Paleomagnetic evidence for oblique collision between Amazonia and Laurentia at about 1.1 Ga

Godkänd; 2004; 20080813 (andbra)
The connection between Amazonia and Laurentia at late Meso- proterozoic times through the Grenville/Sunsas-Aguapei collisional belts is a key feature of Rodinia paleogeography.However, at least three different geometries are proposed for such connection, mainly due to the paucity of paleomagnetic data for Amazonia.Connections along Greenland and Labrador were initially proposed based on the fit of geological provinces and scarse virtual geomagnetic poles.More recently, a connection through the Llano belt in Texas was proposed based on a single well dated 1.2 Ga paleopole obtained in mafic rocks from the Nova Floresta Formation. We present a series of poles obtained on sedimentary rocks of the Aguapei Group (western Matto Grosso State-Amazonian Craton) and intrusive mafic rocks, whose evolution is related to the Meso-Neoproterozoic Aguapei-Sunsas orogeny (1.3-0.9 Ga).Together with the 1.2 Ga Nova Floresta pole, they define a straight apparent polar wander path which matches the Laurentia APWP by 1.1 Ga for a connection along the (present day) Labrador region. The pole's trajectories imply a high degree of obliquity for such a collision in agreement with tectonic models put forward for the southwestern margin of Amazonia, the southeastern margin of Laurentia and the southwestern margin of Baltica.

Pacca, Igor GalUniversity of Sao Paolo (författare)
Elming, Sten-åkeLuleå tekniska universitet,Geovetenskap och miljöteknik(Swepub:ltu)sael (författare)
Trinidade, R.I.F.University of Sao Paolo (författare)
University of Sao PaoloGeovetenskap och miljöteknik (creator_code:org_t)

Av författaren/redakt...: D'Agrella-Filho, ...; Pacca, Igor Gal; Elming, Sten-åke; Trinidade, R.I.F ...

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