gsminmag Mineralogical Magazine Mineralogical Magazine 0026-461X Mineralogical Society 10.1180/minmag.1994.58A.1.74 The Influence of Erosion and Palaeogeography on Seawater Neodymium During the Past 20 Million Years Burton K. W. O'Nions R. K. Martel D. J. Dept. of Earth Sciences, Univ. of Cambridge, Downing St., Cambridge, CB2 3EQ, UK; email: kwb10@esc, cam.ac.uk Hein J. R. U.S. Geological Survey, Pacific Marine Geology, 345 Middlefield Road, Menlo Park, California, CA 94025, USA 8 1994 58A 1 136 137 Copyright © 1994, The Mineralogical Society 1994