Arizona Geology Blog

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blog of the State Geologist of ArizonaLee Allison
Updated: 24 min 7 sec ago

Quakes hit northern Arizona

Mon, 2015-09-28 13:03
 A magnitude 3.3 earthquake hit northern Arizona about mid-way between Flagstaff and Grand Canyon village on Saturday, Sept. 26 at about 4:14 pm, local time. [Right, orange star marks quake epicenter. Credit, USGS]

Later that evening, at 9:23 pm, a magnitude 2.9 event occurred about 7 miles SSW of Kachina Village. This could be another aftershock to last November's M=4.8 earthquake between Flagstaff and Sedona.

The region from around Flagstaff to Grand Canyon is the most seismically active in the state.
Categories: AZGS Web Posts

Symposium on sustainable mining in the Southwest US & NW Mexico

Thu, 2015-09-24 16:47

The University of Arizona Global Initiatives group is working with UA Mining & Geological Engineering to host a 3-hour symposium on Mineral Resources: from Exploration to Environmentally Sustainable Mining in the SW United States and NW Mexico.

It will be held Monday, September 28, 2015,09:00 to 12:00.

Location: ENR2, Room S 225, University of Arizona, Tucson

The full program can be viewed at
Categories: AZGS Web Posts

Expanding the national geothermal data system

Wed, 2015-09-23 08:35
We're in the last day of the Geothermal Resources Council annual meeting in Reno, with an exhibit booth in the Geothermal Energy Association's Expo, giving demonstrations of the National Geothermal Data System ( 

AZGS manages the NGDS on behalf of the rest of the state geological surveys, with 65+ data providers in all 50 states contributing over 10 million data records currently. Any geothermal energy project funded by the US Dept. of Energy has to make their data publicly available through the NGDS.   Most projects chose to send their data to the Geothermal Data Repository node on NGDS.  GDR is run by the National Renewable Energy Lab in Colorado. 

We've been meeting with leaders of various research projects in the Play Fairway Analysis and FORGE programs to discuss adding their growing reams of data into NGDS. We've also had conversations with representatives from East African countries about supporting their data management programs for the booming geothermal development in that region. [Right,  AZGS' Steve Richard -right- talks with Andrew Palmateer with the US Energy Association's East Africa Geothermal Program, and Rick Zehner with Geothermal Development Associates, about data needs in East Africa]

Categories: AZGS Web Posts

"Life as Geoscientist" photo contest

Sun, 2015-09-20 07:03

The American Geosciences Institute (AGI) looking for entries in its 2015 "Life as a Geoscientist" Photo Contest

They are looking for any and all geoscience images featuring your internships, research, or geoscience work as a whole. Photos can be entered into three different categories: Outdoor Lab, Indoor Lab, and Data Visualization. They "want your best photos showing what geoscience work and research looks like and why you love being a geoscientist. Submitting epic photos allows participants the opportunity to win prizes."

All submitted materials should be sent to

Deadline to submit is November 6th, 2015

Categories: AZGS Web Posts

Search engine allows access to 19 environmental databases

Fri, 2015-09-18 11:30

The Arizona Department of Environmental Quality (ADEQ) announced it now has available through its website an online search engine allowing faster, more direct access to the agency’s 19 environmental databases containing information such as a facility’s operating permits and compliance history.

Known as MegaSearch (, the tool allows customers to enter search criteria such as a facility’s name and address or its unique ADEQ file number to view a list of relevant environmental records and files of interest. Once identified, the files may be selected from the results page and emailed to the ADEQ Records Center for retrieval and viewing. By conducting their own independent research, customers can save time by eliminating the need to wait for results from a traditional records request with the help of Records Center staff.
“MegaSearch helps prospective land and business owners or anyone who wants to see instantly what environmental activity has been reported for a given location,” ADEQ Records Manager Eric Flohr said.
For example, Flohr said if you previously had wanted to know if a nearby gas station had a history of leaking underground storage tanks, you would have contacted ADEQ to submit a research request. Staff would then have accessed these same databases now available online to see what records of activity had occurred at the site. The process could take several days depending on the number of pending research requests, he said.
“Tools like MegaSearch give customers direct and instantaneous access to ADEQ’s vast amounts of environmental data from all over the state, which supports more transparent government for our citizens,” Flohr said.
For questions about MegaSearch, please contact Eric Flohr at (602) 771-4335 or by email at

[excerpted from from the ADEQ announcement]
Categories: AZGS Web Posts

Geothermal data repository reaches 500 submission

Fri, 2015-09-18 10:47

The Geothermal Data Repository node on the National Geothermal Data System has received its 500th submission of data and results from DOE-funded geothermal projects -  NGDS was developed by the Arizona Geological Survey on behalf of the Association of American State Geologists and other participants, with funding from the US Dept. of Energy.  [Right, map of the US highlighting the locations of GDR users. Critical data about the subsurface is added to the GDR from sites all across the country. Credit: Jon Weers, NREL.]
The GDR is managed by the National Renewable Energy Lab and is the online repository for the results of any DOE-funded geothermal project if the project does not want to host the data themselves.   We are developing additional data content models to accommodate new data types submitted to DOE by the various projects.   [Bottom, relative amounts of different types of data useful to the geothermal community, housed by the GDR. Credit: Jon Weers, NREL] We will have an exhibit booth at the Geothermal Resources Council annual meeting in Reno next week to demonstrate the system to the geothermal industry.
Categories: AZGS Web Posts

Mining diorama finds new home at Papago Park museum

Sat, 2015-09-12 11:20
The giant diorama of an open pit mine that was a feature of the former Arizona
Mining & Mineral Museum in Phoenix, has found a new home at the Arizona Historical Society's Papago Park Museum.  

A grand opening of a new mining gallery is planned for mid-November.

Volunteers Bob Mertz and Larry Dykers briefed the Arizona Mining Alliance luncheon meeting  in Tucson on Friday, showing pictures of the reconstruction of the diorama currently underway.

The diorama has been in storage since the former mining museum closed in 2011 in preparation for conversion to a centennial museum, but funding never materialized and the building remains empty and closed.

The diorama has a number of interactive stations for visitors to see every aspect of mining.  The display is built to HO train scale.

Categories: AZGS Web Posts

New Interactive Map of Gold King Mine water sampling in CO, NM, UT and AZ

Wed, 2015-09-09 12:27

The Arizona Geological Survey (AZGS) has launched an interactive map, Gold King Mine Spill Water & Sediment Sample Locations, showing more than 200 water and/or sediment sampling sites that represent more than 1,000 water analyses from: US Environmental Protection Agency (EPA), Colorado Department of Public Health & Environment, New Mexico Environmental Department, and the Utah and Arizona Department of Environmental Quality. Additional sample sites and data from the US Geological Survey, the Navajo Nation Environmental Protection Agency, and the Arizona Game & Fish Dept., will also be included if made available. 
The 3-million gallon Colorado Gold King Mine spill of August 5, 2015, spurred water sampling along the Animas and San Juan Rivers, Lake Powell, and from nearby wells and irrigation canals in Colorado, New Mexico, Utah, Arizona, and Navajo Nation lands.
The chief objective of AZGS interactive map is to show the scope of the state, tribal, and federal response to the spill; to provide cooperating agencies and the public with access to the sample results; to assist responding agencies in coordinating, collaborating, and communicating who is sampling, where they are sampling, and when samples are being taken. 
The map displays 115 sample sites in Colorado, nearly 80 in New Mexico, 20 in Utah, and 5 sample sites in Arizona. Map features include: sample date and location, links to data sources reporting water analyses, sample type (water or sediment), time slider, and toggling sample sites reporting concentrations of arsenic, cadmium, lead and/or mercury in exceedance of the federal safe drinking water standard.  These four elements were identified by the US EPA as the primary contaminants of concern due to their potential to pose significant health risks.  
To access the map visit the Gold King Mine spill information page managed by Arizona cooperating agencies at

[modified from the AZGS news release]
Categories: AZGS Web Posts

Misleading counts of inactive mines in the U.S.

Sun, 2015-09-06 10:37

It's not surprising that in the wake of the Gold King mine waste water spill there would be numerous efforts to uncover other potential mine problems elsewhere.  But some of the efforts are misinformed or misleading and appear to be overstating the scale of the problem.
On August 31 an organization called Skytruth put online an interactive map of "inactive metal mines" in the U.S.:
This map was created by accessing the USGS Mineral Resources Data System (MRDS) database and selecting mines listed as ‘past producer’ and then “excluding sites that exclusively produced non-metallic commodities.”  This was done to avoid ‘cluttering’ the map with gravel pits and the like.  
However, there are problems with the claims made about this map.
The map claims to show inactive metal mines but a quick scan of Arizona sites turned up many sites as being primarily silica, perlite,  or unidentified products.
The Skytruth group reports they were using 2012 data. It doesn’t change things much, but most of the US Bureau of Mines  MILS (Mineral Industry Location System) compilations in the USGS MRDS dataset today are records that were made in the late 1970s. The status field has not been updated since then for the majority of the records.  In Arizona we think many of the mines labeled as "active" would be considered past producers today.  

update 9-6-15 8pm:  It was also pointed out to me that one of the biggest problems in using the MRDS/MILS data base from the USGS is there are many duplicate entries for the same mine (one from the MRDS data set and one for MILS data set.). For example, in Arizona's Helvetia Rosemont mining distrct, their map shows two Broadtop mines, two East Helvetia mines, two Leader mines and two Copper World mines.  One of the entries is from the MRDS data and the other is from the MILS data.
Our colleagues in Maine reviewed all the Maine sites on the interactive map and found that more than 70 of them were gemstone or feldspar mines, mostly active in the late 1800s through mid-1900s.  They made Skytruth’s cut because some metallic minerals are listed in MRDS commodities fields, thus failing the exclusively non-metallic test.  From their direct knowledge of these sites, they know that any metallic minerals mined were by-products of the chief commodity – gemstones or feldspar.
They noted that several years ago they compiled a comprehensive list of mineral localities, including undeveloped deposits and ‘past producer’ sites, augmenting and improving the MRDS.  They found about 180 sites that had some level of past production from underground workings.  Most were small adits or shafts of less than 50 feet length with miniscule environmental footprints.  All but two of these sites have no chance of a catastrophic release of waste into the environment.  The two large inactive mine sites are well known and undergoing environmental remediation.
So, before panicking that there are 64,883 mines capable of producing the kind of problem that occurred at Colorado's Gold King mine, realize that many of those "mines" were not much more than initial scrapings in the ground, did not produce metals, do not have potential for backing up waste waters, or are not in acid-water conditions.  Are there acid mine drainage problems in some old or abandoned mines?   Yes, of course, but let's focus our efforts on the real problems and not run around claiming the sky is falling.

[Thanks to David Briggs for spotting the duplicate entries from the MRDS and MILS data bases]
Categories: AZGS Web Posts

New room found at Grand Canyon Caverns

Sat, 2015-09-05 15:48
Cavers discovered a new room at the back of Grand Canyon Caverns this summer after a 7-year search.  They believe it may lead to a larger passageway.  Explorers from the Arizona Grotto Association are mapping the find now, and the cavern owners
hopes to open tours soon.

Grand Canyon Caverns are privately owned and reported to the be the largest dry cave in the U.S.   [Right, one of the first pictures from the new room. Photo credit, Grand Canyon Caverns]

The National Park Service reports that "Hidden within the Grand Canyon are an estimated 1,000 caves. Of those, 335 have been recorded. Very few have been mapped or inventoried. Most have developed in the limestone of the Redwall and Muav formations, although some are known to exist in other formations."

Our Grand Canyon expert believes the Grand Canyon Caverns are in the Kaibab Limestone.

Correction (9-16-15):   Our team is saying the cave is in the Redwall Limestone, not the Kaibab as thought. Take a look at our geologic map 35.5291, -113.2316. There are no Permian age rocks in the area.  And take a look at the cave’s website  They don’t report the formation name, but they report it’s Mississippian age.

On a side note, Lhoist’s Nelson lime operation is located near the cave area. The quarry’s Redwall limestone is so pure it’s reported to be the only U.S. source used to produce metallic calcium at a New England plant.
Categories: AZGS Web Posts

New images from UA's HiRISE Mars camera

Sat, 2015-09-05 14:49
It's been a while since I checked in with the University of Arizona's HiRISE camera on the Mars Reconnaissance Orbiter.  They have just posted 122 new images with the September release and as usual the pictures are striking and amazing.

Rather than try to pick my favorite out of this latest set, I'm capturing a screen shot of one of the six pages of thumbnails.   Give yourself a treat and browse through the album.    According the numbering system, it looks like there are now 42,000 images of Mars now available.

Something else to check out is the Special Releases page - - with HiRISE photos of the various Mars landers and rovers, views of Mars' two moons, as well as the Earth and our own Moon, as seen from Mars orbit.

Categories: AZGS Web Posts

Slab of Navajo Sandstone threatens to fall on Glen Canyon dam facilities

Sat, 2015-09-05 07:27

A 250-ton slab of Navajo Sandstone is threatening to peel off the rock wall above Lake Powell overlooking power plant facilities below Glen Canyon Dam.   Photos from local professional  photographer Frank Talbott
( show work by Bureau of Reclamation crews rappelling off the cliff face in an attempt to install rock bolts and prevent the slab from falling.   [Top and bottom left photos from Bur. Rec.   Upper left and lower right photos from Frank Talbott]

Categories: AZGS Web Posts

Online mapper shows flooding status across the country

Thu, 2015-09-03 20:47
The USGS is testing a new online interactive mapping tool to display flood inundation status cross the US.  On first look it appears to be a great tool for visualizing what portions of the country are troubled by flooding. The green balls represent areas where NO flood is occurring. The black triangles indicate areas under flood watch.

Clicking on a site such as i did in northeast Arizona in the image below, brings up an info box that includes a link to the original data source.
Categories: AZGS Web Posts

Lake Powell safe for recreation after Colorado mine spill

Thu, 2015-09-03 20:31

ADEQ and cooperating agencies report Lake Powell is safe for all uses and encourage Lake Powell recreation.
PHOENIX (September 3, 2015) – As the Labor Day holiday weekend approaches, Arizona Department of Environmental Quality (ADEQ) officials announced today that their analysis of water entering Lake Powell shows that the lake is safe for normal uses.
“ADEQ wants Arizona residents and visitors to know that Lake Powell is safe for Labor Day recreational activities including swimming and boating,” said ADEQ Water Quality Division Director Trevor Baggiore. “ADEQ and the multiple cooperating agencies are reviewing and analyzing new information as it becomes available as part of our everyday work to protect Arizona’s waters,” he added.
Scientists and specialists from several Arizona agencies have been and are continuing to monitor and assess data related to the mine spill. Arizona’s cooperating agencies agree that Lake Powell and the downstream Colorado River are safe for all uses including recreation and agriculture as well as a drinking water source for public water systems.
To establish baseline water quality, ADEQ conducted water quality sampling on August 12, 2015. Test results of these samples are consistent with historic water quality data from Lee’s Ferry (downstream of Glen Canyon Dam). These results, along with ADEQ’s data analysis of water entering Lake Powell (San Juan River test data collected by Utah) are available for review on the Arizona cooperating agencies’ Gold King Mine spill information website:,located on the Arizona Emergency Information Network (AZEIN) website.
As part of the ongoing water quality monitoring and assessment work, the Arizona Game and Fish Department is collecting and testing fish tissue and water quality samples from the Arizona portion of Lake Powell. As new test results become available, ADEQ will compare them with Arizona surface water quality standards and historical data to support water quality protection efforts and continue to share updated information on the AZEIN website.

[news release from ADEQ]
Categories: AZGS Web Posts

Geology class is the best science elective

Thu, 2015-09-03 19:35
“You should take geology because it will fundamentally transform the way you see the world.”

 That's the gist of an article on Slate magazine's site (great name to extol geology, right?) on why taking a geology class is the best elective science class.  Title, "Your World, Rocked," is one of a collection of articles on classes you should take.   It was written by Slate editor-in-chief Julia Turner.

Another great quote - "Geology is a gorgeous way to contemplate the abyss."

[Image credit, EuroGeoSurveys]

Categories: AZGS Web Posts

Dramatic videos of Gold King Mine spill released by EPA

Thu, 2015-09-03 11:47
The Environmental Protection Agency has posted a set of short videos taken as the spill began of mineral-rich waste water from the Gold King mine in Colorado on August 5.     I've embedded one of the ten posted below, showing what looks like the full force of the waters surging out of the mine tunnel.
Thanks to David Briggs, Tucson-based mining consultant, for bringing these to our attention.
Categories: AZGS Web Posts

Mining and ag industries in Arizona file suit over EPA rule on 'waters of the United States'

Wed, 2015-09-02 18:30

The Arizona Mining Association passed along this announcement. This is a complex debate with dramatically different interpretations and claims of what the rule means.   Farmers are convinced EPA will regulate water in man-made ditches in their fields, leading to a nationwide campaign to "Ditch the Rule."    [Below, National Association of Manufacturers]

PHOENIX, AZ – September 1, 2015. The Arizona Mining Association (AMA), Arizona Farm Bureau, Arizona Chamber of Commerce & Industry, Arizona Rock Products Association, New Mexico Mining Association, New Mexico Chamber of Commerce & Industry, and New Mexico Farm & Livestock Bureau filed a lawsuit today in the U.S. District Court for the District of Arizona challenging the U.S. EPA’s new rule dramatically expanding the scope of federal jurisdiction under the Clean Water Act.
Kelly Shaw Norton, President of the Arizona Mining Association, explained, “EPA’s new rule rests on the implausible idea that vast expanses of bone-dry, southwestern desert can be subject to intrusive federal regulation as ‘waters of the United States.’  The focus of this lawsuit will be the new rule’s definition of ‘tributary,’ which expands ‘waters’ jurisdiction based on the presence of certain topographical features that are ubiquitous in the arid southwest, even in areas where it has been decades or centuries since any water has actually flowed on the ground.  What is worse, under the new rule, an agency official in Washington, DC, can deem an expanse of desert to be a ‘water of the United States’ even if relevant topographical features do not actually exist.”
Norton organized this broad coalition of affected southwest business groups to ensure that issues important to the arid west are front and center in efforts to rein in EPA’s dramatic overreach, and to protect southwestern businesses and landowners from unreasonable new regulatory burdens.
Categories: AZGS Web Posts

Geology and Geomorphology of the San Pedro River, Southeastern Arizona- special report released

Tue, 2015-09-01 18:32
AZGS geologist Dr. Phil Pearthree is testifying this week at

a new round of San Pedro River Subflow hearings to decide the extent of the subflow zone, in response to a long-standing judicial determination that river subflow and groundwater are different resources.
Phil is explaining our findings and conclusions regarding the geology and geomorphology of the San Pedro River, and the implications of our work for the potential extent of Holocene river deposits in the subsurface. The objectives of our work were to provide basic data and interpretations to ADWR to assist them in their efforts to delineate the lateral extent of the Holocene river alluvium, which is used as a proxy for the extent of the subflow zone.
AZGS released a report on geology and geomorphology of the San Pedro River earlier this summer.

The San Pedro River flows through the rugged landscape of San Pedro Valley from the U.S. – Mexico border to its confluence with the Gila River at Winkelman (Figure 1). The river has incised (downcut) moderately to deeply into the valley floors that were accumulating sediment until the past few million years or less. River incision has in turn driven incision of all of its tributaries and erosion of the surrounding landscape. The inception of river incision resulted in a dramatic narrowing of the extent of river deposits, and this trend has continued to the present. As the river has incised, it has carved an erosional trough in older basin-fill deposits and bedrock, and has left behind remnants of older river deposits (river terraces) that record previous levels of the river. During the Holocene (the past ~10,000 yrs) the river has operated within a relatively narrow corridor bounded by eroded basin deposits, older river terrace deposits, tributary deposits, and bedrock, so all Holocene river deposits are restricted to this corridor. The primary purpose of this paper is to summarize the geologic setting and the geomorphic development and evolution of San Pedro River during the middle and late Quaternary. The latter point is particularly important for understanding the physical setting of Holocene San Pedro River deposits. This work was undertaken to assist Arizona Department of Water Resources staff in their efforts to delineate areas associated with river subflow in the San Pedro River Watershed.

Ref: Pearthree, P.A. and Cook, J.P., 2015, “Geology and Geomorphology of the San Pedro River, Southeastern Arizona,” Arizona Geological Survey Special Paper #10, 23p, 
Categories: AZGS Web Posts

Harald Drewes, former USGS geologist

Tue, 2015-09-01 18:09
We recently learned that Harald Drewes died on July 21 in Colorado.  Harald was a career USGS scientist, well known to Arizonans for his many years of  geological mapping in southern Arizona.   Friends report that no memorial service is planned.

[Photo credit, John M. Ghrist, courtesy of the Colorado Scientific Society.]

Categories: AZGS Web Posts

An inconvenient truth - 60 tons of uranium come down Grand Canyon every year naturally

Sun, 2015-08-30 09:12
In the wake of the EPA mine water spill in Colorado a variety of groups are calling for rewriting the nation's mining laws and regulations.    Kevin Dahl, Arizona program manager for the National Parks Conservation Association is quoted in today's Tucson newspaper as saying,   “Five million people visit the Grand Canyon every year. What if the water had arsenic or uranium in it?  Every visitor would have to bring in his own water."

Sorry, Kevin, but the Colorado River has been eroding uranium, arsenic, and many other natural elements from its watershed and transporting those elements through the Grand Canyon since it began to form millions of years ago.

The US Geological Survey has been monitoring the waters on the river for decades.  A study we did here at the Arizona Geological Survey (Spencer, J.E. and Wenrich, K., 2011, Breccia-pipe Uranium Mining in the Grand Canyon Region and Implications for Uranium Levels in Colorado River Water. Arizona Geological Survey Open File Report, OFR-11-04, 1 appendix, 11 p) found the Colorado River carries an average of 60 tons (yes, tons - 120,000 pounds) of uranium every year through the Grand Canyon.   The range is 40-80 tons per year, depending on runoff, rainfall rates, etc.  

The University of Arizona Superfund Research Program has released a preliminary report on "Understanding the Gold King Mine Spill" that includes calculated estimates of each of  24 minerals/elements that were in the 3 million gallons of mine waters from that mine. The also list the amounts of uranium, arsenic,cadmium, and lead (above).    All are naturally-occurring in the Colorado River, but well below drinking water standards. 

The Colorado River drains a vast area and even normal levels of uranium and other minerals are enough to add up to large amounts when concentrated by the rivers.     On top of that, northern Arizona has among the highest concentrations of uranium in the world, which also erode into the rivers and groundwaters.

So, before panicking visitors to Grand Canyon and other recreation sites along the Colorado River system, we need to look at the base levels already in the water and sediments.  The Colorado River carries uranium and arsenic naturally at low levels through Grand Canyon.  Any increases from the Gold King Mine spill are well below drinking water standards.

We have 50+ years of data to examine to help visitors and residents understand the significance and impacts of what is actually a relatively small addition of minerals to the river and canyon.

Categories: AZGS Web Posts