Abstract

Widely scattered dark gray lamprophyre dikes in the Mount Rosa area strike generally north-northwest and dip steeply. Outcrops of the lamprophyres, which can usually be traced for less than 500 feet, range in width from 2 to 25 feet. The lamprophyres are of two types, sodic syenites and sodic diorites. They intrude Pikes Peak granite, its variants, and Mount Rosa-type pegmatites. The lamprophyres are believed to be of late Precambrian age and their period of intrusion overlapped that of Mount Rosa-type pegmatites.

Veins of fluorite strike mainly north or northeast and dip steeply. These are probably of Tertiary age. Strongly radioactive altered zones in Mount Rosa granite contain uranothorite and thorogummite, which also occur as late hydrothermal minerals in Mount Rosa-type pegmatites.

This content is PDF only. Please click on the PDF icon to access.

First Page Preview

First page PDF preview
You do not currently have access to this article.