Geologic Map of the Tortolita Mountains, Pinal and Pima Counties, Arizona, v. 1.0
Dataset Identification:
Resource Abstract:
The geologic map of the Tortolita Mountains encompasses the Tortolita Mountains 7.5 quadrangle plus parts of 3 adjoining 7.5
quadrangles; Desert Peak and Marana to the west andsouthwest, and Ruelas Canyon to the south. The Tortolita Mountains mark
the northwesternextent of the Catalina metamorphic core complex (Davis, 1980; Banks, 1980; Keith et al., 1980;Dickinson, 1991;
Force, 1997). Metamorphic and plutonic rocks of the complex were exhumedalong a low-angle detachment fault of Mid-Tertiary
age that is exposed along the southern edgeof the Rincon and Santa Catalina Mountains and is inferred to lie buried beneath
piedmontdeposits along the southern edge of the Tortolita Mountains. A single small exposure of MiddleProterozoic Dripping
Spring Quartzite on the southern piedmont of the Tortolita Mountains isinterpreted to lie in the hanging wall of the Catalina
detachment fault.This study documents a ductile shear zone in the northern part of the range, herein namedthe Carpas Wash
shear zone, and a system of brittle normal faults that are interpreted as thenorthern continuation of the Catalina detachment
fault system. Other important conclusionsbased on our mapping include: 1) recognition of a major, east-dipping normal fault
bounding thewestern edge of a west-tilted sequence of volcanic rocks at Owl Head Buttes, 2) reinterpretationof a sequence
of metasedimentary rocks near the head of Parker Canyon as PaleoproterozoicPinal Schist instead of Mesoproterozoic Apache
Group, 3) recognition of a north-dipping, top-tothe-west low-angle normal fault with an exceptionally wide and well-developed
chloritic breccialedge in its footwall along the western edge, 4) reinterpretation of the Cochie Canyon shear zoneas a septum
of Pinal Schist separating two major plutonic complexes, and 5) reinterpretation of apart of an easterly strand of the Guild
Wash fault zone as a series of south-dipping reverse faultsthat cut the lower part of the Tertiary supracrustal stratigraphic
sequence and that are overlain byTertiary conglomeratic units.
Citation
Title Geologic Map of the Tortolita Mountains, Pinal and Pima Counties, Arizona, v. 1.0
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Metadata contact
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pointOfContact
individual Name Missing
organisation Name
Arizona Geological Survey
position Name missing
Contact information
Telephone
Voice 520.770.3500
Address
416 W. Congress, Ste # 100, Tucson, AZ, 85701-1381
Country USA