VllA-12 0830h POSTER

Upper Mantle and Crustal Origin of Olivine-Pyroxene- Kaersutite Megacryats, and Peridotite Curnulates and Xenoliths Rom the Bandama Volcanic Complex (Gran Ca- naria, Spain)

Jose Mangas1 (36928451296; joae.mangasQhsica.ulpgc.es) Robert Clac&iatti2 (33-1-69084815; cloc&iatti@drecam cedr) Ftancisco Jase Perez-Torrado' (34-928451298; francisco.perezt3 fisi~a.ulpgces) Dominique Massare2 (33-1-69084815) (Sponsor: Emilio Herrer+A~rvpr~!

'Departamento de Fisica, Campup de Tafira, ULPGC, Las Palmas 35.017. Spain 2Laboratorie Pierre Sue, CEA, Gif sur lvette 91191, hance The Quatcrnary volcamc complex of Bandama is formed by a strornbo- lian cone and a caldera of phreatomagmatic-collapse origin It shows two lava flows of basanite cornposition and fall and base surge pyro- clastic deposits The lava Rows have alivine and augstediapside phe- riocrysts and as subordinate minerals spinel and magnetite. The pyro- ilastic deposits shvw olivine. clinopyroxene and kaersutite phenocrysts and megacrysts, pendotite cumulates (dimite, wehrlite, clinopyroxen-

ite wtth olivinp, rhnopirmenite) and xenoliths (dunite 2nd Iherzolite) containing olivinc, augite-diopstde, enslatite, spmel, magnetite, phlo- gopite, apatite and pyrrhotitepentlandite Taking into aceount the val- canologd study and the microscopic, electron microprobe, microther- mometric (fluid and melt inclusions) and bulk-rock analysis of the 26 samples. we concliide that the mincrals which make up the megacrysts, curnulates and xenoliths dsplay dlfTerent characteristm between them and from the ratio to minerals oí the lava flow We interprete that thme samples were original4 under difieren1 LhermobarogeochemiraI conditions and that the basanitic magma which gave rise to the Ban- dama complex ascended fram upper mantle to the surface (-33 km ta O 5 km), trapping pendotile ciirnulates and xenoliths, and megacrysts of diKerents depths and genesis Irom the spinel stability field in the uppcr mantle lo the owanir crust (-27 km to -4.5 km)