Stratigraphic features of the sedimentary formations of the Clarion-Clipperton province (eastern equatorial Pacific)

The area studied is characterized by a regional stratigraphic gap from the early Miocene up to the Quaternary. Deposits from the late Eocene to the early Miocene were revealed at the bottom surface or under a thin sedimentary cover. Ferromanganese nodules, mostly of the Oligocene age, are deposited over the surface layers of the Tertiary or Quaternary sediments. A detailed micropaleontological study of a block of dense ancient clay coated with a ferromanganese crust was carried out. A study of the composition of the radiolarian and diatomaceous complexes found proved that the crust was formed in the Quaternary over an eroded surface of late Oligocene clay. In the Quaternary, the Neogene sediments were eroded and washed away by the near-bottom currents. It is likely that the erosion began 0.9-0.7 Ma at the beginning of the "Glacial Pleistocene." The erosion could be initiated by the loosening and resuspension of the surface sediments, resulting from the seismic action generated by strong earthquakes in the subduction zone of Central America. The same vibration maintained residual nodules at the seafloor surface. Thus, for the area studied, a common reason and a common Quaternary interval for the formation of the following features is supposed: the regional stratigraphic gap, the formation of the residual nodule fields, and the position of the ancient nodules over the surface of the Quaternary sediments.