An appraisal of the Serra da Cangalha impact structure using the Euler deconvolution method

Abstract

Abstract-The applicability of the Euler deconvolution method in imaging impact crater structure vis-à-vis delineation of source depth of the circular magnetic anomaly and/or basement depth beneath the crater is addressed in this paper. The efficacy of the method has been evaluated using the aeromagnetic data obtained over the Serra da Cangalha impact crater, northeastern Brazil. The analyses of the data have provided characteristic Euler deconvolution signatures and structural indices associated with impact craters. Also, through the interpretation of the computed Euler solutions, our understanding of the structural features present around the impact structure has been enhanced. The Euler solutions obtained indicate shallow magnetic sources that are interpreted as possibly post-impact faults and a circular structure. The depth of these magnetic sources varies between 0.8 and 2.5 km, while the Precambrian basement depth was found at ~1.5 km. This is in good agreement with the estimates of the Precambrian basement depth of about 1.1 km, calculated using aeromagnetic data. The reliability of the depth solutions obtained through the implementation of the Euler method was confirmed through the use of the existing information available in the area and the result of previous studies. We find that the Euler depth solutions obtained in this study are consistent with the results obtained using other methods.

Insights into the morphology of the Serra da Cangalha impact structure from geophysical modeling

“…Sources located outside the collar are spread out along the annular basin, showing the largest calculated depth values in the 500–1500 m range. These results, especially those along the collar of the central uplift, show that the magnetic sources under the central uplift are shallower than suggested by Adepelumi et al. (2005) based on analysis of low‐resolution data.…”

“…2010a). According to Adepelumi et al. (2005b), the crystalline basement underneath the structure lies at a depth of 1–1.5 km.…”

The complex impact structure Serra da Cangalha, Tocantins State, Brazil

“…The wider region of the sedimentary basin around Serra da Cangalha appears undeformed, with flat‐lying strata and a morphology dominated by table mountains. Recently, several geophysical studies have been carried out at Serra da Cangalha (Adepelumi et al. 2004, 2005; Abraham et al.…”

Investigation of Shuttle Radar Topography Mission data of the possible impact structure at Serra da Cangalha, Brazil

“…Some geophysical analysis of the structure and modeling of the data has been performed in recent years (Adepelumi et al 2003a(Adepelumi et al , 2003b(Adepelumi et al , 2004(Adepelumi et al , 2005a(Adepelumi et al , 2005b. Interpretation of aeromagnetic data (Adepelumi et al 2003b(Adepelumi et al , 2004) indicated a diameter of 12.7 km for the Serra da Cangalha structure, and the magnetotelluric investigation by Adepelumi et al (2004) resulted in the hypothesis that the likely impact-induced structural deformation below and in the environs of the crater did not exceed a depth of 2 km.…”

“…Interpretation of aeromagnetic data (Adepelumi et al 2003b(Adepelumi et al , 2004) indicated a diameter of 12.7 km for the Serra da Cangalha structure, and the magnetotelluric investigation by Adepelumi et al (2004) resulted in the hypothesis that the likely impact-induced structural deformation below and in the environs of the crater did not exceed a depth of 2 km. A 2-D resistivity model (Adepelumi et al 2005a(Adepelumi et al , 2005b) suggested a 4-layer model for the structure: a thin resistive layer underlain by a conductive layer, weathered basement and, ultimately, resistive crystalline basement. The depth to the basement is estimated at 1.1 km.…”