XENOLITH GROUP
Sulfuros y fluidos del Manto Litosférico
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El estudio del manto litosférico subcontinental del extremo sur de Sudamérica es posible gracias a la ocurrencia ocasional de xenolitos mantélicos transportados a la superficie por magmas basálticos de origen astenosférico durante el Eoceno-Holoceno, los que se encuentran principalmente en la región del tras-arco andino. Estudios geoquÃmicos e isotópicos realizados previamente en estos materiales, han permitido reconocer diversos procesos de fusión parcial y metasomatismo ocurridos en el manto
litosférico subcontinental.
Alteration patterns of chromian spinels
Photomicrographs of representative samples from La
Cabaña. A) Disseminated anhedral Cr-spinel grains from Lavanderos in a serpentine (antigorite) matrix
with interlocking texture. B) Anhedral Cr-spinel grains
surrounded by clinochlore c Clinochlore plates replaced by talc in antigorite matrix. (Barra et al. 2014)
Melt inclusions
Photomicrograph of melt inclusions (MI) in olive crystal has an ellipsoidal shape at room temperature (25°C). Sample collected at Chile chico (30 μm diameter)
Oxygen as a light element: a solution to single-stage core formation
Small metal droplets settle through the magma ocean, equilibrating with the surrounding silicate melt. The molten metal then accumulates at the base of the magma ocean, before forming periodically large diapirs, which descend rapidly to the growing core without significant equilibration with the solid mantle (Corgne et al. 2009)
