Origin of the Blue Ridge escarpment along the passive margin of Eastern North America

Basin Research
By: , and 



The Blue Ridge escarpment is a rugged landform situated within the ancient Appalachian orogen. While similar in some respects to the great escarpments along other passive margins, which have evolved by erosion following rifting, its youthful topographic expression has inspired proposals of Cenozoic tectonic rejuvenation in eastern North America. To better understand the post-orogenic and post-rift geomorphic evolution of passive margins, we have examined the origin of this landform using low-temperature thermochronometry and manipulation of topographic indices. Apatite (U-Th)/He and fission-track analyses along transects across the escarpment reveal a younging trend towards the coast. This pattern is consistent with other great escarpments and fits with an interpretation of having evolved by prolonged erosion, without the requirement of tectonic rejuvenation. Measured ages are also comparable specifically to those measured along other great escarpments that are as much as 100 Myr younger. This suggests that erosional mechanisms that maintain rugged escarpments in the early post-rift stages may remain active on ancient passive margins for prolonged periods. The precise erosional evolution of the escarpment is less clear, however, and several end-member models can explain the data. Our preferred model, which fits with all data, involves a significant degree of erosional escarpment retreat in the Cenozoic. Although this suggests that early onset of topographic stability is not required of passive margin evolution, more data are required to better constrain the details of the escarpment's development. 

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Publication type Article
Publication Subtype Journal Article
Title Origin of the Blue Ridge escarpment along the passive margin of Eastern North America
Series title Basin Research
DOI 10.1111/j.1365-2117.2003.00219.x
Volume 16
Issue 1
Year Published 2004
Language English
Publisher Wiley Online Library
Contributing office(s) Florence Bascom Geoscience Center
Description 23 p.
First page 41
Last page 63
Country United States
Other Geospatial Blue Ridge escarpment
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