Closing the Clymene ocean and bending a Brasiliano belt: Evidence for the Cambrian formation of Gondwana, southeast Amazon craton

被引：85

作者：

Tohver, E. ^{[1
]}

Trindade, R. I. F. ^{[2
]}

Solum, J. G. ^{[3
]}

Hall, C. M. ^{[4
]}

Riccomini, C. ^{[5
]}

Nogueira, A. C. ^{[6
]}

机构：

[1] Univ Western Australia, Sch Earth & Environm, Crawley, WA 6009, Australia

[2] Univ Sao Paulo, Inst Astron & Geofis, BR-01222010 Sao Paulo, Brazil

[3] Shell Int Explorat & Prod BV, Bellaire Technol Ctr, Shell Explorat, Houston, TX 77025 USA

[4] Univ Michigan, Dept Geol Sci, Ann Arbor, MI 48104 USA

[5] Univ Sao Paulo, Inst Geociencias, BR-01222010 Sao Paulo, Brazil

[6] Univ Para, Inst Geociencias, BR-66075110 Guama, Brazil

来源：

GEOLOGY | 2010年 / 38卷 / 03期

基金：

美国国家科学基金会;

关键词：

CARBONATE; BRAZIL; MA; REMAGNETIZATION; ACCRETION; EVOLUTION; 40AR/39AR; RODINIA; MARGIN;

D O I：

10.1130/G30510.1

中图分类号：

P5 [地质学];

学科分类号：

0709 ; 081803 ;

摘要：

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 +/- 36 Ma or later; the mean age is established by 40Ar/39Ar 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 40Ar/39Ar 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.

引用

页码：267 / 270

页数：4

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