The content you've requested is available without charge only to active Sigma Xi members and
If you are an active member or an individual subscriber, please log in now in order to access this article.
If you are not a member or individual subscriber, you can:
Since the broad acceptance of the plate-tectonic theory in the late 1960s, mountains have been thought to form through three distinct tectonic processes, all the result of essentially horizontal forces. The authors propose to add a fourth mountain-building mechanism—the vertical motion of hot plumes of material rising from the earth's core-mantle boundary—and site as an example the complicated structures of the southwestern U.S. The westward progress of the North American plate over the relatively stationary Yellowstone plume during the past 75 million years may explain geological features as diverse as the Laramide Orogeny, the distended Basin and Range Province, and the accretion of exotic terranes along the continent's west coast.
Connect With Us:
An early peek at each new issue, with descriptions of feature articles, columns, and more. Issues contain links to everything in the latest issue's table of contents.News of book reviews published in American Scientist and around the web, as well as other noteworthy happenings in the world of science books.
To sign up for automatic emails of the American Scientist Update and Scientists' Nightstand issues, create an online profile, then sign up in the My AmSci area.
JSTOR, the online academic archive, contains complete back issues of American Scientist from 1913 (known then as the Sigma Xi Quarterly) through 2005.
The table of contents for each issue is freely available to all users; those with institutional access can read each complete issue.
View the full collection here.
Receive notification when new content is posted from the entire website, or choose from the customized feeds available.