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Abstract
Associated with terciary sedimentary rocks, outcrops a complex of volcanic and plutonic mafic and ultramafic igneous rocks wich in thin section, reveal a great variety of textures, Petrographically, the plutonic rocks are gabros and peridotites and their volcanic ones found in Gorgona are only ones of mesozoic age reported up to now throughout the world. All Komatiites reported in the literature are of precambrian age and are always associated with ancient shields. Komatiites and komatiitic basalts present the most spec- tacular textures. Cheroically, all samples analized belong to sub-alkaline igneous rocks. We suggest they were originated by differentiation of lavas of ultramafic composition thro- ugh a process of fractional crystallization.
References
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