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dc.contributor.authorRichard, S.M.
dc.contributor.authorSpencer, J.E.
dc.contributor.authorFerguson, C.A.
dc.contributor.authorPearthree, P.A.
dc.date.accessioned2018-11-10T02:56:59Z
dc.date.available2018-11-10T02:56:59Z
dc.date.issued1999
dc.identifier.citationRichard, S.M., Spencer, J.E., Ferguson, C.A., and Pearthree, P.A., 1999, Geologic map of the Picacho Mountains and Picacho Peak, Pinal County, southern Arizona. Arizona Geological Survey Open File Report, OFR-99-18, 2 map sheets, map scale 1:24,000, 43 p.
dc.identifier.urihttp://hdl.handle.net/10150/630820
dc.descriptionThe Picacho Mountains are north-south trending mountain range completely surrounded by Quaternary alluvium, and consists of Tertiary and older granitic and gneissic rocks (Figure 1). Picacho Peak, located south of the south end of the range, is also surrounded by alluvium, and consists of Tertiary andesitic volcanic rocks. Picacho Peak and the Picacho Mountains are separated by a gap of shallowly buried bedrock through which pass Interstate 10, the Southern Pacific Railroad, and the Central Arizona Project canal. The Picacho Mountains consists of a compositionally diverse suite of Tertiary, Cretaceous or Proterozoic granitoids, heterogeneous to gneissic granite, muscovite granite, schist, and gneiss, much of which has been affected by middle Tertiary mylonitic deformation and probably by late Cretaceous synplutonic deformation [Rehrig, 1986]. Mylonitization is inferred to have accompanied normal faulting and ascent of the bedrock from mid-crustal depths in the footwall of a moderate to low-angle normal fault commonly known as a "detachment fault". Older gneissic fabrics may record Laramide mid-crustal deformation, or relict Proterozoic fabric. The crystalline rocks of the Picacho Mountains are part of the footwall of a south- to southwest-dipping detachment fault that is exposed in only one small area in the southern Picacho Mountains. Picacho Peak, which consists almost entirely of northeast-dipping basaltic and andesite volcanic rocks, is part of the hanging wall of the detachment fault. Geologic map of the Picacho Mountains and Picacho Peak, Pinal County, southern Arizona - report and two map sheets, scale 1:24,000.
dc.language.isoen
dc.publisherArizona Geological Survey (Tucson, AZ)
dc.relation.ispartofseriesOFR-99-18
dc.relation.urlhttp://repository.azgs.az.gov/uri_gin/azgs/dlio/377
dc.rightsArizona Geological Survey. All rights reserved.
dc.subjectArizona Geological Survey Open File Reports
dc.subjectPicacho Peak
dc.subjectPicacho Mountains
dc.subjectPinal County
dc.subjectArizona
dc.subjectmap
dc.subjecttopography
dc.subjectgeomorphology
dc.subjectGeology
dc.subjectProterozoic
dc.subjectcretaceous
dc.subjectQuaternary
dc.subjectTertiary
dc.subjectdetachment fault
dc.subjectmylonitic fabric
dc.subjectLaramide orogeny
dc.subjectgranitoids
dc.subjectandesites
dc.titleGeologic map of the Picacho Mountains and Picacho Peak, Pinal County, southern Arizona
csdgm.bounding.west-111.443
csdgm.bounding.east-111.294
csdgm.bounding.north32.8727
csdgm.bounding.south32.6024
dc.description.collectioninformationDocuments in the AZGS Document Repository collection are made available by the Arizona Geological Survey (AZGS) and the University Libraries at the University of Arizona. For more information about items in this collection, please contact azgs-info@email.arizona.edu.
refterms.dateFOA2018-11-10T02:56:59Z


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