Interpretation of the aeromagnetic signatures of the Serra da Cangalha impact crater

In this paper, the results obtained from the processing and inversion of aeromagnetic data of the Serra da Cangalha impact crater region coupled with the results of the geodynamics modeling of crater formation obtained through scaling relations are presented. An understanding of the tectonic features around the Serra da Cangalha impact crater were obtained through the interpretation of the aeromagnetic data. The most propable incident angle for the bolide that struck the region about 300 million years ago was deduced based on the pi-scaling relation to be between 25o - 30o above the horizon. Based on information obtained from the landsat image, the trajectory of the impacting bolide is suggested to be in the northwest-to-southeast direction. The development of the impact crater was controlled by the pre-impact NE – SW geoctectonic structures existing in the region. The crater boundary is well resolved from the horizontal and vertical gradient maxima maps. In addition, we obserrve that the magnetic gradient is fairly high in the impact region and adjacent areas, while it is surrounded by low magnetic gradients throughout most of the northwest and southeast portions of the crater center. The 3D analytic signal calculated produces a maximum over the source edges of the magnetic anomaly that delineate the impact crater boundary. Generally, the analysis of the aeromagnetic data suggest a predominantly shallow source with high frequency magnetic anomalies seen at the Serra da Cangalha region. The central structural uplift at the centre is estimated to be 1.2 Km relative to the surrounding basement surface while the depth to the crater floor is deduced to be 1.02 km using pi-scaling relations. A distinct uplifed basement that we suspected was due to the impact of the meteorite was delineated at about 1.2 km depth.