AUTHOR=Plawiak Rafael André Belotto , Carvalho Marcelo José , Sombra Cristiano Leite , Brandão Davy Raeder , Mepen Michelle , Ferrari André Luiz , Gambôa Luiz Antônio Pierantoni 

TITLE=Structural controls of the migration of mantle-derived CO2 offshore in the Santos Basin (Southeastern Brazil)

JOURNAL=Frontiers in Earth Science

VOLUME=11

YEAR=2024

URL=https://www.frontiersin.org/journals/earth-science/articles/10.3389/feart.2023.1284151

DOI=10.3389/feart.2023.1284151

ISSN=2296-6463

ABSTRACT=<p>We present a multi-scale conceptual model based on structural controls of the migration of mantle-derived CO<sub>2</sub> offshore in the Santos Basin (Southeastern Brazil). We assembled the model from a regional 2D seismic reflection line integrated with potential gravimetric field data and a local 3D seismic reflection volume integrated with well data (lithologies and <italic>in situ</italic> stress). (i) The geochemical isotope range of δ<sup>13</sup>C<sub>CO2</sub> falls mostly within −7‰ and −5‰ and shows relatively high values for <sup>3</sup>He/<sup>4</sup>He represented by an R/Ra rate of up to 5.60, indicating CO<sub>2</sub> mantle generation and degassing. (ii) Seismic interpretation feasibly validated by potential gravimetric responses of the crustal structure (Moho discontinuity) show CO<sub>2</sub> migration through deep-seated faults in a region of highly stretched continental crust with oceanward mantle uprising. (iii) Early Cretaceous basement highs generated in an obliquely syn-rift faulting system control CO<sub>2</sub> accumulation in thermogenic travertines (hydrothermal carbonate reservoirs of continental lakes), and Aptian evaporites subsequently trap it.</p>