Abstract:
In mesozonal crustal levels of southern São Francisco Craton, mafic dykes, dated at 2.19 Ga, were formed in response to NW contraction occurred during the Transamazonian Orogeny. In such event, tholeiitic magma has syntectonically intruded, crystallized and metamorphosed along transcurrent shear zones that developed under high amphibolite facies conditions. Because of this, these dykes, which make up the Paraopeba dyke swarm, are made of amphibolite and keep, locally, a coarse metadiabase with partially preserved igneous textures in the inner part but an amphibolite in sheared margins, with a distinct nematogranoblastic texture.
Keywords:
mafic dykes; transcurrent shear zones; Transamazonian; amphibolites