San Luis Peak

Geology (San Luis Peak)

Title: Volcanism in the LaGarita Range - San Juan Mountains

Entered by: Mark A Steiner

Added: 11/05/2011, Last Updated: 11/05/2011

The geology of the entire LaGarita range, including San Luis Peak, depicts a history of explosive volcanism. When seen from the air, the LaGarita caldera is about 10 miles across. According to the US Geological Survey, vents within the LaGarita Caldera have produced as much as 1,250 cubic miles of volcanic ejecta (ash, cinders and lava flows). This is enough volcanic debris to cover the entire continental United States with about 1-3 feet of volcanic solids. Some of these light-colored ash deposits, called by geologists "tuff" may be found along Tomichi Creek and US 50 between Sargents and Gunnison. The almost moonscape-like terrain in the highest peaks of the LaGaritas frequently alternates between layers of resistant lava beds and incompetent ash beds. Consequently, slumping of volcanic landforms is a common feature in these mountains. High featureless plateaus such as Snow Mesa are expressions of the rim of the caldera.

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Name History (San Juan Mountains)

Title: Eolus

Entered by: wojtekrychlik

Added: 01/21/2014, Last Updated: 01/21/2014

Aeolus was the ruler of the winds, according to Greek mythology.

Name History (San Luis Peak)

Title: Naming of San Luis Peak

Entered by: 14erFred

Added: 05/14/2010, Last Updated: 05/14/2010

Sources: Hart, J.L.J. (1977). Fourteen thousand feet: A history of the naming and early ascents of the high Colorado peaks (Second Edition). Denver, CO: The Colorado Mountain Club.

The mountain's name, which first appeared on Hayden's 1877 Atlas of Colorado, is probably taken from the name of the valley that lies at its base. The valley was named by an early unknown Spanish explorer, the patron saint of whose village was San Luis.

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