The Pikes Peak Pebble Pups started their 2013 field trip season by exploring the historic Mary Nevin Mine. Next on the agenda was lunch in the park at Victor. We then went to the American Eagle Mine to look at the modern mining operations. After that we collected lamprophyre.
Mary Nevin Mine Powder magazine Luke Sattler Casey Martin Blake Reher Camden Martin View of Mary Nevin Mine View of Beacon Hill and the El Paso Mine Lamprophyre with entrained rock or xenolith
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Lamprophyre occurring in Cripple Creek is a dark gray to
black intrusive igneous rock characterized by a porphyritic texture in which
large crystals (phenocrysts) of dark, iron-magnesium (mafic) minerals are
enclosed in a fine-grained to dense matrix (groundmass). The mafic minerals
include biotite, hornblende, augite, or olivine. Lamprophyres are unique
because of their low silica content and a high iron, magnesium, and alkali
content. Lamprophyres show an affinity to weather and decompose. During historic times gold was concentrated along some of the lamporphyre pipes, such as the Cresson Pipe.