TITLE:
An Overview of the Amazonian Craton Evolution: Insights for Paleocontinental Reconstruction
AUTHORS:
Mauro Cesar Geraldes, Armando Dias Tavares, Anderson Costa Dos Santos
KEYWORDS:
Amazonian Craton, Tectonic Evolution, Paleocontinents
JOURNAL NAME:
International Journal of Geosciences,
Vol.6 No.9,
September
28,
2015
ABSTRACT: The Amazonian craton major
accretionary and collisional processes may be correlated to supercontinent
assemblies developed at several times in the Earth history. Based on geologic,
structural and paleomagnetic evidence paleocontinent reconstructions have been
proposed for Archean to younger times. The oldest continent (Ur) was formed
probably by five Achaean cratonic areas (Kaapvaal, Western Dhawar, Bhandara,
Singhhum and Pilbara cratons). Geologic evidences suggest the participation of
the Archaean rocks of the Carajás region in the Ur landmass. Supercontinental
2.45 Ga Kenorland amalgamation is indicated by paleomagnetic data including
Laurentia, Baltica, Australia, and Kalahari and Kaapvaal cratons. There is no
evidence indicating that Amazonian craton was part of the Kenorland
supercontinent. From 1.83 Ga to 1.25 Ga Columbia and Hudsonland supercontinents
including Amazonian craton were proposed based on NE portion of the Amazonian
craton (Maroni/Itacaiunas province) connection with West Africa and Kalahari
cratons. Rodinia supercontinent reconstructions show Amazonia joined to
Laurentia-Baltica as result of 1.1 Ga to 1.0 Ga fusion based on the
Sunsas-Aguapei belts and Greenville and Sveconorwegian belts, respectivelly.
The large Late Mesoproterozoic landmass included also Siberia, East Antartica,
West Nile, Kalahari, Congo/Sao Francisco and Greenland. The 750 - 520 Ma
Gondwana assembly includes most of the continental fragments rifted apart
during the break-up of Rodinia followed by diachronic collisions (Araguaia,
Paraguay and Tucavaca belts). The supercontinent Pangea is comprised of
Gondwana and Laurentia formed at about 300 - 180 Ma ago. The Amazonian craton
margins probably were not envolved in the collisional processes during Pangea
because it was embebed in Neoproterozoic materials. As consequence, Amazonian
craton borders have no record of the orogenic processes responsible for the
Pangea amalgamation.