Comparison of iron isotope variations in modern and Ordovician siliceous Fe oxyhydroxide deposits
Formation pathways of ancient siliceous iron formations and related Fe isotopic fractionation are still not completely understood. Investigating these processes, however, is difficult as good modern analogues to ancient iron formations are scarce. Modern siliceous Fe oxyhydroxide deposits are found...
Published in: | Geochimica et Cosmochimica Acta |
---|---|
Main Authors: | , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Elsevier Science
2014
|
Subjects: | |
Online Access: | https://boris.unibe.ch/45296/1/moeller_geochim.pdf https://boris.unibe.ch/45296/ |
id |
ftunivbern:oai:boris.unibe.ch:45296 |
---|---|
record_format |
openpolar |
spelling |
ftunivbern:oai:boris.unibe.ch:45296 2023-08-20T04:06:58+02:00 Comparison of iron isotope variations in modern and Ordovician siliceous Fe oxyhydroxide deposits Möller, Kirsten Schoenberg, Ronny Grenne, Tor Thorseth, Ingunn H. Drost, Kerstin Pedersen, Rolf B. 2014-02-01 application/pdf https://boris.unibe.ch/45296/1/moeller_geochim.pdf https://boris.unibe.ch/45296/ eng eng Elsevier Science https://boris.unibe.ch/45296/ info:eu-repo/semantics/restrictedAccess Möller, Kirsten; Schoenberg, Ronny; Grenne, Tor; Thorseth, Ingunn H.; Drost, Kerstin; Pedersen, Rolf B. (2014). Comparison of iron isotope variations in modern and Ordovician siliceous Fe oxyhydroxide deposits. Geochimica et cosmochimica acta, 126, pp. 422-440. Elsevier Science 10.1016/j.gca.2013.11.018 <http://dx.doi.org/10.1016/j.gca.2013.11.018> 550 Earth sciences & geology info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion PeerReviewed 2014 ftunivbern https://doi.org/10.1016/j.gca.2013.11.018 2023-07-31T21:04:31Z Formation pathways of ancient siliceous iron formations and related Fe isotopic fractionation are still not completely understood. Investigating these processes, however, is difficult as good modern analogues to ancient iron formations are scarce. Modern siliceous Fe oxyhydroxide deposits are found at marine hydrothermal vent sites, where they precipitate from diffuse, low temperature fluids along faults and fissures on the seafloor. These deposits exhibit textural and chemical features that are similar to some Phanerozoic iron formations, raising the question as to whether the latter could have precipitated from diffuse hydrothermal fluids rather than from hydrothermal plumes. In this study, we present the first data on modern Fe oxyhydroxide deposits from the Jan Mayen hydrothermal vent fields, Norwegian-Greenland Sea. The samples we investigated exhibited very low δ56Fe values between -2.09‰ and -0.66‰. Due to various degrees of partial oxidation, the Fe oxyhydroxides are with one exception either indistinguishable from low-temperature hydrothermal fluids from which they precipitated (-1.84‰ and -1.53‰ in δ56Fe) or are enriched in the heavy Fe isotopes. In addition, we investigated Fe isotope variations in Ordovician jasper beds from the Løkken ophiolite complex, Norway, which have been interpreted to represent diagenetic products of siliceous ferrihydrite precursors that precipitated in a hydrothermal plume, in order to compare different formation pathways of Fe oxyhydroxide deposits. Iron isotopes in the jasper samples have higher δ56Fe values (-0.38‰ to +0.89‰) relative to modern, high-temperature hydrothermal vent fluids (ca. -0.40‰ on average), supporting the fallout model. However, formation of the Ordovician jaspers by diffuse venting cannot be excluded, due to lithological differences of the subsurface of the two investigated vent systems. Our study shows that reliable interpretation of Fe isotope variations in modern and ancient marine Fe oxyhydroxide deposits depends on comprehensive knowledge of ... Article in Journal/Newspaper Greenland Greenland Sea Jan Mayen BORIS (Bern Open Repository and Information System, University of Bern) Greenland Jan Mayen Norway Geochimica et Cosmochimica Acta 126 422 440 |
institution |
Open Polar |
collection |
BORIS (Bern Open Repository and Information System, University of Bern) |
op_collection_id |
ftunivbern |
language |
English |
topic |
550 Earth sciences & geology |
spellingShingle |
550 Earth sciences & geology Möller, Kirsten Schoenberg, Ronny Grenne, Tor Thorseth, Ingunn H. Drost, Kerstin Pedersen, Rolf B. Comparison of iron isotope variations in modern and Ordovician siliceous Fe oxyhydroxide deposits |
topic_facet |
550 Earth sciences & geology |
description |
Formation pathways of ancient siliceous iron formations and related Fe isotopic fractionation are still not completely understood. Investigating these processes, however, is difficult as good modern analogues to ancient iron formations are scarce. Modern siliceous Fe oxyhydroxide deposits are found at marine hydrothermal vent sites, where they precipitate from diffuse, low temperature fluids along faults and fissures on the seafloor. These deposits exhibit textural and chemical features that are similar to some Phanerozoic iron formations, raising the question as to whether the latter could have precipitated from diffuse hydrothermal fluids rather than from hydrothermal plumes. In this study, we present the first data on modern Fe oxyhydroxide deposits from the Jan Mayen hydrothermal vent fields, Norwegian-Greenland Sea. The samples we investigated exhibited very low δ56Fe values between -2.09‰ and -0.66‰. Due to various degrees of partial oxidation, the Fe oxyhydroxides are with one exception either indistinguishable from low-temperature hydrothermal fluids from which they precipitated (-1.84‰ and -1.53‰ in δ56Fe) or are enriched in the heavy Fe isotopes. In addition, we investigated Fe isotope variations in Ordovician jasper beds from the Løkken ophiolite complex, Norway, which have been interpreted to represent diagenetic products of siliceous ferrihydrite precursors that precipitated in a hydrothermal plume, in order to compare different formation pathways of Fe oxyhydroxide deposits. Iron isotopes in the jasper samples have higher δ56Fe values (-0.38‰ to +0.89‰) relative to modern, high-temperature hydrothermal vent fluids (ca. -0.40‰ on average), supporting the fallout model. However, formation of the Ordovician jaspers by diffuse venting cannot be excluded, due to lithological differences of the subsurface of the two investigated vent systems. Our study shows that reliable interpretation of Fe isotope variations in modern and ancient marine Fe oxyhydroxide deposits depends on comprehensive knowledge of ... |
format |
Article in Journal/Newspaper |
author |
Möller, Kirsten Schoenberg, Ronny Grenne, Tor Thorseth, Ingunn H. Drost, Kerstin Pedersen, Rolf B. |
author_facet |
Möller, Kirsten Schoenberg, Ronny Grenne, Tor Thorseth, Ingunn H. Drost, Kerstin Pedersen, Rolf B. |
author_sort |
Möller, Kirsten |
title |
Comparison of iron isotope variations in modern and Ordovician siliceous Fe oxyhydroxide deposits |
title_short |
Comparison of iron isotope variations in modern and Ordovician siliceous Fe oxyhydroxide deposits |
title_full |
Comparison of iron isotope variations in modern and Ordovician siliceous Fe oxyhydroxide deposits |
title_fullStr |
Comparison of iron isotope variations in modern and Ordovician siliceous Fe oxyhydroxide deposits |
title_full_unstemmed |
Comparison of iron isotope variations in modern and Ordovician siliceous Fe oxyhydroxide deposits |
title_sort |
comparison of iron isotope variations in modern and ordovician siliceous fe oxyhydroxide deposits |
publisher |
Elsevier Science |
publishDate |
2014 |
url |
https://boris.unibe.ch/45296/1/moeller_geochim.pdf https://boris.unibe.ch/45296/ |
geographic |
Greenland Jan Mayen Norway |
geographic_facet |
Greenland Jan Mayen Norway |
genre |
Greenland Greenland Sea Jan Mayen |
genre_facet |
Greenland Greenland Sea Jan Mayen |
op_source |
Möller, Kirsten; Schoenberg, Ronny; Grenne, Tor; Thorseth, Ingunn H.; Drost, Kerstin; Pedersen, Rolf B. (2014). Comparison of iron isotope variations in modern and Ordovician siliceous Fe oxyhydroxide deposits. Geochimica et cosmochimica acta, 126, pp. 422-440. Elsevier Science 10.1016/j.gca.2013.11.018 <http://dx.doi.org/10.1016/j.gca.2013.11.018> |
op_relation |
https://boris.unibe.ch/45296/ |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1016/j.gca.2013.11.018 |
container_title |
Geochimica et Cosmochimica Acta |
container_volume |
126 |
container_start_page |
422 |
op_container_end_page |
440 |
_version_ |
1774718350412218368 |