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• Geology, Geochemistry, and Potential Origins of the Basin volcano-sedimentary lithium deposit, Kaiser Spring volcanic field, Arizona

  • When
    02 Sep 2025
  •  
    5:30 PM - 8:00 PM (MST)
  • Location
    Hexagon Office at 40 East Congress Street, Suite 150, Tucson, Arizona 85701
  • Registered
    1 registrant

  Register

  
  

  Arizona Geological Society
  

  2025 Speaker Series

  Tuesday,  2 September 2025 | 5:30 - 8:00 PM

  Location:  Hexagon Mining Division Office

  40 East Congress Street, Suite 150, Tucson, Arizona 85701

  
  

  Parking: On the street or parking garage (Old Pueblo Parking)

  Social Hour with Sandwiches from Beyond Bread (5:30-6:30 PM), Presentation (6:35 PM)

  For those planning to attend the event, please register by 6:00 PM on Sunday,  August 31, 2025

  Livestream URL

  Join the meeting now

  Meeting ID: 397 466 345 275 1

  Passcode: Gu2Db7KZ

  
  

  The Arizona Geological Society thanks Hexagon

  for generously providing the venue and drinks

  
  

  Geology, Geochemistry, and Potential Origins of the Basin volcano-sedimentary lithium deposit, Kaiser Spring volcanic field, Arizona

  Lisa A. Thompson

  Arizona Geological Survey Geoscientist

  Coauthors:  Carson Richardson¹, Brian Gootee¹, Joey Wilkins², Brenden Fenerty²

  ¹Arizona Geological Survey, ²Bradda Head Lithium, Inc.

  Abstract: The Basin volcano-sedimentary lithium deposit in the Kaiser Spring volcanic field, northwestern Arizona, hosts a combined indicated, inferred, and measured mineral resource of 641 million metric tonnes (Mt) of mineralized rock with grades of 823 ppm lithium (Li). Basin contains 2,809 kt of Li carbonate equivalent (LCE). Geologic mapping, logging of drill core, and geochemistry analyses shed new light on the geologic setting, stratigraphy, clay sedimentology, Li mineralization, and potential origins of this small, deep depocenter within the eastern half of the bimodal Kaiser Spring volcanic field, which contains 12 high-silica rhyolite domes. Basin stratigraphy consists of two Li-rich clay units, the Upper Clay and Lower Clay, both in sharp contact and interbedded with tuffs, basalt lava flows, coarse volcanic and nonvolcanic alluvial conglomerates, and volcanic sinter. These rocks were deposited and subsided into a semicircular, synclinal basin—likely a maar crater—lacking basin-bounding faults that would have controlled the formation of accommodation space. Stratigraphic correlations from mapped surface geology and drill core in the southeastern side of the basin suggest the depocenter is at least 300 m deep. Lithium ore principally occurs as continuous, stratified zones of magnesian smectite-group clays in both the Upper and Lower Clay. The Upper Clay contains averages of 778 to 983 ppm Li with a high-grade zone of >1,200 ppm Li, whereas the Lower Clay averages 690 ppm Li. The high-grade zone in the Upper Clay is coincident with anomalous molybdenum (Mo), with weighted average concentrations between 69 and 206 ppm, though Mo concentration is highly variable throughout the interval. Potential lithium sources include hydration of Li-rich high-silica rhyolite dome vitrophyre, dissolution of volcanic ash, and hydrothermal fluid circulation. The origin of the Li-rich clay remains unresolved but could include the neoformation of magnesian smectite at an alkaline lake bottom, hydrothermal fluid alteration of volcanic ash or smectite, and/or diagenesis of Li-rich volcanic ash deposits.

  
  

  Stratigraphic Column and Geochemistry of

  Basin volcano-sedimentary Lithium Deposit

  This research was a result of collaboration between AZGS Research Geologists and Bradda Head Lithium, Inc. It was funded in part by the U.S. Geological Survey Earth MRI (Mapping Resources Initiative) and National Cooperative Geological Mapping Program under cooperative agreement G20AC00166. The views and conclusions contained in this abstract and presentation are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. government. This manuscript is submitted for publication with the understanding that the U.S. government is authorized to reproduce and distribute reprints for governmental use.

  Bio:  Lisa Thompson is a research scientist at the Arizona Geological Survey (AZGS), University of Arizona. Prior to her appointment, she held a senior lecturer position at Northern Arizona University, where she taught geographic information systems (GIS), field methods, geologic disasters, and volcanology. She received her M.S. degree at Northern Arizona University (2005) and her B.S. degree at Temple University (2002). Lisa’s interests include physical volcanology, sedimentology and stratigraphy, field geology, and GIS, with applications to carbon sequestration and sedimentary lithium mineralization. Her current research includes investigating the carbon sequestration potential of mineralizing CO2 in glassy, mafic rocks ex-situ, CO2 storage in stacked saline reservoirs, H2 storage in salt bodies, and volcano-sedimentary depositional systems.

  
  

  
  

  
  

  Hexagon Mining Division Office - 40 East Congress Street,

  Suite 150, Tucson, Arizona 85701

  
  

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