Composition of hydrothermal fluids and mineralogy of associated chimney material on the East Scotia Ridge back-arc spreading centre
© The Author(s), 2014. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Geochimica et Cosmochimica Acta 139 (2014): 47-71, doi:10.1016/j.gca.2014.04.024. The East Scotia Ridge is an active back-arc spreading centre locat...
Published in: | Geochimica et Cosmochimica Acta |
---|---|
Main Authors: | , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Elsevier
2014
|
Subjects: | |
Online Access: | https://hdl.handle.net/1912/6821 |
id |
ftwhoas:oai:darchive.mblwhoilibrary.org:1912/6821 |
---|---|
record_format |
openpolar |
spelling |
ftwhoas:oai:darchive.mblwhoilibrary.org:1912/6821 2023-05-15T18:25:58+02:00 Composition of hydrothermal fluids and mineralogy of associated chimney material on the East Scotia Ridge back-arc spreading centre James, Rachael H. Green, Darryl R. H. Stock, Michael J. Alker, Belinda J. Banerjee, Neil R. Cole, Catherine German, Christopher R. Huvenne, Veerle A. I. Powell, Alexandra M. Connelly, Douglas P. 2014-05-06 application/pdf https://hdl.handle.net/1912/6821 en_US eng Elsevier https://doi.org/10.1016/j.gca.2014.04.024 Geochimica et Cosmochimica Acta 139 (2014): 47-71 https://hdl.handle.net/1912/6821 doi:10.1016/j.gca.2014.04.024 Attribution 3.0 Unported http://creativecommons.org/licenses/by/3.0/ CC-BY Geochimica et Cosmochimica Acta 139 (2014): 47-71 doi:10.1016/j.gca.2014.04.024 Article 2014 ftwhoas https://doi.org/10.1016/j.gca.2014.04.024 2022-05-28T22:59:09Z © The Author(s), 2014. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Geochimica et Cosmochimica Acta 139 (2014): 47-71, doi:10.1016/j.gca.2014.04.024. The East Scotia Ridge is an active back-arc spreading centre located to the west of the South Sandwich island arc in the Southern Ocean. Initial exploration of the ridge by deep-tow surveys provided the first evidence for hydrothermal activity in a back-arc setting outside of the western Pacific, and we returned in 2010 with a remotely operated vehicle to precisely locate and sample hydrothermal sites along ridge segments E2 and E9. Here we report the chemical and isotopic composition of high- and low-temperature vent fluids, and the mineralogy of associated high-temperature chimney material, for two sites at E2 (Dog’s Head and Sepia), and four sites at E9 (Black & White, Ivory Tower, Pagoda and Launch Pad). The chemistry of the fluids is highly variable between the ridge segments. Fluid temperatures were ∼350 °C at all vent sites except Black & White, which was significantly hotter (383 °C). End-member chloride concentrations in E2 fluids (532–536 mM) were close to background seawater (540 mM), whereas Cl in E9 fluids was much lower (98–220 mM) indicating that these fluids are affected by phase separation. Concentrations of the alkali elements (Na, Li, K and Cs) and the alkaline earth elements (Ca, Sr and Ba) co-vary with Cl, due to charge balance constraints. Similarly, concentrations of Mn and Zn are highest in the high Cl fluids but, by contrast, Fe/Cl ratios are higher in E9 fluids (3.8–8.1 × 10−3) than they are in E2 fluids (1.5–2.4 × 10−3) and fluids with lowest Cl have highest Cu. Although both ridge segments are magmatically inflated, there is no compelling evidence for input of magmatic gases to the vent fluids. Fluid δD values range from 0.2‰ to 1.5‰, pH values (3.02–3.42) are not especially low, and F concentrations (34.6–54.4 μM) are lower than bottom seawater ... Article in Journal/Newspaper Southern Ocean Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) Southern Ocean Pacific East Scotia Ridge ENVELOPE(-29.250,-29.250,-57.917,-57.917) Ivory Tower ENVELOPE(-142.400,-142.400,-85.467,-85.467) Geochimica et Cosmochimica Acta 139 47 71 |
institution |
Open Polar |
collection |
Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) |
op_collection_id |
ftwhoas |
language |
English |
description |
© The Author(s), 2014. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Geochimica et Cosmochimica Acta 139 (2014): 47-71, doi:10.1016/j.gca.2014.04.024. The East Scotia Ridge is an active back-arc spreading centre located to the west of the South Sandwich island arc in the Southern Ocean. Initial exploration of the ridge by deep-tow surveys provided the first evidence for hydrothermal activity in a back-arc setting outside of the western Pacific, and we returned in 2010 with a remotely operated vehicle to precisely locate and sample hydrothermal sites along ridge segments E2 and E9. Here we report the chemical and isotopic composition of high- and low-temperature vent fluids, and the mineralogy of associated high-temperature chimney material, for two sites at E2 (Dog’s Head and Sepia), and four sites at E9 (Black & White, Ivory Tower, Pagoda and Launch Pad). The chemistry of the fluids is highly variable between the ridge segments. Fluid temperatures were ∼350 °C at all vent sites except Black & White, which was significantly hotter (383 °C). End-member chloride concentrations in E2 fluids (532–536 mM) were close to background seawater (540 mM), whereas Cl in E9 fluids was much lower (98–220 mM) indicating that these fluids are affected by phase separation. Concentrations of the alkali elements (Na, Li, K and Cs) and the alkaline earth elements (Ca, Sr and Ba) co-vary with Cl, due to charge balance constraints. Similarly, concentrations of Mn and Zn are highest in the high Cl fluids but, by contrast, Fe/Cl ratios are higher in E9 fluids (3.8–8.1 × 10−3) than they are in E2 fluids (1.5–2.4 × 10−3) and fluids with lowest Cl have highest Cu. Although both ridge segments are magmatically inflated, there is no compelling evidence for input of magmatic gases to the vent fluids. Fluid δD values range from 0.2‰ to 1.5‰, pH values (3.02–3.42) are not especially low, and F concentrations (34.6–54.4 μM) are lower than bottom seawater ... |
format |
Article in Journal/Newspaper |
author |
James, Rachael H. Green, Darryl R. H. Stock, Michael J. Alker, Belinda J. Banerjee, Neil R. Cole, Catherine German, Christopher R. Huvenne, Veerle A. I. Powell, Alexandra M. Connelly, Douglas P. |
spellingShingle |
James, Rachael H. Green, Darryl R. H. Stock, Michael J. Alker, Belinda J. Banerjee, Neil R. Cole, Catherine German, Christopher R. Huvenne, Veerle A. I. Powell, Alexandra M. Connelly, Douglas P. Composition of hydrothermal fluids and mineralogy of associated chimney material on the East Scotia Ridge back-arc spreading centre |
author_facet |
James, Rachael H. Green, Darryl R. H. Stock, Michael J. Alker, Belinda J. Banerjee, Neil R. Cole, Catherine German, Christopher R. Huvenne, Veerle A. I. Powell, Alexandra M. Connelly, Douglas P. |
author_sort |
James, Rachael H. |
title |
Composition of hydrothermal fluids and mineralogy of associated chimney material on the East Scotia Ridge back-arc spreading centre |
title_short |
Composition of hydrothermal fluids and mineralogy of associated chimney material on the East Scotia Ridge back-arc spreading centre |
title_full |
Composition of hydrothermal fluids and mineralogy of associated chimney material on the East Scotia Ridge back-arc spreading centre |
title_fullStr |
Composition of hydrothermal fluids and mineralogy of associated chimney material on the East Scotia Ridge back-arc spreading centre |
title_full_unstemmed |
Composition of hydrothermal fluids and mineralogy of associated chimney material on the East Scotia Ridge back-arc spreading centre |
title_sort |
composition of hydrothermal fluids and mineralogy of associated chimney material on the east scotia ridge back-arc spreading centre |
publisher |
Elsevier |
publishDate |
2014 |
url |
https://hdl.handle.net/1912/6821 |
long_lat |
ENVELOPE(-29.250,-29.250,-57.917,-57.917) ENVELOPE(-142.400,-142.400,-85.467,-85.467) |
geographic |
Southern Ocean Pacific East Scotia Ridge Ivory Tower |
geographic_facet |
Southern Ocean Pacific East Scotia Ridge Ivory Tower |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
Geochimica et Cosmochimica Acta 139 (2014): 47-71 doi:10.1016/j.gca.2014.04.024 |
op_relation |
https://doi.org/10.1016/j.gca.2014.04.024 Geochimica et Cosmochimica Acta 139 (2014): 47-71 https://hdl.handle.net/1912/6821 doi:10.1016/j.gca.2014.04.024 |
op_rights |
Attribution 3.0 Unported http://creativecommons.org/licenses/by/3.0/ |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1016/j.gca.2014.04.024 |
container_title |
Geochimica et Cosmochimica Acta |
container_volume |
139 |
container_start_page |
47 |
op_container_end_page |
71 |
_version_ |
1766207722349395968 |