。stromatoporoid的物理性质和钻孔的致密微晶填充之间的差异允许应用CT扫描技术对这种罕见的痕迹进行2D和3D可视化。立体技术在这些CT图像和电影上的额外应用增强了其解开空间方向的价值。这种非破坏性的方法具有很大的潜力，为未来的宏观以及微观钻孔分析。痕迹标记，最有可能是一个蠕虫，感染宿主殖民地死后高达120毫米长的钻孔测量直径5-17毫米。在同一层孔虫中，较小的锥虫和古闪虫优先出现在外腔骨中，偶尔也出现在O。坎普托。在地层位置上，O. kampto在时间上遵循“奥陶纪生物多样性大事件”，反映了钻孔物种多样性的增加。然而，120毫米穿透深度的钻孔是古生代的独特发现，直到大约2.6亿年后（Bajocian，中侏罗世），当“中生代海洋革命”导致收敛重新发明作为增强捕食，放牧压力和生态空间竞争的结果时，才被超过。
This study describes the largest known Palaeozoic boring trace, Osprioneides kampto igen, et isp. nov., found within a stromatoporoid Densastroma pexisum from the Upper Visby Formation (lower Wenlock, Silurian) on the island of Gotland, Sweden. Differences between the physical properties of the stromatoporoid and the dense micritic infilling of the borings allowed the application of the CT-scan technology for the 2D and 3D-visualisation of this rare trace. The additional application of a stereoscopic technique on these CT images and movies enhances its value for unravelling spatial orientations. This non-destructive method has a great potential for future macro- as well as microboring analyses. The trace maker, most likely a worm, infested the hosting colony post-mortem with up to 120 mm long borings measuring 5–17 mm in diameter. Smaller forms of Trypanites and Palaeosabella within the same stromatoporoid preferentially occur in the outer coenosteum and occasionally in abandoned borings of O. kampto. The stratigraphic position of O. kampto follows the “Great Ordovician Biodiversification Event” in time, and reflects the increase in diversity of boring species. Borings with penetration depths of 120 mm are, however, unique findings for the Palaeozoic and were not exceeded until some 260 million years later (Bajocian, Middle Jurassic) when the “Mesozoic Marine Revolution” led to convergent reinventions as a result of enhanced predation, grazing pressure, and ecospace competition.