Geologists Duane and Ruth Braun discuss Mount Desert Island’s geologic makeup in an online presentation on June 1.  PHOTO COURTESY OF THE BRAUNS

Geologic evolution of Mount Desert Island  

SOUTHWEST HARBOR Have you ever wondered about the geologic origins of Mount Desert Island? Geologists Duane and Ruth Braun will talk about the island’s geological makeup on Tuesday, June 1, at 5:30 p.m., in a Zoom presentation sponsored by the Southwest Harbor Public Library.  

The Brauns geologic tour begins around a billion years ago when MDI was attached to the super continent, Gondwana, and eventually attached itself to North America. MDI experienced three major geologic events that resulted in the formation of 10 different rock units that now make up the island.  

Ruth earned her master’s degree in science from Johns Hopkins University. She has taught science, math and geology courses in a variety of high schools and universities.  

Duane received this doctorate from Johns Hopkins University. Before he retired, he was a geosciences professor at Bloomsburg University. He also mapped the glacial deposits of a 9,000-square-mile area of northeastern Pennsylvania for the Pennsylvania Geology Survey.  

Both Brauns have been instructors for Acadia Senior College, teaching courses about the geology of MDI, and have written an MDI geology guidebook, which is available for purchase at the library in person or by phone. The cost of the book is $20, and proceeds will benefit the library.  

For more information, visit or call (207244-7065. 

Register for the presentation at 

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