Coeval perpendicular shortenings in the Brasília belt: Collision of irregular plate margins leading to oroclinal bending in the Neoproterozoic of central Brazil

The three belts which form the Tocantins province (central Brazil) records Neoproterozoic-EoPaleozoic collisions involving the Amazon and São Francisco paleocontinents and the Paraná continental block. The Brasília belt is a typical orocline bended around the WNW–ESE striking Pirineus Zone of High S...

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Bibliographic Details
Published in:	Journal of South American earth sciences Vol. 32; no. 1; pp. 1 - 13
Main Authors:	D’el-Rey Silva, Luiz J.H., de Oliveira, Ítalo L., Pohren, Camila B., Tanizaki, Maria Luiza N., Carneiro, Rodolfo C., Fernandes, Gabriel L. de F., Aragão, Priscila E.
Format:	Journal Article
Language:	English
Published:	Elsevier Ltd 01-07-2011
Subjects:	Brasília belt Irregular continental margins Oroclines Paraná block Structural analysis Tocantins province Irregular continental margins Oroclines Paraná block Brasília belt Structural analysis Tocantins province
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Summary:	The three belts which form the Tocantins province (central Brazil) records Neoproterozoic-EoPaleozoic collisions involving the Amazon and São Francisco paleocontinents and the Paraná continental block. The Brasília belt is a typical orocline bended around the WNW–ESE striking Pirineus Zone of High Strain (PZHS) and is comprised of the NE-trending (northern) and SE-trending (southern) segments. The Brasília dome is an N–S elliptical structural window situated in the center of the belt, at the eastern end of the PZHS. It evidences D 1–D 2 and D 3N shortenings (∼750–590 Ma) due to ocean closure and Amazon-São Francisco collision following a WNW–ESE path, and demonstrates similar evolution for both segments of the belt. However, in the southern segment, D 1–D 2 structures are deformed by shortening in the SW-NE direction (D 3S). New data demonstrating D 1–D 2 and D 3N tectonites deformed by D 3S structures in the area close to the dome’s SW margin and SE of the PZHS support understanding the Brasília belt and oroclinal bending as a consequence of the collision of two (Amazon and São Francisco) irregular continental margins leading to separation-rotation of the Paraná block from the Amazon paleocontinent and the Paraná-São Francisco collision. ► New features in the area SW of the Brasília dome, Brasília orocline, central Brazil. ► Crossed foldings (3rd phase) demonstrate the dome shortly predates oroclinal bending. ► Deciphering how the Paraná block took part in the Amazon-São Francisco collision. ► The block rifted--drifted from the SW margin of the Amazon paleoplate, ca. 620 Ma ago. ► Understanding the evolution of the São Francisco craton and marginal belts.
ISSN:	0895-9811 1873-0647
DOI:	10.1016/j.jsames.2011.02.013