1. Joanna M. Reuter M.S. Proposal April 30, 2003 Paul Bierman, advisor
Basin-scale analysis of long-term sediment-generation rates derived from 10Be in river sediment: The Susquehanna River basin and beyond
Joanna M. Reuter
M.S. Proposal
April 30, 2003
Paul Bierman, advisor

2. Outline Big picture questions
Fundamentals of cosmogenic nuclide analysis of sediment
Framework of study
Susquehanna River
Example: Drift Creek, Oregon Coast Range
Geographic Information Systems
Multivariate statistics
Applications and summary

3. Where and how quickly does Earth’s surface erode?
big picture geomorphic question that has of course been addressed before
new and different: combination of spatial and temporal scale
combination of analytical techniques: cosmo nuclide analysis of seds, GIS, and multivariate statistics
pictures to suggest differences in veg, climate, tectonics, lithology, topo...

4. Climate Tectonics Sediment generation Biota Topography Local geology
complex feedbacks—and so causation is inherently going to be difficult to determine
but if can figure out what is strongly correlated—gives us an idea of relative importance
looking for correlations is an approach that others have taken in the past...
Local geology

5. From:
Ahnert, 1970

6. From:
Montgomery and Brandon, 2002

7. Climate Tectonics Sediment generation Biota Topography Local geology
Precipitation
Temperature
Tectonic setting
Sediment generation
Biota
Topography
Land cover
Relief
Slope
Aspect
Stream network
Sinuosity
map these on a basin scale...and summarize for the basin--then hypothesize that the basin-scale parameters will correlate with sed gen rates
[ can only feasibly map present day features of the landscape]
Local geology
Lithology

8. Temporal Scale: Methods for Inferring Erosion Rates
Apatite fission track, (U-Th)/He thermochronometry
106 – 108 years
Cosmogenic nuclide analysis of sediment
103 – 106 years
sed yield from filling reservoirs or suspended sediment sampling for ex...
talk about possibilities for comparison—to assess human impact on sediment yield
generally insensitive to current land use
Measurement of present day sediment yield
100 – 102 years
Time scale

9. Quartz Si 26Al O 10Be Cosmogenic Nuclides: Key Ideas Depth, in meters
cosmic rays continually bombard Earth
interact with material near the surface...we’re interested in quartz...si to al; o to be—these are otherwise rare
cosmic rays don’t penetrate very deeply into the earth
production rate drops off rapidly with depth
so amount of 10be and 26al provides info about how long material has been near the surface
Depth, in meters
Quartz
Production Rate

10. Quartz Si 26Al O 10Be Cosmogenic Nuclides: Key Ideas Depth, in meters
cosmic rays continually bombard Earth
interact with material near the surface...we’re interested in quartz...si to al; o to be—these are otherwise rare
cosmic rays don’t penetrate very deeply into the earth
production rate drops off rapidly with depth
so amount of 10be and 26al provides info about how long material has been near the surface
Depth, in meters
Quartz
Production Rate

11. 0% %
3 m

12. 10Be is a proxy for erosion rate
0% %
3 m
10Be is a proxy for erosion rate

13. Sample Sediment for Basin-Integrated Sediment-Generation Rates

14. Spatial Distribution: Cosmogenic Sediment Data
Drift Creek, OR Coast Range
Susquehanna
River Basin
Rio
Puerco
North
Slope, AK
Bhutan
Great Smoky
Mountains
Yuma Wash
Nahal Yael,
Israel
Venezuela
Bolivian
Andes
Namibia
Paul and colleagues have used this technique in regions representing a variety of climatic & tectonic settings around the world...
but haven’t rigorously examined the data in terms of basin characteristics—to see if variation in data can be explained by characteristics of the basins... so I’m going to revisit these data sets—do GIS analysis
talk today will focus on two basins:
Drift Creek—demonstrate GIS and multivariate statistical approach
Susquehanna—my field area
Drift Creek, OR: Bierman et al., 2001
Yuma Wash: Clapp et al., 2002
Rio Puerco: Clapp et al., 2001, Bierman et al., 2001
Great Smoky Mountains: Matmon et al., 2003
Nahal Yael, Israel: Clapp et al., 2000
Climate
Tectonics
Erosion
Biota
Topography
Local geology

15. Framework of M.S. Research
Acquire GIS data
All basins
(Drift Creek example)
Summarize data by basins
Susquehanna Basin
Select sample
sites and
collect samples
Separate
quartz
and
measure 10Be
Interpret data as sediment generation rates
GIS and multivariate statistical analyses

16. The Susquehanna River Basin
Basin size: >70,000 km2
North American passive margin
Motivation: Chesapeake Bay
Partly glaciated

17. Piedmont
Appalachian
Plateaus
Valley and Ridge

18. The Susquehanna River basin
22 preliminary samples
Collected at USGS streamgages
Challenges of data interpretation
Large basin
Glaciated basin
Sediment storage in terraces
Sampling strategy
Utilize GIS to select sampling sites
Focus on small headwater basins
Focus on unglaciated parts of the basin
going through process of Susquehanna data analysis and interpretation will help me critically assess the 10be data from other basins

19. Data Analysis Acquire GIS data
Delineate drainage basin from digital elevation model
Summarize data for each basin
Explore data qualitatively—longitudinal profiles, etc.
Explore data statistically
Investigate whether sediment generation rates inferred from 10Be activities correlate with basin-scale parameters

20. Drift Creek 180 km2 basin in the Oregon Coast Range
Oregon Coast Range has received extensive geomorphic study
Independent evidence suggests that the Oregon Coast Range approximates a topographic steady state
small basin facilitates rapid GIS data processing and analysis

22. Elevation

23. Basin Area

24. Stream Network

25. Slope

26. Land Use/Land Cover

27. Geology

28. Precipitation

29. Multivariate statistics
Ascertain which variables have most explanatory value
Principal components analysis
Multiple linear regression
Canonical correlation analysis
examining multiple variables at once is more robust than one or two at a time
may be limitations because I’m working with data sets that were not collected with this type of analysis as the primary original purpose—but the existing data are still worth examining...

30. Anticipated Outcome Insight regarding relative importance of: Climate
Tectonics
Topography
Biota
Local geology
Erosion
complex feedbacks—and so causation is inherently going to be difficult to determine
but if can figure out what is strongly correlated—gives us an idea of relative importance

31. Motivation and Applications
Assess human impacts on sediment yield
Chesapeake Bay sedimentation
Development of EPA Total Maximum Daily Load (TMDL) regulations

32. Funding USGS NSF Graduate Research Fellowship
Graduate College Summer Research Fellowship
Graduate Teaching Fellowship

33. Timeline Spring 2003 (Graduate Teaching Fellowship)
Preliminary Susquehanna samples: from quarts of sample to samples of quartz; data before summer field work
GIS data acquisition (focus on US basins) and preliminary analysis
Summer 2003 (Graduate College Summer Research Fellowship)
Susquehanna field work, purify quartz from new samples
GIS work continued
Fall 2003 (NSF Graduate Research Fellowship)
Continue intensive GIS analysis, analyze summer field data
Present at GSA
Spring & Summer 2004 (NSF Graduate Research Fellowship)
Complete data analysis
Write and defend thesis
Presentation of results at national meetings

36. JUNK

37. Cosmogenic nuclide analysis of sediment: key ideas
Earth is continually bombarded by cosmic rays
The interaction of cosmic rays with near-surface materials produces cosmogenic nuclides, including 10Be and 26Al in quartz
Abundance of cosmogenic nuclides in stream sediments reflects the erosional history of the basin

38. Climate Tectonics Topography Biota Local geology
complex feedbacks
give some specific examples...
if there’s more rainfall, if there’s greater relief, if the lithology is less resistant, is there more sediment generation?
mention Molnar chicken & egg
mention that many of these factors can be mapped for the present day landscape
Biota
Local geology

39. Data organization

40. What’s New & Different Combination of: Temporal scale
Spatial distribution
Combination of analytical tools:
Cosmogenic nuclide analysis of sediment
Geographic Information Systems (GIS)
Multivariate statistics
“where and how quickly does Earth’s surface erode?” is a long standing question in geomorphology—obviously other work has been done...so, what’s new and different about my work?

41. Framework of M.S. Research
Obtain and interpret 10Be data from Susquehanna River basin sediments
Analyze worldwide basins from which Bierman and collaborators have obtained cosmogenic nuclide data from sediment
Consider relationship of 10Be activities to basin-scale parameters using GIS

42. Spatial Distribution Cosmogenic Data Sets
EXPLANATION
DC: Drift Creek, OR (Bierman et al., 2001) SQ: Susquehanna River
YW: Yuma Wash, AZ (Bierman et al., 2001) NS: North Slope, Alaska
RP: Rio Puerco, NM (Clapp et al., 2001) VZ: Venezuela
GS: Great Smoky Mtns. (Matmon et al., 2003) NA: Namibia
NY: Nahal Yael, Israel (Clapp et al., 2000) BH: Bhutan
BA: Bolivian Andes

44. Anticipated Outcome
Results of the analysis of cosmogenic nuclide data and basin-scale parameters will provide insight regarding the relative importance of climate, tectonics, topography, biota, and lithology in determining sediment generation rates.