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Crustal evolution in large hot orogens from pre-collisional continental margin through the collision and collapse stages: evidence from field, analytical and numerical studies


Large hot orogens (LHOs) are major sites of heat loss and recycling of continental crust. The tectonic evolution of LHOs has traditionally been considered in terms of processes during the formation of double thickness crust under an orogenic plateau, but recent work suggests it is also influenced by the pre-collisional history of the margins. In addition,  gravitationally driven collapse and associated magmatism and fluid influx may exert important controls on the final crustal architecture. With respect to thermal structure, the origin and duration of the peak granulite-facies temperatures in the middle and lower crust of LHOs and their link to syn-orogenic magmatism remain incompletely understood.

This special session will feature contributions on recent modelling and field-based studies of the Grenville Province, an example of the exhumed roots of an LHO, but contributions from other LHOs such as the Variscan Belt and the Himalaya-Tibet Orogen are strongly encouraged.

Session ID: 6036 

2015 Joint Assembly

For information and Guide Books from previous FOG adventures click below

FOG Guidebook  2009
FOG 2010
FOG 2011
FOG 2012
To download a copy of the 2010 Guidebook, click on search databases and then select OGS Publication.  On the first screen that comes up, in the first option given pick begins with, and then type in OFR6230.  That will bring up the guidebook.  If you click on view publication, it will bring up the guidebook and you can save a copy of it.  


NYSGA (New York State Geological Association Web Page (2008 field conference in Lake George)
GSA  Geological Society of America

Eric L Johnson FOG Coordinator
Dr. Eric Lee Johnson


The Friends of the Grenville (FOG) is a loose-knit fraternity that formally came into existence in 1972 but whose roots really go back to a monumental, 3000-km-long, 12-day field trip led by Hugh R. Wynne-Edwards. Since 1970, there has been an unbroken chain of annual, September-October, two-day excursions that alternate between Ontario, Quebec, and New York.  FOG is a "nonorganization" with no dues and no formal membership. A Friday-night gathering welcomes participants with an overview of the fieldtrip and a Saturday-night banquet salutes fieldtrip leaders and the participant having travelled the farthest to join the "Friends". It is the mixture of friendships developed over the years , the rocks and their beautiful enigmas, and the frank and broad discussions on their potential solutions that keep drawing FOG members back, year after year, rain or shine.

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FOG 2014

New ideas on the post-peak development of the Central Gneiss Belt


Muskoka Region

Special thanks to Drs. Toby Rivers and Fried Schwerdtner for a terrific FOG.

FOG2014 participants at Prospect Lake, ON

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Courtesy of Hartwick College, Oneonta, NY  13820