Susquehanna River Susquehanna River Basin Erosion Rates Basin Erosion Rates Derived from Derived from 1010Be in Be in

Stream SedimentStream Sediment

Joanna M. Reuter Paul R. Bierman, Jennifer Larsen

University of Vermont

Milan J. Pavich, Allen C. GellisUSGS

Robert C. FinkelLawrence Livermore National Laboratory

• Erosion rates on a millennial time scale?

• Relationships with:–physiographic province?–slope?– lithology?

• Comparison with other erosion rate estimates

• 1

O 10Be

Quartz

Production of 10Be from cosmic ray bombardment

of quartz

Cosmic Rays

0

1

2

3

0 50 100% % %

Depth (meters)

Production Rate

10Be is a proxy for erosion rate

Small basins

USGS gage basins

EXPLANATION

Small basins

USGS gage basins

EXPLANATION

Small basins

USGS gage basins

EXPLANATION

Sampling Strategy

0

10

20

30

40

50

60

AP SS USGS AP USGS AP

10Be 10Be Sediment Yield

Erosionrate

(meters/millionyears)

n = 22

n = 2

n = 1

Appalachian Plateaus

10BeSmall basins

sandstone

Suspendedsediment yieldUSGS basins

10BeUSGS basins

Basinaverageerosion

rate(meters/millionyears)

0

10

20

30

40

50

60

VR SS VR SH USGS VR USGS VR

10Be 10Be 10Be Sediment Yield

Erosionrate

(meters/millionyears)

n = 17

n = 9n = 7

n = 7

Valley & Ridge

Basinaverageerosion

rate(meters/millionyears)

10BeSmall basins

sandstone

10BeSmall basins

shale

10BeUSGS basins

Suspendedsediment yieldUSGS basins

0

10

20

30

40

50

60

PD SC USGS PD USGS PD

10Be 10Be Sediment Yield

Erosionrate

(meters/millionyears)

320 m/my

n = 12

n = 7

n = 6

Piedmont

Basinaverageerosion

rate(meters/millionyears)

10BeSmall basins

schist

Suspendedsediment yieldUSGS basins

10BeUSGS basins

0

10

20

30

40

50

60

AP SS VR SS VR SH PD SC

10-Be EROSION 10-Be EROSION 10-Be EROSION 10-Be EROSION

Basinaverageerosion

rate(meters/millionyears)

Physiographic province summary: small basins

10BeAppalachian

Plateaussandstone

10BeValley & Ridge

sandstone

10BeValley & Ridge

shale

10BePiedmont

schist

0

10

20

30

Meanslope

of basin(degrees)

0

10

20

30

40

50

60

70

0 5 10 15 20 25

Mean slope of basin (degrees)

Erosionrate

(meters/millionyears)

0

10

20

30

40

50

60

70

0 5 10 15 20 25

Mean slope of basin (degrees)

0

10

20

30

40

50

60

70

0 5 10 15 20 25

Mean slope of basin (degrees)

0

10

20

30

40

50

60

70

0 5 10 15 20 25

Mean slope of basin (degrees)

Does slope matter?

0

10

20

30

40

50

60

70

0 5 10 15 20 25

Mean slope of basin (degrees)

0

10

20

30

40

50

60

70

0 5 10 15 20 25

Mean slope of basin (degrees)

R2 = 0.72

no correlation0

10

20

30

40

50

60

70

0 5 10 15 20 25

Mean slope of basin (degrees)

R2 = 0.37

R2 = 0.51

10Be Erosion of the Appalachians

0

10

20

30

40

50

60

0 5 10 15 20 25 30Mean slope of basin (degrees)

Susquehanna

Great Smoky Mountains

Erosionrate

(meters/millionyears)

R2 = 0.54

Smokies data from Matmon et al., 2003

60

50

40

30

20

10

0

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 10Be erosion rates, except for some Piedmont basins.

• A relationship exists between slope and erosion rate across different regions of the Appalachians.

Acknowledgments

• Funding: – USGS

– NSF

• Sample collection & processing:– Eric Butler

– Megan McGee

– Luke Reusser