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In the portuguese section of the Central Iberian Zone, the Guimaraes region hosts a wide diversity of plutonic variscan lithologies including biotite-rich granitoids and vaugnerites. Vaugnerite outcrops occur as small bodies, typically enclosed by the main regional granite (the coarse-grained, biotite-rich, porphyritic Guimaraes and Santo Tirso monzogranite). Mafic enclaves of vaugnerites can also be identified in the host granite. The granitoids are peraluminous (ASI = 1.10 ? 1.15), having crystallized from melts...

The aim of this study is to contribute to the detection and identification of hydrothermal alteration zones in Variscan granites using magnetic susceptibility. The studied area is located in the North-western of Portugal and is characterised by the occurrence of Au mineralizations in quartz veins hosted in Variscan granites. Three different granite facies were studied, using two methodologies: (i) measurements, in situ, of magnetic susceptibility using a portable susceptibility meter (TerraPlus KT-10), allowing th...