Geology of the igneous rocks of the Spanish Peaks region, Colorado

Abstract

The Spanish Peaks region is well known for its highly diverse igneousrocks and structures. The region is dominated by mountains, peaks,hills, buttes, and walls that are formed by stocks, laccoliths, soleinjections, plugs, sills, and dikes. Dikes are characteristic of theregion and are members of a large radial system associated with theSpanish Peaks, a smaller radial system associated with Dike Mountain,or a large subparallel system. Many dikes, however, belong to smallsets or occur singly. The igneous rocks make up a continuous serialgradation from granite to gabbro, and include phaneritic, aphanitic,porphyritic, and lamprophyric varieties. The rocks range from felsicto ultramafic, oversaturated to undersaturated, peraluminous tosubaluminous, and calcic to alkalic types.

75 samples from this reference