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

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

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...

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

From: Ahnert, 1970

From: Montgomery and Brandon, 2002

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

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

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

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

0% 100% 3 m

10Be is a proxy for erosion rate 0% 100% 3 m 10Be is a proxy for erosion rate

Sample Sediment for Basin-Integrated Sediment-Generation Rates

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

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

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

Piedmont Appalachian Plateaus Valley and Ridge

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

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

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

Elevation

Basin Area

Stream Network

Slope

Land Use/Land Cover

Geology

Precipitation

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...

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

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

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

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

JUNK

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

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

Data organization

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?

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

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

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.