Abstract The base of the Cambrian System is recognized by a characteristic (marine) trace fossil suite assigned to the Treptichnus pedum Biozone, which signals increasing complexity of animal behaviour and demarcates the Cambrian from the (older) Ediacaran System (Proterozoic Eonathem). Ichnotaxa of the T. pedum Biozone are not the earliest trace fossils, and are preceded in the latest Proterozoic by a progressive increase in the diversity of trace-producing organisms and the communities they comprised, the structural and behavioural complexity of the trace fossils, and even the depth of burrowing in sediments. Parallels can be drawn with the increasing complexity of subsurface structures associated with human cities, which also reflect evolution of an increasingly complex community. Before the nineteenth century, these structures were limited and simple, but beginning with the development of London in the mid-nineteenth century as the world’s first megacity, subsurface structures have become increasingly complex, reflecting the technology-driven behaviour of twentieth- and twenty-first-century humans.

Abstract Trace fossils or ichnofossils are the fossilized tracks, excavations, and domiciles of animals. In general, these are taken to represent the vestiges of animal behavior. As such, trace fossils can be related to animal coping strategies in sedimentary environments. Those strategies can be associated with sedimentary / environmental conditions. Burrows are classified according to their overall morphologies. The morphology of trace fossils is evaluated using the following nomenclature: shafts, tunnels, tubes, lining, infill, meniscae, spreite, and trample. The shape and form of trace fossils is also considered. Behavioral classifications are inferred, and provide a higher level of organization for ichnofossils. Behavioral inferences form the basis for the definition of ichnofacies. Preservation of trace fossils depends on sedimentological and diagenetic factors. The fundamental physical parameters regarding ichnofossil preservation are the net sedimentation rate, the biogenic mixing rate, and the magnitude of physical reworking. Physical parameters relate to the presence or absence of textural contrast. Ichnofossil diagenesis comprises: (1) cementation of a finer-grained burrow wall [preferred tube cementation]; (2) cement precipitation or cement dissolution within a coarser-grained burrow fill [preferred burrow cementation]; (3) cement precipitation or dissolution adjacent to an ichnofossil [fabric-mimicking hypoburrow cementation]; and (4) concretion formation [nodular hypoburrow cementation]. This paper also documents the various animal responses to physical processes, referred to herein as “process ichnology”. Considered are ichnofossils associated with high or sporadically high sedimentation rates, the use of ichnofossils for their potential in revealing the cohesiveness of a substrate at the time of burrowing, trace fossils and burrow linings as sediment traps, and finally, trace fossils as penecontemporaneous strain indicators. Other general applications of ichnology, including ichnofacies, stratigraphic utility, and reservoir analysis, are considered. These reside in a well-established framework and thus serve as a brief summary of previously conducted research.

Abstract Ichnology is the study of trace fossils, which preserve the activity of animals as recorded by their tracks, trails, burrows and borings. Rather than giving information about the taxonomic affinities of a given type of organism, trace fossils yield information about an animal's behaviour in response to its environment. Trace fossils are almost always in situ , are commonly specific to a particular suite of environmental conditions, can be readily studied in core and may be common in strata devoid of body fossils. They are invaluable in thorough sedimentological analysis and are thus of great utility to petroleum geologists, sedimentologists and palaeontologists alike. Over the last 30 years or so, ichnology has been a rapidly developing branch of palaeontology that not only has important applications in classical palaeobiology (e.g. Donovan 1994 ; Bromley 1996 ), but is also of great value in the more applied disciplines of palaeoenvironmental and stratigraphical analysis. Much progress has been made in the development of this discipline, but there remain many fascinating and challenging issues, particularly in combining ichnology and sedimentology. This book aims to provide a summary of recent progress, with an up-to-date summary of most themes in modern ichnology. The volume stems from the 2003 Lyell Meeting sponsored by The Geological Society, The Palaeontological Association, BP, Shell, Exxon Mobil, Statoil, Total and Amerada Hess. The introductory paper by McIlroy (a) provides a condensed summary of some ichnological themes and frontiers, and outlines a practical approach for the description of trace fossils and