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| Karpoff, A. M.; Sauter, D.; Cannat, M.; Ulrich, M.; Manatschal, G.. |
| On the smooth seafloor of exhumed mantle-rocks of the slow-spreading Southwest Indian Ridge, the secondary oxide and carbonate mineralizations record specific chemical signatures of the alteration of serpentinites by low-temperature hydrothermal seawater-dominated fluids. The uncommon characteristics of Fe-oxides forming nodule cortex or thick encrustments are their high Si, low Mn contents, trace elements (e.g. Cr) and REE behavior. Oxides composition evolves through time. Associated to oxides, carbonates (aragonite, calcite, dolomite) characterize the matrix of young indurated serpentinite breccias found at ridge axis. Such mineralogical and geochemical sequences trace, as proxies, the ongoing mantle-exhumation and serpentinization process linked to the... |
| Tipo: Text |
Palavras-chave: Si-Fe-oxides; Hydrothermalism; Seawater-dominated fluids; Serpentinites; Mantle exhumation; Indian Ocean; SWIR. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00367/47771/47821.pdf |
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| Lagabrielle, Yves; Asti, Riccardo; Fourcade, Serge; Corre, Benjamin; Poujol, Marc; Uzel, Jessica; Labaume, Pierre; Clerc, Camille; Lafay, Romain; Picazo, Suzanne; Maury, Rene. |
| In two companion papers, we report the detailed geological and mineralogical study of two emblematic serpentinized ultramafic bodies of the western North Pyrenean Zone (NPZ), the Urdach massif (this paper) and the Saraille massif (paper 2). The peridotites have been exhumed to lower crustal levels during the Cretaceous rifting period in the future NPZ. They are associated with Mesozoic pre-rift metamorphic sediments and small units of thinned Paleozoic basement that were deformed during the mantle exhumation event. Based on detailed geological cross-sections and microprobe mineralogical analyses, we describe the lithology of the two major extensional fault zones that accommodated: (i) the progressive exhumation of the lherzolites along the Cretaceous basin... |
| Tipo: Text |
Palavras-chave: North Pyrenean Zone; Urdach; Mantle exhumation; Fluid-rock interactions; Listvenites; Greenschist facies; Detachment faults; Late Cretaceous. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00637/74920/76106.pdf |
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