stripes
Narrow bands of carbonatite up to 0.7 m thick and 100 m long are associated with carbonated lamprophyre dykes. Wall rock gneisses are fenitized with the formation of riebeckite, aegirine and red K-feldspar. Fetid gasses including fluorinated hydrocarbons are released from freshly broken igneous and associated metamorphic rocks of the occurrence (Heinrich and Anderson, 1965). The carbonatites vary from simple calcite rocks to varieties containing baryte, fluorite and a range of rare fluorides including cryolite, pachnolite, prosperite, ralstonite and weberite.
HEINRICH, E.W. 1977. Aluminofluoride minerals of the Goldie carbonatite Fremont County, Colorado. Mountain Geologist, 14: 33-46.
HEINRICH, E.W. and ANDERSON, R.J. 1965. Carbonatites and alkalic rocks of the Arkansas River area, Fremont County, Colorado. 2. Fetid gas from carbonatite and related rocks. American Mineralogist, 50: 1914-20