Middle Tertiary plutonism in the Santa Catalina and Tortolita Mountains, Arizona

Open-File Report 76-262
By: , and 

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Abstract

Recent reconnaissance geologic mapping in the Santa Catalina and Tortolita Mountains of southeastern Arizona, supplemented by new and published potassium-argon and fission-track ages, suggests that a large middle Tertiary (about 25 m.y.) composite batholith crops out extensively in both mountains. More than two-thirds of the batholith and the contiguous wallrocks are gneissic, the gneissosity comprising strong cataclasis and mylonitization, penetrative planar and linear structures, and crystallization of muscovite and biotite in the foliation planes. New radiometric ages indicate the deformation followed the crystallization of the batholith so closely that the K-Ar dating method cannot distinguish a difference, whereas previously published ages from the gneisses indicate a short time interval between the two events.

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Publication type Report
Publication Subtype USGS Numbered Series
Title Middle Tertiary plutonism in the Santa Catalina and Tortolita Mountains, Arizona
Series title Open-File Report
Series number 76-262
DOI 10.3133/ofr76262
Year Published 1976
Language English
Publisher U.S. Geological Survey
Description ii, 20 p.
Country United States
State Arizona
Other Geospatial Santa Catalina Mountains, Tortolita Mountains
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