Ask a Geologist Common Q&A

Mat, This is my first encounter with the healing dirt of Chimyo, New Mexico.

By one account, the dirt large consists sand-sized grains of minerals and small bits of rock. The addition of hydrochloric acid causes the material to fizz indicating a fair amount of calcite ( a common calcium carbonate). The pit from which the dirt is harvested is regularly refilled with fresh dirt by the church authorities.

This article seems authoritative, https://www.csicop.org/si/show/miracle_dirt_of_chimayo

Thanks for the question.
Mike

Hi Barb:

Collecting minerals is more difficult now than it was in the not-so-distant past. As frequently as not, tailing piles and mining dumps - once the cornerstone of mineral collecting - are no longer open to the public. There are a number of books on the topic and several common ones are bulleted below. Unfortunately, while the authors can point you to sites where minerals may be found, they can not assure you that collecting is permitted.

My advice: select some areas or sites of interest and then contact local rock hound or prospecting groups, historical museums and others regarding where you can legally scout for minerals.

Places you can collect moderate volumes of minerals or rocks include federal lands managed by the Bureau of Land Management; this includes US Forest Service lands. Check out Arizona-BLM 'Rock Hounding in Arizona' flyer for guidelines.

Places you cannot collect minerals or rocks, include: National Parks and Monuments, State Parks, Arizona State Trust Land, private lands (unless permission is provided), and Native American Reservations, among other places.

Recent books on Arizona Minerals

• ‘Gem Trails of Arizona’, inexpensive, revised and re-released in 2010. The text identifies collecting sites, but buyer beware, I don't believe you can be assured of collecting.
• Neil Bearce’s ‘Minerals of Arizona’ was an excellent text for collectors - now out of print. Note, much may have changed in site availability since it was published in 1999.
• Anthony and others (1995) ‘Mineralogy of Arizona’ is the bible of mineral types and locations in Arizona. It does not, however, lean towards the individual collector.
• Geology & Mineral Resources of Arizona (Bulletin 180) has details on mineral resources, but it was never intended to be a guide for collectors and it does not broach the subject of collecting minerals.

Good luck with it.
Mike

Randy, That is a robust description. Magnetism occurs in terrestrial rocks, but it is not terribly common. You may have found a lodestone formed when magma intrude limestones. Unfortunately, I would need to handle the rock and do some physical test to be sure.  Try scratching the edge of white porcelain plate or coffee cup with the rock. If you see a black streak, the rock is rich in magnetite, a mineral that forms naturally on Earth. Good luck.

Bruce: We host 400,000 unpublished pages of mine files for ~21,000 Arizona mines at our Arizona Geological Survey Mining Data website. You can search those files by: mine name, mineral commodity, keyword, or, importantly, location. The site includes a powerful geographic search tool. Additionally, you may find information regarding the mine in one our published Bulletins, Open-file Report, Contributed Reports, Contributed Maps, or Digital Geologic Map reports, all of which are available for free download through the Arizona Geological Survey's Document Repository. 

Good luck with your search.

Note: The mine name, Blue Quetzal, is an alias, we changed the name to protect the privacy of the inquirer.  (AZGS Staff)

Paul, You should begin your search at the interactive Arizona Oil and Gas Viewer. The viewer comprises locations and data (well logs and geophysical logs) for more than 1,100 wells drilled for oil and gas in Arizona. The viewer was built by the Arizona Geological Survey, but is maintained and updated by the Arizona Dept of Environmental Quality, working under the guidance of the Arizona Oil and Gas Conservation Commission.

If you need assistance, please reach out to the ADEQ's oil and gas administrator at OGCC@azdeq.gov.

Hi Dawn:  

It just so happens that AZGS geologists Steve Skotnicki and Charles Ferguson mapped and reported on the Sacaton Mtn. geology in 1996. That report and the two maps that accompany it are online at http://repository.azgs.az.gov/uri_gin/azgs/dlio/415 .

But to address your question, the Sacaton Mtns formed as part of the Basin & Range extension which began about 30 million years ago and continues, albeit at a very slow rate, today. The Sacaton Peak Granite and other nearby granites, including Girl Scout Mtn (Kgk) are considerably older then the Sacaton Mtns. The granites were intruded into  Earth's crust between 49 and 63 million years ago. The Sacaton Mtns. as a geomorphic feature probably formed 20 to 10 million years ago – that is a ballpark figure.

Basin and Range uplift, i.e., mountain building,  certainly led to substantial erosional and exhumation of these intrusive granites. And precipitation and running water would played an important erosional role, removing and transporting sediments into the nearby basins.

The fractures in the granite, ‘joints’, are the result of the tectonic forces at work on the granite over the past 50 million years.  You will probably note that the exposed rock here appears to be somewhat rounded – half spheres. That is the result of chemical weathering of the feldspar minerals that dominate the mineral constituents of this rock and is referred to as spherical weathering – very typical of the way granites weather over time.

Glacial activity is almost certainly not important here.  
Let me know if I can help further.  Mike

P.s. A nice exercise for students is to provide color pencils or crayons and shade in the different units to get a better understanding of the relationship of the rock units. In this case, probably just Kgk and Kgq (the Sacaton Peak granite).

Sacaton Mtn geologic map with Girl Scout Mtn in orange circle.

Bo,

I’ll see what I can dig up on geothermal in Holbrook region.  There is currently one helium producer in the Holbrook Basin and a second company doing exploratory drilling.
Regarding helium there, have a look at:

• Annual Oil, Gas and Helium production in Arizona: 1954-2009. 
• Review of helium production and potential in Arizona Geological Survey
• Coal, Oil, Natural Gas, Helium, and Uranium in Arizona

Good luck with the research.

MC

Shirley, Your housing addition is situated on unconsolidated sediments shed off of the nearby Hieroglyphic Mtns to the north. In this setting, the sediments are loosely compacted and frequently rich in clay lenses that swell when wetted and shrink when dryed - shrink-swell soils. Placing a load on them or watering them frequently can result in local compaction and surface subsidence - i.e., potholes and larger irregular depressions.

We do have some resources at our website that describe the nature, impacts and distribution of swell-shrink or problem soils in Arizona. Also, have a look at our Home buyer's guide to geologic hazards in Arizona.

There is no simple solution to mitigating earth fissures. Multiple efforts have been made to backfill the Y-crack fissure in the Chandler Heights area with gravel, debris and concrete blocks. All those attempts have failed. Runoff from monsoon rainstorms frequently triggers fissure collapse and widening. Preventing water from washing into the fissure and eroding its sidewalls might successfully combat further widening and reactivation. The fissure, however, remains in-place in the subsurface.

For the location of all mapped fissure in central and southern Arizona, toggle the earth fissure theme at the Natural Hazards in Arizona viewer.

Other resources:

• Earth fissures & Ground Subsidence
• Home buyer's guide to geologic hazards
• Why did the earth fissure cross the road?

Hello Seth: There is a lot of primary mine and mineral information available through the US Geological Survey and AZGS. First thing to do is review the information, publications and links that we host at the Minerals - Mining in Arizona section of our website.

For more granular data, I recommend these sites.

• Arizona Geological Survey Mining Data - with files (reports, maps, correspondence, photos) for more than 20,000 AZ mines.
• US Geological Survey Mineral Resources Data System - with reports on mines from all 50 states, including 1000s of mines in Arizona.

Good luck with the hunt.  MC