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| Ponce, Alexis D.; Bertotto, Gustavo W.; Zanetti, Alberto; Brunelli, Daniele; Giovanardi, Tommaso; Aragon, Eugenio; Bernardi, Mauro I.; Hemond, Christophe; Mazzucchelli, Maurizio. |
| Cenozoic basalts carrying ultramafic mantle xenoliths occur in the Matilde, Leon and Chenque hills in the Paso de Indios region, Argentina. The mantle xenoliths from the Chenque and Leon hills mainly present porphyroclastic textures, whereas the Matilde hill xenoliths have coarse-grained to porphyroclastic textures. The equilibrium temperatures are in the range of 780 to 940 degrees C, indicating a provenance from shallow sectors of the lithospheric mantle column that were subjected to a relatively low heat flux at Cenozoic Era. According to the modal compositions of xenoliths, the mantle beneath Matilde and Leon hills was affected by greater than 22% partial melting, while less depleted peridotites occur in the Chenque suite (starting from 10% partial... |
| Tipo: Text |
Palavras-chave: Mantle xenoliths; Alkaline basalts; Paso de Indios; Patagonia. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00639/75150/75503.pdf |
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| Di Giuseppe, Dario; Perchiazzi, Natale; Brunelli, Daniele; Giovanardi, Tommaso; Nodari, Luca; Della Ventura, Giancarlo; Malferrari, Daniele; Maia, Marcia; Gualtieri, Alessandro F.. |
| Tremolite is one of the most common amphibole species and, in the fibrous form (i.e., characterized by crystals/particles consisting of fibres with length > 5 µm, width < 3 µm and aspect ratio > 3), one of the six asbestos minerals. Until now the attention of crystallographers has focused only on samples from continental environment. Here we report the first chemical and structural data of a tremolite asbestos found along the Mid Atlantic Ridge (MAR) at the eastern intersection of the Romanche Transform Fault (Equatorial MAR). Tremolite is associated with chlorite and lizardite and was formed through the green shale facies lower than zeolite in a predominantly fluid system. MAR tremolite asbestos shows very slight deviations from the ideal crystal... |
| Tipo: Text |
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| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00685/79703/82492.pdf |
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