1. The Mantle Flow Field beneath Western North America Silver and Holt, Science 295, 1054, 2002 Abigail L. Bull Earthscope Seminar, January 2007

2. Earthscope Seminar Abigail L. Bull 2 Motivation: Western US Tectonics www.earth.northwestern.edu

3. Earthscope Seminar Abigail L. Bull 3 Motivation: Mantle Flow Pattern Smith et al., Science 292, 713 (2001). Peyton et al., Geophys. Res. Lett. 28, 379 (2001).

4. Earthscope Seminar Abigail L. Bull 4 Motivation: Modeling Mantle Flow * Flow: due to plate motion * Flow: due to density anomalies http://www.geo.lsa.umich.edu/~crlb/www.cas.muchio.edu

5. Earthscope Seminar Abigail L. Bull 5 Data: Surface Deformation and Splitting data Silver et al., Science 295, 1054 (2002).

6. Earthscope Seminar Abigail L. Bull 6 Results Silver et al., Science 295, 1054 (2002).

7. Earthscope Seminar Abigail L. Bull 7 Conclusions and Implications www.geo.lsa.umich.edu Mantle constitutes weak drag force

8. Earthscope Seminar Abigail L. Bull 8 Discussion Topics * Is mantle flow related to velocities of overlying plates? * Does mantle flow have any effect on a plate’s motion? * Are there other methods to determine mantle flow? * What would flow field look like in various tectonic regions?