Oxygen isotopes in ophicalcites: an ever-lasting controversy?
Abstract Tectono-sedimentary breccias, known as ophicalcites, overlie serpentinised peridotites at a Jurassic ocean–continent transition along the Penninic-Austroalpine transition in the Eastern Alps of Switzerland. Deformation of the exhumed mantle rocks and breccia formation occurred under decreas...
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crspringernat:10.1007/s00531-020-01934-5 2023-05-15T17:22:41+02:00 Oxygen isotopes in ophicalcites: an ever-lasting controversy? Bernoulli, Daniel Weissert, Helmut Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung Swiss Federal Institute of Technology Zurich 2020 http://dx.doi.org/10.1007/s00531-020-01934-5 https://link.springer.com/content/pdf/10.1007/s00531-020-01934-5.pdf https://link.springer.com/article/10.1007/s00531-020-01934-5/fulltext.html en eng Springer Science and Business Media LLC https://creativecommons.org/licenses/by/4.0 https://creativecommons.org/licenses/by/4.0 CC-BY International Journal of Earth Sciences volume 110, issue 1, page 1-8 ISSN 1437-3254 1437-3262 General Earth and Planetary Sciences journal-article 2020 crspringernat https://doi.org/10.1007/s00531-020-01934-5 2022-01-04T07:12:49Z Abstract Tectono-sedimentary breccias, known as ophicalcites, overlie serpentinised peridotites at a Jurassic ocean–continent transition along the Penninic-Austroalpine transition in the Eastern Alps of Switzerland. Deformation of the exhumed mantle rocks and breccia formation occurred under decreasing temperatures and along low-angle detachment faults exposing the mantle rocks at the sea floor and was coupled with hydrothermal activity and carbonation of the serpentinites at shallow depth and/or at the sea floor. Carbon isotopes in the ophicalcites persistently show marine values; however, the interpretation of oxygen-isotope values remained controversial: are they related to Jurassic hydrothermal activity or do they reflect Alpine metamorphic overprint? Here we discuss recent interpretations that relate oxygen isotope values measured in ophicalcites exclusively to Jurassic hydrothermal activity; to this end we use data that we earlier obtained along a north–south profile across Graubünden (eastern Switzerland). We revisited the sites of controversial interpretation along a north–south profile in eastern Switzerland. Along this profile, oxygen isotope values in ophicalcites and overlying pelagic sediments, up to 25 my younger than the ophicalcites, show identical values and become systematically lower with increasing Alpine metamorphism; they strongly deviate from values in ophicalcites and pelagic sediments measured along the Mid-Atlantic Ridge or ancient Atlantic ocean-continent transitions as e.g. in the Iberia–Newfoundland transect. The oxygen-isotope values measured in Alpine ophicarbonates thus reflect isotopic resetting during the Alpine orogeny, related to fluid-rock interaction during regional metamorphism. Hydrothermal processes that accompanied the formation of ophicalcites are not disputed; however, they cannot be traced by oxygen isotope geochemistry. Article in Journal/Newspaper Newfoundland Springer Nature (via Crossref) Mid-Atlantic Ridge International Journal of Earth Sciences 110 1 1 8 |
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Springer Nature (via Crossref) |
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English |
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General Earth and Planetary Sciences |
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General Earth and Planetary Sciences Bernoulli, Daniel Weissert, Helmut Oxygen isotopes in ophicalcites: an ever-lasting controversy? |
topic_facet |
General Earth and Planetary Sciences |
description |
Abstract Tectono-sedimentary breccias, known as ophicalcites, overlie serpentinised peridotites at a Jurassic ocean–continent transition along the Penninic-Austroalpine transition in the Eastern Alps of Switzerland. Deformation of the exhumed mantle rocks and breccia formation occurred under decreasing temperatures and along low-angle detachment faults exposing the mantle rocks at the sea floor and was coupled with hydrothermal activity and carbonation of the serpentinites at shallow depth and/or at the sea floor. Carbon isotopes in the ophicalcites persistently show marine values; however, the interpretation of oxygen-isotope values remained controversial: are they related to Jurassic hydrothermal activity or do they reflect Alpine metamorphic overprint? Here we discuss recent interpretations that relate oxygen isotope values measured in ophicalcites exclusively to Jurassic hydrothermal activity; to this end we use data that we earlier obtained along a north–south profile across Graubünden (eastern Switzerland). We revisited the sites of controversial interpretation along a north–south profile in eastern Switzerland. Along this profile, oxygen isotope values in ophicalcites and overlying pelagic sediments, up to 25 my younger than the ophicalcites, show identical values and become systematically lower with increasing Alpine metamorphism; they strongly deviate from values in ophicalcites and pelagic sediments measured along the Mid-Atlantic Ridge or ancient Atlantic ocean-continent transitions as e.g. in the Iberia–Newfoundland transect. The oxygen-isotope values measured in Alpine ophicarbonates thus reflect isotopic resetting during the Alpine orogeny, related to fluid-rock interaction during regional metamorphism. Hydrothermal processes that accompanied the formation of ophicalcites are not disputed; however, they cannot be traced by oxygen isotope geochemistry. |
author2 |
Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung Swiss Federal Institute of Technology Zurich |
format |
Article in Journal/Newspaper |
author |
Bernoulli, Daniel Weissert, Helmut |
author_facet |
Bernoulli, Daniel Weissert, Helmut |
author_sort |
Bernoulli, Daniel |
title |
Oxygen isotopes in ophicalcites: an ever-lasting controversy? |
title_short |
Oxygen isotopes in ophicalcites: an ever-lasting controversy? |
title_full |
Oxygen isotopes in ophicalcites: an ever-lasting controversy? |
title_fullStr |
Oxygen isotopes in ophicalcites: an ever-lasting controversy? |
title_full_unstemmed |
Oxygen isotopes in ophicalcites: an ever-lasting controversy? |
title_sort |
oxygen isotopes in ophicalcites: an ever-lasting controversy? |
publisher |
Springer Science and Business Media LLC |
publishDate |
2020 |
url |
http://dx.doi.org/10.1007/s00531-020-01934-5 https://link.springer.com/content/pdf/10.1007/s00531-020-01934-5.pdf https://link.springer.com/article/10.1007/s00531-020-01934-5/fulltext.html |
geographic |
Mid-Atlantic Ridge |
geographic_facet |
Mid-Atlantic Ridge |
genre |
Newfoundland |
genre_facet |
Newfoundland |
op_source |
International Journal of Earth Sciences volume 110, issue 1, page 1-8 ISSN 1437-3254 1437-3262 |
op_rights |
https://creativecommons.org/licenses/by/4.0 https://creativecommons.org/licenses/by/4.0 |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1007/s00531-020-01934-5 |
container_title |
International Journal of Earth Sciences |
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110 |
container_issue |
1 |
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1 |
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8 |
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1766109502770249728 |