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Composición y evolución de las lavas de la isla de Branco (Cabo Verde)

Brandle, J.L. and Hernán, F. and Huertas Coronel, María José and Ancochea Soto, Eumenio (2006) Composición y evolución de las lavas de la isla de Branco (Cabo Verde). Geogaceta (40). pp. 91-94. ISSN 0213-683X

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Abstract

The first data about the composition of lava flows from Branco Island (Cabo Verde) are presented in this
work. Most lava flows in the sequence are alkali basalts (Fo84-76 olivine, En44-36 diopside, An83-31 plagioclase)
showing geochemical affinity of typical ocean island basalts. The scarce most evolved members are
mugearites (olivine absent, En41-31 clinopyroxene, An51-26 plagioclase, and kaersutite). The compositional
variations between both the types are explained by crystal fractionation and extraction of pyroxene (up to
29%) and lesser proportions of olivine and Fe and Ti oxides (Cpx: 75; Ol: 21; OxFeTi: 4). The transition to
mugearites from the most evolved basalts would mainly be due to extraction of pyroxene (24%) and Fe
and Ti oxides (Cpx: 68; Ol: 3; Plag: 5; OxFeTi: 30).

Item Type:Article
Uncontrolled Keywords:Oceanic islands, Branco, Barlovento Islands, Cape Verde, Alkaline basalts
Subjects:Sciences > Geology > Petrology
ID Code:9943
Deposited On:04 Feb 2010 09:57
Last Modified:06 Feb 2014 08:34

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