Chemical composition of mineral phases of serpentinized and steatized peridotite from the Mid Atlantic Ridge (15°20'N Fracture Zone, ODP Leg209)
Serpentinization of abyssal peridotites is known to produce extremely reducing conditions as a result of dihydrogen (H2,aq) release upon oxidation of ferrous iron in primary phases to ferric iron in secondary minerals by H2O.We have compiled and evaluated thermodynamic data for Fe-Ni-Co-O-S phases a...
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ftpangaea:oai:pangaea.de:doi:10.1594/PANGAEA.736007 2024-09-15T18:24:30+00:00 Chemical composition of mineral phases of serpentinized and steatized peridotite from the Mid Atlantic Ridge (15°20'N Fracture Zone, ODP Leg209) Klein, Frieder Bach, Wolfgang MEDIAN LATITUDE: 15.064389 * MEDIAN LONGITUDE: -45.434795 * SOUTH-BOUND LATITUDE: 14.721160 * WEST-BOUND LONGITUDE: -46.676360 * NORTH-BOUND LATITUDE: 15.647780 * EAST-BOUND LONGITUDE: -44.884730 * DATE/TIME START: 2003-05-22T05:45:00 * DATE/TIME END: 2003-06-18T21:45:00 2010 application/zip, 9 datasets https://doi.pangaea.de/10.1594/PANGAEA.736007 https://doi.org/10.1594/PANGAEA.736007 en eng PANGAEA https://doi.pangaea.de/10.1594/PANGAEA.736007 https://doi.org/10.1594/PANGAEA.736007 CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess Supplement to: Klein, Frieder; Bach, Wolfgang (2009): Fe-Ni-Co-O-S Phase Relations in Peridotite-Seawater Interactions. Journal of Petrology, 50, 37-59, https://doi.org/10.1093/petrology/egn071 209-1268A 209-1270C 209-1270D 209-1271A 209-1271B 209-1274A DERIDGE DRILL Drilling/drill rig From Mantle to Ocean: Energy- Material- and Life-cycles at Spreading Axes Joides Resolution Leg209 North Atlantic Ocean Ocean Drilling Program ODP dataset publication series 2010 ftpangaea https://doi.org/10.1594/PANGAEA.73600710.1093/petrology/egn071 2024-08-21T00:02:25Z Serpentinization of abyssal peridotites is known to produce extremely reducing conditions as a result of dihydrogen (H2,aq) release upon oxidation of ferrous iron in primary phases to ferric iron in secondary minerals by H2O.We have compiled and evaluated thermodynamic data for Fe-Ni-Co-O-S phases and computed phase relations in fO2,g-fS2,g and aH2,aq-aH2S,aq diagrams for temperatures between 150 and 400°C at 50MPa.We use the relations and compositions of Fe-Ni-Co-O-S phases to trace changes in oxygen and sulfur fugacities during progressive serpentinization and steatitization of peridotites from the Mid-Atlantic Ridge in the 15°20'N Fracture Zone area (Ocean Drilling Program Leg 209). Petrographic observations suggest a systematic change from awaruite- magnetite-pentlandite and heazlewoodite-magnetite-pentlandite assemblages forming in the early stages of serpentinization to millerite-pyrite-polydymite-dominated assemblages in steatized rocks. Awaruite is observed in all brucite-bearing partly serpentinized rocks. Apparently, buffering of silica activities to low values by the presence of brucite facilitates the formation of large amounts of hydrogen, which leads to the formation of awaruite. Associated with the prominent desulfurization of pentlandite, sulfide is removed from the rock during the initial stage of serpentinization. In contrast, steatitization indicates increased silica activities and that highsulfur-fugacity sulfides, such as polydymite and pyrite-vaesite solid solution, form as the reducing capacity of the peridotite is exhausted and H2 activities drop. Under these conditions, sulfides will not desulfurize but precipitate and the sulfur content of the rock increases. The co-evolution of fO2,g-fS2,g in the system follows an isopotential of H2S,aq, indicating that H2S in vent fluids is buffered. In contrast, H2 in vent fluids is not buffered by Fe-Ni-Co-O-S phases, which merely monitor the evolution of H2 activities in the fluids in the course of progressive rock alteration.The co-occurrence of ... Other/Unknown Material North Atlantic PANGAEA - Data Publisher for Earth & Environmental Science ENVELOPE(-46.676360,-44.884730,15.647780,14.721160) |
institution |
Open Polar |
collection |
PANGAEA - Data Publisher for Earth & Environmental Science |
op_collection_id |
ftpangaea |
language |
English |
topic |
209-1268A 209-1270C 209-1270D 209-1271A 209-1271B 209-1274A DERIDGE DRILL Drilling/drill rig From Mantle to Ocean: Energy- Material- and Life-cycles at Spreading Axes Joides Resolution Leg209 North Atlantic Ocean Ocean Drilling Program ODP |
spellingShingle |
209-1268A 209-1270C 209-1270D 209-1271A 209-1271B 209-1274A DERIDGE DRILL Drilling/drill rig From Mantle to Ocean: Energy- Material- and Life-cycles at Spreading Axes Joides Resolution Leg209 North Atlantic Ocean Ocean Drilling Program ODP Klein, Frieder Bach, Wolfgang Chemical composition of mineral phases of serpentinized and steatized peridotite from the Mid Atlantic Ridge (15°20'N Fracture Zone, ODP Leg209) |
topic_facet |
209-1268A 209-1270C 209-1270D 209-1271A 209-1271B 209-1274A DERIDGE DRILL Drilling/drill rig From Mantle to Ocean: Energy- Material- and Life-cycles at Spreading Axes Joides Resolution Leg209 North Atlantic Ocean Ocean Drilling Program ODP |
description |
Serpentinization of abyssal peridotites is known to produce extremely reducing conditions as a result of dihydrogen (H2,aq) release upon oxidation of ferrous iron in primary phases to ferric iron in secondary minerals by H2O.We have compiled and evaluated thermodynamic data for Fe-Ni-Co-O-S phases and computed phase relations in fO2,g-fS2,g and aH2,aq-aH2S,aq diagrams for temperatures between 150 and 400°C at 50MPa.We use the relations and compositions of Fe-Ni-Co-O-S phases to trace changes in oxygen and sulfur fugacities during progressive serpentinization and steatitization of peridotites from the Mid-Atlantic Ridge in the 15°20'N Fracture Zone area (Ocean Drilling Program Leg 209). Petrographic observations suggest a systematic change from awaruite- magnetite-pentlandite and heazlewoodite-magnetite-pentlandite assemblages forming in the early stages of serpentinization to millerite-pyrite-polydymite-dominated assemblages in steatized rocks. Awaruite is observed in all brucite-bearing partly serpentinized rocks. Apparently, buffering of silica activities to low values by the presence of brucite facilitates the formation of large amounts of hydrogen, which leads to the formation of awaruite. Associated with the prominent desulfurization of pentlandite, sulfide is removed from the rock during the initial stage of serpentinization. In contrast, steatitization indicates increased silica activities and that highsulfur-fugacity sulfides, such as polydymite and pyrite-vaesite solid solution, form as the reducing capacity of the peridotite is exhausted and H2 activities drop. Under these conditions, sulfides will not desulfurize but precipitate and the sulfur content of the rock increases. The co-evolution of fO2,g-fS2,g in the system follows an isopotential of H2S,aq, indicating that H2S in vent fluids is buffered. In contrast, H2 in vent fluids is not buffered by Fe-Ni-Co-O-S phases, which merely monitor the evolution of H2 activities in the fluids in the course of progressive rock alteration.The co-occurrence of ... |
format |
Other/Unknown Material |
author |
Klein, Frieder Bach, Wolfgang |
author_facet |
Klein, Frieder Bach, Wolfgang |
author_sort |
Klein, Frieder |
title |
Chemical composition of mineral phases of serpentinized and steatized peridotite from the Mid Atlantic Ridge (15°20'N Fracture Zone, ODP Leg209) |
title_short |
Chemical composition of mineral phases of serpentinized and steatized peridotite from the Mid Atlantic Ridge (15°20'N Fracture Zone, ODP Leg209) |
title_full |
Chemical composition of mineral phases of serpentinized and steatized peridotite from the Mid Atlantic Ridge (15°20'N Fracture Zone, ODP Leg209) |
title_fullStr |
Chemical composition of mineral phases of serpentinized and steatized peridotite from the Mid Atlantic Ridge (15°20'N Fracture Zone, ODP Leg209) |
title_full_unstemmed |
Chemical composition of mineral phases of serpentinized and steatized peridotite from the Mid Atlantic Ridge (15°20'N Fracture Zone, ODP Leg209) |
title_sort |
chemical composition of mineral phases of serpentinized and steatized peridotite from the mid atlantic ridge (15°20'n fracture zone, odp leg209) |
publisher |
PANGAEA |
publishDate |
2010 |
url |
https://doi.pangaea.de/10.1594/PANGAEA.736007 https://doi.org/10.1594/PANGAEA.736007 |
op_coverage |
MEDIAN LATITUDE: 15.064389 * MEDIAN LONGITUDE: -45.434795 * SOUTH-BOUND LATITUDE: 14.721160 * WEST-BOUND LONGITUDE: -46.676360 * NORTH-BOUND LATITUDE: 15.647780 * EAST-BOUND LONGITUDE: -44.884730 * DATE/TIME START: 2003-05-22T05:45:00 * DATE/TIME END: 2003-06-18T21:45:00 |
long_lat |
ENVELOPE(-46.676360,-44.884730,15.647780,14.721160) |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Supplement to: Klein, Frieder; Bach, Wolfgang (2009): Fe-Ni-Co-O-S Phase Relations in Peridotite-Seawater Interactions. Journal of Petrology, 50, 37-59, https://doi.org/10.1093/petrology/egn071 |
op_relation |
https://doi.pangaea.de/10.1594/PANGAEA.736007 https://doi.org/10.1594/PANGAEA.736007 |
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.73600710.1093/petrology/egn071 |
_version_ |
1810464866978234368 |