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Archive · collection · 1987

Marine barite in sediments of DSDP Site 54-424

Listed in PANGAEA

The distribution of barite in sediments from D.S.D.P. sites 424 and 424A at the Galapagos hydrothermal mounds field is determined and the process of its formation is deduced.

Description

Barite in these deposits is associated with calcareous sediments and is completely absent from the hydrothermal material (manganese crusts and nontronite). Its concentrations tend to increase in the deeper sediments.

Since manganese crusts contain significant amounts of Ba, a lack of barite in them is probably due to low concentrations of [SO4]2 in the sediment-seawater interface where they form. The formation of barite occurs within buried sediments, the interstitial waters of which are saturated with [SO4]2. The most probable source of [SO4]2- is the oxidation of H2S which is released from the hydrothermal fluids percolating upwards through the sediments.

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Although nontronite is formed within buried sediments the environmental conditions occurring during its formation (reducing) prevent barite formation. The association of barite with calcareous sediments is due to the release of Ba by calcareous microorganisms and/or to high concentrations of Ca in the pore waters which maintain a high pH and hence [SO4]2- is stable.

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Catalogue records · 1

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Inferred from text
Geochemistry 69%
Provenance · 1 source records, 8 field assertions
SourceKeyLast seenRaw
PANGAEAoai:pangaea.de:doi:10.1594/PANGAEA.75699512 d agoJSON v1
FieldAssertionExtractorEvidence
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concepts[field].anzsrc:group:3703enrichment · PANGAEAtaxonomy-embedding@1.1.0title+keywords+description (69%)
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