Geologic map of the Picacho Mountains and Picacho Peak, Pinal County, southern Arizona

Richard, S.M.; Spencer, J.E.; Ferguson, C.A.; Pearthree, P.A.

dc.contributor.author	Richard, S.M.
dc.contributor.author	Spencer, J.E.
dc.contributor.author	Ferguson, C.A.
dc.contributor.author	Pearthree, P.A.
dc.date.accessioned	2018-11-10T02:56:59Z
dc.date.available	2018-11-10T02:56:59Z
dc.date.issued	1999
dc.identifier.citation	Richard, 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.uri	http://hdl.handle.net/10150/630820
dc.description	The 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.iso	en
dc.publisher	Arizona Geological Survey (Tucson, AZ)
dc.relation.ispartofseries	OFR-99-18
dc.relation.url	http://repository.azgs.az.gov/uri_gin/azgs/dlio/377
dc.rights	Arizona Geological Survey. All rights reserved.
dc.subject	Arizona Geological Survey Open File Reports
dc.subject	Picacho Peak
dc.subject	Picacho Mountains
dc.subject	Pinal County
dc.subject	Arizona
dc.subject	map
dc.subject	topography
dc.subject	geomorphology
dc.subject	Geology
dc.subject	Proterozoic
dc.subject	cretaceous
dc.subject	Quaternary
dc.subject	Tertiary
dc.subject	detachment fault
dc.subject	mylonitic fabric
dc.subject	Laramide orogeny
dc.subject	granitoids
dc.subject	andesites
dc.title	Geologic map of the Picacho Mountains and Picacho Peak, Pinal County, southern Arizona
csdgm.bounding.west	-111.443
csdgm.bounding.east	-111.294
csdgm.bounding.north	32.8727
csdgm.bounding.south	32.6024
dc.description.collectioninformation	Documents 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.dateFOA	2018-11-10T02:56:59Z