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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Hot Versus Cold Orogenic Behavior: Comparing the Aracuai-West Congo and the Caledonian Orogens

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Fossen, Haakon [1] ; Carolina Cavalcante, G. [2] ; de Almeida, Renato Paes [3]
Total Authors: 3
[1] Univ Bergen, Museum Nat Hist, Dept Earth Sci, Bergen - Norway
[2] Univ Fed Parana, Dept Geol, Curitiba, Parana - Brazil
[3] Univ Sao Paulo, Inst Geociencias, Sao Paulo - Brazil
Total Affiliations: 3
Document type: Journal article
Source: TECTONICS; v. 36, n. 10, p. 2159-2178, OCT 2017.
Web of Science Citations: 5

Observations and modeling show that temperature controls crustal rheology and therefore also the orogenic evolution of continent-continent collision zones and the associated tectonic style. In order to explore the effect of temperature in a natural environment, we compare eroded sections through the unusually cold lower Paleozoic North Atlantic Caledonian (Scandian) collision zone and the very hot Brasiliano/Pan-African Aracuai-West Congo orogen. A cold and stiff subducting Caledonian continental margin was able to subduct as a rather coherent unit to ultrahigh-pressure conditions, twice as deep as the Pan-African/Brasiliano crust that was quickly heated and softened and got involved in partial melting. Furthermore, the Caledonian collision developed large coherent thrust sheets that were transported hundreds of kilometers toward the foreland. This was never achieved in the hot Aracuai-West Congo orogen, where much of the tectonic stress was absorbed by the partially molten central part of the orogen through magmatic state deformation. Major mylonite zones (thrusts) such as those seen in the Caledonides are therefore less common in the Aracuai-West Congo orogen. Further, the deep continental subduction in the Caledonides developed a strongly asymmetric collision zone, with rapid variations in pressure and temperature. In contrast, the Aracuai-West Congo orogen soon developed into a more symmetric geometry due to its easily flowing hot crust, with a relatively flat base and a corresponding plateau in its upper part. Deformation of the cold Caledonian crust was controlled by plate-tectonic stress, while gravitational forces more strongly influenced the hot Brasiliano/Pan-African example. (AU)

FAPESP's process: 13/19061-0 - Rheological evolution of the continental crust: microstructures and deformation mechanisms in the Além Paraíba-Pádua shear zone (Araçuaí-Ribeira belt)
Grantee:Geane Carolina Gonçalves Cavalcante
Support type: Scholarships in Brazil - Post-Doctorate
FAPESP's process: 10/03537-7 - Tectonoseismic Study of the Carlos Chagas Leucogranite and Adjacent Units, Araçuaí Belt (Eastern Brazil).
Grantee:Geane Carolina Gonçalves Cavalcante
Support type: Scholarships in Brazil - Doctorate