A Geochemical Analysis of Soils from the Rio Chagres Basin, Panama: Insight into Regional Chemical Weathering Processes and Controls

Chemical weathering is a critical process in the development of soil from rock, and is facilitated and expedited by the presence of water and heat. This process is not as well understood in moist tropical climates like that of the Rio Chagres Basin in central Panama, where conditions are ideal for rapid chemical weathering and erosion. The purpose of this project is to investigate the relationship between the resultant chemistry and extent of weathering of soils from the Rio Chagres Basin. One of the critical considerations of this study is to examine how the chemistry and composition of the soils vary with depth along a vertical cross section from surface to bedrock in different lithologies. By understanding how the chemistry changes along these profiles, insight can be obtained into what processes are occurring where, and how rapidly they are progressing. During weathering, some ions become highly mobile, like K+, Na+ and Ca2+, and are readily leached from source material. Other ions are fairly immobile, like Al3+, and will remain in higher concentrations in the weathered product or soil. A high ratio of immobile ions to mobile ions indicates extensive weathering, where a low ratio of immobile ions to mobile ions suggests mild to moderate weathering. For this project two sample sites were chosen in non adjacent areas with unique geologic morphologies and underlying lithologies. The goal of this study is to become more aware of how climate, source rock type, topography and depth affect the progression of weathering and resultant chemistry of tropical soils.No embargoAcademic Major: Geological Science