HR: 1330h
AN: S22A-0438    [PDF]
TI: Mantle heat flow in the Canadian Shield from joint inversion of seismic and heat flow data
AU: * Borde, S
EM: sarah@olympus.geotop.uqam.ca
AF: GEOTOP-UQAM-McGill, University of Quebec at Montreal, P.O.Box 8888, sta. "downtown", Montreal, QC H3C3P8 Canada
AU: Shapiro, N
EM: nshapiro@ciei.colorado.edu
AF: Center for Imaging the Earth's Interior,, Dept of Physics, University of Colorado, Boulder, CO 80309-0390 United States
AU: Ritzwoller, M
EM: ritzwoll@ciei.colorado.edu
AF: Center for Imaging the Earth's Interior,, Dept of Physics, University of Colorado, Boulder, CO 80309-0390 United States
AU: Jaupart, C
EM: cj@ccr.jussieu.fr
AF: Institut de Physique du Globe, 4 Pl. Jussieu, Paris, 75252 France
AU: Mareschal, J
EM: jcm@olympus.geotop.uqam.ca
AF: GEOTOP-UQAM-McGill, University of Quebec at Montreal, P.O.Box 8888, sta. "downtown", Montreal, QC H3C3P8 Canada
AB: We have used a Monte Carlo inversion of seismic surface wave data to obtain a thermal model of the upper mantle beneath the Canadian Shield in terms of Moho temperature, and mantle heat flow, and the potential temperature of the convecting mantle. The study area (40-60\deg~N, 120-55 \deg W) includes several Provinces ranging in age from Archean to Paleozoic (the Appalachians). The inversion is constrained by heat flow and surface heat production data wherever they are available. The Monte Carlo inversion gives an ensemble of models that fit the data, providing estimates of uncertainties in model parameters. We also estimate the effect of uncertainties in the interconversion between temperature and seismic velocity. The analysis suggests that the lithosphere is coldest beneath the northernmost part of the study area. Mantle heat flow and lithospheric thickness vary from 11 $\mathrm{mW~m^{-2}}$ and nearly 400km beneath the PaleoProterozoic Trans Hudson Orogen to the northwest to about 24 $\mathrm{mW~m^{-2}}$ and less than 150 km beneath the Appalachians to the southeast. Within the Precambrian Shield, variations in shear wave velocity and Moho temperatures appear on a spatial scale of several hundred km. These variations appear not to be correlated with geological provinces tectonic history but they may be related to sub provinces with distinctive petrological characteristics.
DE: 7218 Lithosphere and upper mantle
DE: 8130 Heat generation and transport
DE: 8159 Rheology--crust and lithosphere
SC: Seismology [S]
MN: 2003 Fall Meeting