Chemical and mineralogical studies of deep-sea sediments

Abstract

Chemical and spectrographic analyses are presented for the major and several minor elements in ten calcareous, twelve argillaceous and three siliceous deep-sea sediments from the Atlantic, Pacific and Indian Oceans and Mediterranean Sea; a 5 m core from the Atlantic; three deep-sea volcanic sediments; an unusual calcareous manganiferous ooze, and the <2 μ fractions from two near-shore muds. The distribution of the minor elements was very similar to that described by Goldberg and Arrhenius for Pacific sediments. Except for their higher content of ferrous iron and organic carbon the chemical composition of the <2 μ fraction of the near shore clays closely resembled that of the deep-sea argillaceous sediments. This resemblance and the similarity of the abundances of certain of the minor elements, such as Ti, Zr, Cr and V, in the pelagic to their abundances in igneous rocks, suggests a mainly terrigenous origin for red clay. The argillaceous material of two globigerina oozes from the Mediterranean was very similar in composition to that of the deep ocean sediments. The proportions of all the major elements down the length of the 5.05 m core of red clay from off the Bermuda rise in the Atlantic were very constant. Niggli values have been used to compare the sediments, on a carbonate-free basis, the sediments from the Atlantic are characterized by their higher al and lower fm values compared with those from the Pacific and Indian Oceans. Illite and chlorite, with lesser amounts of montmorillonite, are the principal clay minerals in the deep-sea sediments. The near shore clays are richest in kaolinite, but illite and montmorillonite are also present