Saturday, September 29, 2012

Salinities of Arizona's deep groundwater

Arizona receives about 43% of its water supply from groundwater. A new statewide study documenting salinity concentrations of 270 deep groundwater wells in Arizona found that fresh water can extend as deep as 5,000 feet (1,500 m) in some areas but below 6,600 feet (2,000 m) only brackish or saline groundwater was encountered.

As part of a program to examine the suitability of sedimentary basins in Arizona as potential geologic repositories for industrial carbon dioxide (CO2) injection and disposal (called "geologic sequestration"), geologists of the Arizona Geological Survey (AZGS) reviewed geophysical well logs to catalog the concentration of total dissolved solids (TDS, i.e., salinity) of 270 water wells. This included all water wells that penetrated deeper than about 2,600 feet (800 m), which is the minimum depth necessary to sequester carbon dioxide.  [Right, distribution of elevated salinity in groundwater wells]

Of the 56 wells that penetrated 2,600 feet (800 m) depth, 36 were on the Colorado Plateau and 18 were in sedimentary basins of Arizona's Basin and Range Province. Twenty-two deep wells (wells > 2,600 feet) had TDS values greater than 10,000 milligram per liter (mg/L), while 34 showed TDS concentrations less than 10,000 mg/L. The study concludes that fresh, brackish, saline, and brine water exist below 2,600 feet (800 m) depth in the Colorado Plateau and sedimentary basins. Fresh water can extend as deep as 5,000 feet (1,500 m) but below 6,600 feet (2,000 m only) brackish or saline groundwater was encountered.
To further characterize salinity of Arizona's groundwater, AZGS geologists documented all shallower wells with elevated salinity values. This resulted in an additional 214 wells being analyzed: 115 wells with TDS greater than 10,000 mg/L, and 99 wells with TDS between 5,000 and 10,000 mg/L.
From these data AZGS geoscientists inferred that:
  • Correlations between salinity and depth are difficult to discern regionally or even in individual basins.
  • Brackish and saline conditions are present in both provinces below 6,500 feet (2,000 m) depth.
  • Groundwater salinity of basins varies broadly and there is no obvious trend between basin-sediment volume and groundwater salinity.
  • Basin groundwater is influenced by sampling methods, depth, borehole-screened intervals, drilling fluids at the time of sampling, and a variety of geologic factors (e.g. rock chemistry, faults, geothermal gradients, and salt domes).
Groundwater data was provided by the US Geological Survey – National Water Information System, Arizona Dept. of Environmental Quality, Arizona Department of Water Resources - Groundwater Site Inventory, Arizona Oil and Gas Conservation Commission, and consulting geologist James Witcher's Geothermal Resource Data Base. For well reports reporting conductivity in place of TDS, a conversion factor was used to calculate the equivalent TDS value.

The U.S. Department of Energy (DOE) funded this research as part of nationwide program to explore a variety of geologic repositories for their carbon dioxide sequestration potential. The report is available online for review or downloading at no cost.

Citation: A Summary of Salinities in Arizona's Deep Groundwater, 2012, Gootee, B.F., Mahan, M.K and Love, D.S. Arizona Geological Survey Open-File Report, OFR-12-26. 10 p.

New Source of Geothermal Energy in Western U.S.

Discovery of a new type of geothermal energy resource in Utah offers hope for significantly more potential across the western U.S., and a boost in geothermal power production. 

In 2011 and 2012, Utah Geological Survey geoscientists, in partnership with a U.S. Geological Survey research drilling crew, drilled nine temperature gradient holes in Utah’s Black Rock Desert basin south of Delta to test a new concept that high temperature geothermal resources might exist beneath young sedimentary basins.  Preliminary results show that near-surface temperature gradients in the basin vary from about 60C/km (33F/1000 feet) to 100C/km (55F/1000 feet).  This implies temperatures of 150 to 250C (300 to 500F) at 3 – 4 km depth (10,000 to 13,000 feet) beneath the basin.  An abandoned oil exploration well drilled near Pavant Butte in the central part of the basin in 1981 confirms these exceptionally high temperatures.  Seven of the drill holes were funded by the U.S. Department of Energy as part of a National Geothermal Data System project, managed by the Arizona Geological Survey.  The new holes also confirm the results from three other research holes that were drilled in the basin over the past few years; these were funded by the Utah State Energy Program and the Utah Division of Wildlife Resources. 

The 1,000 square kilometer Black Rock Desert basin is filled with unconsolidated sediments to a depth of 3 km, while the underlying basin floor comprises a variety of Paleozoic and older bedrocks.  In some parts of the basin, porous and permeable carbonates (limestones and dolomites) are known to be present and these would be natural hosts for a geothermal reservoir.  Using the drilling results, a reservoir modeling team at the University of Utah estimates a basin-wide power density of about 3 to 10 MWe/km2, (megawatts of power per square kilometer) depending on reservoir temperature and permeability.  Given the large area of this basin, the power potential is conservatively estimated to be hundreds of megawatts, and preliminary economic modeling suggests a cost of electricity of about 10c per kilowatt-hour over the life of a geothermal power project.  The modeling assumes air-cooled binary power generation with all produced water injected back to the reservoir so that there would be no emissions or consumption of water.  The heat in the produced water would be exchanged at the surface in an air-cooled binary power plant.  Such power plants are common these days in geothermal power developments. The cool, injected water would move laterally in the reservoir between injection and production wells, and can be considered as heat-farming at depth.  
This basin is especially attractive for geothermal development because of the existing nearby infrastructure ─ it is next to a large coal-fired power plant, a 300 MWe wind farm, and a major electrical transmission line to California[Right, location of the new temperature gradient wells in the Black Rock Desert, and the inferred temperature at 3 kilometer depth (10,000 feet; 150C = 300F; 200C = 400F).  The contours of gravity outline a basin coinciding with the region of high temperature.  Credit, UGS]

Geothermal exploration in the Basin and Range Province of western Utah and Nevada has traditionally focused on narrow, hydrothermal upwelling zones along bounding faults of mountain ranges.  Most current power developments have reservoir areas of less than 5 km2 (2 square miles).  However basins within the Basin and Range usually have areas of many hundreds of square kilometers.   Although the depth to potential reservoirs beneath these basins is deeper than the geothermal industry is used to, the large reservoir area offers economies of scale.  Drilling to depths of 3 – 4 km is not unusual in oil and gas developments.

Dr. Rick Allis, Director of the Utah Geological Survey and joint lead scientist of the sedimentary basin geothermal research project, said that existing heat flow maps of the Basin and Range don’t have the resolution to identify this type of geothermal energy resource. “There are other potentially hot basins across the Basin and Range province that need to be investigated using this exploration model.  We have identified the Steptoe Valley and Mary’s River –Toano basins in northeast Nevada as obvious geothermal targets.  There may also be hot basins across the western U.S. that have similar unrecognized geothermal energy potential.”   

The project findings are being presented at 2:30pm on Monday, October 1, at the annual meeting of the Geothermal Resources Council in Reno, Nevada.  A question and answer period with Dr. Allis will take place following the close of the session at 3:45pm at the Department of Energy Geothermal Technologies Program booth, 610-612.

The National Geothermal Data System is in operational test mode, integrating large amounts of information from all 50 states to enhance the nation’s ability to discover and develop geothermal energy. Visit the State Contributions site at

A 3 minute video with and without subtitles is available at

Thursday, September 27, 2012

New edition of "Carving Grand Canyon"

The second edition of Wayne Ranney's acclaimed "Carving Grand Canyon" is out, with dozens of new maps and figures, and includes new ideas on the origin of the canyon from the 2010 Geology Summit held in Flagstaff (including research from AZGS geologists Jon Spencer and Phil Pearthree).

I wish I could add my personal observations but our copy of the book was grabbed by others on staff as soon as the package was opened and I haven't gotten  to even thumb through it yet.

We should have it available for sale in the AZGS "Arizona Experience" store in Tucson shortly.

Saturday, September 22, 2012

Water well registry online for Arizona

The Arizona Dept. of Water Resources announced that the GIS Well Registry web application is now linked to imaged records.  After completing your search from either the Search Wizard tool or the Web map tool, you can use the new Imaged Records button to view the well’s document.  You can access the Well Registry User’s Guide.

GIS web applications:

Congrats to Karen Fisher, ADWR's GIS Developer, for  getting this online.

Friday, September 21, 2012

New home dedicated for earth sciences at ASU

The new home of ASU's School of Earth and Space Exploration was formally dedicated on Wednesday with a grand opening ceremony and forum.  SESE shares the building with a number of engineering programs.

The Interdisciplinary Science & Technology Building 4 (ISTB4, right. Credit ASU) "is the single largest research building at ASU, with roughly 300,000 square feet of premier high-technology research laboratories, office areas, and collaboration spaces specifically designed to promote transdisciplinary team interactions."

The construction took over 70 million pounds of concrete (>20,000 cubic yards), 837 tons of structural steel, and 1,855,149 feet of wire (all of which had to be mined by the way).

The main floor is set up like an interactive science museum with a spectacular giant globe where visitors choose what planet-wide phenomena to view.  Video screens are everywhere, but your attention is drawn to the Mars operation center behind a wall of glass, with live feeds from the Red Planet.   A Mars rover sits just inside the main doors and a wide variety of ASU's extensive meteorite collection is on display on the second floor veranda.

Tuesday, September 18, 2012

Small quake east of Fredonia

A magnitude 2.1 earthquake struck Monday morning at 9:05 am local time, about 7 miles east of Fredonia, just south of the Utah border.   [Right, orange star marks quake epicenter. Location map from USGS]

Crunch coming on uranium supplies?

The mining industry has recognized for years that the world's nuclear power plants use more uranium than is being mined. The shortfall has been made up from stockpiles in Russia and other countries but that agreement ends in 2012.

An interview with mining analyst Alka Singh lays out the numbers:  433 currently operating nuclear power reactors around the world annually consume 177 million pounds (Mlb) of uranium. World  production was 130 Mlb last year.  The U.S.'s 104 operating nuclear power reactors used 55 Mlb while the U.S. produced only 4 Mlb.  [Right, highly enriched uranium.  Credit, US DOE]

Thus, the industry's rush to find and develop enough uranium resources to keep the plants fueled, and one reason that the breccia pipes in northern Arizona, which have among the highest concentrations of uranium of any deposits, are a strategic target for mining.

Sunday, September 16, 2012

G. K. Gilbert - "A Captain Bold"

The National Geographic Society is profiling their 33 founding members in recognition of their upcoming 125th anniversary, and published a short bio of Grove Karl Gilbert, one of the most influential geologists in the field, who did some of the early explorations of Arizona.  [Photo credit Wikipedia]

The article starts out, "Grove Karl Gilbert was considered by his own and future generations to be the greatest of all American geologists, and “a captain bold,” according to Australian geologist E.C. Andrews."

Intense battle over Florence copper project

Real estate developers have the support of Florence town leaders in opposing the proposed underground in situ copper leaching process.  The town has closed down the offices of Curis Resources, made copper recovery illegal within two miles of the town, and banned the use of the sulfuric acid in copper operations (but not other applications). The Arizona Republic's put together an overview of what looks to be one of the nastiest such battles in Arizona history.

The paper followed up with articles on the in situ process where a weak acidic solution is pumped underground to leach the copper out of the rocks and pumped back to the surface for recovery [right, credit Curis Resources], and another on some of the political back story

A Curis representative told the Arizona Mining Alliance luncheon crowd on Friday that they are moving forward with permits to start the copper project on state lands by next year.

Saturday, September 15, 2012

Arizona copper production since 1874

Arizona has produced 62.8 million tons or 125.6 billion pounds of copper during 1874-2010 per USGS, USBM, ADMMR, and AZGS publications, according to figures compiled by Nyal Niemuth in the AZGS Phoenix branch office.   About half of that was produced since 1978. 

World production through 2007 is reported by the USGS as 1.23 trillion pounds; 1.1 trillion pounds of that total is still in use because copper's recycling rate is higher than that of any other engineering metal.  By my calculation, Arizona is the source of about 10% of the total world production of copper.  [Right, native copper. Credit, USGS]

Web site promotes nuclear waste processing, disposal in Arizona

Proponents of processing spent nuclear fuel in Arizona set up a web site to promote the idea  - - with a slide presentation at  The plan calls for burying the remaining nuclear waste in salt deposits in Arizona.

State Sen. Al Melvin is the spokesman for the group and summarized the proposals at the Arizona Mining Alliance luncheon in Tucson on Friday.

AZGS has identified and characterized salt deposits in the state at the request of Legislature members but this does not constitute an evaluation by us of the potential for waste storage or an endorsement of the proposal. [Right, significant subsurface salt deposits in Arizona.  AZGS]

Tracking mining-induced seismicity in Arizona

Our friends at Geology.com reminded us that the USGS tracks mining-induced seismicity across the US, principally caused by blasting to break up the rocks.   The figure below shows a concentration around the Kayenta coal mine on the Navajo and Hopi reservations in the northeast and near the Morenci copper mine near Clifton.    It's not obvious why the Clifton area blasts extend to the southeast into New Mexico.  The USGS map does not show seismic events around Lake Mead that are supposedly quarry blasts.  [Right, mining-induced seismicity, Arizona-New Mexico, from 1997-2000.  Credit, USGS]

Thursday, September 13, 2012

State Highway 264 reopens after flood damage

 The Arizona Dept. of Highways re-opened State Highway 264 east of Tuba City after a section was washed out by heavy rains on Wednesday. The temporary fix allows travelers on the Navajo and Hopi reservations access to the cliff-side road until more permanent repairs can be made next week, according to news reports.

[Right, washed out section of road just to right of center. Credit, ADOT]

Sunday, September 09, 2012

Geologic mapping priorities set for next year

 AZGS's Geological Mapping Advisory Committee [right] met in Phoenix last week to set priorities for mapping projects for the Survey.   The 12 members come from state and federal agencies, and professional and trade associations across Arizona.

The group  reviewed proposals from the geoscience community and GMAC members for mapping in 11 different areas and the rationale for mapping each area.  The meeting is open with a few other geology representatives sitting in.   

The GMAC voted and the top choices are:
  • Tucson area aggregate mapping and database
  • Kingman area geologic mapping
  • Holbrook area geologic mapping
  • Lower Colorado River valley geologic mapping
AZGS Chief Geologist is using this list to identify specific quadrangles to propose for matching funding from the USGS Statemap program.   I'll share more details on why each area was chosen and what we hope to learn from the mapping.

Saturday, September 08, 2012

AZGS releases framework for geoscience 'big data' initiative

"Big Data" is the popular term for cyberinfrastructure and it's becoming one of the most significant disruptors in industry today, and on the verge of doing the same in the geosciences.

Early this week, AZGS released a 200-page report, "EarthCube Governance Framework: A Proposal for the Community," that was prepared for the National Science Foundation.      The report was prepared by the EarthCube Governance Steering Committee and additional EarthCube contributors since the June 2012 NSF EarthCube charrette. It is based upon the implementation the EarthCube Governance Roadmap that we presented there: to determine the management and organizational functions required to build the national cyberinfrastructure for the geosciences, and to engage the larger community about how to do this over the next six months. [Right, components of a given scientific community that have to be addressed in building cyberinfrastructure.   Credit, Carroll Hood, Raytheon; from the report]

The EarthCube initiative is the prototype for the high-profile NSF Cyberinfrastructure for the 21st Century (CIF21) program, and touted as one of the premier components of the White House "Big Data" effort.   The functions and guiding principles we compiled could serve as the basis for a solicitation from NSF to set up an EarthCube office to carry the concepts to fruition.

AZGS has the workshop grant from NSF to develop the initial roadmap and I chair the Governance Steering Committee.    AZGS researcher Genevieve Pearthree served as editor of both the roadmap and framework documents.

We've been on the road already this summer, carrying the concepts out to the wider geoscience and IT communities.  A number of workshops are being organized around the country over the next six months to align community needs with the EarthCube vision.

Friday, September 07, 2012

Geothermal energy workshop draws industry crowd

A crowd of about 50 showed up yesterday in the Capitol Executive Tower for a day-long workshop on geothermal energy in Arizona.  The morning session focused on ground source heat pumps (GSHP), with animated discussions about how to calculate their efficiency and cost savings, and how to get home owners over the long held myth that these heating-cooling systems don't work in Arizona.

The  afternoon session looked at the potential for developing geothermal power plants.  Arizona Public Service, the state's largest electric utility, and Ormat, the nation's largest geothermal plant developer, went through the requirements needed.

The workshop was organized by Leisa Brug, the Governor's Energy Policy Advisor and her staff.

I spoke in the morning giving an overview of the state's geothermal energy potential including power generation, direct-use (space heating, aquaculture, etc) and GSHP, and describing the National Geothermal Data System that we are helping build and deploy.   We got offers at the meeting from half a dozen companies to contribute data on their geothermal installations to the database for Arizona, that can help everyone better evaluate and calculate system requirements.

The day ended with a great roundtable among the group about what's needed to speed up geothermal energy development in Arizona.  At a minimum, the networking during the day offered some connections for sharing information and data and a consensus that further meetings of the group will be of great value.

Thursday, September 06, 2012

Swallowed by the haboob

I was heading home from the Capitol this afternoon around 4:30 and about 20 miles south of Phoenix the wall of dark rain clouds ahead turned to brown. 

The wind picked up and things started getting dusty.  But within seconds we disappeared into what I hear was a giant haboob.   Speeds dropped from 75 to 10 mph, flashers came on and there was an orderly migration off the highway, across the shoulder and over to the freeway fence.  I was in the middle of a small convoy that crept along carefully, everyone cautious about changing lanes or doing anything sudden that might catch our fellow travelers by surprise.  [Right, cell phone photo out the windshield taken at about 5 mph]

My wife Ann says she was watching the news when reports came in that this haboob was heading north and hit Chandler on the south side of Phoenix about 15 minutes after I went through it.

Sunday, September 02, 2012

Program set for Volcanism in the American Southwest conference

The latest agenda, circular and preliminary abstract volume for the Oct 18-20 Volcanism in the American Southwest conference are all on the conference website.

Hotels:  Evidently, Saturday is Homecoming at Northern Arizona University.  Hotels are rapidly filling up.  If you are not going on the field trip, this may not be an issue.  However, if you are staying in Flagstaff Saturday night after the field trip, you will want to get reservations made soon.

Abstracts:  The draft abstract volume is posted at the conference website.

Conference organizer Jake Lowenstern, USGS, says a Thursday evening dinner is being planned and the field trip is definitely happening. More later...

Saturday, September 01, 2012

Potash - the "pink gold" rush interviewed Fadi Benjamin, a mining analyst with Northern Securities Co., an investment bank based in Canada about a report from the International Fertilizer Industry Association that says "the fertilizer market is on the mend, with demand for potash rising 3.7% per year. Today, U.S. potash prices are at about $575 per metric ton (mt), compared with $380/mt last year."  Potash is used primarily for fertilizer.  The US imports 85% or more of its needs.

Benjamin argues that  farmers "stopped applying the mineral to cropland for a couple of years [due to high prices]. The holiday was possible because crops do not consume all of the fertilizer immediately, and the remainder stays in the soil as a reserve. But now, all around the globe, the potash content in soils is too low. The demand for potash has returned, and crop prices have significantly increased. We are now in a world of $7.90 spot corn prices, $16.65 spot soy and $8.89 spot wheat. It may take two to three years of aggressive potash application for North American soils to reach 2008 soil levels."

Three companies are currently exploring the Holbrook basin potash deposit in eastern Arizona.

Uranium isotope data from Tuba City dump

A new report from the USGS describes uranium isotope data from "analyses completed at Northern Arizona University for groundwater and solid-phase leachate samples that were collected in and around Tuba City Open Dump, Tuba City, Arizona, in 2008."

Ref:  Johnson, R.H., Horton, R.J., Otton, J.K., and Ketterer, M.K., 2012, 234U/238U isotope data from groundwater and solid-phase leachate samples near Tuba City Open Dump, Tuba City, Arizona: U.S. Geological Survey Open-File Report 2012–1126, 2 p.