Tuesday, January 10, 2017

4 New Geologic Map Quadrangles in Arizona

Map showing approximate location of maps
AZGS just released four (4) new geologic map quadrangles for western and southeastern AZ, (see map for approximate locations). The maps are free to download at our online document repository - 'Recent Submissions' at http://repository.azgs.az.gov/ (bottom of the page).

The Corona de Tucson map includes the northern portion of the Santa Rita Mountains, an area of interest to the copper mineralization industry.

1. Geologic map of the Dome Rock Mountains SW 7 ½' Quadrangle, La Paz County, Arizona

2. Geologic map of the Mule Wash 7 ½' Quadrangle, La Paz County, Arizona and Riverside County, California

3. Geologic map of the Mount Nutt 7½' Quadrangle, Mohave County, Arizona.

4. Geologic map of the Corona de Tucson 7 ½' Quadrangle, Pima County, Arizona.

Friday, January 06, 2017

New Leadership at Arizona Geological Survey

Dr. Phil Pearthree
AZGS has a new director and Arizona a new State Geologist. University of Arizona Dean of Science, Dr. Joaquin Ruiz, confirmed that Phil Pearthree, Ph.D., is the new director of the Arizona Geological Survey. As part of his duties, Dr. Pearthree assumes the role of Arizona State Geologist. Phil follows former State Geologist Lee Allison who died tragically in a fall in Aug. 2016.

Phil received his B.S. at Oberlin College, and M.S. and Ph.D. at the University of Arizona. He joined AZGS in 1988 and was chief of the Environmental Geology section for more than a decade. As an AZGS research geologist, Phil has authored or co-authored more than 100 geologic reports and maps over the past 29 years.

In 2013, Phil and two co-authors received the prestigious Kirk Bryan Award from the Geological Society of America’s Quaternary Geology and Geomorphology Division for their report, 'Stratigraphic evidence for the role of lake-spillover in the inception of the lower Colorado River in southern Nevada and western Arizona'.
Dr. Pearthree mapping surficial deposits in the Organ Pipe Cactus National Park

Tuesday, November 29, 2016

History of the Morenci Mining District, Greenlee County, Arizona

Smelter of the Detroit Copper Mining Co., ca. 1896.

The definitive mining history of Arizona's iconic Morenci mining district by geologist David Briggs is now available online at http://repository.azgs.az.gov/uri_gin/azgs/dlio/1695.  This 76-p manuscript with 41 illustrations exhaustively examines  mining activity in the Morenci area from 1870 to 2015.

From DISCOVERY 1863-1872

'During the early 1870s, prospectors who first ventured into the area that would become the Morenci mining district found evidence of primitive excavations at the site. Although Native Americans did not attempt to smelt the colorful copper-bearing oxides extracted from these ancient mine workings, it appears they used these minerals as pigments in their pottery and for other decorative purposes (Colquhoun, 1924).

The first record of copper mineralization near Morenci appears in a report prepared by soldiers of General Carleton's Regiment of California Volunteers, who camped near the junction of Chase Creek and San Francisco River for a few days in January 1863 (Watt, 1956). While there, they noted the presence of strong copper oxide staining on numerous outcrops that lined the slopes along Chase Creek and named the area Copper Mountain. Scouting parties also discovered placer gold along tributaries of the Rio Prieta, now known as Eagle Creek, in concentrations that ran as high as "forty cents (i.e. 0.02 troy ounces) to the pan" (Cogut and Conger, 1999a).

After learning of this discovery, Henry Clifton, the recorder of the Hassayampa mining district near Prescott, Arizona led a prospecting party to search for gold along the Gila and San Francisco rivers during 1864. Although the party also noted the presence of copper along Chase Creek, the remote location and hostilities with Apaches made further development imprudent at that time. '

Posted 11/29/2016 MC

Monday, November 28, 2016

Small Magnitude Earthquakes in NW Arizona 22-25 Nov 2016

Three (3) small magnitude earthquakes occurred in northwestern Arizona over the past week. The largest event was M 2.2, ~ 22 miles south of Colorado City, AZ, on 22 Nov. at 7:31 pm. USGS estimates the focus (depth) at 13.3 km.

On the included map, yellow circles represent earthquake epicenters.

M 1.5, 40 miles SE of Littlefield, Arizona, Depth ~ 5 miles, 2016-11-25 - 6:05 (MST)
M 1.1, 9 miles SSW of Colorado City, Arizona, Depth ~ 7.5 miles, 2016-11-23 – 15:23 (MST)
M 2.2, 22 miles S of Colorado City, Arizona, Depth ~ 8.5 miles, 2016-11-22 – 19:31 (MST)

Source: US Geological Survey

Posted 11/28/2016 MC

Monday, November 14, 2016

High Grade Uranium & Copper Intercepts at the Canyon Mine , Coconino County, Arizona

Energy Fuels Inc. Canyon Mine property, 9 miles south of the South Rim of Grand Canyon, Arizona, is reporting high-grade uranium and copper intercepts. Uranium markets are floundering at about $20/pound, so the discovery of high-grade copper intercepts is an unlooked for economic boon. Copper grade in 5 holes approaches 9%, and one intercept found copper grades over 31%.

According to a recent report by Energy Fuels Inc., 13 holes have been drilled and most have intercepted uranium mineralization at multiple levels. One section, 8.5-feet long, yielded an average grade of 6.88% eU3O8*, and another 48-feet section averaged 1.02% eU3O8. Energy Fuels Inc. plans to drill a total of 15 core holes.

*eU3O8' refers to an equivalent uranium oxide grade that is based on the conversion of a radiometric gamma log determination of radioactive mineral abundance to calculated uranium content.

BACKGROUND “According to a June 27, 2012 technical report (“Technical Report”) prepared in accordance with National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”), the Canyon deposit contains 83,000 tons of Inferred Mineral Resources with an average grade of 0.98% eU3O8, containing 1.63 million pounds of uranium. The existing Technical Report was based on the results of surface drilling. The current underground drilling program is intended to further define and delineate the uranium resources in the Canyon deposit – and to potentially expand and upgrade the resources – above what are described in the Technical Report. If required, the Company expects to have an updated Technical Report prepared for the Canyon deposit, in accordance with NI 43-101.”


1) Juita Group http://jutiagroup.com/20161110-copper-discovery-improves-economics-of-high-gradecanyon-uraniummine/

2) Energy Fuels Inc. http://www.energyfuels.com/news-pr/energy-fuels-announces-high-grade-uranium-intercepts-canyon-mine/

Posted by M. Conway 11/14/2016

Thursday, November 10, 2016

Guide to the Geology of Sedona & Oak Creek Canyon, Arizona

Sedona's Red Rock country includes some of the most spectacular scenery to be found in Arizona.

AZGS’ Down-To-Earth booklet, 'A Guide to the Geology of the Sedona & Oak Creek Canyon Area, Arizona' by John Bezy describes and illustrates just how that landscape formed. The booklet, which is free to download, includes 44 pages with maps, satellite images and more than 25 photos and illustrations. Since Tuesday more than 400 people have visited the site: http://repository.azgs.az.gov/uri_gin/azgs/dlio/1694

From author John Bezy’s introduction: The Sedona-Oak Creek Canyon area offers some of the most unique and spectacular geologic features in northern Arizona. Because of the relatively sparse vegetation most of these features are easy to recognize and photograph.

Some of these geologic features are common on the Colorado Plateau of northern Arizona, western Colorado, southern Utah, and northeastern New Mexico. Others occur in many other parts of the American Southwest. This booklet is your field guide to the geology of this magnificent landscape of red rock pinnacles, buttes, mesas and canyons. All of the geologic features described in the text can be reached by short walks from Highways 89A and 79, Road 78, and from U.S. Forest Service roads. This booklet is written for the visitor who has an interest in geology, but who may not have had formal training in the subject. It may also help assure that the visiting geologist does not overlook some of the features described.

Posted 11/10/2016 by M. Conway