Some Wave-Related, Heavy Mineral Placer Deposits

Abstract

Examples of heavy mineral placer deposits are presented in which wave reflection, refraction, diffraction and resonance would appear to have played a major concentrating role. Their geometry is compared with the computer generated patterns predicted for the reflection, refraction and diffraction of surface waves moving over fairly simple, idealised bathymetries. Much of this work is founded on the idea that similar sediments document equivalent (or once equivalent) flow-tractional environments. Most of the examples could be satisfactorily explained in this fashion. It may therefore be possible to ignore the exact physics of the boundary layer, longshore and tidal return currents etc. at the scale on which these examples occur, leaving the way open for the qualitative use of results obtained using the likes of the mild slope wave equation. A ``Monte Carlo'' approach based on wave induced tractions should therefore succeed in elucidating presently known heavy mineral placer deposits and, consequently, in predicting other deposits which remain as yet undiscovered.