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“Journey to Avalonia: Exploring the Deep Geologic History of Coastal New England,” Presented by Barry Sidwell

April 24 @ 7:00 pm - 8:30 pm


We have all heard the expression “As Old as the Hills” but one might ask “Just how old are those hills?” The answer depends on the question: “What is the age of the actual rocks that make up those hills?” or “How long have those hills existed as a landscape feature?”


Barry Sidwell’s “Journey to Avalonia” will consider both questions and help us to discover that even though the answer to both is vastly longer than the human time frame, that the ages differ by orders of magnitude. He will also show us that in the past 70 or so years, our understanding of the Earth has fundamentally changed with the advent of the concepts of sea-floor spreading and continental drift. Plate Tectonics has revealed that the Earth is much more dynamic than previously thought. In particular, Barry will discuss how the rocks of Salem Sound and much of coastal New England have their origins in a lost “micro-continent” that lay in an ocean, which existed prior to the Atlantic Ocean. Many geologists have come to call this ocean “Iapetus” and to refer to this lost micro-continent as “Avalonia”.


Barry Sidwell in Iceland

Barry Sidwell
worked in petroleum geology in the Rocky Mountain region during the boom years of the 80s. The focus of his training and interests has been in sedimentary rocks and processes, paleogeography and paleoclimatology. He is a member of the Geological Society of America.


With a long-standing interest in the landscape and natural history of the Mountain West, his coming to New England, with its forested and glaciated landscape, was an eye-opening experience with many learning opportunities. “The more I have learned, the more fascinated I have become.” This talk is an outgrowth of this fascination.



“Underwater in Salem Sound” is jointly sponsored by Salem Sound Coastwatch and the Abbot Public Library. For more information, please visit www.salemsound.org.


2019 is the 7th year of the annual “Underwater in Salem Sound” Lecture Series. This is the last lecture of the 2019 series. All the lectures are free and open to the public.


April 24
7:00 pm - 8:30 pm
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Meeting Room
235 Pleasant Street
Marblehead, 01945
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