The unknown mineral is the prominent mineral in this thin section. It forms a dusty brown, isotropic matrix with a faint dendritic texture in which subhedral clinopyroxene and plagioclase grains are set. Clinopyroxene, where isolated, is strongly altered to iddingsite. The degree of alteration is much lower where plagioclase and clinopyroxene grains are intergrown. The two minerals have an almost graphic intergrowth texture. Western Minerals Inc. as an 'interstitial ferrotholeiite, very highly fractionated…textures are similar to those associated with rapidly frozen or highly viscous melts.'
The author has given permission for this work to be deposited in the Digital Archive of Colorado College.
see handout and map
The author has given permission for this work to be deposited in the Digital Archive of Colorado College.
