Radium, thorium, uranium, and Pb210 in deep-sea sediments and sediment pore waters from the North Equatorial Pacific.

Determination of Ra, Th, U isotopes, and ²¹⁰Pb in sediments and sediment pore waters from deep-sea clay-siliceous oozes shows that the Ra and U isotopes are mobile in the pore water. The concentration-depth profiles of Ra can be understood in terms of a diagenetic model which takes into account mixing of sediment particles by bioturbation, molecular diffusion in the pore water, adsorption onto particle surfaces, as well as radioactive production and decay.-from Authors