Element concentrations, and Sr and Os isotope ratios of DSDP Leg 92 metalliferous carbonates

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Auteur principal: Ravizza, Gregory E
Format: Dataset Open Access
Langue:en
Publié: PANGAEA 2009
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author Ravizza, Gregory E
author_facet Ravizza, Gregory E
collection Datos científicos de ciencias marinas y ambientales
contents The Os concentration and isotopic composition of metalliferous carbonates deposited on the East Pacific Rise over the past 28 Ma are reported with complimentary Sr isotope data. Variations in the Os isotopic composition of these samples are interpreted as a record of past changes in the Os isotopic composition of seawater. These results are consistent with isotopic analyses of leachable Os in pelagic clays which have also been interpreted as a record of the 187Os/186Os ratio of seawater through time (Pegram et al., 1992, doi:10.1016/0012-821X(92)90132-F). The metalliferous carbonate record clearly shows that seawater Os and Sr isotope systems are partially decoupled from one another over the past 28 Ma. Accelerated weathering of ancient organic-rich sediments is suggested as a possible mechanism to account for this decoupling and the rapid increase in the 187Os//186Os ratio of seawater over the past 15 Ma. This rapid increase suggests that the seawater Os record can potentially be used as a stratigraphic tool in some Neogene marine deposits.
format Dataset Open Access
id pangaea_https___doi_org_10_1594_PANGAEA_711523
institution PANGAEA
language en
publishDate 2009
publisher PANGAEA
record_format pangaea
spellingShingle Element concentrations, and Sr and Os isotope ratios of DSDP Leg 92 metalliferous carbonates
Ravizza, Gregory E
92-597; 92-598; 92-599; 92-600; 92-601; Deep Sea Drilling Project; DRILL; Drilling/drill rig; DSDP; Glomar Challenger; Leg92; South Pacific/CONT RISE; South Pacific/PLATEAU; South Pacific Ocean
The Os concentration and isotopic composition of metalliferous carbonates deposited on the East Pacific Rise over the past 28 Ma are reported with complimentary Sr isotope data. Variations in the Os isotopic composition of these samples are interpreted as a record of past changes in the Os isotopic composition of seawater. These results are consistent with isotopic analyses of leachable Os in pelagic clays which have also been interpreted as a record of the 187Os/186Os ratio of seawater through time (Pegram et al., 1992, doi:10.1016/0012-821X(92)90132-F). The metalliferous carbonate record clearly shows that seawater Os and Sr isotope systems are partially decoupled from one another over the past 28 Ma. Accelerated weathering of ancient organic-rich sediments is suggested as a possible mechanism to account for this decoupling and the rapid increase in the 187Os//186Os ratio of seawater over the past 15 Ma. This rapid increase suggests that the seawater Os record can potentially be used as a stratigraphic tool in some Neogene marine deposits.
title Element concentrations, and Sr and Os isotope ratios of DSDP Leg 92 metalliferous carbonates
topic 92-597; 92-598; 92-599; 92-600; 92-601; Deep Sea Drilling Project; DRILL; Drilling/drill rig; DSDP; Glomar Challenger; Leg92; South Pacific/CONT RISE; South Pacific/PLATEAU; South Pacific Ocean
url https://doi.org/10.1594/PANGAEA.711523