gsminmag Mineralogical Magazine Mineralogical Magazine 0026-461X Mineralogical Society 10.1180/minmag.1987.051.360.09 The Composition and Distribution of Nodular Monazite in the Lower Palaeozoic Rocks of Great Britain Read D. * University of Wales, Institute of Science and Technology, P.O. Box 13, Cardiff CF1 3XF Cooper D. C. British Geological Survey, Keyworth, Nottingham NG12 5GG McArthur J. M. University College London, Gower Street, London WC1E 6BT

Present address: W. S. Atkins and Partners, Longcross Court, Newport Road, Cardiff CF2 1AD.

 6 1987 51 360 271 280 22 11 1985 3 6 1986 Copyright © 1987, The Mineralogical Society 1987 Abstract

Millimetric, ellipsoidal monazite nodules found within Lower Palaeozoic sedimentary rocks in Wales, south-west England and Brittany are characterised by a pronounced zonation of light and heavy REE, an inclusion fabric of low-grade metamorphic minerals indistinguishable from the host rock and a low Th content. They are interpreted as the product of in situ recrystallization of detrital monazites derived from pegmatitic or granitic source rocks and are potentially useful as indicators of Lower Palaeozoic sedimentary rock provenance.

 Keywords monazite nodules Lower Palaeozoic rocks rare earth elements Great Britain