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Welcome to the Geological Society of Minnesota

The Geological Society of Minnesota is a public-spirited, nonprofit educational organization that has been in operation since 1938. Our ongoing mission has been to promote public interest and supply educational support in the geological sciences. We do this by sponsoring free lectures and labs at the University of Minnesota, conducting statewide and regional field trips, holding classroom presentations for schools, maintaining a media library, publishing relevant information for public distribution, and maintaining and expanding upon a series of geological markers located throughout the state.

GSM's exciting, illustrated Seminars are presented by leading professionals in their fields of Geology or Earth Science. These engaging talks are free and open to the public, and are especially valuable for enthusiastic learners from secondary school students to adults. A question and answer opportunity is always included. Where else can you enjoy an intriguing exchange with a leading scientist or educator? Our novice-friendly labs demonstrate at a comfortable pace the ideas and principles of geology and earth science. They allow an involved, hands-on learning experience for beginners, or a helpful refresher for the seasoned enthusiast. These instructive sessions are also free and open to the public. Where else can you actively practice science, under expert guidance, for free? 


Seminars and Labs

The schedule of seminars and labs for 2015-2016 is now available; click here

The seminars are on Mondays at 7:00 PM on the University of Minnesota campus, except where noted otherwise.


Next Seminar: February 22, 2016 7:00 PM


Next Lab: Saturday, February 20, 2016 10:00 AM - 12:00 PM

CSI Mineralogy – Using Photons, Electrons and X-rays to Investigate Geologic Unknowns

Conducted by Jeff Thole, M.Sc., Macalester College

Macalester College

Olin-Rice Science Center (south end of campus, by tennis courts)

Geology Dept. is in SW area of basement.

Building 14 on Campus Map   Road Map

This lab will use a Scanning Electron Microscope (SEM), Energy-Dispersive X-ray Spectroscopy (EDS), and X-ray Diffraction (XRD) to characterize unknown samples that will be supplied to Jeff. We also plan to have thin-section mineral samples available for viewing through polarizing optical microscopes, and 3-D samples like sand and microfossils for viewing through stereoscopes.

Jeff has asked us to provide him beforehand some samples to analyze during the lab. So if you have an unknown geological specimen or gem you would like analyzed, or a known specimen that you feel might stump Jeff, here is your opportunity. Bring your specimen(s) to the GSM lecture on February 8 and Steve Erickson will make them available to Jeff for the lab on Saturday, February 20. Here are guidelines for the specimens:

SEM/EDS:  Samples for SEM analysis to identify mineral chemistry should be small (~ less than 1 cm in width) or we should be able to take a small chip off a larger sample.  Samples can be very small (if visible, we can analyze it).  It is best if we can coat non-conductive samples (most minerals that are not metallic) with carbon but this is not necessary.  Coating with carbon allows the acquisition of a 'clean' image but will also discolor the sample.  Generally this is not a concern if the small piece is considered 'expendable'.  Gems and jewelry are also good candidates for analysis and would not be coated for obvious reasons.

X-ray Diffraction:  Mineral samples are ground to a fine powder (destructive). Again, only a very small sample is needed.  A good size to shoot for would be the size of ladybug or down to about 1/2 that size.  Larger is better.  Mixtures (for example, fine-grained, multi-mineralic rocks like basalts) are harder to identify.  Generally the XRD is used to identify individual minerals. 



Field Trips

During the months of May through October, GSM conducts a series of professionally-guided, statewide and regional field trips. These are one to three day excursions made to points of geologic interest not usually experienced by the casual traveler. They afford a very memorable and satisfying learning experience as there are always plenty of hands-on and question-answering opportunities. A comaraderie with enthusiastic learners and people curious about their natural environment is always a reward in itself. There is a small charge for any shared expense, and a liability waiver must be signed for each participant.

Next field trip:


Speakers for metro area elementary schools are available through the Public Service Committee to help enrich the education of young learners, particularly the 2nd to 4th grade levels.


Membership in the society is open to anyone with an interest in geology. The benefits of membership include:

  • Extensive Media Library - GSM maintains a collection of more than 240 geological DVDs. These are available to the members at lectures or through the mail for a nominal rental fee. Catalog
  • GSM Newsletter - A quarterly publication containing announcements of upcoming activities, interesting and informative articles on the earth sciences, GSM project and activity reports, and general club news and notices. Past issues
  • GSM Directory - An annual book that is a handy information resource, and makes it easy to access your organization.
  • The opportunity to meet others of diverse backgrounds who share an enthusiasm for learning and a curiosity for the natural world around them.
  • The rewarding feeling of supporting a public-spirited, nonprofit organization dedicated to public education.

Membership Information

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