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Assessing Origins of End-Triassic Tholeiites From Eastern North America Using Hafnium Isotopes ArchiMer
Elkins, Lynne J.; Meyzen, Christine M.; Callegaro, Sara; Marzoli, Andrea; Bizimis, Michael.
The driving processes responsible for producing the Central Atlantic Magmatic Province, the Large Igneous Province associated with end-Triassic rifting of Pangea, remain largely debated. Because their compositions encompass most of the Central Atlantic basalt spectrum, tholeiites from southern Eastern North America are considered pivotal for identifying magma origins. New(176)Hf/Hf-177 measurements for 201 Ma Eastern North American tholeiites dominantly record a local petrogenetic history. Their epsilon(Hf)ratios, corrected to an emplacement age of 201 Ma (-7.85 to +5.86), form a positive but shallowly sloped array slightly deviating from the terrestrial array on a epsilon(Hf)versus epsilon(Nd)diagram. Comparison of(176)Hf/Hf-177 to other isotope ratios...
Tipo: Text Palavras-chave: Basalt; CAMP; Hafnium; Rift; LIP; Isotope.
Ano: 2020 URL: https://archimer.ifremer.fr/doc/00687/79862/82716.pdf
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Extreme source heterogeneity and complex contamination patterns along the Cameroon Volcanic Line: New geochemical data from the Bamoun plateau ArchiMer
Ziem A. Bidias, Luc Achille; Chazot, Gilles; Moundi, Amidou; Nonnotte, Philippe.
We investigated mafic and felsic volcanic rocks from the Bamoun plateau, a magmatic province located north of Mount Cameroon, in the continental part of the Cameroon Volcanic Line (CVL). Basalts and dacites were probably emplaced more than 40 Ma ago, while basanites represent very young volcanic eruptions. Among the basalts, some of them have suffered crustal contamination during their uprise through the continental crust, and their primary trace element and isotopic compositions have been slightly modified. The formation of the dacites was also accompanied by some crustal contamination. Non-contaminated rocks show that the oldest magmas are transitional basalts formed by relatively high degrees of partial melting of a moderately enriched mantle source,...
Tipo: Text Palavras-chave: Cameroon Volcanic Line; Geochemistry; Mantle source; Crustal contamination; Basalt.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00638/74996/75730.pdf
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Flow-by-flow chemical stratigraphy and evolution of thirteen Serra Geral Group basalt flows from Vista Alegre, southernmost Brazil Anais da ABC (AABC)
Pinto,Viter M; Hartmann,Léo A.
The geochemical characterization of thirteen Serra Geral Group flows in the Vista Alegre region (RS-SC), southern Brazil, displays the homogeneous basaltic composition near 50 wt.% SiO2. Each of the five basal flows (Pitanga-type, high-Ti/Y ~600, TiO2 > 3 wt.%) and eight upper flows (Paranapanema-type, medium Ti/Y ~400, TiO2 > 2 wt.%) can be identified from their chemical composition; sets of flows have parallel variation in chemical composition. The flow-by-flowcorrelation in four sections shows the horizontal position of the flows in three profiles and an approximately 200-m downdrop of the Itapiranga block with respect to the Frederico Westphalen block. The world-class amethyst geode mineralization and the systematic presence of native copper in...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Geochemical correlation; Basalt; Stratigraphy; Serra Geral Group; Vista Alegre.
Ano: 2011 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652011000200006
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