The Cerro del Almirez ultramafic massif offers an example of high pressure and high temperature antigorite serpentinites. A sharp antigorite-out isograd separates them from Chl-harzburgites, consisting of olivine + enstatite + chlorite. Antigorite is characterized by aluminium contents as high as 4 wt.% Al2O3. The microstructural study shows that, prior to the transformation antigorite is exceptionally ordered and consists of the polysome m = 17. No polysomatic defect occurs in antigorite forming most of the Cerro del Almirez serpentinites. Close to the antigorite-out isograd, limited disorder features may occur, mainly as (001) twins, reaction rims and reduction of m down to 14–15. Here, local recrystallization phenomena lead to sporadic growth of large antigorite and chlorite crystals.
Citazione: | Padrón-Navarta, J.A., López Vizcaíno, V., Garrido, C.J., Gómez Pugnare, M.T., Jabaloy, A., Mellini, M., et al. (2008). Highly ordered antigorite from Cerro del Almirez HP–HT serpentinites, SE Spain. CONTRIBUTIONS TO MINERALOGY AND PETROLOGY, 156(5), 679-688. |
Tipo: | Articolo in rivista - Articolo scientifico |
Carattere della pubblicazione: | Scientifica |
Titolo: | Highly ordered antigorite from Cerro del Almirez HP–HT serpentinites, SE Spain |
Autori: | Padrón-Navarta, JA; López Vizcaíno, V; Garrido, CJ; Gómez Pugnare, MT; Jabaloy, A; Mellini, M; Capitani, G |
Autori: | |
Data di pubblicazione: | 2008 |
Lingua: | English |
Rivista: | CONTRIBUTIONS TO MINERALOGY AND PETROLOGY |
Digital Object Identifier (DOI): | 10.1007/s00410-008-0309-x |
Appare nelle tipologie: | 01 - Articolo su rivista |