Serpentinization of mantle peridotites along an uplifted lithospheric section, Mid Atlantic Ridge at 11° N
| Autor: | Boschi C. [1], Bonatti E. [2, Ligi M. [2], Brunelli D. [2, Cipriani A. [3, 4] Dallai L. [1], D'Orazio M. [5], Früh-Green L. [6], Tonarini S. [1], Barnes J. [7], Bedini R. [8] |
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| Jazyk: | angličtina |
| Rok vydání: | 2013 |
| Předmět: |
010504 meteorology & atmospheric sciences
temporal evolution Vema Fracture Zone Geochemistry Mid-Atlantic Ridge 010502 geochemistry & geophysics 01 natural sciences Mantle (geology) thermal modeling Tectonic uplift serpentinite Geochemistry and Petrology Lithosphere Ultramafic rock Serpentinite Mid-Atlantic ridge Temporal evolution 14. Life underwater isotope 0105 earth and related environmental sciences geochemistry Basalt Geology Crust Vema fracture zone Oxygen 13. Climate action mantle Mylonite |
| Zdroj: | Lithos (Oslo. Print) 178 (2013): 3–23. doi:10.1016/j.lithos.2013.06.003 info:cnr-pdr/source/autori:Boschi C. [1], Bonatti E. [2, 3], Ligi M. [2], Brunelli D. [2, 3], Cipriani A. [3, 4] Dallai L. [1], D'Orazio M. [5], Früh-Green L. [6], Tonarini S. [1], Barnes J. [7], Bedini R. [8]/titolo:Serpentinization of mantle peridotites along an uplifted lithospheric section, Mid Atlantic Ridge at 11° N./doi:10.1016%2Fj.lithos.2013.06.003/rivista:Lithos (Oslo. Print)/anno:2013/pagina_da:3/pagina_a:23/intervallo_pagine:3–23/volume:178 LITHOS |
| DOI: | 10.1016/j.lithos.2013.06.003 |
| Popis: | Mantle peridotites from an exposed lithospheric section (Vema Lithospheric Section, VLS), generated during ~ 26 Ma at a ~ 80 km long Mid Atlantic Ridge segment (11° N), have been sampled and studied to understand the evolution of the serpentinization process. The VLS was uplifted due to a 10 Ma transtensional event along the Vema transform. Before the uplift residual mantle rocks were lying beneath a 0.8–1.3 km thick basaltic crustal layer. The major and trace element compositions of the serpentinites, as well as their H, O, Sr, Cl and B isotopic compositions were interpreted based on thermal models of lithospheric spreading from ridge axis. The results suggest that serpentinization occurred mostly near the ridge axis. Serpentinization temperatures, estimated from stable isotopes, are consistent with resetting of the closure temperatures during the tectonic uplift of the lithospheric sliver, reflected by decreasing δ 18 O and increasing δ 11 B values. Modeling shows that the thermal influence of the transtensional event affected mainly the region close to the RTI (ridge–transform intersection). Petrological, elemental and isotopic data suggest that, when the ultramafic basal unit of the VLS was uplifted and exposed on the ocean floor, serpentinization became superseded by low temperature water–rock reactions, with Fe–Mn crust formation, which is still progressing, as recorded by δD. Ultramafic mylonites, prevalent in a short stretch of the VLS, show only a partial serpentinization process, together with pervasive contamination by low-temperature Fe–Mn crust. |
| Databáze: | OpenAIRE |
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