Arizona Geological Survey at the University of Arizona

Montezuma Well from the cover of this month’s Arizona Geological Society newsletter (https://www.arizonageologicalsoc.org/).

“ Montezuma Well is a collapsed travertine dome in the Verde Valley of central Arizona and place of emergence of the Yavapai people. Miocene-Pliocene Verde Formation limestone cliffs are exposed in the sinkhole walls, with alcoves expanded and inhabited by early Verde Valley residents. The spring water is sourced from the karstic Mississippian Redwall Limestone aquifer, with additions of mantle-sourced carbon dioxide and helium, directed to the surface at its intersection with a late Miocene basalt dike.”

“Check out Johnson et al. (2011) … for more information about this spectacular geologic site (https://pubs.usgs.gov/of/2011/1063/).”

Citation: Johnson, R.H., DeWitt, Ed, Wirt, Laurie, Arnold, L.R., and Horton, J.D., 2011, Water and rock geochemistry, geologic cross sections, geochemical modeling, and groundwater flow modeling for identifying the source of groundwater to Montezuma Well, a natural spring in central Arizona: U.S. Geological Survey Open-File Report 2011–1063, 62 p.

This year’s ‘super’ El Nino may throw Arizona a wicked curve ball – or a devilish knuckleball. According to the University of Arizona’s “AZ Institute for Resilience”, the 2026 monsoon season may bring “record-breaking heat, deadly flooding and intense wildfires”.

Image: Monsoon storm building over the Superstition Mtns of central Arizona. (This image was produced by ChatGPT.)

Background from an article by Jerod MacDonald-Evoy: “El Niño is the term used for a climate pattern that forms in the Pacific Ocean associated with warming of ocean temperatures in the central and eastern Pacific that impacts weather worldwide. A strong El Niño is often associated with dryer and warmer conditions in the northern United States, while causing increased flooding in the Gulf region and Southeast.” You can read the short-form article at https://air.arizona.edu/news/super-el-nino-could-make-arizonas-already-brutal-summers-even-worse-climate-scientists-warn

The US Geological Survey has just released a 52-p report on the water and river bed of the Colorado River in Grand Canyon. https://pubs.usgs.gov/publication/sir20265010

IMAGES: Cover photo at Sapphire Rapid, Colorado River, Grand Canyon; Study area map; Photograph of the Research Vessel Frank Protiva .

From the ‘Plain Language" summary: “We measured the elevation of 282 miles of the water surface and riverbed of the Colorado River in Grand Canyon, from Lees Ferry, Arizona, to Pearce Ferry, Ariz. We collected water surface and riverbed elevations during a period of steady releases from Glen Canyon Dam in 2021. We used multiple, concurrent methods to measure the elevation of the water surface and assessed error for each measurement method to use the most accurate data possible in the final elevation profile. The final water surface profile is measured to the centimeter every river hundredth mile, with vertical uncertainty less than or equal to 0.07 meter for 85 percent of the river and less than or equal to 0.19 meter for the remainder of the river. We collected bathymetry of the river centerline everywhere possible, which did not include rapids and shallow areas. This study is the third measurement of a complete water surface profile; the first was collected in 1923, 40 years before Glen Canyon Dam was completed, and the second was collected in 2000, 37 years after Glen Canyon Dam was completed. A continuous riverbed profile had not been collected previously.”

Citation: Sartain, S.L., Kaplinski, M.A., Kohl, K., Chapman, K.A., Bransky, N.D., Sankey, J.B., and Grams, P.E., 2026, Continuous and high-resolution longitudinal profiles of the water surface and riverbed elevation for 282 miles of the Colorado River from Lees Ferry to Pearce Ferry, Arizona, 2021: U.S. Geological Survey Scientific Investigations Report 2026–5010, 40 p., https://doi.org/10.3133/sir20265010.

Golly Batman, it's Cave Week in the USA. Hey, we have caves in Arizona. For a note on karst features, e.g. caves, in Arizona's Tonto National Forest - https://azgs.arizona.edu/news/karst-features-tonto-national-forest

For more on Cave Week - https://nckri.org/cave-week/

The Carrizozo Malpais – also called Valley of Fires lava flow – is bisected by U.S. 380 near Carrizozo NM. The 44 miles long, 4 to 6 miles wide lava flow has a maximum thickness of 160 feet in the Tularosa Basin. The basaltic lava flow is ~ 5,000 years; it’s is a pristine flow with little or no mantling vegetation. The Little Black Peak vent is at the north end of the flow. It is a pahoehoe lava distributed through lava tubes. Photo by M.Conway, 1 June 2026).

Images. Overview of portion of the lava flow field. Vesicular basalt. Ropy pahoehoe feature.

For additional information see the USGS’s Carrizozo Lava flow page at https://www.usgs.gov/volcanoes/carrizozo-lava-flow

Awesome description of alluvial fan deposits of NM.

Celebrating James Hutton’s 300th Birthday – June 3, 2026. An invited post by Flagstaff-based geologist and educator Wayne Ranney (with gracious thanks to my wife, Helen, who heard about this on the BBC while completing her morning run in a city park called Glasgow Green.)

Scotsman James Hutton is considered by those in the English-speaking world to be the “Founder of Modern Geology.” Hutton observed critical and instructive outcrops in his native Scotland, with particular attention to an outstanding exposure of an angular unconformity at Siccar Point (Photo 2). This led Hutton to a pivotable understanding of an ancient Earth. I am fortunate to be traveling here during the Tercentenary of Hutton’s birth, giving lectures about geology in Scotland and Norway for a group of Smithsonian travelers on the ship, Le Laperouse.
Hutton articulated his thoughts during the time of the Scottish Enlightenment and presented them in lectures on March 7 and April 4, 1785, to members of the Royal Society of Edinburgh. He had benefitted from 25 years of field work to bring his ideas to light. According to his contemporary John Playfair, he was “much more delighted with the contemplation of truth, than the praise of having discovered it.”

On the 4th of July 1785, he presented another talk called, “Concerning the System of Earth, It’s Duration and Stability” in which he astutely and correctly postulated that:
“The solid parts of the present land appear in general, to have been composed of productions from the sea, and of other materials similar to those now found upon the shores… Hence we find reason to conclude: That the land on which we rest is not simple and original, but that it is a composition, produced by operations natural to this globe [including] the consolidation of… loose or incoherent materials (sediments) [and] the elevation of those consolidated masses (sedimentary rocks) from the bottom of the sea…

He went on to pen his most famous observation about Earth history in 1788:
“The result, therefore, of our present enquiry is, that we find no vestige of a beginning, no prospect of an end.”

These were strong words among people of all persuasions in the late 18th century, and ones that an increasingly enlightened world was ready to accept. How fitting that just one month and one day after the geologic community will celebrate James Hutton’s 300th birthday, a nation across the Atlantic will then celebrate its 250th birthday – a nation founded by like-minded and similarly enlightened individuals!

James Hutton is a giant among giants in the development of geologic thought! Join me and everyone at the Arizona Geological Survey in celebrating the 300th birthday of James Hutton, the “Founder of Modern Geology” on June 3. To learn more about James Hutton’s Tercentenary, see this: https://james-hutton.org/tercentenary/.

Photo 1 – James Hutton June 3, 1726 - March 26, 1797. Portrait by Henry Raeburn, 1776.

Photo 2 – Siccar Point unconformity; photo by Dave Souza accessed on Wikipedia. Showing vertically oriented Silurian greywacke (below) overlain by slightly tilted Devonian Old Red Sandstone (middle). Location: 55.9315ºN 2.3013ºW. A new, Deep Time Trail has opened at Siccar Point. You read about it here: https://www.heraldscotland.com/news/26142767.james-hutton-deep-time-trail-opens-siccar-point/.

NEW! An excellent economic geology field guide to southeastern Arizona’s Courtland-Gleeson Area Corral Copper Exploration Project, courtesy of the Arizona Geological Society. The 62-page report includes an economic geology summary, geologic maps and cross sections, 27 figures, and 2 tables; download the PDF at https://www.arizonageologicalsoc.org/ .

From Dave Maher’s introduction, “The district is characterized by a Jurassic porphyry copper system emplaced into Paleozoic host rocks (and related carbonate replacement mineralization) that have been complexly deformed during Laramide compression and then subsequently variably dismembered and tilted during Middle Tertiary extension.

From the field guide SUMMARY, “Corral Copper is a copper-gold exploration property in the Southern Dragoon Mountains of Cochise County, southeastern Arizona, known historically as the Courtland-Gleeson or Turquoise Mining District. Carbonate-replacement (CRD) style sulfide mineralization has been delineated in historic and recent drilling within a +3.5km trend, associated with Jurassic intrusions. Additional skarn-type and supergene chalcocite styles of mineralization have also been drilled in the project area, and small-scale mining has also occurred. Three main mineralized zones have been tested during 2024-2025 by Intrepid Metals Corp. (IMC): Holliday, Earp and Ringo. These areas have been known historically as the Courtland, Courtland South and Star Hill (MAN) areas. Additional mineralization has been tested further to the south in the Clanton zone.”

Cu-Au highlight intercepts from 2024-2025 diamond drilling include:
CC24_001: 124.00m @ 0.52% Cu and 0.35 gpt Au
CC24_011: 48.85 m @ 2.24% Cu and 0.97 gpt Au
CC24_023: 112.95m @ 1.50% Cu and 0.53 gpt Au
CC25_026: 17.65m @ 2.72% Cu and 0.58 gpt Au
CC25_029: 49.10m @ 1.84% Cu and 0.78 gpt Au
CC25_041: 177.25m @ 0.41% Cu and 0.19 gpt Au

Mineralization styles in the Courtland-Gleeson area include:
1- Massive and semi-massive sulfide replacements of carbonate host rocks, with Cu-Au
mineralization and with variable Zn and Ag contents.
2- Massive and semi-massive magnetite-hematite replacements with sulfide, dominantly Cu-
Au but may contain appreciable Ag and Zn.
3- Supergene chalcocite.
4- Exotic copper oxide.
5- Mineralized breccias comprised predominantly of intrusive clasts.
6- Stockwork veined latite sills and sulfide veined monzonite porphyry.

A good fish story.

The latest edition of “World Mineral Production 2020-2024” from the British Geological Survey.
From the introduction, “database, maintained by the British Geological Survey (BGS), through which we aim to provide a reliable and continuous set of data covering most of the minerals that enter international trade. In this volume we set out the production figures by country for more than 70 mineral commodities over the five-year period from 2020 to 2024. The objective of this series remains to present the latest production information obtained from official bodies in individual countries, although other sources are also used to ensure completeness and accuracy.” https://www.bgs.ac.uk/news/latest-data-on-world-mineral-production-now-available/

Image: Sibanye-Stillwater's East Boulder mine at the US PGM operations in Montana, USA. Copyright © 2026 Sibanye-Stillwater Limited.

Citation: Shaw, I R, Watkins, I, Albornoz-Parra, L, Everett, P, Hobbs, S F and Shaw, R A. 2026. World Mineral Production 2020-24. British Geological Survey, Keyworth, Nottingham.