Leached Cappings and Gossans: Geochemistry Applied to Metals

Leached Cappings and Gossans: Geochemistry Applied to Metals

Mobility in the Weathering Environment of Ore Deposits

Saturday, March 2, 2024
8:30am - 4:30pm EST (UTC-5)
Royal Ontario Museum | Toronto, ON, Canada
In-person workshop, hosted by William X. Chávez, Jr.

In-person workshop consisting of dynamic lectures supplemented with generous lab time for investigating unique hand specimens from the Royal Ontario Museum's Kirwin Collection.



Interpretation of the geochemistry of leached cappings and gossans is essential in mineral exploration, especially for those exposures beneath cover. This one-day workshop illustrates the variable weathering-derived mineralogy of sulfide ore deposits and incorporates the geochemistry of supergene processes to explain how—and why—minerals form in the weathering environment. Element mobility or accumulation in supergene profiles is presented, with Eh-pH diagrams used to help explain why some metals move efficiently in the weathering environment and others display limited or insignificant transport.

The workshop format comprises a series of lectures that emphasize application to mineral exploration and include examples of weathering profiles and the interpretation of metal mobility in each. This will be supplemented by generous time for reviewing and interpreting multiple suites of remarkable hand specimens at the Royal Ontario Museum's mineral classroom.

This offering is directed toward economic geology graduate students and professionals working within the exploration industry. Participants will be able to apply their background knowledge of simple geochemistry to the interpretation of leached capping and gossan mineralogy, as well as to the nature and occurrence of minor and trace elements in the weathering environment.


8:50am: Introduction - Dr. Kim Tate (ROM) and Duncan Proctor (SEG)

9:00am: Leached cappings and gossans - definitions, variations, morphology, maturity

9:45am: Hand specimen review - gossans and leached cappings

11:00am: Coffee break

11:30am: Cu-Zn-Pb in the weathering environment

12:00pm: Hand specimen review - copper oxides

1:00pm: Lunch

2:00pm: Supergene sulfides: Redox environments and sulfide development

2:45pm: Hand specimen review - base metal oxide minerals (Cu-Zn-Pb-Ni-Co-Mo)

3:45pm: Coffee break

4:00pm: Wrap-up discussions and final hand specimen review

4:30pm: Adjourn



William X. Chávez, Jr.

New Mexico Institute of Mining and Technology

SEG Fellow

William received B.Sc. degrees in Geology (1977) and Mine Engineering (1977) from the New México School of Mines; he has M.A. (1980) and Ph.D. (1984) degrees in Geology from the University of California at Berkeley, and has been Professor of Geological Engineering and Economic Geologist at the New México School of Mines since 1985. He is an SEG Honorary Lecturer and is involved with teaching field courses and workshops for the Society, with emphasis on porphyry and epithermal systems, alteration and ore mineralogy, and environmental aspects of mining.

About the Royal Ontario Museum (ROM)

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ROM showcases art, culture and nature from around the world and across the ages. Canada's largest and most comprehensive museum is home to a world-class collection of 13 million artworks, cultural objects and natural history specimens, featured in 40 gallery and exhibition spaces. As the country's preeminent field research institute and an international leader in new discoveries, ROM plays a vital role in advancing our understanding of the artistic, cultural and natural world. www.rom.on.ca/en


Early deadline: February 9, 2024
Regular deadline: February 26, 2024

Maximum participants: 22

  Early Regular
SEG Member US$495 US$595
SEG Student Member* US$95 US$145
Non-member US$595 US$695
All prices are in United States dollars (USD). SEG reserves the right to cancel this event should minimum attendance numbers not be met by February 10, 2023. All registrants will be given a full refund should SEG cancel the course. Cancellation policy, event photography, dietary restrictions, and more are detailed in the SEG Terms and Conditions.
* Five spaces are reserved for students and offered at a discounted rate. Once the limit is met that registration option will become unavailable.
3/2/2024 8:30 AM - 4:30 PM
Royal Ontario Museum 100 Queen's Park Toronto, ON M5S 2C6 CANADA
Sign in or create an account to register Last day to register is 2/26/2024
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