Public Release: 

Mesozoic assembly of the North American Cordillera and the exotic Rubian ribbon

New GSA Special Paper

Geological Society of America


IMAGE: The cover shows a 3-D shaded relief map of the SW US and NW Mexico. The image is courtesy Ray Sterner at the Johns Hopkins University Applied Physics Laboratory. view more

Credit: Image courtesy Ray Sterner at the Johns Hopkins University Applied Physics Laboratory

Boulder, CO, USA - The broadly accepted hypothesis for the development of the segmented Cordilleran orogen above a long-lived eastwardly dipping subduction zone is at odds with many critical observations. In this new Special Paper from The Geological Society of America, Robert S. Hildebrand of the University of California-Davis explores an alternative collisional model. This well-illustrated book, which includes a pull-out map, builds upon Hildebrand's earlier work, published as GSA Special Paper 457 (2009).

Starting with an overview of Cordilleran exotic and suspect terranes, Hildebrand builds upon his model for the Mesozoic collision of the exotic Rubian ribbon continent with the western margin of North America. He integrates the disparate fragments into a dynamic model involving arc magmatism, arc-continent collision, slab failure magmatism, and meridional migration. While the main focus is on the offshore assembly of the Rubian ribbon continent, Hildebrand explores its interactions with North America during the Sevier and Laramide events and concludes that North America was the lower plate in both.

Hildebrand notes that this new volume "will be of great interest to the general geological community, including advanced students, as it presents new ideas on the Mesozoic assembly of California and provides the first overview of the North American Cordillera since GSA's Decade of North American Geology volumes some 20 years ago."


Individual copies of the volume may be purchased through The Geological Society of America online bookstore,, or by contacting GSA Sales and Service,

Book editors of earth science journals/publications may request a review copy by contacting April Leo,

Mesozoic Assembly of the North American Cordillera
By Robert S. Hildebrand
Geological Society of America Special Paper 495
SPE495, 169 p., $75.00; Member price $60.00
ISBN 978-0-8137-2495-9

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