Petrology and weathering of the Iron Dike, Boulder and Larimer counties, Colorado
Petrology and weathering of the Iron Dike, Boulder and Larimer counties, Colorado
Bulletin of the Geological Society of America (1956) 67 (2): 147-163
The Iron Dike in Boulder and Larimer counties, Colorado, is magnetite-rich diabase and can be traced diagonally across the central part of the Front Range of Colorado for nearly 38 miles. The fabric and mineralogy indicate emplacement by a single, rapid eruption originating in a deep, laterally wide-spread source. The magma was partly crystallized by the time it reached the level of the present surface exposures. Intrusive pressure continued during consolidation and produced fracturing and dislocation of previously formed crystals and promoted deuteric alteration by providing channels for concentration and movement of late residual solutions. The dike is chemically unlike and predates probably all the intrusive and extrusive rocks in the normal Cenozoic igneous sequence of the central Front Range.