RT Journal Article
T1 El Piroxeno de las rocas volcánicas miocenas de la isla de Fuerteventura (Islas Canarias)
T1 Pyroxenes in the miocene volcanic rocks of Fuerteventura (Canary islands)
A1 Brändle, José Luis
A1 Ancochea, Eumenio
A1 Huertas, María José
A1 Cubas, C. R.
A1 Hernán, Francisco
AB Pyroxene (dio psid e o r augite) is p re se n t in a ll rocks o f th e M io c e n e V o lc a n ic C om plexes on Fuerteventura. Pyroxene phenocrysts are specially abundant in basalts, in which they represent a third of all phenocrysts.The En/(En+Fs) ratio decreases from core to rim in the scarce zoned phenocrysts and is always lower in the small crystals forming the groundmass. The En-content is also closely related to the total-rock weight percent MgO. The variation in a rock sample is, sometimes, as large as the one observed as a whole. The total range is EnB569 in basalts, EnB163 in trachybasalts, En77M in basaltic trachyandesites, En74-6B in trachyandesites and En70 62 in trachytes.The m axim um En-content o f basalts remains constant regardless the rock MgO concentration. This is due to crystallisation of pyroxene after an important amount of olivine, when the residual liquid is strongly Mg-depleted.The Ca+Na - Ti concentrations are those typical of alkaline rocks, showing an evident increase in Wo-component with increasing rock alkalinity.The Wo-component decreases from phenocrysts to groundmass in mildly alkaline rocks, remains constant in middle alkaline rocks and increases in strongly alkaline and ultra-alkaline rocks
PB Sociedad Geológica de España
YR 1996
FD 1996
LK http://hdl.handle.net/10272/12278
UL http://hdl.handle.net/10272/12278
LA spa
DS Repositorio Institucional de la Universidad de Huelva
RD 31 may 2026