Sequential anatectic processes in mindelo migmatite complex (NW portugal) [Sequência de processos anatéticos no Complexo Migmatítico de Mindelo (NW de Portugal)]

• Type: Article in International Scientific Journal
• Date: 2014

Authors

Areias, M (Author) Other; Ribeiro, MA (Author) FCUP; Santos, JF (Author) Other; Doria, A (Author) Other

Journal

Title: Comunicações Geológicas

Vol. 101

Pages: 35-39

ISSN: 0873-948X

Publisher: LNEG - Laboratório Nacional de Energia e Geologia

Indexing

ISI Web of Knowledge

Scopus - 0 Citations

Other information

Authenticus ID: P-00G-507

Abstract (EN): Mindelo Migmatitic Complex outcrops in the coastal-zone, north of Porto. This complex consists on a set of diverse lithologies including metasedimentary, migmatitic and granitic rocks, and pegmatite veins. Field relationships, petrography, geochemistry and isotopic signature of these lithologies allow inferring the sequence of anatectic processes that are responsible for the lithological heterogeneity. The melting occurred at different structural levels, and thus at different pressure and temperature conditions, generating rocks with specific characteristics: i) in shallow levels (<3.5 Kbar) metatexites are produced essentially by water-saturated melting followed by water-undersaturated biotite melting. Leucogranites resulted from migration of leucosomes; (ii) in slightly deeper levels the melting rate is higher which leads to the formation of diatexites that intruded metatexites; (iii) in even deeper levels (~ 5 Kbar) higher pressure and temperature permit the melting of muscovite producing a large amount of typical two-mica granite melts. This material rises in the crust and incorporates abundant xenoliths forming a very heterogeneous granitic body. In subsolidus conditions, structurally controlled metasomatic processes lead to feldspatization of migmatites and granitoids. Later, installation of aplite-pegmatites and local tourmalinization previously formed granitoids took place. © 2014 LNEG ¿ Laboratório Nacional de Geologia e Energia IP.

Language: Portuguese

Type (Professor's evaluation): Scientific