Erosion of sediment at two sites within the siliceous-clay province of the northeast equatorial Pacific is investigated by examining radionuclide, radiolarian and percent smectite profiles of three cores. A numerical model of the sediment is presented that examines the effect of various particle rain rates, erosion rates and biological mixing parameters on these profiles. 230Th, because of its longer half-life, is a more sensitive tracer of erosion than231Pa. Because the input of these radionuclides into the sediment is not well defined however, conservative tracers, such as the percent smectite of the clay fraction and fossil radiolarians are used to constrain the rate of sediment recycling. Dissolution of radiolarians though can greatly affect the interpretation of the observed biostratigraphy.

The dried, powdered samples (approximately 0.5 g) were dissolved in a mixture of nitric, perchloric and hydrofluoric acids to which 233Pa, 232U, and 238Th spikes were added. The nuclides were precipitated with iron hydroxide, taken up in 8N HCl and further separated.From 1983 until 1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions. At the time it was the most extended data compilation on ferromanganese deposits world wide. Initially published in a proprietary format incompatible with present day standards it was jointly decided by AWI and NOAA to transcribe this legacy data into PANGAEA. This transfer is augmented by a careful checking of the original sources when available and the encoding of ancillary information (sample description, method of analysis...) not present in the NOAA-MMS database.

Supplement to: Kadko, David (1983): A multitracer approach to the study of erosion in the northeast equatorial Pacific. Earth and Planetary Science Letters, 63(1), 13-33