T172 Quantifying Geomorphic Processes and Rates of Landscape Evolution (Posters)

Tuesday, 6 November 2018
9:00 AM - 6:30 PM
Halls J-K

COMPARING SPECTRAL REFLECTANCE PATTERNS TO THE CONCENTRATION OF COSMOGENIC NE-21 TO LINK WEATHERING AND EROSION RATES FOR BEDROCK IN TERRA NOVA BAY, ANTARCTICA

Paper number: T172-19
Program: Technical Sessions
Time: 9:00 AM – 6:30 PM

Authors

Abstract

This study will compare the spectral reflectance patterns from bedrock samples in Antarctica to their measured erosion rates determined from cosmogenic nuclides. In the cold and hyperarid climate of Antarctica, we expect that low erosion rates allow for the development of oxidation weathering surfaces. We have 11 samples of granite and 2 samples of sandstone bedrock, collected from the Terra Nova Bay region of Victoria Land, Antarctica. For the spectroscopy, we used a FieldSpec HandHeld 2 Spectroradiometer and collected reflectance patterns in the 0.3 – 1.0 nm wavelengths. The reflectance data was collected from two surfaces of every sample: the topmost surface of the rock, which had been exposed to the elements and consequently been affected by weathering and erosion, and a freshly cut surface of the sample. The comparison of the spectra between the weathered and cut sides of a sample begins to provide a quantitative value of the amount of weathering the samples have undergone. After collecting the spectral data, we cut and crushed the samples, and isolated quartz minerals from them following standard lab procedures for cosmogenic nuclide preparation. We will measure the concentration of cosmogenic Neon-21 in the quartz from these samples using noble gas mass spectrometry. The concentration of Neon-21 is indicative of the time period the sample has spent in the upper few meters of Earth’s surface, which is equivalent to the bedrock erosion rate. Linking all of these data, we will be able to compare the bedrock erosion rates to the spectrally determined weathering parameter. If a correlation between these data types can be shown, then we may be able to determine bedrock erosion rates over greater spatial extent using satellite-derived spectral data sets.

Geological Society of America Abstracts with Programs. Vol. 50, No. 6

doi: 10.1130/abs/2018AM-324216

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