Geology of the Montigiu Nieddu metamorphic basement, NE Sardinia (Italy)

Abstract

A geological map at 1:10,000 scale is presented that shows the distribution of the metamorphic rock units in the area of Montigiu (Mt.) Nieddu (NE Sardinia). These units belong to the High-Grade Metamorphic Complex in the Inner Zone of the Variscan chain of Sardinia. The rocks include different types of migmatite, amphibolite, and retrogressed eclogites. The geological map and cross section show the complex tectonic and metamorphic setting of the area, whereas the metamorphic assemblages and deformation framework represent a valuable tool for the reconstruction of the P-T metamorphic evolution for the crustal sectors involved in the Variscan orogeny. The metamorphic rock units reported in the map derived from the lower and upper continental plates involved in the Variscan collision and were tectonically juxtaposed during the early Carboniferous exhumation stage.

Garnet-Rich Veins in an Ultrabasic Amphibolite from NE Sardinia, Italy: An Example of Vein Mineralogical Re-Equilibration during the Exhumation of a Granulite Terrane

“…The metamorphic evolution and the P-T path of the Mt. Nieddu ultrabasic amphibolite were reconstructed by [35,61] through thermodynamic modelling via P-T pseudosections and conventional thermobarometry on such textures in selected samples from Layer B. The authors of [35] documented that the ultrabasic amphibolites underwent an anticlockwise P-T path that started with an igneous stage followed by progressive cooling to granulite-, amphibolite-, and greenschist-facies conditions.…”