1. Susquehanna River Basin Erosion Rates Derived from 10 Be in Stream Sediment Joanna M. Reuter Paul R. Bierman, Jennifer Larsen University of Vermont Milan J. Pavich, Allen C. Gellis USGS Robert C. Finkel Lawrence Livermore National Laboratory

2. Erosion rates on a millennial time scale? Relationships with: –physiographic province? –slope? –lithology? Comparison with other erosion rate estimates 1

3. O 10 Be Quartz Production of 10 Be from cosmic ray bombardment of quartz Cosmic Rays

4. Depth (meters) Production Rate Si O 26 Al 10 Be Quartz 10 Be is a proxy for erosion rate

7. Small basins USGS gage basins EXPLANATION

8. Small basins USGS gage basins EXPLANATION

9. Small basins USGS gage basins EXPLANATION

10. Sampling Strategy

12. n = 22 n = 2 n = 1 Appalachian Plateaus 10 Be Small basins sandstone Suspended sediment yield USGS basins 10 Be USGS basins Basin average erosion rate (meters/ million years)

14. n = 17 n = 9 n = 7 Valley & Ridge Basin average erosion rate (meters/ million years) 10 Be Small basins sandstone 10 Be Small basins shale 10 Be USGS basins Suspended sediment yield USGS basins

16. 320 m/my n = 12 n = 7 n = 6 Piedmont Basin average erosion rate (meters/ million years) 10 Be Small basins schist Suspended sediment yield USGS basins 10 Be USGS basins

17. Basin average erosion rate (meters/ million years) Physiographic province summary: small basins 10 Be Appalachian Plateaus sandstone 10 Be Valley & Ridge sandstone 10 Be Valley & Ridge shale 10 Be Piedmont schist 0 10 20 30 Mean slope of basin (degrees)

18. Erosion rate (meters/ million years) Does slope matter? R 2 = 0.72 no correlation R 2 = 0.37 R 2 = 0.51

19. 10 Be Erosion of the Appalachians Erosion rate (meters/ million years) R 2 = 0.54 Smokies data from Matmon et al., 2003 60 50 40 30 20 10 0

20. Conclusions Erosion rate of unglaciated part of Susquehanna River basin: –16 m/my, with a range from 4 to 54 m/my Physiographic province matters. Slope matters. Lithology shows no clear relation to erosion rates. Sediment yields are broadly consistent with 10 Be erosion rates, except for some Piedmont basins. A relationship exists between slope and erosion rate across different regions of the Appalachians.

21. Acknowledgments Funding: –USGS –NSF Sample collection & processing: –Eric Butler –Megan McGee –Luke Reusser