Mantle metasomatism and the generation of alkaline lamprophyres in the Spanish Peaks Intrusive Complex, south-central Colorado

The Spanish Peaks Intrusive Complex, Colorado, is composed of compositionally diverse mid-Tertiary igneous rocks. The intrusive stocks of the Spanish Peaks are surrounded by a famous radial dike system as well as subparallel dikes and sills that include lamprophyres. Some of the lamprophyres are relatively sodic (Na2O>K2O) and others are relatively potassic (Na2O