Antipathetic magnesium-manganese relationship in basal metalliferous sediments

Chemical Geology



Basal metalliferous sediments from sites 77B, 80 and 81 of the Deep Sea Drilling Project represent mixtures of pelagic clay, biogenic ooze, and a metalliferous component of hydrothermal origin. The metalliferous end-member of the sediments displays a strong inverse relationship (r = -0.88) between Mg and Mn. Mg is most likely tied up in an X-ray amorphous Mg-silicate ("sepiolite"), whereas Mn occurs almost exclusively in an oxide phase. Precipitation of the Mg-rich phase is favored by high flow rates and limited mixing of the hydrothermal end-member (source of silica) with seawater (source of Mg). Under those conditions much of the hydrothermal Mn2+, with its slow oxidation kinetics, may escape to the free water column. In contrast, in highly-diluted hydrothermal fluids, which provide a source solution for Mn-rich sediments, dissolved silica is diluted below saturation with respect to "sepiolite". The separation of the Mn and Mg phases may be further compounded by hydraulic fractionation. ?? 1981.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Antipathetic magnesium-manganese relationship in basal metalliferous sediments
Series title Chemical Geology
DOI 10.1016/0009-2541(81)90088-7
Volume 33
Issue 1-4
Year Published 1981
Language English
Publisher Elsevier
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Chemical Geology
First page 101
Last page 113