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Geochemical fingerprint of a Plio-Pleistocene tephra in California Wash in the Benson area, San Pedro Valley, southeastern Arizona

dc.contributor.authorYouberg, A.
dc.contributor.authorSpencer, J.E.
dc.date.accessioned2018-09-29T02:12:05Z
dc.date.available2018-09-29T02:12:05Z
dc.date.issued2007-06-01
dc.identifier.citationYouberg, A. and Spencer, J.E., 2007, Geochemical fingerprint of a Plio-Pleistocene tephra in California Wash in the Benson area, San Pedro Valley, southeastern Arizona. Arizona Geological Survey Open File Report, OFR-07-02, 14 p.
dc.identifier.urihttp://hdl.handle.net/10150/629746
dc.descriptionMuch of the Plio-Pleistocene sediment in the San Pedro River Valley near Benson (Cochise County, southeastern Arizona) reflects a past depositional environment in which clastic debris was shed from valley-flanking mountains into the basin. The basin interior was characterized by a playa environment that is represented by fine sand, silt, and gypsum, whereas flanking, basin margin areas received conglomerate and sandstone derived from nearby bedrock (Smith, 1994; Youberg et al., 2003; Shipman and Ferguson, 2003). During deposition of these valley-filling sediments, several ash beds were deposited from distant volcanic eruptions. The age of this sedimentary sequence is only approximately known based on vertebrate fossils, magnetostratigraphy, and K-Ar dates on glass from the tephras. Theses studies proposed a Pliocene to Pleistocene age. Similar sediments in the lower San Pedro River Valley, which contain a tephra dated at 6 Ma, include extensive lacustrine (lake) deposits (Dickinson, 2003). The similarity between upper and lower San Pedro Valley filling sediments suggests that they are related and are of similar age, whereas available geochronologic data indicate that the lower San Pedro sediments are significantly older. ( 13 pages)
dc.language.isoen
dc.relation.ispartofseriesOFR-07-02
dc.relation.urlhttps://library.azgs.arizona.edu/item/AOFR-1552427226890-275
dc.rightsArizona Geological Survey. All rights reserved.
dc.subjectArizona Geological Survey Open File Reports
dc.subjectCochise County
dc.subjectArizona
dc.subjectSan Pedro Valley
dc.subjectBenson
dc.subjectCalifornia Wash
dc.subjectdeposition
dc.subjectsediment
dc.subjectGeology
dc.subjecttephra
dc.subjectgeochemical fingerprint
dc.subjectPliocene
dc.subjectPleistocene
dc.subjecttephrochronology
dc.subjectgeochemistry
dc.titleGeochemical fingerprint of a Plio-Pleistocene tephra in California Wash in the Benson area, San Pedro Valley, southeastern Arizona
csdgm.bounding.west-110.544
csdgm.bounding.east-109.99
csdgm.bounding.north32.1152
csdgm.bounding.south31.7889
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.dateFOA2018-09-29T02:12:05Z


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