Paleosol Analysis of Columbia River Basalt Soils
By Isabel Hong
Whitman College, Walla Walla WA
Our understanding of ancient climates can help us understand present and future climate change. However, long continental climate records are sparse. The Columbia Plateau is an ideal setting for conducting such research due to the numerous distinct paleosols developed on basalt flows. Temperature and moisture can be partly reconstructed from paleosols, fossilized soil layers, by quantitative analysis of climate-dependent soil forming processes. I quantified leaching in a paleosol of the Columbia River Basalt Group in the Blue Mountains of Oregon and north of Dayton in Washington. I used a portable X-ray fluorescence meter (pXRF) to measure element concentrations along vertical profiles. Leaching of elements occurred during soil formation. Future research will link this analysis to other paleosols to develop a more temporally and spatially complete picture of Miocence climate in the Columbia Basin.