QUANTIFICATION OF SOIL FORMATION ON A RECENT LAVA FLOW AT MT. ARENAL, COSTA RICA

The rate of soil formation from bedrock has long been in question, especially in tropical climates. The 1992 lava flow at Mt. Arenal, Costa Rica provides an excellent opportunity to capture a “time zero” and observe the formation of soil in real time. The lava flow and pyroclastic flows devastated a swath of forest in 1992. Since then the surrounding forest has begun the process of re-colonizing the lava flow and what used to be gaps between boulders are now filling with regolith. The focus of this research was to sample the regolith on the 1992 Lava Flow on Mt. Arenal, Costa Rica and attempt to quantify the amount of soil formation through several sediment analysis techniques. The intention was to develop a baseline at 24 years after the deposition of the lava that could then be easily re-sampled over time as the soil continues to develop. It is hoped that this will be a long-term collaboration between researchers in Costa Rica and the United States.