Contributions to the Geochemistry of Nazca Plate Sediments,Southeast Pacific. 2. Possible Sources of Metals in Pelagic Sediments--with Special Reference to the Bauer Basin.

摘要

A review of studies of volcanic processes and the composition of marine organisms suggests that both volcanic and biologic mechanisms contribute transition and some other metals to the sediments of the Bauer Basin,southeastern Pacific. Deep circulating hydrothermal fluids are concluded to be the most likely volcanic source. Marine plankton are shown to accumulate metals in the surface waters by metabolic processes and by adsorption. Their sinking hard parts transport the metals to pelagic sediments. A table of the elemental compositions of marine plankton has been compiled from the available literature. Comparison of Bauer Basin sediments with the composition of some hard-shelled plankton indicates that organisms may supply sufficient amounts of Ba,Zn,Pb,and Sr to account for these metals in the sediment. Most of the Fe and Mn contents and a substantial part of the Ni and Cu,however,are best explained by precipitation from hydrothermal fluids.