Agents of low temperature ocean crust alteration |
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Authors: | Hubert Staudigel Karlis Muehlenbachs Stephen H Richardson Stanley R Hart |
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Institution: | (1) Center for Geoalchemy, Department of Earth & Planetary Sciences, Massachusetts Institute of Technology, 02139 Cambridge, Massachusetts, USA;(2) Institut für Mineralogie, Ruhr Universität Bochum, D-463 Bochum, West Germany;(3) Department of Geology, University of Alberta, T6G 2E3 Edmonton, Alberta, Canada;(4) Lamont Doherty Geological Observatory of Columbia University, 10964 Palisades, NY, USA |
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Abstract: |
18O and87Sr/86Sr isotopic data from smectites, calcites, and whole rocks, together with published isotopic age determinations, alkali element concentration data and petrographic observations suggest a sequential model of ocean floor alteration. The early stage lasts about 3 m.y. and is characterized by palagonite and smectite formation, and solutions with a large basaltic component, increasing with temperature which varies from 15° to 80° C at DSDP site 418A. Most carbonates are depositedafter this stage from solutions with a negligible basaltic Sr component and temperatures of 15° to 40° C. Water of seawater Sr and O isotopic composition is shown to percolate to at least 500 m into the basaltic basement. No evidence was found for continuing exchange of strontium or oxygen after 3 m.y.Lamont-Doherty Geological Observatory Contribution number 3199 |
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