The Northern Appalachian Anomaly: A modern asthenospheric upwelling

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• 作者：William Menke ; Peter Skryzalin ; Vadim Levin ; Thomas Harper ; Fiona Darbyshire ; Ted Dong
• 刊名：Geophysical Research Letters
• 出版年：2016
• 出版时间：16 October 2016
• 年：2016
• 卷：43
• 期：19
• 页码：10,173-10,179
• 全文大小：937.6KB
• ISSN：1944-8007

文摘

The Northern Appalachian Anomaly (NAA) is an intense, laterally localized (400 km diameter) low-velocity anomaly centered in the asthenosphere beneath southern New England. Its maximum shear velocity contrast, at 200 km depth, is about 10%, and its compressional-to-shear velocity perturbation ratio is about unity, values compatible with it being a modern thermal anomaly. Although centered close to the track of the Great Meteor hot spot, it is not elongated parallel to it and does not crosscut the cratonic margin. In contrast to previous explanations, we argue that the NAA's spatial association with the hot spot track is coincidental and that it is caused by small-scale upwelling associated with an eddy in the asthenospheric flow field at the continental margin. That the NAA is just one of several low-velocity features along the eastern margin of North America suggests that this process may be globally ubiquitous.