![Sample our Earth Sciences journals, sign in here to start your access, latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5930/TOC-Subject-Sample-2021-Earth-Sciences.jpg"})
Abstract
The ichnospecies Cladichnus parallelum consists of upper components characterized by downward branching, decreasingly inclined tubes, and lower components having horizontal, long, parallel tubes formed in the laminated part of a muddy, marly turbidite. The tubes of both components were successively produced, and the lower ones display an annulated fill. The producers of Cladichnus exhibit thigmotactic and phobotactic behavior in that the tubes are regularly spaced apart, do not cross over- or cross-cut, and their orientation is related to the fabric of the turbidite. The tube fill of both components is enriched in terrigenous material and organic matter suggesting selective feeding on the sediment surface, and the tubes do not show any grain sorting around them. The strong compression of the horizontal tubes suggests that the fill initially had high porosity. The producer of Cladichnus parallelum probably took advantage of burrowing in an anoxic setting; microbes likely played a role in converting organic material stored within the tubes or in processing dissolved compounds drained into the highly porous tubes.
ACKNOWLEDGMENTS
The material for this study was collected during joint fieldwork (too) many years ago, financially supported by the Swiss National Science Foundation (grant no. PLPJ 0451522 to AW). Organic matter and carbonate contents were measured by M. Wiesner (Institut für Biogeochemie und Meereschemie, Universität Hamburg, FRG). The figures were drawn and composed by A. Reisdorf (Basel). The photograph of C. fisheri from the Monte Antola Formation was provided by Bruno Rattazzi (Museo Crocefieschi, Genova, Italy), where research by A. Uchman have been sponsored by the Fondazione Luigi, Cesare e Liliana Bertora. A. Uchman got additional support from the Jagiellonian University. E. Olivero (Ushuaia, Argentina) and P. Orr (Dublin, Ireland) critically reviewed the manuscript and provided helpful comments. All these contributions are gratefully acknowledged.