Structural Relations Determined from Interpretation of Geophysical Surveys: Woody Mountain Well Field, Coconino County, Arizona
Affiliation
Northern Arizona UniversityIssue Date
1974-04-20Keywords
Hydrology -- Arizona.Water resources development -- Arizona.
Hydrology -- Southwestern states.
Water resources development -- Southwestern states.
Water resources
Groundwater basins
Faults (geologic)
Water wells
Geophysics
Arizona
Groundwater
Aquifers
Water supply
Aquifer characteristics
Water storage
Groundwater mining
Water sources
Water yield
Hydrogeology
Gravity studies
Magnetic studies
Gravimetric analysis
Sandstones
Municipal water
Flagstaff (Ariz)
Woody Mountain well field (Ariz)
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Copyright ©, where appropriate, is held by the author.Collection Information
This article is part of the Hydrology and Water Resources in Arizona and the Southwest collections. Digital access to this material is made possible by the Arizona-Nevada Academy of Science and the University of Arizona Libraries. For more information about items in this collection, contact anashydrology@gmail.com.Publisher
Arizona-Nevada Academy of ScienceAbstract
The Coconino Sandstone of Permian age is the principal aquifer for the Woody Mountain well field, a source of municipal water for the City of Flagstaff. Wells of highest yield are located where the frequency of occurrence of faults is greatest and where the principal aquifer is down-faulted. The locations and displacements of all but the most prominent faults cannot be determined using conventional geologic mapping techniques because relatively undeformed Late Cenozoic basaltic lavas cover the faulted Paleozoic rock terrain. Approximately 3,500 feet of Paleozoic sedimentary rocks, which have little magnetic effect and which have a density of approximately 2.4, comprise most of the stratigraphic section in the well field. The basalt cover is strongly reversely magnetized and has a density of approximately 2.7. Changes in thickness of the basalt cover cause changes in the geomagnetic and gravitational field strength. Analysis of data from geomagnetic and gravity surveys was used to delineate boundaries and thicknesses of blocks of basalt which fill down -faulted areas. The correlation coefficient (r² = 0.96) for plots of known thicknesses of basalt versus complete Bouguer anomaly supports use of gravity data to estimate displacement of down -faulted blocks.ISSN
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