Please join geologists, Duane and Ruth Braun, for a talk about the geological makeup of Mount Desert Island on Tuesday evening, June 20, at 5:30pm at Southwest Harbor Public Library. At the end of the talk there will be a book signing for their book, Guidebook to the Geology of Mount Desert Island and Acadia National Park. Proceeds will benefit the Library. Seating is limited, reservations are required.
Have you ever wondered about the geologic origin of Mount Desert Island? How it was put together? What effect the glaciers had on the current landscape? The Brauns will take us on a geologic history tour. Their talk will begin around a billion years ago when MDI was attached to the super continent, Gondwana. It split from Gondwana and eventually attached itself to North America. MDI itself experienced three major geologic events, which resulted in the formation of ten different rock units; that now make up MDI. The oldest of these formations is the beautifully crenulated Ellsworth schist. Most of the rock on MDI formed around 420 million years ago as alternating intrusions of pink granite and gray gabbro magma fed a huge volcanic caldera the size of MDI. Two miles of rock have been eroded since then to form the present landscape. Over the last 2.5 million years glaciers have repeatedly covered the Island with up to 5,000 feet of ice. When the glaciers retreated they left behind a number of different deposits and landforms helping to create a beautiful and striking landscape.
Ruth Braun earned her Masters of Science from Johns Hopkins University. Over the years she has taught science, math and geology courses in a variety of high schools and universities.
Duane earned his Ph.D. from Johns Hopkins University. He was the Geosciences Professor at Bloomsbury University. He also mapped the glacial deposits of a 9000 square mile area of northeastern Pennsylvania for the Pennsylvania Geology Survey.
Both Duane and Ruth have been instructors for Acadia Senior College teaching about the geology of MD and have written a new guidebook to the geology of MDI. Duane has revised the geologic maps of MDI for the Maine Geologic Survey. The Surficial Geology (glacial deposit) map of MDI is presently available as a free PDF download and the Bedrock Geology map should be available later in the year.
Please call the Library to reserve your seat or for more information, 244-7065.