Paleomagnetism of paleoproterozoic mafic and felsic volcanic rocks of the Rio Negro-Juruena Province, Southwestern Amazonian Craton, Brazil
2007 (English)Conference paper, Poster (Other academic)
Several paleogeographic configurations for the Amazonian Craton have been suggested along its geological history. Paleomagnetic tests for suggested configurations are however restricted due to very sparce and low quality paleomagnetic data, especially for Paleoproterozoic. In an attempt to improve our understanding of the geodynamic evolution, a paleomagnetic study was performed on felsic volcanic rocks of the Colider Suite, and associated mafic rocks in the Rio Negro-Juruena Province, southwestern Amazonian Craton. These rocks have well dated zircon U-Pb ages between 1.80-1.78 Ga. Very stable northern (southern) directions with moderate to steep negative (positive) inclinations were isolated during AF and thermal demagnetization. Rock magnetism experiments show that the magnetization, which is probably of primary origin, in the felsic rocks is carried by hematite and in the mafic rocks by Ti-poor titanomagnetite. A preliminary mean direction (D=187.4°, I=50.9°, N=16, A95=11.3°, K=11.7) yield a paleomagnetic pole located at 289.4°E, 65.4°S (A95=12.9°), which is classified with quality factor of Q=5. Paleogeographic reconstructions using key Paleoproterozoic poles suggest that Laurentia, Baltica, North China, and Amazonian Craton were located in laterally contiguous positions forming a large continental mass at 1.83-1.77 Ga ago.
Place, publisher, year, edition, pages
Research subject Applied Geophysics
IdentifiersURN: urn:nbn:se:ltu:diva-39492Local ID: e4599900-a423-11dc-8fee-000ea68e967bOAI: oai:DiVA.org:ltu-39492DiVA: diva2:1013005
American Geophysical Union. 2007 Spring meeting : 22/05/2007 - 25/05/2007
Godkänd; 2007; Bibliografisk uppgift: Sider: GP21A-08; 20071206 (ysko)2016-10-032016-10-03Bibliographically approved