M. R. King, Scott E. Botterill, M. Gingras, J. Maceachern
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引用次数: 3
Abstract
Abstract One of the most important contributions that S. George Pemberton made to the field of ichnology was the identification that burrowed firmgrounds associated with the Glossifungites Ichnofacies, commonly demarcate important sequence stratigraphic allogenic surfaces, and more recently described autogenic surfaces. This study considers an outcrop example from the Turonian Ferron Sandstone of central Utah, wherein high and low abundance monospecific suites of Glossifungites isp. are preserved landward of marginal-marine settings, recording colonization in channels under low salinity conditions. High abundances of Glossifungites isp. are associated with sloped areas of the erosional surfaces due to environmental preference, and with clay-rich underlying lithologies owing to either substrate selection or toponomy. These suites of the Glossifungites Ichnofacies demarcate surfaces at the bases of small, stacked channels encased in coastal plain strata. Stacking suggests repeated colonization related to an autogenic process. The enclosing strata and estimated position of the shoreline indicate a more landward affinity than previously reported for the ichnogenus Glossifungites, which is normally related to erosional nearshore processes or, less commonly, to offshore submarine channel development. Glossifungites-like burrows are constructed in modern freshwater settings by subaqueous insects, such as mayfly nymphs, but the trace fossil widths reported from the Ferron Sandstone are up to one and a half times larger than these modern examples. This suggests that the described trace fossils were made by marine-recruited, brackish-water crustaceans that created similar-sized burrows, or if constructed by subaqueous insects, the tracemakers were divergent in size or body plan from known modern tracemakers.
S. George Pemberton对技术领域最重要的贡献之一是发现了与Glossifungites相相关的洞穴状地层,通常划分重要的层序地层异体面,以及最近描述的自生面。本研究考虑了犹他州中部Turonian Ferron砂岩的一个露头例子,其中高丰度和低丰度的单特异性Glossifungites套件。保存在边缘海洋环境的陆地上,记录了低盐度条件下水道的殖民。舌藻的丰度很高。由于环境偏好,它们与侵蚀表面的倾斜区域有关,并且由于基质选择或地形,它们与富含粘土的下伏岩性有关。这些绿藻岩相组在海岸平原地层中被包裹的小而堆积的水道底部划分了表面。堆积表明与自体过程相关的重复定植。封闭地层和海岸线的估计位置表明,与以前报道的相比,海藓属的Glossifungites更倾向于向陆地靠近,这通常与近岸侵蚀过程有关,或者较少与近海海底通道发育有关。在现代淡水环境中,像舌真菌一样的洞穴是由水下昆虫建造的,比如蜉蝣若虫,但从铁砂岩中报告的痕迹化石宽度比这些现代例子大1.5倍。这表明所描述的痕迹化石是由海洋中的咸水甲壳类动物创造的,它们创造了类似大小的洞穴,或者如果是由水下昆虫建造的,那么这些痕迹化石在大小或身体计划上与已知的现代痕迹化石不同。
期刊介绍:
The foremost aim of Ichnos is to promote excellence in ichnologic research. Primary emphases center upon the ethologic and ecologic significance of tracemaking organisms; organism-substrate interrelationships; and the role of biogenic processes in environmental reconstruction, sediment dynamics, sequence or event stratigraphy, biogeochemistry, and sedimentary diagenesis. Each contribution rests upon a firm taxonomic foundation, although papers dealing solely with systematics and nomenclature may have less priority than those dealing with conceptual and interpretive aspects of ichnology. Contributions from biologists and geologists are equally welcome.
The format for Ichnos is designed to accommodate several types of manuscripts, including Research Articles (comprehensive articles dealing with original, fundamental research in ichnology), and Short Communications (short, succinct papers treating certain aspects of the history of ichnology, book reviews, news and notes, or invited comments dealing with current or contentious issues). The large page size and two-column format lend flexibility to the design of tables and illustrations. Thorough but timely reviews and rapid publication of manuscripts are integral parts of the process.