There are basic intrusive rocks that have been identified as dolerites [https://pt.wikipedia.org/wiki/Di%C3%A1base] and which occur in the form of veins 0.5 to 3m thick, with an orientation predominantly N-S and vertical inclination. They are dark grey, fine grain and micro-porphyritic, being altered in the contact with the mineralized veins. They present irregular fractures and polyhedral disjunction. Mineralogically they are essentially formed by labradorite, hornblenda, chlorite Chlorite group and amphibolitized pyroxene. They do not affect the mineralization and are intersected by the hydrothermal vein system. These dykes follow the two phases of deformation.