Print this pageS. Atlantic Plate Reconstruction Constrained Using Crustal Thickness and Oct Location Derived from Gravity Inversion: Implications for the Santos-Campos Brazilian Rifted Margin Segments
Satellite gravity anomaly inversion, incorporating a lithosphere thermal gravity anomaly correction, has been used to map Moho depth, crustal thickness and continental lithosphere thinning factor for the S. Atlantic which have been used to construct new plate reconstructions with focus on the late Aptian - early Albian plate configuration of the Santos and Campos segments of the Brazilian rifted margin and their African conjugates. Continental lithosphere thinning factors from gravity inversion provide independent ocean-continent transition (OCT) location to constrain and test plate reconstructions. Superposition of illuminated satellite gravity data onto crustal thickness maps from gravity inversion provides improved determination of pre-breakup conjugacy and breakup trajectory of the Brazilian and African margins. The new plate reconstructions and crustal thickness maps have been used to explore the relationship between the Sao Paulo Plateau and its African conjugate margin in the late Aptian-early Albian, the geometry of ocean basin to the south down to the Agulhas-Falklands fracture zone, the remaining connectivity of Brazilian-African continental crust, and the nature of the marine region to the north up to Pernambuco. The structure of the Rio Grande High, locally underlain by crust 30 km thick, its formation and its impact on the Santos-Campos segment of the Brazilian rifted margin are also explored. Gravity inversion to determine Moho depth and crustal thickness variation is carried out in the 3D spectral domain and incorporates a lithosphere thermal gravity anomaly correction for both oceanic and continental margin lithosphere. Input data used in this study is satellite gravity, digital bathymetry and NOAA-NGDC sediment thickness.
AAPG Search and Discover Article #90100©2009 AAPG International Conference and Exhibition 15-18 November 2009, Rio de Janeiro, Brazil