%0 Journal Article
%9 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES
%A Bertrand, H.
%A Fornari, Michel
%A Marzoli, A.
%A Garcia-Duarte, R.
%A Sempéré, Thierry
%T The central atlantic magmatic province extends into Bolivia
%D 2014
%L fdi:010061835
%G ENG
%J Lithos
%@ 0024-4937
%K Central Atlantic Magmatic Province ; Bolivia ; Ar-40/Ar-39 age ; Basalt
%K BOLIVIE
%M ISI:000332195100004
%P 33-43
%R 10.1016/j.lithos.2013.10.019
%U https://www.documentation.ird.fr/hor/fdi:010061835
%> https://www.documentation.ird.fr/intranet/publi/2014/04/010061835.pdf
%V 188
%W Horizon (IRD)
%X The Central Atlantic Magmatic Province (CAMP) is the largest continental flood basalt (CFB) province on Earth and was associated with the onset of fragmentation of the supercontinent Pangea at the Triassic-Jurassic boundary. In order to clarify the extent of the CAMP in South America, we investigate basaltic remnants in southern Bolivia (Tarabuco, Entre Rios and Camiri areas) by combining stratigraphic, geochronological (Ar-40/Ar-39 data) and geochemical (major and trace element, Nd-Sr isotopes) approaches. Lava-flows reaching a total thickness up to 150 m and associated sills overlie syn-rift red beds assigned to the Triassic. The magmatic rocks consist of low-Ti tholeiites that are remarkably homogeneous in composition. Notably, their trace element and Nd-Sr isotopic compositions closely match those of CAMP basalts particularly those of southwest Brazil. Ar-40/Ar-39 dating failed to yield robust plateau ages but the best estimates of the crystallization age at 198.1 +/- 1.5 and 199.2 +/- 2.2 Ma are similar to those of CAMP basalts throughout the province. These Bolivian basalts, which may have covered an initial surface of similar to 30,000 km(2), represent the known southernmost occurrence of the CAMP. They were erupted as a single pulse, more than 8000 km away from the northern edge of the province. We discuss the implications of such a huge elongated CFB for the current plume models and we suggest, as an alternative, that large-scale melting beneath the Pangea supercontinent due to mantle global warming could have triggered the emplacement of the CAMP.
%$ 066