HR: 1340h
AN: U43B-0828    [Abstracts]
TI: Plate Boundary Stress, Thermal and Rheological Control of Intraplate Deformation the 1.9 Ga Kapuskasing uplift, Superior Province, Canada
AU: * Mareschal, J
EM: jcm@olympus.geotop.uqam.ca
AF: GEOTOP-UQAM-McGill, University of Quebec at Montreal, P.O.B. 8888, sta. "downtown", Montreal, QC H3C3P8 Canada
AU: Perry, C
EM: perry@ipgp.jussieu.fr
AF: GEOTOP-UQAM-McGill, University of Quebec at Montreal, P.O.B. 8888, sta. "downtown", Montreal, QC H3C3P8 Canada
AU: Perry, C
EM: perry@ipgp.jussieu.fr
AF: Institut de Physique du Globe de Paris, 4 Pl Jussieu, Paris, 75252 France
AU: Jaupart, C
EM: cj@ccr.jussieu.fr
AF: Institut de Physique du Globe de Paris, 4 Pl Jussieu, Paris, 75252 France
AB: The Kapuskasing structural zone was the site of local crustal thrusting and uplift within the Superior craton. This localized deformation was synchronous with the 1.9 Ga Hudsonian orogeny that took place at the margin of the craton >1000km to the west. We use the present heat flow data in the Superior province to calculate the strength of the lithosphere and to show that the uplift took place in the weakest part of the craton. After eliminating heat flow data that were affected by the uplift and later events (Keweenawan rifting), we calculate the heat flow and the temperature field in the lithosphere at 1.9Ga. We show that the Kapuskasing region lies in the center of a ``thermal anomaly". The strength of the lithosphere in this region may have been up to 3 orders of magnitude lower than in surrounding parts of the craton. This explains why deformation was localized in this region. Following the uplift and erosion of the upper crust, the average crustal composition in the Kapuskasing region was modified with reduced heat production resulting in low heat flow, and a strong lithosphere permitting the long term preservation of a crustal root.
DE: 8103 Continental cratons
DE: 8120 Dynamics of lithosphere and mantle: general (1213)
DE: 8130 Heat generation and transport
DE: 8159 Rheology: crust and lithosphere (8031)
DE: 8164 Stresses: crust and lithosphere
SC: Union [U]
MN: Fall Meeting 2005