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
Official URL: http://www.sociedadgeologica.es/
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).
|Uncontrolled Keywords:||Oceanic islands, Branco, Barlovento Islands, Cape Verde, Alkaline basalts|
|Subjects:||Sciences > Geology > Petrology|
|Deposited On:||04 Feb 2010 10:57|
|Last Modified:||02 Mar 2010 09:03|