New digital geologic maps encompass gold/silver mining districts of Mohave County
AZGS released new geologic maps for the Secret Pass 7 ½' Quadrangle and the southern part of the Union Pass 7 ½' Quadrangle. These quadrangles straddle the Black Mountains 20 miles west of Kingman, Mohave County. The northern ½ of the Union Pass Quadrangle was mapped previously by Murphy and Faulds (2013).
Mohave County’s population topped 200,000 in 2010; there were just 7,700 residents in 1960. Plans to reroute and expand State Route 95, linking it to State Route 68, will further drive development and growth in the foothills of the Black Mountains. These geologic maps will inform decision-making by Mohave County civil authorities – zoning and planning committees and the Mohave Dept. of Transportation.
This new mapping complements seven extant AZGS digital geologic maps (DGM) for western Mohave County released in 2015-2016. (see the figure below and Resources for URL addresses of the seven DGMs).
Arizona’s Gold-Silver Mining District. The Union Pass and Secret Pass quadrangles are proximal to the Oatman Mineral District and the Union Pass Mineral District.
The Oatman Mineral District produced more than 2 million ounces of gold from epithermal vein deposits between 1863 and 1943, making it Arizona’s largest gold producing district. Since the 1940s the district largely lay fallow. Today, however, the Northern Vertex Mining Corp. is producing gold and silver at their Moss Mine property, located in the Black Mountains 10 miles east of Bullhead City. During the fiscal quarter that ended on 31 Dec. 2019, the Moss Mine produced 7,131 gold ounces and 58,838 silver ounces.
Arizona Silver, Inc., has an active drilling project on the former Philadelphia-Arabian mine area in the Oatman district. The Arabian Mine produced gold and silver from the 1900s to World War II. Post WW-II flooding of the mine and proximity to a nearby roadway prohibited further exploration until recently.
Mineral exploration teams rely heavily on AZGS geologic map products, which now include digital map data packaged in a geodatabase.
Geologic hazards. Flash floods are the chief geologic hazard encountered in the foothills of the Black Mountains. These new geologic maps provide details on Pleistocene-Holocene surficial deposits along river channels and on alluvial fans prone to flooding. That information will inform judicious zoning and planning by government land-use planners, developers, geologic and environmental engineering companies, businesses, and citizens.
- Arizona Geological Survey, 2016, Geologic Mapping in Northern, Central and Southeastern, Arizona. Proposal to US Geological Survey’ State Geologic Mapping Program (STATEMAP), 36 p.
- Arizona Silver Exploration Projects with Greg Hahn, 2019, Arizona Mining Review, 10.5 minute interview hosted by Carson Richardson.
- Ferguson, C.A., 2016, The Peach Spring Tuff, its source caldera, and implications for structural geology of the Colorado River Extensional Corridor. Arizona Geological Society 2016 Fall Field Trip, 29 p.
- Ferguson, Charles A., Johnson, Bradford J., and Pearthree, Philip A., 2020, Geologic Map of the Southern Part of the Union Pass 7.5' Quadrangle, Mohave County, Arizona: Arizona Geological Survey Digital Geologic Map DGM-129, version 1.0, map scale 1:24,000.
- Ferguson, Charles A., Johnson, Bradford J., and Pearthree, Philip A., 2020, Geologic Map of the Secret Pass 7.5' Quadrangle, Mohave County, Arizona: Arizona Geological Survey Digital Geologic Map DGM-130, version 1.0, map scale 1:24,000.
- Keith, S.B., DeWitt, R.H., Troll, W. and Everson, A.B., 1983, Metallic Mineral Districts and Production in Arizona. Arizona Geological Survey Bulletin 194.
- Murphy, R.T. and Faulds, J.E., 2013, Preliminary Geologic Map of the North Half of the Union Pass Quadrangle, Mohave County, Arizona. Arizona Geological Survey Contributed Map, CM-13-A, 1 map sheet, map scale 1:24,000.
- Northern Vertex Mining Corp. 2020, Moss Mine Project, Mohave County, Arizona.
- Richard, S.M., Reynolds, S.J., Spencer, J.E., and Pearthree, P.A., 2000, Geologic map of Arizona: Arizona Geological Survey Map M-35, scale 1:1,000,000.
Links to AZGS 7.5’ Digital Geologic Maps of western Mohave County below graphic.
- DGM-45 Davis Dam SE
- DGM-53 Needles NE
- DGM-54 Boundary Cone
- DGM-118 Mount Nutt
- DGM-113 Kingman
- DGM-114 Kingman NW
- DGM-119 Oatman includes the geodatabase
Cover image & caption by Charles Ferguson. Looking southwest, across Secret Pass Wash towards the junction of the Secret Pass, Union Pass (west), Mt Nutt (south), and Oatman (southwest) 7.5’ quadrangles. The ridge is composed of 18-19Ma andesitic and dacitic lavas at the base of the Miocene volcanic section.