Arizona Geological Society


Upcoming events

    • 21 Apr 2018
    • 9:00 AM - 1:30 PM
    • Attendees will meet at 8:30 AM at the United Verde General Office, which is located north of town on the Jerome-Perkinsville Road.
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    Jerome, An Early Proterozoic Volcanogenic Massive Sulfide Deposit

    Field Trip Leaders:  Ralph Stegen, Jerry Waegli, and Barbara Nielsen, Freeport-McMoRan, Inc., Paul Lindberg, (Retired Consultant) and David Briggs (Retired Consultant) 

    Acknowledgements - The Arizona Geological Society thanks Freeport-McMoRan, Inc. for granting us permission to visit their Jerome property and providing geologists to lead the tour.

    Field Trip Description - Freeport-McMoran invites AGS Members and guests to visit their United Verde volcanogenic massive sulfide deposit at Jerome in Yavapai County, Arizona.  This tour offers an unique opportunity to examine a deposit type that has been overshadowed by Arizona's porphyry copper systems in recent years.

    The trip itinerary is still being determined, but it will involve stops involving the geology (several in the pit area), examination of core, an historical overview and one or more stops dealing with reclamation work by Freeport-McMoRan. 

    Tour Date/Time -  Saturday, April 21, 2018, 9:00 AM to 1:30 PM. 

    Logistics - Field trip participants should plan to arrive at the United Verde General Office by 9:00 AM on April 21, 2018 to complete on-site check-in and wavier signage.  The field trip will begin promptly at 9:00 AM. This office is located north of the town on the Jerome-Perkinsville Road.

    Location Map for United Verde General Office

    The field trip should end around 1:30 PM.  This will provide an opportunity for those who wish to visit the museum at the Jerome State Historical Park prior to its 5:00 PM closing time.

    Lodging - Participants who choose to overnight on Friday prior to the trip will be responsible for making their own hotel accommodations.  Nearby hotels are present in Jerome, Cottonwood, Prescott and Camp Verde.

    List of Hotels

    Carpooling - Participant contact information for those who want to make carpool arrangements prior to the trip.

    Cost - Members - $40,   Non-members and Guests - $45,  Students - $15

    Meals - Sandwiches, cookies, bottle water and sodas will be provided for lunch.

    Level of Difficulty - The level of difficulty is slight to moderate.  Only one of the stops will involve a one kilometer hike with an elevation gain of about 600 to 700 feet. 

    Temperature are expected to be in pleasant cool range from 45 to 70 degrees F.  Elevation is 1,600 to 1,800 meters (4,800 to 5,400 feet).  Bring a light jacket if it is a windy or rainy day.  Sunscreen lotion and a good hat to protect the head from too much UV are strongly recommended.

    Personal Protective Equipment - Personal protective equipment (hard hat, sturdy boots, long pants, reflective vest and safety glasses) will be required.  Hand protection is also encouraged (work gloves).  A limited amount of these items will be available at the site.

    Field Trip Preview - Situated along the northeastern slope of the Black Hills, the United Verde mine is located in the Verde Mining District approximately 25 miles northeast of Prescott, Arizona.  Initially visited by Spanish explorers in May 1583, this deposit was rediscovered  in 1876.  Mining operations were carried out by the United Verde Copper Company from 1883 until early 1935, when it was purchased by the Phelps Dodge Corporation.  Following the suspension of commercial mining operations in 1953, small scale salvage operations continued recovering remnants of ore that remained in the open pit until 1975.

    To learn more about the history of the Jerome mining camp visit the Arizona Geological Survey repository for an article titled:  History of the Verde Mining District, Jerome, Arizona.

    Approximately 33 million tons of ore, averaging 4.8% copper were mined at United Verde from 1883 to1975, making it the largest volcanogenic massive sulfide producer in the United States.  It is reported to contain an additional unmined resource of 21 million tons, averaging 0.52% copper and 6.6% zinc.

    Volcanogenic massive sulfide ores of the Verde Mining District are hosted by the Early Proterozoic Ash Creek Group, a sequence submarine volcanics and volcaniclastics, which was deposited in an ancient intraoceanic island arc.  Exhibiting textures similar to modern day "black smokers", the United Verde deposit was deposited on the sea floor above submarine hydrothermal vents at the top of the lower member of the altered Cleopatra Rhyolite, approximately 1,738 million years ago.

    The black schist zone in the footwall of the massive sulfide deposit is characterized by intense chloritic alteration, which marks the sites of hydrothermal venting in the altered lower member of the Cleopatra Rhyolite on the sea floor.  Most of the copper ores at United Verde were restricted to irregularly shaped zones in the lower third of the massive sulfide body and as stockwork-replacement bodies of pyrite and chalcopyrite within the underlying black schist with lesser amounts hosted in zones of chalcopyrite veining cutting sericitized lower Cleopatra Rhyolite.

    Copper contents of the massive sulfide body generally diminish upward and peripherally outward into zinc-rich zones containing up to 15% sphalerite that are generally characterized by alternating bands of zinc- and pyrite-rich layers about 1/4-inch thick. 

    Unaltered volcanic and volcaniclastics of the upper member of the Cleopatra Rhyolite and tuffaceous, turbiditic sediments of the overlying Grapevine Gulch Formation located in the hanging wall of the United Verde deposit were deposited on top of the sulfide-rich lens and post-date the mineralization These post-mineral units were subsequently intruded by a synvolcanic gabbro, which is represented by a large sill-like intrusive body that occurs in the western hanging wall of the United Verde massive sulfide deposit.

    Volcanogenic massive sulfide ores at the United Verde mine and its host rocks were deformed in series of open folds that generally plunge north-northwest.  It now occurs as a pipe-like body that extends from the surface to a depth of 4,500 feet; plunging 50 to 65 degrees to the north on an axis of about N20W.

    Unoxidized mineralogy of the United Verde deposit  is simple.  Characterized by an assemblage composed of 40 to 80% sulfide minerals, it primarily consists of pyrite with lesser amounts of interstitial quartz, dolomite and ankerite.  Sulfides other than pyrite (primarily chalcopyrite and sphalerite) constitute less than 25% of the massive sulfide ore.  Other minor constituents include bornite, arsenopyrite, galena, tennantite and electrum.  

    The primary sulfide mineralogy at United Verde was modified by weathering and supergene processes, where it was naturally oxidized above the 160-foot level or oxidized by mine fires between the 160- to 600-foot level.  Oxide- supergene mineral assemblage includes cuprite, chalcocite, azurite, malachite, native copper, wire silver, copper hydroxides and  hydrous copper sulfate minerals.

    Contact Info - If you have additional questions about the Fall Field Trip contact Wolf Schuh (520) 498-6846, Ralph Stegen (520) 498-6811, or David Briggs (520) 784-3954.
    • 01 May 2018
    • 6:00 PM - 9:00 PM
    • Sheraton, 5151 E Grant Rd. (& Rosemont), Tucson AZ 85712

    Sponsored by:   Available

    The Science of Caves and Cave Contributions to Science

    by William B White, Dept of Geosciences, Penn State Univeristy


    Abstract:  Caves have been of interest to humans for millennia, but scientific interest in caves began only in the early 20th Century in the United States and a bit earlier in Europe. Much of the earlier research focused on the caves themselves, how they form, and the processes that take place inside them.  Research of the past few decades has reversed the focus with the interest being in information caves can provide to other parts of the Earth sciences. The talk will provide a broad brush overview of cave sciences in the 21th Century.

    Caves form by two distinct mechanisms. Best known is the top-down dissolution of limestone by circulating ground water made slightly acidic by carbon dioxide. Both equilibrium and kinetics of the reactions are well-known and some elegant models have been made of cave development. A more recent finding is that many caves have formed by deep-seated solutions welling up to the water table with the active agent being sulfuric acid rather than carbonic acid.

    Many caves display spectacular speleothems but the bulk mineralogy tends to be boring: calcite, gypsum, and aragonite. Although less obvious, more than 300 other minerals have been formed by secondary deposition in caves.

    What brought cave studies into the mainstream of the Earth sciences is the importance of karst aquifers as water supplies. Karst aquifers are a major source of domestic water supply. The conduit permeability means that karst aquifers respond rapidly to flood flows with changes in flow paths and water levels. Contaminant transport in karst aquifers is rapid, often to unknown destinations, and strongly dependent of the physical properties of the contaminant.

    Caves have been recognized as useful sources of geomorphic information. Caves are strongly linked to landscape evolution. Clastic sediments in caves can be dated by cosmogenic isotopes providing useful markers for incision rates of surface streams and landscape evolution.

    Calcite stalagmites grow slowly from the bottom up. A precise chronology of the layers can be obtained by U/Th isotope dating methods. Isotopic signatures (O,C,H) and trace element concentrations can be mapped along the growth axis.  These maps reveal climatic variations of the surface above the cave over the time span represented by the speleothem.

    Bio:  William B. (Will) White is professor emeritus of geochemistry in the Department of Geosciences at the Pennsylvania State University. Prior to retirement he held joint appointments in Geosciences and in the Materials Research Institute. He also taught in the Department of Materials Science and Engineering and supervised graduate students in the interdisciplinary program in Environmental Pollution Control. He holds a B.S. degree in chemistry from Juniata College (Huntingdon, PA) (1954). From 1954 to 1958 he was on the staff of the Department of Research in Chemical Physics at the Mellon Institute in Pittsburgh while pursuing graduate study in physics at the University of Pittsburgh. In 1958 he transferred to Penn State, received his Ph.D. in geochemistry in 1962, and after a year and a half in a post-doctoral position, joined the faculty in 1963, reaching the rank of full professor in 1972.

    Dr. White received the Matthew J. and Anne C. Wilson Award for outstanding teaching from the College of Earth and Mineral Sciences in 1974, the Outstanding Service Award (Honorary Life fellow) from the National Speleological Society in 1975, and the Lifetime Achievement Award in the Science of Speleology from the NSS in 1994. In 2001 he received the Karst Waters Institute Award and in 2004 the Distinguished Career Award from the Quaternary Geology and Geomorphology Division of the Geological Society of America. He is a Fellow of the American Association for the Advancement of Science, The Mineralogical Society of America, The American Ceramic Society, and the National Speleological Society. Dr. White's research activities have been divided between materials science and geological science. The former includes investigations of crystal chemistry, glass science, optical and phosphor materials, and infrared, Raman, and luminescence spectroscopy. The geological sciences include mineral physics and the hydrogeology and geomorphology of caves and karst. Overall, the research has been reported in 440 technical papers and 15 books. Recent books include "The Encyclopedia of Caves" (Elsevier, 2012), "The Caves of Burnsville Cove, Virginia" (Springer, 2015), and "Caves and Karst of the Greenbrier Valley in West Virginia" (Springer, 2015).   His textbook on Geomorphology and Hydrology of Karst Terrains (Oxford Univ Press 1988) has been widely used.

    Field investigations for cave and karst studies include the Appalachians (Pennsylvania to Alabama), the Mammoth Cave area, Kentucky, Puerto Rico, and other locations. Dr. White has traveled widely to karst areas of the world including much of the United States, parts of western Europe, the Adrian Coast and China.
    • 05 Jun 2018
    • 6:00 PM - 9:00 PM
    • Sheraton, 5151 E Grant Rd. (& Rosemont), Tucson AZ 85712

    Sponsored by:   Available

    The Geoarcheology of Ancient Water Control in the Southwest:  Lessons from the Past

    by Gary Huckleberry, Dept of Geosciences, University of Arizona

    Abstract -The control and management of water in the North American Southwest dates back at least 3500 years and played a key role in long-term adaptations of ancient societies. Water was captured, diverted, and stored for purposes of domestic consumption and agricultural production. Strategies varied depending on local environmental factors and cultural needs. Hundreds of miles of canals were constructed along perennial rivers like the Salt, Gila, and Verde. Earthen reservoirs were constructed to capture runoff in the desert interior. Evidence for this ancient hydraulic infrastructure can be quite subtle depending on the scale of engineering and geological processes that modify the archaeological record. An understanding of geological surficial processes is essential for studying these ancient waterworks given that the physical remains are often defined by stratigraphy and best understood when placed within a geomorphic context. I will discuss some of my geoarchaeological research on ancient water control, focusing on the southern deserts of Arizona where water management was a hallmark trait of ancient societies like the Hohokam (A.D. 450-1450). This research makes clear that people have long dealt with the challenges of population growth and climate variability in arid environments, and that human resilience to stress varied through time. Such insights are relevant to the challenges we face today in the Southwest.

    Bio -Gary Huckleberry received his doctorate from the Department of Geosciences at the University of Arizona and has conducted over 30 years of consulting and research in North and South America. He was a professor in the Department of Anthropology at Washington State University from 1995 to 2004, and served as Co-Editor of Geoarchaeology: An International Journal from 2007-2017. His specialties include geoarchaeology, geomorphology, soils, and stratigraphy and most of his research has been in desert environments. Current research projects include reconstructing El Niño history through study of flood deposits along the north coast of Peru, analysis of ancient agricultural soils in the high Atacama of Chile, excavating shell midden sites along the Gulf of California to understand ancient coastal adaptations, and identifying indigenous water control features in the North American Southwest for purposes of understanding human ecology and supporting modern Native American water rights claims.



    • 07 Aug 2018
    • 6:00 PM - 9:00 PM
    • Borderlands Brewing, 119 East Toole Avenue, Tucson AZ 85701

    Sponsored by: Boart Longyear

      Rhodochrosite:  Red Treasure of the Rockies -
    the Story of the Sweet Home Mine

    Narrated by Karl Mecklenberg

    August 7, 2018

    Our regular August dinner meeting has been canceled in lieu of a special event, which will be held at Borderlands Brewing (119 East Toole Avenue, Tucson AZ  85701) on Tuesday, August 7, 2018 between 6 and 9 PM.

    Members of the Arizona Geological Society as well as members of the public are invited to come out and view a video on the Sweet Home Mine and have a good time, drink some beer, eat some snacks and "talk rocks".

    - This video tells the story of the Sweet Home Mine from its beginning as a modest, 1870s silver mine to its rebirth as a world-renowned source of crystal specimens.  Experience hard rock mining up close.  Watch miners within Colorado's 14-thousand foot Mount Bross as they drill and blast trying to find elusive pockets of natural riches.  Learn how science guides the underground treasure hunt.  Follow geologists as they try to unravel the mysteries of the ancient mountain.  See some of the most spectacular natural wonders ever brought to light.  Several of these mineral specimens will sell for over a million dollars each in today's market.

    The cumulative value of the rhodochrosite specimens recovered from the Sweet Home mine over the years probably exceeds $100 million, and the mine is clearly the world's premier source of fine rhodochrosite.  All in all, that's not a bad record for a "failed" silver mine.


Past events

03 Apr 2018 Volker Spieth and Stanley Keith Present - Finding Gold in the Kupferschiefer
29 Mar 2018 Future Home of the University of Arizona Gem and Mineral Museum
06 Mar 2018 Joe Wilkins, Jr. Presents - Piedras Verdes and Cuatro Hermanos, Sonora, Mexico - A Tale of Two Porphyries
06 Feb 2018 Paul F. Hlava presents Causes of Color in Minerals and Gemstones
02 Jan 2018 Peter L. Ward presents Bringing Peace to the Climate Wars
05 Dec 2017 Joellen Russell presents The Ocean's Role in the Climate of the Anthropocene
07 Nov 2017 Eric Sundquist presents Geological Perspectives on Carbon Dioxide, the Carbon Cycle and Carbon Management
03 Oct 2017 Lily Jackson presents Andean River Sediments as a Window into the Tectonic History of Ecuador
05 Sep 2017 Vic Baker presents The Influence of the 18th Century Enlightenment on the Natural Sciences
22 Aug 2017 AGS Meet and Greet, A Networking Event
11 Jul 2017 Andrew Zaffos presents Global Tectonics and Marine Animal Diversity
06 Jun 2017 Dan Johnson presents Introduction to the Florence Copper Project and In-Situ Copper Recovery
02 May 2017 Robert Glennon presents America's Water Crisis and What To Do About It
22 Apr 2017 Spring Field Trip - The Laramide-age Chilito Porphyry Copper Deposit
04 Apr 2017 David London presents The Nature and Origins of Internal Zonation within Granitic Pegmatites
07 Mar 2017 Derek J. Thorkelson presents The Precambrian Tectonic Connection between Yukon and Arizona
07 Feb 2017 Daniel Hummer presents Mineral ecology and evolution: Using large datasets to tell the story of the co-evolution of Earth and life
03 Jan 2017 David A. Sawyer presents Dating Geologic Time in the Cretaceous: Integrating Biostratigraphy, Isotope Geochronology, and Astrochronology in Sedimentary Deposits of the Cretaceous Western Interior Seaway
06 Dec 2016 John W. Ewert presents USGS Responses to Some Volcanic Crises and Eruptions Around the World
01 Nov 2016 Alexander Schauss presents Minerals, Trace Elements and Human Health
22 Oct 2016 Fall Field Trip - The Peach Spring Tuff and the Silver Creek Caldera, Northwestern Arizona
04 Oct 2016 Hamish Martin Presents Geology of the Resolution Cu-Mo Deposit, Superior Arizona
06 Sep 2016 Keith R. Long Presents No Bonanza from Cheap Oil
02 Aug 2016 Lee Allison Presents The Future of State Geological Surveys: the Arizona Case Study
05 Jul 2016 Don Applebee Presents Genesis of the Chilito Porphyry Copper Deposit
07 Jun 2016 Robert Hildebrand Presents Collisions, Slab Failure Magmatism and the Development of Cordilleran Batholiths
03 May 2016 Peter Modreski will present "Pegmatites: Mineralogy, Gemstones, Economic Geology, and maybe not quite the same Giant-Crystal Rocks you always thought they were"
30 Apr 2016 Spring Field Trip - An Introduction to the Pinal Schist in Southeastern Arizona
05 Apr 2016 Jordon Bright Presents Looking for an Ocean in the Desert, the Enigmatic Bouse Formation
01 Mar 2016 Peter R. Johnson Presents Tectonics and Mineral Deposits of the Arabian-Nubian Shield
02 Feb 2016 Dr. Karen Wenrich Presents The Ga-Ge Rich Apex Mine, Utah - A Tsumeb, Namibia Analogue
05 Jan 2016 Sarah Baxter Presents Calc-silicate Alteration and Ore Characterization, ASARCO Mission Complex, Pima County, Arizona
01 Dec 2015 Peter Smith Presents The Latest News from Mars
14 Nov 2015 Fall Field Trip - Northern Plomosa Mountains and Bouse Formation in Blythe Basin
03 Nov 2015 Karen Kelley presents The Giant Concealed Pebble Cu-Au-Mo Porphyry Deposit, Southwest Alaska
06 Oct 2015 Caleb King presents Eocene Hydrothermal Systems and Contrasting Hydrothermal Alteration in the Battle Mountain District, Nevada
01 Sep 2015 Carl Bowser presents The Genesis of the Kramer Borax Deposit, Rogers Lake, Mojave Desert, CA:
04 Aug 2015 Dan Lynch presents Volcanoes in the Back Yard
07 Jul 2015 Erik Melchiorre presents The Complex Geological History Recorded by Arizona Placer Deposits:
02 Jun 2015 Jan C. Rasmussen Presents - Arizona Mineralization through Geologic Time
05 May 2015 Gordon Haxel Presents - Alpine peridotite in the desert - Arizona's Laramide subduction complex
02 May 2015 Spring Field Trip - Oak Creek - Mormon Lake Graben
18 Apr 2015 Third Annual Arizona Geological Society Doug Shakel Student Poster Event
03 Mar 2015 Apollo 17 Astronaut and Former Senator Harrison H. Schmitt presents A Geological Visit to a Valley on the Moon
03 Feb 2015 Don Yurewicz Presents Assessing Unconventional (Continuous) Hydrocarbon Resource Plays
06 Jan 2015 Arend Meijer presents: Sulfide-rich Proterozoic Mafic Rocks and Arizona Porphyry Copper Deposits - A Connection?
02 Dec 2014 Victor R. Baker: Megafloods on Earth, Mars, and Beyond
15 Nov 2014 Fall Field Trip - Debris Flows Shape the Sabino Canyon Landscape - look out below!
04 Nov 2014 Isabel F. Barton: Historical Development & Current State of Geological Research in the Central African Copperbelt
07 Oct 2014 Apollo 17 Astronaut and Former Senator Harrison H. Schmitt presents A Geological Visit to a Valley on the Moon
02 Sep 2014 Lewis Land presents Evaluation of Groundwater Residence Time in a Karstic Aquifer System
05 Aug 2014 Jamie Molaro presents Thermal Stress Weathering in the Inner Solar System
01 Jul 2014 Jim Leenhouts presents Surface-water/groundwater Interactions in Arizona
03 Jun 2014 Arend Meijer presents Pinal Schist of So. Arizona--A Paleoproterozoic Fore-Arc Complex
06 May 2014 John C. Lacy presents The Genesis of Mining Law
26 Apr 2014 Spring Field Trip - Geology of the Christmas Porphyry Copper Deposit
24 Apr 2014 Second Annual Arizona Geological Society Doug Shakel Student Poster Event
01 Apr 2014 Eric Seedorff presents, Structural Dismemberment of a Porphyry Molybdenum System, Spruce Mountain District, Northeastern Nevada
04 Mar 2014 John Dreier presents, Copper Deposits of the Coast Ranges of Chile; A trip through time, space, and ore deposit nomenclature
04 Feb 2014 Ralph Stegen presents The Morenci Porphyry Cu-Mo Deposit, Greenlee County, Arizona: A Geologic Summary with Emphasis on Hypogene and Supergene Mineralization
07 Jan 2014 Steve Castor presents, Mountain Pass and other North American Rare Earth Element Deposits
03 Dec 2013 Stephen Jackson, USGS, Looking forward from the past: Ecological impacts of climate change through the lens of history
05 Nov 2013 Malcolm Siegel, PhD, MPH, LJS Consulting, Inc and School of Medicine, University of New Mexico, Albuquerque, NM. 87047: Uranium Mining in the American Southwest: Can Medical Geologists Ask the Right Questions?
04 Oct 2013 Field Trip - H. Wilson Sundt Generating Station
01 Oct 2013 Mark Logsdon, Principal Geochemist, Geochimica, Inc.: What Does “Perpetual” Management and Treatment Mean? Toward a Framework for Determining an Appropriate Period-of-Performance for Management of Reactive, Sulfide-Bearing Mine Wastes
01 Oct 2013 Mark J. Logsdon, Geochimica, Inc., Does acid-rock drainage lead to waste-rock instability? Geological, hydrological, and geochemical framework for the Questa Mine
03 Sep 2013 Pete Reiners, UA, Geosciences Dept., Geochronology of secondary Fe & Mn oxides in bedrock
30 Aug 2013 Field Trip - University of Arizona Tree-Ring Research Laboratory
06 Aug 2013 Bill Stavast, Freeport-McMoRan Copper & Gold, The Safford Mine: What we have learned since production began
02 Jul 2013 Lukas Zurcher, USGS, presents: "Tectono-magmatic evolution of the Central Tethys Region"
04 Jun 2013 Steve Van Nort presents, "Gold Fever! The BRE-X/Busang Story
07 May 2013 Federal lands and mineral resources: Colorado Plateau uranium deposits and the Sonoran Desert Heritage
18 Apr 2013 First Annual Arizona Geological Society Doug Shakel Student Poster Event

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