Marine magnetotelluric mapping of basement and salt bodies in the Santos Basin of Brazil

Fontes, Sergio L.; Lugăo, Patricia Pastana de; Meju, Max A.; Pinto, Vinicius R.; Flexor, J-M.; Ulugergerli, Emin U.; Terra, Emanuele F. La; Gallardo, Luis A.; Rijo, Luiz

doi:10.3997/1365-2397.27.1299.28933

Cited by 12 publications

(6 citation statements)

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“…It is very significant, unlike the past 2D MT results (Fontes et al, 2009;Gallardo et al, 2012) we can clearly identify four key structural features in the basement cover rocks (numbered 1 to 4 in Figure 9) based on the remarkable spatial correlation between the resistivity, seismic and gravity anomaly patterns. The features labeled 1, 2, 3 and 4 represent alternating grabens and horsts in the well-known extensional domain.…”

Section: Shallow Crustal Resistivity Structurementioning

confidence: 62%

“…The sedimentary wedge comprises alternating electrically conductive (C1, C2 and C3) and laterally discontinuous resistive (R1, R2, and R3) layers (Figures 6c, 7b, and 9a). Layer R3 has intercalations of very highly resistive units that we interpret as igneous bodies since sills have been interpreted from seismic data nearby in past studies (e.g., Fontes et al., 2009; Gallardo et al., 2012; de Lugao et al., 2008). It is remarkable that feature R3 is structurally conformable to the zones of Upper Cretaceous roll‐over (“turtle‐back”) structures in the seismic section (Figure 9) and would imply that these are volcanic‐associated seaward‐dipping reflectors.…”

Section: Interpretation and Discussionmentioning

confidence: 72%

“…The stations were rotated using the coherency between the magnetic channels and land data from Vassouras Magnetic Observatory in Rio de Janeiro, Brazil. More details of the data processing can be found in past literature (Fontes et al., 2009; Miquelutti et al., 2016; Pinto, 2013). The processed MT data set covers the full impedance tensor Z with 26 periods ranging from 0.2 to 3,162 s (data pseudosections are shown in Text S4 in Supporting Information S1).…”

Section: Legacy Marine Mt Data and Their Analysismentioning

confidence: 99%

“…De Lugao et al (2008) presented a preliminary 2D application using the MT data for the central profile and suggested a good correlation with the seismic interpretation. Fontes et al (2009) showed the improvement and challenges faced in 2D data analysis to map the basement and salt bodies. Gallardo et al (2012) performed a joint 2D inversion of seismic reflection, MT, gravity and magnetic data for a better understanding of Santos basin architecture.…”

Section: Introductionmentioning

confidence: 99%

“…(b) 2D pre‐stack depth migrated seismic section along magnetotelluric (MT) line L2 taken from Fontes et al. (2009) and our inferred key stratigraphic boundaries and position of the AG (light blue bar) following the interpretation scheme in (a). MT stations are shown by the receiver symbols on the seabed.…”

Section: Introductionmentioning

confidence: 99%

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Deep Structure of the Santos Basin, Offshore Brazil From 3D Inversion of magnetotelluric Data

Benevides,

Meju,

Fontes

et al. 2024

JGR Solid Earth

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The relationship between deep crustal structure and the deformation in the overlying sedimentary wedge in Santos basin, Brazil is not well understood, and the origin and evolution of the salt‐related “Albian Gap (AG)” remain a topic of debate. We investigate the deep structure using three‐dimensional inversion of full tensor marine magnetotelluric (MT) data (of 10−1 to 104 s period bandwidth) from 92 stations along three NW–SE lines in 50–1,700 m water depth, one crossing the Cretaceous hinge line (CHL), AG, and Cabo Frio Fault (CFF). The geological validity of the resulting MT resistivity models was determined using resistivity logs from 11 wells and seismic data. The model shows two regionally persistent electrically conductive layers (C2 and C3) related to key Cenozoic and Cretaceous unconformities in the upper part of the sedimentary wedge. Beneath this wedge, the resistive continental crust is ∼35 km thick across the CHL until the 200 m isobath and thereafter thins rapidly seaward to ∼21 km over a lateral distance of ∼80 km defining a domain of highly extended and faulted crust. Our models show a mantle‐associated basement high and evidence of significant uplift of the lower part of the sedimentary wedge at 100–150 km distance along our central profile which spatially coincides with the AG and a previously proposed Moho high. This implies a mantle‐driven deformation of the crust and basin fill. We propose that mantle flow and magmatism may have played a significant role in the inferred displacement at the AG.

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Section: Shallow Crustal Resistivity Structurementioning

confidence: 62%