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Tectonic Evolution of the Southern Appalachian Mountains—500 Million Years Ago

diagram of ancient ocean basin

500 Million Years Ago—Iapetus Ocean Opens. Continental blocks destined to become North America and Gondwanaland drift apart. The eastern edge of ancient North America developed into a passive continental margin, similar to the modern East Coast. As the margin cooled and subsided, thick sedimentary strata covered the earlier mountains and rift valleys.

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illustrations above modified from “Parks and Plates: The Geology of our National Parks, Monuments and Seashores,” by Robert J. Lillie, New York, W. W. Norton and Company, 298 pp., 2005, www.amazon.com/dp/0134905172.

Public domain:Full Granting Rights

Image

Geologic Resources Division, Code: GRD

NPS.gov Collection

11/26/2019

11/26/2019

Monday, February 3, 2020 12:01:18 PM

Monday, February 3, 2020 12:01:18 PM

diagram 500 mya iapetus ocean opens@10x.jpg

Tuesday, November 26, 2019 11:51:25 PM

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216.1 kB

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