Ichnology of the Ordovician Cruziana rugosa group in Western Europe and in the Near East and its palaeoecological potential for Mediterranean Gondwana

奥陶纪代表了生物圈发生戏剧性变化的时期。由于气候、海洋和外源物质循环的基本转变，海洋生物前所未有的多样化导致了古生态分化和生物-底物相互作用的变化，生物-底物相互作用是许多地质应用的重要工具，例如生物地层学、古地理学、生活和沉积环境的模拟以及它们的区域和跨区域相关性。这种变化是从这一时期开始记录下来的--当时海洋陆架在整个显生界(奥陶纪)达到了最宽的范围--特别是从浅海领域。虽然奥陶纪不同种类的海洋无脊椎动物作为生物地层和古生态工具的重要性已经得到了很好的研究，但到目前为止，奥陶纪遗迹群落的有用性很少被深入研究。尤其是对于广泛分布的没有任何遗体化石的冈底瓦南周沉积，存在着明显的认识差距--填补这一差距必须被列为国际奥陶纪研究的一项主要任务。拟议的项目旨在调查“地中海省”在今天的法国西北部(布列塔尼阿莫里安地块)和近东(土耳其东南部和S约旦，阿拉伯板块)的冈德瓦南陆架区北部的下奥陶统生态动物群，特别是具有特色的Cruziana rugosa群。在项目筹备过程中，项目工作组在上述地区成功地发现了迄今不为人知的Ruziana rugosa群组合的壮观遗迹化石遗址。通过结合古生物-古生物学和沉积相方法的跨学科方法，将有可能捕捉到Cruziana rugosa群的时空特征，并确定其作为地学中的相、古生态、古地理和跨区域对比工具的潜力。修改局部因素将沿着古地理梯度确定，并将导致古纬度多样性转移的重建。在很大程度上，基于西欧和近东/中东新发现的化石遗址的高质量和古地理位置，将通过古生物学和沉积学研究以及古生态、相和古地理结论，开发一个可靠的工具，在冈德瓦南缘北部周缘进行跨区域对比。拟议的项目填补了目前国际上对下奥陶统/中奥陶统生物圈的调查工作以及早古生代生物圈-地圈相互作用的根本质变方面的一个重大空白。

The Ordovician represents a period of dramatic changes in the biosphere. Initiated by fundamental climatic, oceanographic and transitions of exogenic material cycles, an unprecedented diversification of marine life led to palaeoecological differentiation and to changes in the organism-substrate interactions, which are important tools for numerous geological applications, such as biostratigraphy, palaeogeography, modelling of living and depositional environments and their regional and transregional correlation. Such transformations are documented from this period – when marine shelfs reached their widest extension in the entire Phanerozoic (Ordovician) – especially from the shallow marine realm. While different groups of marine invertebrates from the Ordovician period have been well studied with regard to their importance as biostratigraphic and palaeoecological tools, the usefulness of Ordovician ichnocoenoses, however, has so far only rarely been subject of in-depth studies. There is a distinct knowledge gap particularly for the widespread peri-Gondwanan deposits without any body fossil content – the closing of this gap must be classified as a major task of the international Ordovician research. The proposed project aims to investigate the „Mediterranean Province“ of the northern peri-Gondwanan shelf area in present-day NW France (Armorican Massif, Brittany) and in the Near/Middle East (SE Turkey and S Jordan, Arabian Plate) with respect to its Lower Ordovician ichnofauna, in particular to the characteristic Cruziana rugosa group. In preparation to the project, in the above-mentioned areas the project working group succeeded in the discovery of hitherto unknown spectacular trace fossil sites of Cruziana rugosa group assemblages. By an interdisciplinary approach, which combines palaeontological-palaeobiological and sedimentological-facies methods, it will be possible to capture spatiotemporal characteristics of the Cruziana rugosa group and to define their potential as a facies, a palaeoecological, a paleogeographic and a transregional correlation tool in geosciences. Modifying local factors will be identified along a palaeogeographic gradient, and will be result in the reconstruction of palaeo-latitudinal diversity shifts. Largely based on the high quality and the palaeogeographical position of the newly discovered fossil sites in Western Europe and the Near/Middle East a reliable tool for transregional correlation at the northern peri-Gondwanan rim will be developed by palaeontological and sedimentological studies as well as by palaeoecological, facies and palaeogeographical conclusions. The proposed project fills a critical gap in the current international efforts of investigation of the Lower/Middle Ordovician Biosphere and of the fundamental qualitative changes in the biosphere-geosphere interactions in the early Palaeozoic.