Crustal Architecture and Magmatism of the Campos Rifted Margin:
Along-Strike Variability and Segmentation
Abstract
We investigate the crustal architecture and structural domains of the
Campos rifted margin in southeastern Brazil, focusing on rifting
evolution and segmentation. Based on 2-D and 3-D seismic reflection
interpretation and potential field modelling, our results reveal an
along-strike variability, in terms of margin architecture and magmatism,
that segments the basin into three main sectors from south to north.
Through the analysis of seismic reflection profiles, we interpret this
lateral variability as a product of lower- to upper-plate alternations
and different magmatic inputs. We propose the Southern Campos margin to
represent a lower-plate tectonic setting, where the distal domain is
characterized by the formation of the here named Gávea Supradetachment
Basin associated with the development of a metamorphic core-complex. The
Central Campos margin is characterized by a massive residual block,
representing an upper-plate setting, with exhumation of different
crustal levels in the distal domain. Our analysis suggests that the
Central Campos sustained a high magmatic input throughout the rift
evolution, supporting the interpretation of Seaward Dipping Reflectors
and a magmatic crust in a transitional domain. The Northern Campos
margin also represents an upper-plate setting, but characterized by a
progressively delaminated crust. Finally, we compare the Brazilian
margin architecture with the conjugate Angola margin, discuss the role
of transfer zones in the segmentation and propose along-strike
variations in the volume of magmatism.