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The Geology of Cook County: Oceans, Volcanoes, and Glaciers, Oh My!

Jan 10, 2025 09:58AM ● By Content Editor

Al Trippel. Photo provided


From the Grand Marais Public Library - January 10, 2025


The Grand Marais Public Library is delighted to host geologist Al Trippel to present on the geology of the North Shore on Wednesday, January 22, from 6-8 PM.

In this presentation, Al Trippel will explain the geological and historical context to the rocks we find, whether washing up on the shores of Lake Superior or unearthing themselves on the Superior Hiking Trail. Cook County is home to a variety of rock types, some common and some extremely rare on earth. The presentation will show us where we sit in the regional “big picture” of the Canadian Shield “stable” craton.

The presentation will include a slide show, exemplary rocks, as well as digital and print resources about how and where to find agates and other fascinating rocks and minerals. A question and answer session and rock-identification segment will conclude the presentation. If bringing in rocks for identification, limit your rock-ID questions to two rocks per person, for time will be limited.

This free program is for rock hounds of all ages.

Al Trippel lives in Grand Marais and grew up around rocks in the Midwest and Western US.  From a childhood hobby, to high school job, to career in mining, and now a passion during retirement (actually it’s “refirement”), rocks continue to awe and inspire him.  Much of his lapidary and jewelry making utilize rocks and minerals found along the way.

The library is also offering its first learn-to-knit class ever, Thursdays from 10-11 AM, beginning January 16 and concluding February 27 (with no class scheduled for February 13). Follow us on Facebook for more on our free and enriching programs: www.facebook.com/grandmaraislibrary.