Report of the Second International Ichnofabric Workshop in Utah, U.S.A.

Abstract

The concept of ichnofabric is ten years old! Yes, it is only a decade ago that the term was introduced in the literature, and it is indeed remarkable how much progress we have seen in ichnofabric research, and in ichnology as a whole, in these years. Much of this progress has been stimulated by the oil industry, which continues to emphasize the need to understand trace fossils and bioturbation fabrics in vertical, two-dimensional section in core. Logging of sedimentary rocks in core is being undertaken on such a large scale, and employs so many geologists, that this aspect of sedimentary fabric recognition and interpretation is coming to dominate large sectors of sedimentology. The research that this logging activity is inspiring greatly benefits ichnology in general, and has boosted our interest in ichnofabric analysis in particular. Several ichnologic approaches to core are available, including the identification of individual trace fossil taxa, of discrete assemblages and suites, and of ichnofacies. The ichnofabric approach is most applicable in rocks having high levels of bioturbation, and its advantages include close relationship of the depositional environment to bioturbational style, the identification of cross-cutting relationships and tiering, and thereby the analysis of community structure in completely bioturbated rocks. In August, 1993, an enthusiastic group of ichnologists, including some ten-year-old ichnofabricians, as well as others young and keen to learn, gathered in Utah for the Second International Ichnofabric Workshop. Hosted by the University of Utah, the meeting was organized and convened with characteristic verve by A. A. (Tony) Ekdale. Phillips Petroleum Company underwrote part of th expenses of the workshop. The 22 participants represented 9 countries, and included David Bottjer (University of Southern California), James Chaplin (Oklahoma Geological Survey), Jay Close (Resource Enterprises Inc., Salt Lake City), H. Allen Curran (Smith College, Northampton), Mary Droser (University of California at Riverside), Christian Gaillard (Universite Claude Bernard, Lyon, France), Douglas W. Lewis (University of Canterbury, Christchurch, New Zealand), Paul Link (Idaho State University), James Magwood (University of Utah, Salt Lake City, Utah), Tony Martin (Emory University, Atlanta), Molly Miller (Vanderbilt University, Nashville, Tennessee), Nicolas Mufnos (Consultores C.S.C., Caracas, Venezuela), George Pemberton (University of Alberta, Edmonton), Ron Pickerill (University of New Brunswick, Fredericton), John Pollard (University of Manchester, England), Tom Saunders (University of Alberta), Charles Savrda (Auburn University, Alabama), Andreas Wetzel (Universitat Basel, Switzerland) and Shipu Yang (China University of Geosciences, Beijing). The meeting was divided into three unequal parts. Our first venue was the Peruvian Lodge at Alta, high up Little Cottonwood Canyon in the western edge of the Rocky Mountains, with cool, clean air and spacious mountain scenery. In these congenial surroundings, the lodge provided conference facilities for two long days of technical sessions. A half day was then spent in the Department of Geology and Geophysics on the Salt Lake City campus, examining a display of trace fossils, bioturbated rocks and ichnofabrics, including several in cores. Finally, 31/2 days were spent in the field, overnighting in motels. Well-timed showers of rain (which did not interfere with fieldwork) cooled the air nicely, and the high temperatures that are normal for the Lake Bonneville basin in August did not materialize!