Tuesday, June 1 at 5:30 p.m.
Please join geologists Duane and Ruth Braun for a talk about the geological makeup of Mount Desert Island.
Have you ever wondered about the geologic origins of Mount Desert Island? How the island was put together? What effects did glaciers have 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 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 the island. The oldest of these formations is the 510 million year old, beautifully crenulated Ellsworth schist that was later covered by the Bar Harbor sediments. Most of the other 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 one million years glaciers have covered the Island at least five times with up to 5,000 feet of ice, sculpting MDI to its present form. When the last glacier retreated from MDI 15,000 years ago, it left behind a number of different deposits and landforms, shaping this beautiful and striking landscape.
Ruth Braun earned her Master 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 and before he retired he was the Geosciences Professor at Bloomsburg University. In addition, he also mapped the glacial deposits of a 9,000-square-mile area of northeastern Pennsylvania for the Pennsylvania Geology Survey.
Both Duane and Ruth have been instructors for Acadia Senior College teaching courses about the geology of MD and have written a guidebook to the geology of MDI. Duane has revised the geologic maps of MDI for the Maine Geologic Survey.
Purchase their book A Guide to the Geology of Mount Desert Island and Acadia National Park here at the Library for $20.00. Call or make an appointment to buy the book, 207-244-7065.