Stable carbon isotope ratios and the formation of dolomite in ODP Leg 175 sites
We examine the link between organic matter degradation, anaerobic methane oxidation (AMO), and sulfate depletion and explore how these processes potentially influence dolomitization. We determined rates and depths of AMO and dolomite formation for a variety of organic-rich sites along the west Afric...
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ftpangaea:oai:pangaea.de:doi:10.1594/PANGAEA.714864 2024-09-15T18:36:30+00:00 Stable carbon isotope ratios and the formation of dolomite in ODP Leg 175 sites Moore, T S Murray, Richard W Kurtz, A C Schrag, Daniel P MEDIAN LATITUDE: -22.132035 * MEDIAN LONGITUDE: 12.069337 * SOUTH-BOUND LATITUDE: -25.513667 * WEST-BOUND LONGITUDE: 11.319333 * NORTH-BOUND LATITUDE: -19.619944 * EAST-BOUND LONGITUDE: 13.027778 * DATE/TIME START: 1997-09-09T00:00:00 * DATE/TIME END: 1997-09-21T00:00:00 2004 application/zip, 7 datasets https://doi.pangaea.de/10.1594/PANGAEA.714864 https://doi.org/10.1594/PANGAEA.714864 en eng PANGAEA https://doi.pangaea.de/10.1594/PANGAEA.714864 https://doi.org/10.1594/PANGAEA.714864 CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess Supplement to: Moore, T S; Murray, Richard W; Kurtz, A C; Schrag, Daniel P (2004): Anaerobic methane oxidation and the formation of dolomite. Earth and Planetary Science Letters, 229(1-2), 141-154, https://doi.org/10.1016/j.epsl.2004.10.015 175-1081 175-1082 175-1084 Benguela Current South Atlantic Ocean COMPCORE Composite Core Joides Resolution Leg175 Ocean Drilling Program ODP dataset publication series 2004 ftpangaea https://doi.org/10.1594/PANGAEA.71486410.1016/j.epsl.2004.10.015 2024-07-24T02:31:20Z We examine the link between organic matter degradation, anaerobic methane oxidation (AMO), and sulfate depletion and explore how these processes potentially influence dolomitization. We determined rates and depths of AMO and dolomite formation for a variety of organic-rich sites along the west African Margin using data from Ocean Drilling Program (ODP) Leg 175. Rates of AMO are calculated from the diffusive fluxes of CH4 and SO4, and rates of dolomite formation are calculated from the diffusive flux of Mg. We find that the rates of dolomite formation are relatively constant regardless of the depth at which it is forming, indicating that the diffusive fluxes of Mg and Ca are not limiting. Based upon the calculated log IAP values, log K(sp) values for dolomite were found to narrowly range between -16.1 and -16.4. Dolomite formation is controlled in part by competition between AMO and methanogenesis, which controls the speciation of dissolved CO2. AMO increases the concentration of CO3[2-] through sulfate reduction, favoring dolomite formation, while methanogenesis increases the pCO2 of the pore waters, inhibiting dolomite formation. By regulating the pCO2 and alkalinity, methanogenesis and AMO can regulate the formation of dolomite in organic-rich marine sediments. In addition to providing a mechanistic link between AMO and dolomite formation, our findings provide a method by which the stability constant of dolomite can be calculated in modern sediments and allow prediction of regions and depth domains in which dolomite may be forming. Other/Unknown Material South Atlantic Ocean PANGAEA - Data Publisher for Earth & Environmental Science ENVELOPE(11.319333,13.027778,-19.619944,-25.513667) |
institution |
Open Polar |
collection |
PANGAEA - Data Publisher for Earth & Environmental Science |
op_collection_id |
ftpangaea |
language |
English |
topic |
175-1081 175-1082 175-1084 Benguela Current South Atlantic Ocean COMPCORE Composite Core Joides Resolution Leg175 Ocean Drilling Program ODP |
spellingShingle |
175-1081 175-1082 175-1084 Benguela Current South Atlantic Ocean COMPCORE Composite Core Joides Resolution Leg175 Ocean Drilling Program ODP Moore, T S Murray, Richard W Kurtz, A C Schrag, Daniel P Stable carbon isotope ratios and the formation of dolomite in ODP Leg 175 sites |
topic_facet |
175-1081 175-1082 175-1084 Benguela Current South Atlantic Ocean COMPCORE Composite Core Joides Resolution Leg175 Ocean Drilling Program ODP |
description |
We examine the link between organic matter degradation, anaerobic methane oxidation (AMO), and sulfate depletion and explore how these processes potentially influence dolomitization. We determined rates and depths of AMO and dolomite formation for a variety of organic-rich sites along the west African Margin using data from Ocean Drilling Program (ODP) Leg 175. Rates of AMO are calculated from the diffusive fluxes of CH4 and SO4, and rates of dolomite formation are calculated from the diffusive flux of Mg. We find that the rates of dolomite formation are relatively constant regardless of the depth at which it is forming, indicating that the diffusive fluxes of Mg and Ca are not limiting. Based upon the calculated log IAP values, log K(sp) values for dolomite were found to narrowly range between -16.1 and -16.4. Dolomite formation is controlled in part by competition between AMO and methanogenesis, which controls the speciation of dissolved CO2. AMO increases the concentration of CO3[2-] through sulfate reduction, favoring dolomite formation, while methanogenesis increases the pCO2 of the pore waters, inhibiting dolomite formation. By regulating the pCO2 and alkalinity, methanogenesis and AMO can regulate the formation of dolomite in organic-rich marine sediments. In addition to providing a mechanistic link between AMO and dolomite formation, our findings provide a method by which the stability constant of dolomite can be calculated in modern sediments and allow prediction of regions and depth domains in which dolomite may be forming. |
format |
Other/Unknown Material |
author |
Moore, T S Murray, Richard W Kurtz, A C Schrag, Daniel P |
author_facet |
Moore, T S Murray, Richard W Kurtz, A C Schrag, Daniel P |
author_sort |
Moore, T S |
title |
Stable carbon isotope ratios and the formation of dolomite in ODP Leg 175 sites |
title_short |
Stable carbon isotope ratios and the formation of dolomite in ODP Leg 175 sites |
title_full |
Stable carbon isotope ratios and the formation of dolomite in ODP Leg 175 sites |
title_fullStr |
Stable carbon isotope ratios and the formation of dolomite in ODP Leg 175 sites |
title_full_unstemmed |
Stable carbon isotope ratios and the formation of dolomite in ODP Leg 175 sites |
title_sort |
stable carbon isotope ratios and the formation of dolomite in odp leg 175 sites |
publisher |
PANGAEA |
publishDate |
2004 |
url |
https://doi.pangaea.de/10.1594/PANGAEA.714864 https://doi.org/10.1594/PANGAEA.714864 |
op_coverage |
MEDIAN LATITUDE: -22.132035 * MEDIAN LONGITUDE: 12.069337 * SOUTH-BOUND LATITUDE: -25.513667 * WEST-BOUND LONGITUDE: 11.319333 * NORTH-BOUND LATITUDE: -19.619944 * EAST-BOUND LONGITUDE: 13.027778 * DATE/TIME START: 1997-09-09T00:00:00 * DATE/TIME END: 1997-09-21T00:00:00 |
long_lat |
ENVELOPE(11.319333,13.027778,-19.619944,-25.513667) |
genre |
South Atlantic Ocean |
genre_facet |
South Atlantic Ocean |
op_source |
Supplement to: Moore, T S; Murray, Richard W; Kurtz, A C; Schrag, Daniel P (2004): Anaerobic methane oxidation and the formation of dolomite. Earth and Planetary Science Letters, 229(1-2), 141-154, https://doi.org/10.1016/j.epsl.2004.10.015 |
op_relation |
https://doi.pangaea.de/10.1594/PANGAEA.714864 https://doi.org/10.1594/PANGAEA.714864 |
op_rights |
CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1594/PANGAEA.71486410.1016/j.epsl.2004.10.015 |
_version_ |
1810480170075684864 |