Seminar Details

Seminar Lab Date: May 4, 2026

Seminar Lab Subject: Spring Banquet: 45 Years Mapping Minnesota’s Bedrock: My Life on the Rocks

Seminar Lab Presenter: Mark Jirsa, M.Sc., Minnesota Geological Survey (retired)

Seminar Lab Location:

Spring Banquet in the hall of Bethlehem Lutheran Church, 436 N Roy St, St Paul, MN (Midway area near I-94 & Snelling)

Seminar Lab Detail:

Banquet: We will start gathering at 5 PM, a catered buffet will arrive at 5:30, and our lecture will start at 7. The buffet dinner is being catered by nearby Black Sea Restaurant ( https://blacksearestaurant.com/). The selections will include vegetarian and gluten-free dishes; dessert will be baklava. The cost is $15/person, payable in cash at the banquet (exact change if possible).

Summary: Although this presentation is “autobiographical,” I’m hoping it provides some perspective on the history of Minnesota Geological Survey projects, albeit from this bedrock mapper’s point of view. It chronicles mapping projects and progress from 1976 to 2021.

Since Winchell’s 1872 geologic map of Minnesota, every generation built on the work of the previous one to continually improve our understanding and portrayal of Minnesota geology, represented here by state-wide bedrock geologic maps. 

My generation has done the same and I’ve been incredibly fortunate to have played a role in that.  In my case, it was a coincidence of very fortunate events!

Biography: I grew up in the “wilds” of northern Wisconsin: an area of lakes, rivers, and woods. This uniquely prepared me for a 45-year long career of geologic mapping, primarily of Precambrian bedrock in the wilds of Minnesota and parts of Canada. I attended Graduate School at UMD (1976-1979).  In 1976 I worked with John Green mapping along Lake Superior shorelines and inland for the Coastal Zone Management Program to address impacts of shoreline erosion due to then rising water levels. Having fallen in love with the North Shore, I created a thesis using interflow sedimentary rocks to develop a tectonic model of western Lake Superior. After graduating UMD, I worked briefly for Exxon Minerals in NW Mn and Wisconsin. Thanks to G. B. Morey and Dave Southwick, I was hired by the Minnesota Geologic Survey in 1979. I authored or coauthored many of the bedrock geologic maps and publications produced by the MGS. I retired during covid in 2021. I continue to work with the Institute on Lake Superior Geology, and give lectures to small groups.