Author(s):
A. Mateus
; Fernando Noronha
Date: 2010
Persistent ID: http://hdl.handle.net/10216/52262
Origin: Repositório Aberto da Universidade do Porto
Description
Deep geological processes, such as the removal of the thermal boundary layer or detachment of the
lithospheric mantle, were crucial to sustain a large-scale high thermal regime during the Variscan orogeny.
The genesis and emplacement of voluminous granitoid rocks represent the main effect of an HT-event
related to that thermal regime, peaking at ca. 340-325 Ma but remaining high enough for several Ma; as a
result of a rapid crustal uplift occurred at ca. 300 Ma, surface heat flow anomalies were developed,
enduring at least till ca. 280 Ma. This evolving thermo-tectonic setting, reducing the crustal strength for a
large time-span, allowed the progress of continuous/discontinuous deformation mechanisms, thus
promoting the development of different tectonic structures, namely shear zones further subjected to
successive reactivation events. Concurrently, it supported an extensive hydrothermal activity throughout
the entire crust, involving distinct fluid sources in successively lower P-T conditions along a continuum that
provided long-lived systems, some of them comprising significant amounts of ore mineral phases.