Recrystallization and anatexis along the plutonic-volcanic contact of the Turkey Creek caldera, Arizona

Geological Society of America Bulletin
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Abstract

Unusual geologic and geochemical relations are preserved along the contact between intracaldera tuff and a resurgent intrusion within the 26.9 Ma Turkey Creek caldera of southeast Arizona. Thick intracaldera tuff is weakly argillically altered throughout, except in zones within several hundred meters of its contact with the resurgent intrusion, where the groundmass of the tuff has been variably converted to granophyre and unaltered sanidine phenocrysts are present. Dikes of similarly granophyric material originate at the tuff-resurgent intrusion contact and intrude overlying intracaldera megabreccia and tuff. Field relations indicate that the resurgent intrusion is a laccolith and that it caused local partial melting of adjacent intracaldera tuff. Geochemical and petrographic relations indicate that small volumes of partially melted intracaldera tuff assimilated and mixed with dacite of the resurgent intrusion along their contact, resulting in rocks that have petrographic and compositional characteristics transitional between those of tuff and dacite. Some of this variably contaminated, second-generation magma coalesced, was mobilized, and was intruded into overlying intracaldera rocks.

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Publication type Article
Publication Subtype Journal Article
Title Recrystallization and anatexis along the plutonic-volcanic contact of the Turkey Creek caldera, Arizona
Series title Geological Society of America Bulletin
DOI 10.1130/0016-7606(1999)111<0143:RAAATP>2.3.CO;2
Volume 111
Issue 1
Year Published 1999
Language English
Publisher Geological Society of America
Description 11 p.
First page 143
Last page 153
Country United States
State Arizona
Other Geospatial Turkey Creek caldera
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