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Paleomagnetic evidence for the evolution of Meso- to Neo-proterozoic glaciogenic rocks in central-eastern Brazil |
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| Authors: | Manoel S D'Agrella-Filho Igor G Pacca Wilson Teixeira Tullis C Onstott and Paul R Renne |
| Institution: | a Instituto Astronômico e Geofisico, Universidade de São Paulo, C.P. 30627, São Paulo, S.P., Brazil b Instituto de Geociências, Universidade de São Paulo, C.P. 20899, São Paulo, S.P., 05541, Brazil c Department of Geological and Geophysical Sciences, Princeton University, Princeton, NJ 08544, USA |
| Abstract: | Paleomagnetic studies on basic dikes in the eastern São Francisco Craton which have isotopic ages of 1.0–1.1 Ga, define an apparent polar wander path for South America over this time interval. The data indicate that the São Francisco Craton was at paleolatitudes between 40° and 65° at the time of emplacement of these dikes. Neo-Proterozoic sedimentary glaciogenic rocks, the Macaúbas Group, Bebedouro Formation, Ibiá Formation and Carandai Formation, crop out in central-eastern Brazil. An age of about 1.0 Ga has been proposed for these glacial deposits. Paleogeographical reconstructions of South America show a continental movement coherent with paleoenvironmental models proposed for the Macaúbas Group and suggest that the glacial period may have occurred between 1.01 and 1.08 Ga. |
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