ASSESSING PALEO FLORAL HETEROGENEITY IN BOGOTÁ FORMATION, COLOMBIA

Tropical rainforests are diverse biomes that are important carbon sinks, but the conditions of these biomes in the future of increasing atmospheric carbon and temperature is unknown. To understand the fate of these rainforests during times of increased temperature and atmospheric carbon, it is important to study past tropical rainforests. The Bogotá Formation, Colombia is a depositional sequence that provides evidence of one of the earliest Neotropical rainforests, dating back to the late Paleocene. This site contains fossiliferous beds of well-studied macrofossil flora containing families like Fabaceae, Arecaceae, Melastomataceae and Malvaceae. In addition to these floras are three siltstone beds with abundant charcoalified remains, that may indicate the presence of fires. However, based on mean annual precipitation (182-184 cm/year) and the paleofloras present, there is no reason to assume fire presence. In this study I aim to test for fire occurrence and compile the phytolith assemblage to compare it to the Bogota macrofossil flora. To test for fires, I will extract polycyclic aromatic hydrocarbons (PAHs), biomarkers from bulk sediment, and run these samples on a gas chromatography-mass spectrometry for PAH concentrations. Additionally, I will isolate, identify and count the phytolith assemblage at each site to understand the vegetation present in times of fire, which will be compared to the Bogotá Flora. Understanding the state of these tropical rainforests in high atmospheric CO2 levels and temperatures provides an analog to study modern climate change, as it mirrors similar conditions that rainforests will experience in the future.