Ponencia
Experimental constraints on adakitic metasomatism of mantle wedge peridotites below Patagonia
Autor
Corgne, Alexandre
Institución
Resumen
We performed a series of high-pressure (1.5
GPa) and high-temperature (1000-1300 ºC) experiments to
investigate the geochemical imprints of adakitic
metasomatism on mantle wedge peridotite. Reaction
couples were prepared using a powdered adakite from
Cerro Pampa (Argentina) placed next to a fragment of
spinel lherzolite from Pali Aike (Chile). Preliminary results
show that the main changes in phase relations are
incongruent dissolution of olivine and associated
precipitacion of secondary orthopyroxene, incongruent
dissolution of primary spinel and formation of secondary
spinel, as well as precipitation of secondary clinopyroxene
and in some instances zoned plagioclase. In experiments
with high added water, precipitacion of pargasitic amphibole
also occurred. Also, trace element contents of secondary
clinopyroxene are reported as a potential geochemical
marker of adakitic metasomatism.
Keywords: Adakite, Metasomatism, Mantle, Peridotite,
Subduction