PRELIMINARY SOIL EROSION AND SEDIMENT BUDGETS IN THE VALLEY OF LEYVA, BOYACA, COLOMBIA

The Valley of Leyva, Boyacá, Colombia is a strikingly eroded landscape, with upland surfaces that are stripped except for remnant soil pedestals. Here we build on previous studies of erosion by assessing the timing of sedimentation. Erosion of this environment could have been caused by human land use changes, climate changes, or both. In the field, we cored and trenched floodplains and a high mountain pond and found stratified sediments down to 2-3 m, a fence post buried by 70 cm, and a well-developed buried paleosol in some floodplain sites below 2 m depth. Our main techniques are to date sediment deposition with Pb-210 and AMS and characterize sediment chemistry and texture in order to correlate sediments with broader land uses in the watershed. These sites are near the archaeological site of El Infiernito, which has Muisca settlement from over the last 1200 years, and has a long European settlement occupation of nearly 500 years. We want to pinpoint deposition with cultural periods and land uses, such as the Early or Late Muisca periods or European settlement with livestock. This region has not had a paleoclimate study record thus far, but erosion may also have responded to ENSO cycles, the Medieval Climate Anomaly, and/or the Little Ice Age. Ultimately, this research will contribute to a larger project examining how Early Muisca chiefdoms responded to climate change and how their land uses influenced soil erosion.