New Mexico Geological Society Annual Spring Meeting — Abstracts

The Florida Mountain pluton consists of a complex group of syenite, quartz syenite, alkali-feldspar granite, and diorite that record Cambrian-Ordovician magmatism and display a well-exposed series of magmas frozen during repeated episodes of mixing. Southern exposures of the pluton are composed of alkali-feldspar granite, alkali-feldspar syenite, syenite, hybridized magmas, mafic enclaves, and diorite dikes with varying compositional characteristics. Hybridized magmas and mafic enclaves are found in zones between sheet-like dikes of diorite and often display large 5-10 mm feldspar grains. Mixing zones display mafic enclaves with various shapes, crenulate margins, quench textures, and mineral reaction rims. These features of magma mixing were formed by the injection and mixing of mafic magma in the partially crystallized lower portion of the Florida Mountain pluton. Major and trace element data will be presented that, when interpreted in concert with petrographic and field data, delineate multiple phases of mixing.