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Structure of Golden Gate Mountain, Pima County, Arizona

Golden Gate Mountain appears as a spur projecting westward from the Tucson Mountain range. It is made up of the capping Cat Mountain Rhyolite, the slope - forming Amole Formation, and a variety of intrusions of differing compositions. The emplacement of the andesitic portion of the intrusions occurred during, and probably lasted long after, the deposition of Amole Formation. The hot magma fluidized the wet sediments. Part of the fluidized materials formed pipes and dikes of tuffisites and part was brought up into the basin and contributed to the sedimentation of Amole Formation. During upper Amole time the intrusion of andesite increased in intensity. Part of the basin rapidly subsided and thick deltaic sediments and graywacke were formed. The development of a hinge line accompanied this subsidence. The hinge line controlled the occurrence of fluidization which undercut the Amole beds. The beds slumped into the fluidized parts. The process culminated in forming a large orifice through which the Cat Mountain Rhyolite welled up. The orifice is reflected in the sedimentary beds by the development of a funnel- shaped structure in the central part of which the capping of Cat Mountain Rhyolite is located. The bordering brecciated Amole beds represent the associated slump effects.

Identiferoai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/231231
Date January 1964
CreatorsAssadi, Seid Mohamad
ContributorsMayo, Evans B., Harshbarger, John M., Pye, Willard D., Assadi, Seid Mohamad
PublisherThe University of Arizona.
Source SetsUniversity of Arizona
Languageen_US
Detected LanguageEnglish
Typetext, Thesis-Reproduction (electronic)
RightsCopyright © is held by the author. Digital access to this material is made possible by the Antevs Library, Department of Geosciences, and the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author or the department.

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