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MICfíO-EfíOSION METER MEASUREMENTS OF EfíOSION ON LIMESTONE, OXWICH POINT, GOWER: SOME TECHNICAL CONSIDEfíATIONS AND PfíELIMINAfíY RESUL TS RICHARD A. SHAKESBY RORY P.D. WALSH CAMBRIA Shakesby, Richard A. and Walsh, Rory P.D. 1986 Micro-erosion meter measurements of erosion on limestone, Oxwich Point, Gower: some technical considerations and preliminary results. Cambria, Vol.13 (2), pp. 213-224. ISSN 0306-9796. Several technical changes to the installation and calibration of micro-erosion meter sites are discussed. Improvements to stud installation include use of a wedge anchor for fixing reference studs, a newly designed stud and a method of protection which has proved highly successful after a year's field trial in an exposed intertidal location. An improved method for the calibration of the instrument is suggested and results from three sites and some problems of interpretation are discussed. Richard A. Shakesby and Rory P.D. Walsh, Department of Geography, University College of Swansea, Singleton Park, Swansea, SA2 8PP, U.K. (Revised October 1985) INTRODUCTION Following development of the micro-erosion meter (MEM) by High and Hanna (1970), a number of workers have used the instrument to measure directly very small amounts of erosion on rock surfaces (e.g. Robinson 1976; Kirk 1977; Trudgill 1976a,1976b. 1983). Limestone has figured as the main rock type subjected to study with the MEM because it presents sound surfaces for the probe and erodes relatively rapidly compared to many other rock types, which means that measurements over periods of less than a year can yield measurable rates of erosion. However, many measurements of erosion are frequently taken over periods of less than a year (e.g. Mottershead 1981 Trudgill 1977) and few studies are carried out over periods longer than 2-3 years (cf. Viles and Trudgill 1984). There is considerable difficulty therefore in extrapolating the results from short interval measurements to derive long-term erosion rates (Trudgill 1977). In an attempt to provide more reliable results over a wider area of bedrock, the traversing MEM was developed by Trudgill et al.(1981) which allows c.30 readings to be made per site. The problem of longer term measurements (> 3 yrs), however, remains and is problematical with equipment built to the