Abstract
The coarse fractions of 56 bottom-surface samples from 5 east—west profiles off West Africa (13–19°N) from waterdepths of 30–3000 m were analysed to find lithologic and biologic parameters dependent only upon waterdepth rather than upon facies or latitude. The following parameters show depth-dependent variations: % sand fraction and % quartz > 125 μ m decrease with depth; % relict material and ratios of benthonic/planktonic foraminifers decrease with depth; fragmentation of planktonic foraminifers is minimum between 100 and 300 m; ratios of planktonic/benthonic molluscs is maximum between 100 and 300 m; ratio of radiolaria/planktonic foraminifers is zero between 30 and 600 m and increases below 600–1000 m; echinoderms are minimum between 600 and 1000 m; total loss of bivalves and gastropods below 600–1000 m; ratios of imperforate/perforate benthonic foraminifers shows a regular decrease to zero from 30 to between 600 and 1000 m and subsequent increase at greater depths.
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