Universidad Complutense de Madrid
E-Prints Complutense

Metamorphic evolution of anthophyllite/cummingtonite-cordierite rocks from the upper unit of the Ordenes Complex (Galicia, NW Spain)

Impacto

Downloads

Downloads per month over past year



Abati Gómez, Jacobo and Arenas Martín, Ricardo (2005) Metamorphic evolution of anthophyllite/cummingtonite-cordierite rocks from the upper unit of the Ordenes Complex (Galicia, NW Spain). European Journal of Mineralogy, 17 . pp. 57-68. ISSN ISSN 0935-1221, e-ISSN 1617-4011

[img] PDF
Restringido a Repository staff only

9MB

Official URL: http://eurjmin.geoscienceworld.org/content/17/1/57




Abstract

Two types of low-Ca amphibolites are described for the first time in the Ordenes Complex (Galicia, NW Spain). The first type exhibits an initial mineral assemblage containing sillimanite, staurolite and anthophyllite, which are found as microinclusions in cordierite crystals. This association indicates medium pressure and temperatures above 600ºC, and is replaced in the matrix by a medium to low-pressure assemblage of anthophyllite, cordierite and garnet. The second type is represented by lowpressure amphibolitic gneisses formed mainly of cummingtonite, cordierite, andalusite and garnet. The first type of amphibolite would appear to give rise to the second type as a result of metamorphic evolution to lower pressures . A fragment of the decompressive P-T path was obtained by a detailed study of the mineral assemblage succession and the textural relationships of these rocks. The P-T path begins with an almost isothermal decompression from ca. 6-7 kbar and 650ºC. This kind of P-T path (isothermal) is usually interpreted, according to thermal models, as originating during exhumation favoured by some tectonic process. Hence, the exhumation of the uppermost unit of the Ordenes Complex, in which the anthophyllite-cummingtonite rocks are located, appears to have been facilitated by some kind of extensional tectonic process.


Item Type:Article
Uncontrolled Keywords:Metamorphic evolution, Anthophyllite, Cummingtonite, Cordierite, Low-Ca amphibolites, Ordenes Complex, NW Spain.
Subjects:Sciences > Geology > Petrology
ID Code:43395
Deposited On:02 Aug 2017 08:13
Last Modified:02 Aug 2017 08:13

Origin of downloads

Repository Staff Only: item control page