Sulfur contents and S, C and O isotopic compositions in serpentinized peridotites at ODP Site 153-920
The opaque mineralogy and the contents and isotope compositions of sulfur in serpentinized peridotites from the MARK (Mid-Atlantic Ridge, Kane Fracture Zone) area were examined to understand the conditions of serpentinization and evaluate this process as a sink for seawater sulfur. The serpentinites...
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ftpangaea:oai:pangaea.de:doi:10.1594/PANGAEA.708592 2024-09-15T18:24:22+00:00 Sulfur contents and S, C and O isotopic compositions in serpentinized peridotites at ODP Site 153-920 Alt, Jeffrey C Shanks, Wayne C MEDIAN LATITUDE: 23.338650 * MEDIAN LONGITUDE: -45.017375 * SOUTH-BOUND LATITUDE: 23.338500 * WEST-BOUND LONGITUDE: -45.017400 * NORTH-BOUND LATITUDE: 23.338700 * EAST-BOUND LONGITUDE: -45.017300 * DATE/TIME START: 1993-12-05T06:15:00 * DATE/TIME END: 1993-12-21T02:00:00 2003 application/zip, 2 datasets https://doi.pangaea.de/10.1594/PANGAEA.708592 https://doi.org/10.1594/PANGAEA.708592 en eng PANGAEA https://doi.pangaea.de/10.1594/PANGAEA.708592 https://doi.org/10.1594/PANGAEA.708592 CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess Supplement to: Alt, Jeffrey C; Shanks, Wayne C (2003): Serpentinization of abyssal peridotites from the MARK area, Mid-Atlantic Ridge: Sulfur geochemistry and reaction modeling. Geochimica et Cosmochimica Acta, 67(4), 641-653, https://doi.org/10.1016/S0016-7037(02)01142-0 153-920B 153-920D DRILL Drilling/drill rig Joides Resolution Leg153 North Atlantic Ocean Ocean Drilling Program ODP dataset publication series 2003 ftpangaea https://doi.org/10.1594/PANGAEA.70859210.1016/S0016-7037(02)01142-0 2024-08-21T00:02:25Z The opaque mineralogy and the contents and isotope compositions of sulfur in serpentinized peridotites from the MARK (Mid-Atlantic Ridge, Kane Fracture Zone) area were examined to understand the conditions of serpentinization and evaluate this process as a sink for seawater sulfur. The serpentinites contain a sulfur-rich secondary mineral assemblage and have high sulfur contents (up to 1 wt.%) and elevated d34S_sulfide (3.7 to 12.7‰). Geochemical reaction modeling indicates that seawater-peridotite interaction at 300 to 400°C alone cannot account for both the high sulfur contents and high d34S_sulfide. These require a multistage reaction with leaching of sulfide from subjacent gabbro during higher temperature (~400°C) reactions with seawater and subsequent deposition of sulfide during serpentinization of peridotite at ~300°C. Serpentinization produces highly reducing conditions and significant amounts of H2 and results in the partial reduction of seawater carbonate to methane. The latter is documented by formation of carbonate veins enriched in 13C (up to 4.5‰) at temperatures above 250°C. Although different processes produce variable sulfur isotope effects in other oceanic serpentinites, sulfur is consistently added to abyssal peridotites during serpentinization. Data for serpentinites drilled and dredged from oceanic crust and from ophiolites indicate that oceanic peridotites are a sink for up to 0.4 to 6.0 mln ton seawater S per year. This is comparable to sulfur exchange that occurs in hydrothermal systems in mafic oceanic crust at midocean ridges and on ridge flanks and amounts to 2 to 30% of the riverine sulfate source and sedimentary sulfide sink in the oceans. The high concentrations and modified isotope compositions of sulfur in serpentinites could be important for mantle metasomatism during subduction of crust generated at slow spreading rates. Other/Unknown Material North Atlantic PANGAEA - Data Publisher for Earth & Environmental Science ENVELOPE(-45.017400,-45.017300,23.338700,23.338500) |
institution |
Open Polar |
collection |
PANGAEA - Data Publisher for Earth & Environmental Science |
op_collection_id |
ftpangaea |
language |
English |
topic |
153-920B 153-920D DRILL Drilling/drill rig Joides Resolution Leg153 North Atlantic Ocean Ocean Drilling Program ODP |
spellingShingle |
153-920B 153-920D DRILL Drilling/drill rig Joides Resolution Leg153 North Atlantic Ocean Ocean Drilling Program ODP Alt, Jeffrey C Shanks, Wayne C Sulfur contents and S, C and O isotopic compositions in serpentinized peridotites at ODP Site 153-920 |
topic_facet |
153-920B 153-920D DRILL Drilling/drill rig Joides Resolution Leg153 North Atlantic Ocean Ocean Drilling Program ODP |
description |
The opaque mineralogy and the contents and isotope compositions of sulfur in serpentinized peridotites from the MARK (Mid-Atlantic Ridge, Kane Fracture Zone) area were examined to understand the conditions of serpentinization and evaluate this process as a sink for seawater sulfur. The serpentinites contain a sulfur-rich secondary mineral assemblage and have high sulfur contents (up to 1 wt.%) and elevated d34S_sulfide (3.7 to 12.7‰). Geochemical reaction modeling indicates that seawater-peridotite interaction at 300 to 400°C alone cannot account for both the high sulfur contents and high d34S_sulfide. These require a multistage reaction with leaching of sulfide from subjacent gabbro during higher temperature (~400°C) reactions with seawater and subsequent deposition of sulfide during serpentinization of peridotite at ~300°C. Serpentinization produces highly reducing conditions and significant amounts of H2 and results in the partial reduction of seawater carbonate to methane. The latter is documented by formation of carbonate veins enriched in 13C (up to 4.5‰) at temperatures above 250°C. Although different processes produce variable sulfur isotope effects in other oceanic serpentinites, sulfur is consistently added to abyssal peridotites during serpentinization. Data for serpentinites drilled and dredged from oceanic crust and from ophiolites indicate that oceanic peridotites are a sink for up to 0.4 to 6.0 mln ton seawater S per year. This is comparable to sulfur exchange that occurs in hydrothermal systems in mafic oceanic crust at midocean ridges and on ridge flanks and amounts to 2 to 30% of the riverine sulfate source and sedimentary sulfide sink in the oceans. The high concentrations and modified isotope compositions of sulfur in serpentinites could be important for mantle metasomatism during subduction of crust generated at slow spreading rates. |
format |
Other/Unknown Material |
author |
Alt, Jeffrey C Shanks, Wayne C |
author_facet |
Alt, Jeffrey C Shanks, Wayne C |
author_sort |
Alt, Jeffrey C |
title |
Sulfur contents and S, C and O isotopic compositions in serpentinized peridotites at ODP Site 153-920 |
title_short |
Sulfur contents and S, C and O isotopic compositions in serpentinized peridotites at ODP Site 153-920 |
title_full |
Sulfur contents and S, C and O isotopic compositions in serpentinized peridotites at ODP Site 153-920 |
title_fullStr |
Sulfur contents and S, C and O isotopic compositions in serpentinized peridotites at ODP Site 153-920 |
title_full_unstemmed |
Sulfur contents and S, C and O isotopic compositions in serpentinized peridotites at ODP Site 153-920 |
title_sort |
sulfur contents and s, c and o isotopic compositions in serpentinized peridotites at odp site 153-920 |
publisher |
PANGAEA |
publishDate |
2003 |
url |
https://doi.pangaea.de/10.1594/PANGAEA.708592 https://doi.org/10.1594/PANGAEA.708592 |
op_coverage |
MEDIAN LATITUDE: 23.338650 * MEDIAN LONGITUDE: -45.017375 * SOUTH-BOUND LATITUDE: 23.338500 * WEST-BOUND LONGITUDE: -45.017400 * NORTH-BOUND LATITUDE: 23.338700 * EAST-BOUND LONGITUDE: -45.017300 * DATE/TIME START: 1993-12-05T06:15:00 * DATE/TIME END: 1993-12-21T02:00:00 |
long_lat |
ENVELOPE(-45.017400,-45.017300,23.338700,23.338500) |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Supplement to: Alt, Jeffrey C; Shanks, Wayne C (2003): Serpentinization of abyssal peridotites from the MARK area, Mid-Atlantic Ridge: Sulfur geochemistry and reaction modeling. Geochimica et Cosmochimica Acta, 67(4), 641-653, https://doi.org/10.1016/S0016-7037(02)01142-0 |
op_relation |
https://doi.pangaea.de/10.1594/PANGAEA.708592 https://doi.org/10.1594/PANGAEA.708592 |
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.70859210.1016/S0016-7037(02)01142-0 |
_version_ |
1810464710328320000 |