Seismostructural Interpretation of a Seismic Subvolume in the Pitu Field, Potiguar Basin Offshore
Equatorial Margin; Potiguar Basin; rift architecture; evolutionary stages; seismic interpretation
The tectonic evolution of the Potiguar Basin has traditionally been interpreted as the result of two rifting stages integrated into a single evolutionary trajectory. However, divergences persist regarding the understanding of these phases in terms of tectonic regime and basin evolution, especially given the use of the terms “onshore” and “offshore” for distinct structural domains. In this thesis, the integrated analysis of 3D seismic data and well information allowed these interpretations to be revisited and a reinterpretation of the architecture of the rift system to be proposed. The results indicate that the two rifting events correspond, in fact, to distinct tectonic systems— here termed Potiguar I and Potiguar II—and not internal phases of a single basin. Structural mapping reveals that the analyzed area shows no evidence of faults attributable to the first rifting episode, being dominated by structures compatible with the second event, affecting the Pendência, Pescada, and Alagamar formations. This observation implies a revision of the placement of the Alagamar Formation, often described as post-rift based on records from the onshore portion. In the analyzed data, tectonic activity contemporaneous with its deposition is observed, suggesting a late syn-tectonic character in the Potiguar II domain, whereas in the Potiguar I domain the unit retains a post-tectonic character. This differentiation aligns with discussions regarding the existence of a transitional sequence between the rift and post-rift (breakup), for which the Alagamar Formation displays consistent attributes. The application of seismic attributes and filters contributed to the detailed recognition of structural discontinuities, allowing refinement of fault patterns and internal heterogeneities of the basin. In summary, the results obtained demonstrate that the tectonic evolution of the Potiguar Basin is more segmented than suggested by classic regional models. The distinction between Potiguar I and Potiguar II provides a more robust framework for understanding its evolution and contributes to advancing discussions on the complexity of the equatorial margins of the South Atlantic. The results also open possibilities for further investigations, particularly regarding integration with sedimentary data and regional comparisons along the Brazilian Equatorial Margin.