Current Year Schedule
GSM seminars with slide show presentations are free and open to the public. They are presented by leading professionals in their fields and are aimed at learners from high school to adult. A question-and-answer session concludes each seminar. The labs, also free and open to the public, allow a hands-on learning experience and demonstrate the ideas and principles of geology and earth science. Live lectures and labs require no registration; just show up a few minutes early on the evening of the lecture.
Click on date of any seminar for attendance information and other details. For a printable version of our schedule of seminars and labs, click here.
Except as noted, in-person lectures during winter/spring 2026 are Mondays at 7:00 PM CT on the University of Minnesota campus, Keller Hall, Room 3-210. A lecture with (V) following its title is an online virtual lecture. For these, free registration is required by non-members; the instructions are supplied with the lecture description.
Our schedule is planned over 6 months in advance, so changes may occur. Always check this website shortly before each lecture for the latest seminar information.
Winter weather will come and snow might impact our lectures. The GSM will make any decision about cancelling or postponing a lecture due to inclement weather no later than 3:00 PM the day of the lecture. This information will be posted on the GSM home page (http://www.gsmn.org/). So check our home page shortly before each lecture in case there is a cancellation or a last-minute change. Also, we will e‐mail lecture postponement and cancellation information to our members.
Past seminars marked with * were recorded and the recording is available on the Geological Society of Minnesota YouTube channel. Subscribe to this channel for updates.
Seminar Details
Seminar Lab Date: February 9, 2026
Seminar Lab Subject: *Hematite Ore Formation in the Lake Vermilion-Soudan Underground Mine State Park, Northeastern Minnesota (V)
Seminar Lab Presenter: Zsuzsanna Allerton, Ph.D. Candidate, University of Minnesota
Link to Presenter https://www.zoominfo.com/p/Zsuzsanna-Allerton/10241274026
Second Link to Presenter https://www.linkedin.com/in/zsuzsanna-p-allerton-45ab62171
Seminar Lab Location:
*** NOTE: THIS LECTURE HAS BEEN CHANGED FROM IN-PERSON TO ONLINE ***
Virtual lecture 7:00 PM CT.
This lecture is now available on the Geological Society of Minnesota YouTube channel:
https://www.youtube.com/watch?v=q5uHQyfD8kM&pp=ygUSWnN1enNhbm5hIEFsbGVydG9u
Seminar Lab Detail:
Summary: The Soudan iron mine in northeastern Minnesota’s Vermilion Range—now preserved as part of Lake Vermilion-Soudan Underground Mine State Park—operated from 1882 until 1962. It was the state’s oldest and deepest iron mine, extracting millions of tons of exceptionally high-grade massive hematite ore (>65 wt% Fe) hosted within Neoarchean (~2.7 Ga) banded iron formations (BIFs). These ore bodies, initially discovered during gold prospecting, supported premium steel production before competition from Mesabi Range taconite led to closure. The hematite ore formed through hydrothermal processes that dissolved silicates and concentrated iron oxides in the ancient sedimentary deposit. Recent research employing U-Pb and (U-Th)/He radiometric dating of hematite provides the first direct ages for the high-grade ore at Soudan. These studies reveal a previously unrecognized Paleoproterozoic mineralization event (~1.8–1.6 Ga), challenging earlier assumptions of Neoarchean origins. The data further suggest a thermal overprint from the Mesoproterozoic Midcontinent Rift System (~1.1 Ga). This new geochronological evidence refines models of iron ore genesis in the Lake Superior region, linking hematite ore upgrading in BIFs to Proterozoic tectonic events.
Biography: Zsu Allerton was born in Hungary and moved to the United States in 2017. Before pursuing geology, she worked as a social worker, scuba diving instructor and guide, and underwater and land photographer and photography instructor.
Her doctoral research specialized in the thermal and hydrothermal evolution of Archean iron formations and Proterozoic mineralization in northeastern Minnesota, with a dissertation focused on hematite ore genesis in the Soudan iron mine, hydrothermal alteration, and the thermal imprint of the Midcontinent Rift System on the Superior Province.
Current research interests include the geology of iron deposits, geochronology, mineral and meteorite characterization, and public geoscience outreach. She is involved in ongoing projects at Lake Vermilion–Soudan Underground Mine State Park.