Skip to main content
x
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.

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.


RESOURCES

Links to AZGS 7.5’ Digital Geologic Maps of western Mohave County below graphic.

 

Simplified geologic map
DGM footprints superposed on Geologic Map of Arizona (Richard et. al., 2000)

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.