The Seven Sisters Hydrothermal System: First Record of Shallow Hybrid Mineralization Hosted in Mafic Volcaniclasts on the Arctic Mid-Ocean Ridge
We document the discovery of an active, shallow, seafloor hydrothermal system (known as the Seven Sisters Vent Field) hosted in mafic volcaniclasts at a mid-ocean ridge setting. The vent field is located at the southern part of the Arctic mid-ocean ridge where it lies on top of a flat-topped volcano...
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ftmdpi:oai:mdpi.com:/2075-163X/10/5/439/ 2023-08-20T04:04:28+02:00 The Seven Sisters Hydrothermal System: First Record of Shallow Hybrid Mineralization Hosted in Mafic Volcaniclasts on the Arctic Mid-Ocean Ridge Ana Filipa A. Marques Desiree L. Roerdink Tamara Baumberger Cornel E. J. de Ronde Robert G. Ditchburn Alden Denny Ingunn H. Thorseth Ingeborg Okland Marvin D. Lilley Martin J. Whitehouse Rolf B. Pedersen agris 2020-05-15 application/pdf https://doi.org/10.3390/min10050439 EN eng Multidisciplinary Digital Publishing Institute Mineral Deposits https://dx.doi.org/10.3390/min10050439 https://creativecommons.org/licenses/by/4.0/ Minerals; Volume 10; Issue 5; Pages: 439 seafloor hydrothermal system volcaniclast-hosted VMS fluid chemistry radiometric dating Text 2020 ftmdpi https://doi.org/10.3390/min10050439 2023-07-31T23:30:21Z We document the discovery of an active, shallow, seafloor hydrothermal system (known as the Seven Sisters Vent Field) hosted in mafic volcaniclasts at a mid-ocean ridge setting. The vent field is located at the southern part of the Arctic mid-ocean ridge where it lies on top of a flat-topped volcano at ~130 m depth. Up to 200 °C phase-separating fluids vent from summit depressions in the volcano, and from pinnacle-like edifices on top of large hydrothermal mounds. The hydrothermal mineralization at Seven Sisters manifests as a replacement of mafic volcaniclasts, as direct intraclast precipitation from the hydrothermal fluid, and as elemental sulfur deposition within orifices. Barite is ubiquitous, and is sequentially replaced by pyrite, which is the first sulfide to form, followed by Zn-Cu-Pb-Ag bearing sulfides, sulfosalts, and silica. The mineralized rocks at Seven Sisters contain highly anomalous concentrations of ‘epithermal suite’ elements such as Tl, As, Sb and Hg, with secondary alteration assemblages including silica and dickite. Vent fluids have a pH of ~5 and are Ba and metal depleted. Relatively high dissolved Si (~7.6 mmol/L Si) combined with low (0.2–0.4) Fe/Mn suggest high-temperature reactions at ~150 bar. A δ13C value of −5.4‰ in CO2 dominated fluids denotes magmatic degassing from a relatively undegassed reservoir. Furthermore, low CH4 and H2 (<0.026 mmol/kg and <0.009 mmol/kg, respectively) and 3He/4He of ~8.3 R/Racorr support a MORB-like, sediment-free fluid signature from an upper mantle source. Sulfide and secondary alteration mineralogy, fluid and gas chemistry, as well as δ34S and 87Sr/86Sr values in barite and pyrite indicate that mineralization at Seven Sisters is sustained by the input of magmatic fluids with minimal seawater contribution. 226Ra/Ba radiometric dating of the barite suggests that this hydrothermal system has been active for at least 4670 ± 60 yr. Text Arctic MDPI Open Access Publishing Arctic Pinnacle ENVELOPE(-54.900,-54.900,-61.067,-61.067) Minerals 10 5 439 |
institution |
Open Polar |
collection |
MDPI Open Access Publishing |
op_collection_id |
ftmdpi |
language |
English |
topic |
seafloor hydrothermal system volcaniclast-hosted VMS fluid chemistry radiometric dating |
spellingShingle |
seafloor hydrothermal system volcaniclast-hosted VMS fluid chemistry radiometric dating Ana Filipa A. Marques Desiree L. Roerdink Tamara Baumberger Cornel E. J. de Ronde Robert G. Ditchburn Alden Denny Ingunn H. Thorseth Ingeborg Okland Marvin D. Lilley Martin J. Whitehouse Rolf B. Pedersen The Seven Sisters Hydrothermal System: First Record of Shallow Hybrid Mineralization Hosted in Mafic Volcaniclasts on the Arctic Mid-Ocean Ridge |
topic_facet |
seafloor hydrothermal system volcaniclast-hosted VMS fluid chemistry radiometric dating |
description |
We document the discovery of an active, shallow, seafloor hydrothermal system (known as the Seven Sisters Vent Field) hosted in mafic volcaniclasts at a mid-ocean ridge setting. The vent field is located at the southern part of the Arctic mid-ocean ridge where it lies on top of a flat-topped volcano at ~130 m depth. Up to 200 °C phase-separating fluids vent from summit depressions in the volcano, and from pinnacle-like edifices on top of large hydrothermal mounds. The hydrothermal mineralization at Seven Sisters manifests as a replacement of mafic volcaniclasts, as direct intraclast precipitation from the hydrothermal fluid, and as elemental sulfur deposition within orifices. Barite is ubiquitous, and is sequentially replaced by pyrite, which is the first sulfide to form, followed by Zn-Cu-Pb-Ag bearing sulfides, sulfosalts, and silica. The mineralized rocks at Seven Sisters contain highly anomalous concentrations of ‘epithermal suite’ elements such as Tl, As, Sb and Hg, with secondary alteration assemblages including silica and dickite. Vent fluids have a pH of ~5 and are Ba and metal depleted. Relatively high dissolved Si (~7.6 mmol/L Si) combined with low (0.2–0.4) Fe/Mn suggest high-temperature reactions at ~150 bar. A δ13C value of −5.4‰ in CO2 dominated fluids denotes magmatic degassing from a relatively undegassed reservoir. Furthermore, low CH4 and H2 (<0.026 mmol/kg and <0.009 mmol/kg, respectively) and 3He/4He of ~8.3 R/Racorr support a MORB-like, sediment-free fluid signature from an upper mantle source. Sulfide and secondary alteration mineralogy, fluid and gas chemistry, as well as δ34S and 87Sr/86Sr values in barite and pyrite indicate that mineralization at Seven Sisters is sustained by the input of magmatic fluids with minimal seawater contribution. 226Ra/Ba radiometric dating of the barite suggests that this hydrothermal system has been active for at least 4670 ± 60 yr. |
format |
Text |
author |
Ana Filipa A. Marques Desiree L. Roerdink Tamara Baumberger Cornel E. J. de Ronde Robert G. Ditchburn Alden Denny Ingunn H. Thorseth Ingeborg Okland Marvin D. Lilley Martin J. Whitehouse Rolf B. Pedersen |
author_facet |
Ana Filipa A. Marques Desiree L. Roerdink Tamara Baumberger Cornel E. J. de Ronde Robert G. Ditchburn Alden Denny Ingunn H. Thorseth Ingeborg Okland Marvin D. Lilley Martin J. Whitehouse Rolf B. Pedersen |
author_sort |
Ana Filipa A. Marques |
title |
The Seven Sisters Hydrothermal System: First Record of Shallow Hybrid Mineralization Hosted in Mafic Volcaniclasts on the Arctic Mid-Ocean Ridge |
title_short |
The Seven Sisters Hydrothermal System: First Record of Shallow Hybrid Mineralization Hosted in Mafic Volcaniclasts on the Arctic Mid-Ocean Ridge |
title_full |
The Seven Sisters Hydrothermal System: First Record of Shallow Hybrid Mineralization Hosted in Mafic Volcaniclasts on the Arctic Mid-Ocean Ridge |
title_fullStr |
The Seven Sisters Hydrothermal System: First Record of Shallow Hybrid Mineralization Hosted in Mafic Volcaniclasts on the Arctic Mid-Ocean Ridge |
title_full_unstemmed |
The Seven Sisters Hydrothermal System: First Record of Shallow Hybrid Mineralization Hosted in Mafic Volcaniclasts on the Arctic Mid-Ocean Ridge |
title_sort |
seven sisters hydrothermal system: first record of shallow hybrid mineralization hosted in mafic volcaniclasts on the arctic mid-ocean ridge |
publisher |
Multidisciplinary Digital Publishing Institute |
publishDate |
2020 |
url |
https://doi.org/10.3390/min10050439 |
op_coverage |
agris |
long_lat |
ENVELOPE(-54.900,-54.900,-61.067,-61.067) |
geographic |
Arctic Pinnacle |
geographic_facet |
Arctic Pinnacle |
genre |
Arctic |
genre_facet |
Arctic |
op_source |
Minerals; Volume 10; Issue 5; Pages: 439 |
op_relation |
Mineral Deposits https://dx.doi.org/10.3390/min10050439 |
op_rights |
https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.3390/min10050439 |
container_title |
Minerals |
container_volume |
10 |
container_issue |
5 |
container_start_page |
439 |
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1774714841064275968 |