The Romanche fracture zone sediments, equatorial Atlantic: main controls on their distribution and composition
Abstract
In the present study, the lithology, mineralogy and chemistry of sediment cores collected from different parts of the
equatorial Atlantic have been investigated in order to determine the factors controlling their composition and distribution.
From the sediment characteristics revealed in this study, the dominant control on the sediment composition appears to be the
relative abundance of CaC03 and alumino silicate minerals. Water depth appears to play an important role in controlling the
distribution of the sediments in the region. Sediments from above the CCD are dominantly calcareous oozes, whereas those
sediments from below CCD are dominantly clays.
It can also be seen that sediment relationship to their source areas tend to control the distribution of elements in the
sediments in the region. Post-burial diagenesis has also taken place within the sedimentary column involving the shifting of
Fe-Mn oxides and associated trace elements from easily reducible to more resistant phases. The element interrelations within
the geochemical data indicate that the elements studied are present in biogenic, terrigenous, ultramaiic and hydrogenous
components of sediments. The proportion of each of these components in the sediments is controlled largely by water depth
and proximity to the source of the deposits.
Citation
AJST Series B Vol. 7 No.1 Januarv 1995Publisher
Department of Geology, University of Nairobi,