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GEOREF RECORD

Closing the Clymene ocean and bending a Brasiliano Belt; evidence for the Cambrian formation of Gondwana, southeast Amazon Craton

E. Tohver, R. I. F. Trindade, J. G. Solum, C. M. Hall, C. Riccomini and A. C. Nogueira
Closing the Clymene ocean and bending a Brasiliano Belt; evidence for the Cambrian formation of Gondwana, southeast Amazon Craton
Geology (Boulder) (March 2010) 38 (3): 267-270

Abstract

We report new paleomagnetic and geochronological data from Ediacaran rift-drift carbonates in the Paraguai belt at the southern end of the suture zone between the Amazon craton and the Sao Francisco and Rio de Plata cratons, South America. Early thrusting resulted in remagnetization ca. 528+ or -36 Ma or later; the mean age is established by (super 40) Ar/ (super 39) Ar encapsulation dating of mixed authigenic and detrital illite from remagnetized carbonates from the unmetamorphosed fold-thrust belt. This remagnetization overlaps with a 525 Ma Gondwana reference pole. Metamorphic illite from the slate belt yields (super 40) Ar/ (super 39) Ar ages of 496-484 Ma, the timing of peak regional metamorphism. Oroclinal bending of the Paraguai belt was caused by a 90 degrees clockwise rotation of the east-west limb after ca. 528 Ma, probably reflecting the irregular margin of the southeast Amazon craton. The age of the Paraguai belt overlaps with that of the Pampean orogeny farther south along the western margin of the Rio de Plata craton, suggesting a coeval closure for the Clymene ocean separating the Amazon craton from the Sao Francisco and Rio de Plata cratons.


ISSN: 0091-7613
EISSN: 1943-2682
Coden: GLGYBA
Serial Title: Geology (Boulder)
Serial Volume: 38
Serial Issue: 3
Title: Closing the Clymene ocean and bending a Brasiliano Belt; evidence for the Cambrian formation of Gondwana, southeast Amazon Craton
Affiliation: University of Western Australia, School of Earth and Environment, Crawley, West. Aust., Australia
Pages: 267-270
Published: 201003
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 31
Accession Number: 2010-030936
Categories: StratigraphySolid-earth geophysics
Document Type: Serial
Bibliographic Level: Analytic
Annotation: With GSA Data Repository Item 2010069
Illustration Description: illus. incl. geol. sketch maps
S21°00'00" - S09°00'00", W47°00'00" - W37°00'00"
Secondary Affiliation: Universidade de Sao Paulo, BRA, BrazilShell International Exploration and Production, USA, United StatesUniversity of Michigan, USA, United StatesUniversidade de Para, BRA, Brazil
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201018
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