Chemical and mineral compositions of bottom sediments from the East Pacific Rise near 13°N

The bottom is covered by them as by a jacket on both sides from the EPR axial zone. However, exposed pillow-lavas and clumpy blocks in rift ledges are covered by a thin metal-bearing film.

It is supposed that sedimentation results mainly from hydrothermal input of dissolved chemical elements in seawater, their transformation on the geochemical barrier, and subsequent deposition as particulates. Contents of ore components in metalliferous sediments have been measured by atomic-absorption and X-ray radiometry methods. Sediment age has been determined as Middle Pleistocene - Holocene.