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Evidence for Mesoproterozoic ca. 1470-1444 Ma regional deformation of the Mazatzal Group and equivalent rocks in the type area of the Mazatzal Orogeny, Tonto Basin, Arizona

Michael F. Doe and Christopher G. Daniel
Evidence for Mesoproterozoic ca. 1470-1444 Ma regional deformation of the Mazatzal Group and equivalent rocks in the type area of the Mazatzal Orogeny, Tonto Basin, Arizona (in Geologic excursions in southwestern North America, Philip A. Pearthree (editor))
Field Guide (Geological Society of America) (September 2019) 55: 237-272

Abstract

New detrital zircon data from deformed metasedimentary rocks of the Mazatzal Group in the northern Mazatzal Mountains, Arizona, indicate that formation of a regional fold-and-thrust belt occurred after ca. 1570 Ma. Regional correlations with pelites within the syncline at Four Peaks and deformed and intruded sediments in the upper Salt River Canyon allow us to revise the timing of deformation to ca. 1470-1444 Ma, contemporaneous with the Picuris orogeny in New Mexico. Fold- and thrust-style deformation of the Mazatzal Group was previously interpreted to be Paleoproterozoic and was a hallmark of the ca. 1650 Ma Mazatzal orogeny in the southwestern United States. However, recognition that protoliths of the deformed rocks formed in the Mesoproterozoic requires reconsideration of the age and regional tectonic significance of the orogenic event in its type locality. Our new findings are incompatible with published tectonic models invoking a regional ca. 1650 Ma Mazatzal orogeny and localized, pluton-enhanced deformation across the region ca. 1450 Ma. This field trip visits and reviews three localities across the Tonto Basin of central Arizona: (1) the northern Mazatzal Mountains; (2) Four Peaks of the southern Mazatzal Mountains; and (3) exposures of the early Mesoproterozoic Yankee Joe Group in the upper Salt River Canyon. At each location, deformation previously attributed to ca. 1650 Ma is, instead, demonstrably younger and represents a different episode of regional orogenesis. Thus, the nomenclature and tectonic significance of ca. 1650 Ma versus 1450 Ma regional orogenic events must be reconsidered and revised to reflect our present data and understanding, with implications for the tectonic evolution of Proterozoic rocks of southwestern North America.


ISSN: 2333-0937
EISSN: 2333-0945
Serial Title: Field Guide (Geological Society of America)
Serial Volume: 55
Title: Evidence for Mesoproterozoic ca. 1470-1444 Ma regional deformation of the Mazatzal Group and equivalent rocks in the type area of the Mazatzal Orogeny, Tonto Basin, Arizona
Title: Geologic excursions in southwestern North America
Author(s): Doe, Michael F.Daniel, Christopher G.
Author(s): Pearthree, Philip A.editor
Affiliation: Bucknell University, Lewisburg, PA, United States
Affiliation: University of Arizona, Arizona Geological Survey, Tucson, AZ, United States
Pages: 237-272
Published: 20190904
Text Language: English
Publisher: Geological Society of America, Boulder, CO, United States
References: 92
Accession Number: 2020-016669
Categories: Solid-earth geophysics
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. geol. sketch maps, 1 table, strat. cols.
N33°00'00" - N35°00'00", W113°00'00" - W110°00'00"
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2020, American Geosciences Institute.
Update Code: 202011
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