Arcabouço estrutural da Bacia do São Francisco nos arredores da Serra da Água Fria (MG), a partir da integração de dados de superfície e subsuperfície

The Água Fria Range, located in the eastern portion of the São Francisco Basin, central Brazil, has an essential unique seismic profile (240-RL- 300). This section allows the interpretation of the three main structural styles recognizable in this area, which belongs to a tectonic compartment named “Pirapora Salient”, which is characterized by basement-involved deformation syngenetic to a tectonic inversion of an “intracratonic” basin. Integration of both seismic and field data made possible to establish three structural domains: Eastern, Central and Western. They are defined in the shallower tectonic level respectively as: a fault-related folds predominance; an extensive monoclinal; undulated subhorizontal strata. The deformation rate decreases westward. The eastern domain shows a dramatic structural relief of about 2500m resulting from a strong uplift of this portion related to a regional datum. Deeper structural investigation around Água Fria Range shows an inverted half-graben (Mild Inversion), which is limited by a basement high in its western border (Boqueirão High). While the easternmost normal fault system of Boqueirão High experimented weak structural inverson, the associated covering strata underwent significative shortening as a result of folding related to horizontal displacement. The Boqueirão High formed a rigid buttress that controlled the internal folding/shortening of the synrift sequence. The generation of the Boqueirão Monoclinal was governed by the uplift of the Boqueirão High.The total shortening throughout the area is a result of two mechanisms: the inversion of originally normal faults asssociated to uplift of the basement blocks, together with the folding of covering strata enlarged by horizontal forces.