Early sediment fabrics

Abstract

The papers in this thematic set arise from a meeting sponsored by the British Sedimentological Research Group and held at Burlington House on 3 November 1992. About 50 people heard 14 papers of which seven are published in this thematic set. The study of early sediment fabrics is an interdisciplinary field in which practitioners are required to interpret the combined effects of a very wide range of physical, chemical and biological processes. Not surprisingly, scientists from several different backgrounds are involved in this area of research, including biologists, civil engineers, environmental scientists and geographers as well as geologists. This broad spectrum of researchers was well represented at the meeting, and it was particularly gratifying to see the development of interactions between scientists from different disciplines. A superbly illustrated overview of the potential and limitations of scanning electron microscopy in sediment fabric analysis was presented by A. T. Kearsley (Oxford Brookes University) who highlighted the expansion of the use of backscattered electron imagery (BSEI) in sedimentary petrography. He emphasized commonly overlooked limitations on the interpretation of BSEI resulting from the effects of complex beam-specimen interactions and variation in instrument parameters. Compositional ambiguities arising from BSEI can be resolved by the concurrent use of digital X-ray mapping and he further outlined the power of the more newly developed technique of scanning cathodoluminscence imagery for differentiating grain cores and overgrowths. J. Macquaker (University of Manchester) continued the theme of BSEI by presenting a synthesis of fabric variation within Mesozoic mudstones. He demonstrated that,