Tuesday, February 22, 2011

RAGGED TOP: TERTIARY RHYOLITE



Ragged Top is an interesting mountain located in the Silver Bell Mountains west of Tucson, Arizona, and in the newly designated (Clinton Administration) Ironwood Forest National Monument,   The Silver Bells have complexly folded and faulted igneous, metamorphic, and sedimentary rocks that range in age from the Precambrian to Quaternary (Kreidler, 1987).  Ragged Top is a mass of Tertiary rhyolite that may represent a volcanic neck or a hypabyssal stock.  The peak gets its name from the massive erosion that has left behind spires and sharp-pointed peaks.  There is an elevation gain of about 1767 feet from the desert floor (2140 feet) to the summit (3907 feet) and the hiking trail (mostly just bushwhacking) is quite strenuous.  Ironwood Forest National Monument features plants of the Sonoran Desert, including the desert ironwood, a shrub-like tree that has beautiful purple flowers in the spring.  In addition, there are a number of Hohokam petroglyph sites in the Monument.  But I believe that the major scenic feature is the majestic Ragged Top.

REFERENCES CITED
Kreidler, T. J., 1987, Mineral Investigation of the Ragged Top Wilderness Study Area (AZ-020-197), Pima County, Arizona: U. S. Bureau of Mines  Mineral Land Assessment Open File Report 80-87.

mike