Restoring Pan-African-Brasiliano connections: more Gondwana control, less Trans-Atlantic corruption

Abstract

The concept of South America and Africa as rigid continents during the formation, growth and motion of their respective plates has frustrated reconstruction of a tight, geologically economic fit between these two fragments in their Gondwana framework. We recognize that (1) internal strains released during and following Gondwana break-up have distorted their actual shapes within Gondwana and (2) these two continents comprise mosaics of smaller microblocks, or platelets, of relatively undistorted Precambrian terrains that experienced modest, episodic relative motions along rift zones that separate them. This permits a fresh approach to quantitative reconstructions of palaeo-continents. Former geological ties forged at the time of Gondwana amalgamation, now exposed at the continental margins of the South Atlantic as piercing points, provide robust anchors for new paleo-cartographic experiments. We present two new tectonic maps of the Brasiliano and Pan-African structures of West Gondwana on which we identify ten piercing points that, if re-joined simultaneously, could facilitate quantification of a well-substantiated Gondwana fit and help retrace the evolution of its continental margins with greater accuracy than has been achieved until now. This has significant bearing on understanding the origin and evolution of passive continental margins, and the geodynamics of Gondwana break-up.

Neoproterozoic geodynamic evolution of SW-Gondwana: a southern African perspective

“…To the south, this mylonite extends into the Ogden Rocks Mylonite Zone at the coast, where it is the western boundary of the Southern Kaoko Zone. The continuation of this mylonite zone across the South Atlantic into the Sierra Ballena-Canguçú-Major Gercino Shear Zone, as suggested by De Wit et al (2008), is unlikely because the latter follows the western boundary of the Cuchilla Dionisio-Pelotas Arc in South America.…”

Timing of the HT/LP transpression in the Neoproterozoic Seridó Belt (Borborema Province, Brazil): Constraints from UPb (SHRIMP) geochronology and implications for the connections between NE Brazil and West Africa

“…Part of the problem is the perception that during their break-up and drift, the major continents have not always responded as single rigid blocks, leading to the distortion of the plates. To overcome this problem De Witt et al (2008) proposed detailing the geology of ten piercing points to improve the correlations across the central and south Atlantic. Four of these piercing points are situated in the Borborema (NE Brazil) and Nigeria shields, and one of them corresponds to the vertical shear zones that deform the dominantly pelitic Neoproterozoic deposits (schist belts) of the Seridó-Jaguaribe and Igarra-Ifewara-Ilesha domains ( Fig.…”

Influence of Neoproterozoic tectonic fabric on the origin of the Potiguar Basin, northeastern Brazil and its links with West Africa based on gravity and magnetic data

“…Roughly half of Gondwana's rifted margins, for instance, are parallel to lineaments of craton margins (De Wit et al, 2008). These lineaments are useful in matching up corresponding geological domains in Africa and South America separated during the breakup of Pangea.…”