Early Precambrian basic rocks of South America

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Authors:Wirth, K. R.; Oliveira, E. P.; Silva, J. H.; Tarney, J.
Author Affiliations:Primary:
Cornell Univ., Dep. Geol. Sci., Ithaca, NY, United States
Volume Title:Early Precambrian basic magmatism
Volume Authors:Hall, R. P., editor; Hughes, D. J.
Source:Early Precambrian basic magmatism, edited by R. P. Hall and D. J. Hughes, p.379-404. Publisher: Chapman and Hall, New York, NY, United States
Publication Date:1990
Note:In English; illus. incl. 15 analys., 2 tables, geol. sketch maps
Summary:Precambrian mafic-ultramafic igneous rocks of South America are diverse in composition, age, and origin. They include greenstone belts, layered complexes, and anorogenic volcanic rocks and dyke swarms, exposed in the three main cratonic regions: the Amazonian craton, the Sao Francisco craton and the Goias massif. The geology has been interpreted in terms of orogenic cycles, notably the Guriense (> 3000 m.y.), the Jequie (2700 m.y.), Transamazonian (2000 m.y.), Uruacuano-Espinhaco (1500-1100 m.y.) and Brasiliano (1100-500 m.y.) cycles, during which the Precambrian crust progressively accreted. It has been estimated that 80% of the Precambrian of South America had formed by the end of the Transamazonian. Because of the large number and diversity of Precambrian mafic and ultramafic rocks in South America the authors focus on a few selected examples, grouped according to: 1) Archaean greenstone belts and other basic volcanic sequences, 2) early Proterozoic greenstone sequences, 3) layered mafic- ultramafic complexes, and 4) Proterozoic mafic dyke swarms. [J.M.H.]
Subjects:Composition; Dike swarms; Dikes; Greenstone belts; IGCP; Igneous rocks; Intrusions; Mafic composition; Metamorphic belts; Petrology; Plutonic rocks; Precambrian; Sills; Volcanism; South America; Igneous activity
Abstract Numbers:91M/2106
Record ID:1991002620
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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