Fossil black smoker yields oxygen isotopic composition of Neoproterozoic seawater
| Type | Article | ||||||||||||||||||||||||||||
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| Date | 2018-04 | ||||||||||||||||||||||||||||
| Language | English | ||||||||||||||||||||||||||||
| Author(s) | Hodel F.1, 2, Macouin M.1, Trindade R. I. F.2, Triantafyllou A.3, Ganne J.1, Chavagnac V.1, Berger J.1, Rospabé Mathieu 1, Destrigneville C.1, Carlut J.4, Ennih N.5, Agrinier P.4 |
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| Affiliation(s) | 1 : Univ Toulouse, GET, Observ Midi Pyrenees, CNRS,IRD,UPS, F-31400 Toulouse, France. 2 : Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, Dept Geofis, BR-05508090 Sao Paulo, Brazil. 3 : Univ Nantes, UMR CNRS 6112, Lab Planetol & Geodynam, F-44322 Nantes, France. 4 : Univ Paris Diderot, Univ Sorbonne Paris Cite, Inst Phys Globe Paris, CNRS,UMR 7154, F-75005 Paris, France. 5 : Univ Chouaib Doukkali, Fac Sci, Dept Geol, EGGPG, El Jadida 24000, Morocco. |
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| Source | Nature Communications (2041-1723) (Nature Publishing Group), 2018-04 , Vol. 9 , P. 1453 (7p.) | ||||||||||||||||||||||||||||
| DOI | 10.1038/s41467-018-03890-w | ||||||||||||||||||||||||||||
| WOS© Times Cited | 30 | ||||||||||||||||||||||||||||
| Abstract | The evolution of the seawater oxygen isotopic composition (delta O-18) through geological time remains controversial. Yet, the past delta O-18(seawater) is key to assess past seawater temperatures, providing insights into past climate change and life evolution. Here we provide a new and unprecedentedly precise delta O-18 value of -1.33 +/- 0.98% for the Neoproterozoic bottom seawater supporting a constant oxygen isotope composition through time. We demonstrate that the Ait Ahmane ultramafic unit of the ca. 760 Ma Bou Azzer ophiolite (Morocco) host a fossil black smoker-type hydrothermal system. In this system we analyzed an untapped archive for the ocean oxygen isotopic composition consisting in pure magnetite veins directly precipitated from a Neoproterozoic seawater-derived fluid. Our results suggest that, while delta O-18(seawater) and submarine hydrothermal processes were likely similar to present day, Neoproterozoic oceans were 15-30 degrees C warmer on the eve of the Sturtian glaciation and the major life diversification that followed. |
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