PETROGRAPHY OF THE DARE MINE KNOB LAMPROPHYRE

The Dare Mine Knob ultramafic intrusion is located in Pennsylvanian sedimentary strata of the lower Atoka Formation of the Boston Mountains in northern Pope Co., Arkansas. Little publicly available data on the mineralogy of the intrusion exists with unpublished reports only briefly describing the single known dike. Various other reports refer to the rock as a camptonite, an alnoite, or a lamproite with no discussion of the petrographic aspects utilized in naming the specimens. The dike is a melanocratic lamprophyre surrounded by alternating shales and sandstones which show some moderate contact metamorphism in the form of a halo of hornfels and quartzites. New thin section analysis of the lamprophyre and quartzites performed as part of this study better define the petrography of the samples and their possible relationship to other regional igneous bodies.