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Bibliographic Details
Main Author: Bloch, Salman
Format: Dataset Open Access
Language:en
Published: PANGAEA 1981
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Online Access:https://doi.org/10.1594/PANGAEA.705173
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_version_ 1867167660292177920
author Bloch, Salman
author_facet Bloch, Salman
collection Datos científicos de ciencias marinas y ambientales
contents 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 Mn(2+), 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.
format Dataset Open Access
id pangaea_https___doi_org_10_1594_PANGAEA_705173
institution PANGAEA
language en
publishDate 1981
publisher PANGAEA
record_format pangaea
spellingShingle Chemical composition of basal metalliferous sediments from DSDP Leg 9
Bloch, Salman
9-77B; 9-80; 9-81; Deep Sea Drilling Project; DRILL; Drilling/drill rig; DSDP; Glomar Challenger; Leg9; North Pacific/HILL; South Pacific/VALLEY
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 Mn(2+), 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.
title Chemical composition of basal metalliferous sediments from DSDP Leg 9
topic 9-77B; 9-80; 9-81; Deep Sea Drilling Project; DRILL; Drilling/drill rig; DSDP; Glomar Challenger; Leg9; North Pacific/HILL; South Pacific/VALLEY
url https://doi.org/10.1594/PANGAEA.705173