The Cubatão Megafault System represents an extensive strike slip system exposed along about 800 km with a minimum breadth of about 150 km and a maximum of 350 km when considered as part of the Socorro-Guaxupé thrust wedges. The main fault zone is represented by the Cubatão-Além Paraíba and Lancinha faults. The extension of this fault zone has been detected beneath the sediments of the Paraná Basin for at least an additional 1,200 km implying a length of more then 2,000 km, which is longer than the San Andreas fault. The fault affects different structural levels of the crust and has exhibited different behaviour throughout its history of activity. It was essentially ductile at depth during the Proterozoic where deep granuütes were dragged about 40 km along the Além Paraíba fault segment. The mylonites are folded and show an overprinted schistosity marked by neocrystallized biotites of Proterozoic age. The drags show the effect of right lateral kinematics during this phase; however left lateral activation is suggested by the distribution of a pattern of secondary faults related to later events. The fault system is offset at its intersection with the NW striking Guapiara, Ubatuba and Cabo Frio-Poços de Caldas Lineaments. The Cubatão fault sensu strictu shows a controversial thrust-strike slip pair envolving a wedge of low grade metamorphic rocks. Oblique slip and transtensional basin formation envolved the fault system during the Tertiary and originated the Serra do Mar Rift. Plots of earthquake activity show that NW striking faults which cut the system transversally are still being activated. The origin of this enormous transcurrency may be related to a collision between Proterozoic cratonic masses and consequent escape tectonics or, oblique subduction effects.
