Paleomagnetism of the Amazonian Craton and its role in paleocontinents

Abstract

In the last decade, the participation of the Amazonian Craton on Precambrian supercontinents has been clarified thanks to a wealth of new paleomagnetic data. Paleo to Mesoproterozoic paleomagnetic data favored that the Amazonian Craton joined the Columbia supercontinent at 1780 Ma ago, in a scenario that resembled the South AMerica and BAltica (SAMBA) configuration. Then, the mismatch of paleomagnetic poles within the Craton implied that either dextral transcurrent movements occurred between Guiana and Brazil-Central Shield after 1400 Ma or internal rotation movements of the Amazonia-West African block took place between 1780 and 1400 Ma. The presently available late-Mesoproterozoic paleomagnetic data are compatible with two different scenarios for the Amazonian Craton in the Rodinia supercontinent. The first one involves an oblique collision of the Amazonian Craton with Laurentia at 1200 Ma ago, starting at the present-day Texas location, followed by transcurrent movements, until the final collision of the Amazonian Craton with Baltica at ca. 1000 Ma. The second one requires drifting of the Amazonian Craton and Baltica away from the other components of Columbia after 1260 Ma, followed by clockwise rotation and collision of these blocks with Laurentia along Grenvillian Belt at 1000 Ma. Finally, although the time Amazonian Craton collided with the Central African block is yet very disputed, the few late Neoproterozoic/Cambrian paleomagnetic poles available for the Amazonian Craton, Laurentia and other West Gondwana blocks suggest that the Clymene Ocean separating these blocks has only closed at late Ediacaran to Cambrian times, after the Amazonian Craton rifted apart from Laurentia at ca. 570 Ma.

Volume 1

“…1.00-0.95 Ga are shown in Figure 3a. This configuration, which remains similar to the earliest reconstructions of the late Proterozoic supercontinent now known as Rodinia (e.g., Bond et al, 1984 1991), has stood the test of time and to date remains the most plausible and widely-accepted reconstruction (Cawood & Pisarevski, 2017;D'Agrella-Filho et al, 2016a;Li et al, 2008;Weil et al, 1998). Some key aspects of this reconstruction, and the relative role of these three major cratons just prior to and during the assembly of Rodinia, are summarized below.…”

The Columbia supercontinent revisited

“…Geological and paleomagnetic data preclude the existence of "Atlantica" prior to the Neoproterozoic (Saalmann et al, 2007Alkmim et al, 2001D'Agrella-Filho et al, 2016;Gray et al, 2008) although there is evidence that elements of Atlantica may have longer lived connections (El Bahat et al, 2013;Texeira et al, 2013;Reis et al, 2013;Kouyate et al, 2013;D'Agrella-Filho et al, 2016;Texeira et al, 2016). The West African craton and portions of the Amazonian craton are featured in many Columbia models with Rio de la Plata commonly situated nearby (Kouyate et al, 2013;Saalman et al, 2007;Texeira et al, 2013;Reis et al, 2013;El Bahat et al, 2013;Texeira et al, 2016).…”

Tectonic evolution of the Juvenile Tonian Serra da Prata magmatic arc in the Ribeira belt, SE Brazil: Implications for early west Gondwana amalgamation

“…A subject of debate concerning the Neoproterozoic evolution of the belts in southeastern Brazil and western Africa (Araçuaí, Ribeira, Dom Feliciano and Kaoko) is the width of the Adamastor Ocean located between the São-Francisco-Congo, Angola, Rio de La Plata and Kalahari paleoplates (Kröner and Cordani, 2003;D'Agrella Filho et al, 2016;Pisarevsky et al, 2003Pisarevsky et al, , 2008Meert and Torsvik 2003;Cordani et al, 2013;Heilbron et al, 2008;Tupinambá et al, 2012;Pedrosa Soares et al, 2008;Gray et al, 2008). Reported long intervals of subduction highlight the large time span of magmatic arc production (ca.…”