Hi Jenna:

According to Prof. Beth Boyd, Yavapai College, Thumb Butte is an outcrop of volcanic rock that formed about 14.8 million years ago.  That puts it in-place at the time of formation of the Hickey Formation, which comprises mostly basaltic lava flows and vent. Thumb Butte is made up of latite - a volcanic rock with alkali feldspar, plagioclase and a low volume of quartz. Thumb Butte looks like a volcanic neck, but there is evidence to suggest that it is simply a thick pile volcanic lava.

MC

Penny, According to the Mineralogical Society of America, about 4,000 minerals have been identified, with 30 to 50 new minerals discovered each year. The International Mineral Association keeps a running list of minerals. 

Establishing a new, previously unidentified mineral is not a simple task and requires high precision microscopic analysis, geochemistry, and optical measurements.  Naming a new mineral requires addressing the the International Mineralogical Association – Commission on New Minerals, Nomenclature and Classification protocols. Have a look at their 'A new mineral! What to do? webpage.

I hope this helps.  MC

Kay, Not at this time. Several years ago the Arizona Dept. of Water Resources contracted with us for mapping Holocene (past 10,000 years) deposits along the San Pedro and Verde Rivers and their major tributaries.

That work resulted in several geological products - maps and reports -  available for all to download at the AZGS Document Repository.

• Mapping of Holocene River Alluvium along the San Pedro River, Aravaipa Creek, and Babocomari River, Southeastern Arizona: Arizona Geological Survey Digital Map - River Alluvium Map 01 (DM-RM-01), map scale 1:24,000.
• Mapping of Holocene River Alluvium along the Verde River, Central Arizona, Arizona Geological Survey Digital Map - River Alluvium 02 (DM-RM-02), map scale 1:24,000.
• Mapping of Holocene River Alluvium along Oak Creek, Wet Beaver Creek, West Clear Creek, Fossil Creek, and the East Verde River, Central Arizona: Arizona Geological Survey Digital Map - River Map 03 (DM-RM-03), map scale 1:24,000.

Curtis, There are a number of generalized Basin & Range models that crop up during a google search. Bob Scarborough, formally of AZGS, published a suite of detailed Basin and Range cross sections in 1985. The 20+ cross sections and short report are available here, Geologic cross sections of western Arizona Basin and Range, with accompanying geologic maps and other information. You might start with Plate 4; plate 3 superposed the cross section lines on a map of Arizona. 

For a cross-section from the Baboquivari Mtns to the Transition Zone near Safford Basin, see Arca's Geologic map from the Baboquivari Mtns to the Transition Zone of the Colorado Plateau.

Ed, Determining mineral rights can prove difficult. As land ownership is transferred, it is frequently unclear who owns the mineral rights. Attorney John Lacy published the 'Manual for Determination of Status and Ownership; Arizona Mineral and Water Rights' with the Arizona Dept. of Mines and Mineral Resources in 1999, revised most recently in 2010. You should probably start there. 

Hi Steven,
Glassford Hill is a cinder cone - the most common of volcanoes. It's surrounded by basaltic lava flows that probably erupted during the final stage of eruption at Glassford Hill. This volcano is about 12-million years old. The breach to the east is probably erosional in nature.
At the nearby Walmart, they are probably quarrying cinders, which are pyroclastics, or even fragmented basalt.

Thanks for the question.

I think we can help. AZGS geologist Charles Ferguson is the guy to talk to.  Charles first identified the Silver Creek Caldera and its relationship to the Peach Spring Tuff. He's led several field trips to the area and can advise you.

You can find mapping released in Dec. 2017, Geologic map of the Oatman 7 ½' Quadrangle, Mohave County, Arizona, at http://repository.azgs.az.gov/uri_gin/azgs/dlio/1737

There are several earth fissure study areas south of Arizona City in southern Pinal County, including: Greene Reservoir, Tator Hills, and Friendly Quarters.

To view these and the other 23 fissure study areas in Cochise, La Paz, and Cochise Counties - visit the Natural Hazards in Arizona viewer: http://data.azgs.az.gov/hazard-viewer/

I think I can help. We have published several free-to-download popular geology booklets on rocks of the Santa Catalina, Rincon and Tucson Mountains. These include illustrations, descriptions and maps showing where the rocks are exposed.

In terms of collecting rocks, US National Forest lands are fair game, but National Parks, National Monuments and State Parks are off limits.

• A Guide to the Geology of the Santa Catalina Mountains, Arizona: The Geology and Life Zones of a Madrean Sky Island. http://repository.azgs.az.gov/uri_gin/azgs/dlio/1679  
• A Guide to the Geology of Saguaro National Park http://repository.azgs.az.gov/uri_gin/azgs/dlio/1525 
• A Guide to the Geology of Sabinho Canyon and the Catalina Highway. 
• http://repository.azgs.az.gov/uri_gin/azgs/dlio/1526 
• A Guide to the Geology of Catalina State Park and the Western Santa Catalina Mountains. http://repository.azgs.az.gov/uri_gin/azgs/dlio/1453 

There is a small dam at the foot of Sabino Creek that is backfilled with pebbles and sands from the Santa Catalina mountains. People frequently pan for 'desert rubies' there; desert rubies are really red garnet that weather out of some intrusive igneous rocks exposed in the Santa Catalina Mtns.

Good luck!

This is slag, a residual product of smelting copper ore. It’s is rich in iron so it might be magnetic. The vesicles – little holes – are left as gas (H2O) escapes the melt. The slag cools quickly leaving this glassy byproduct.