ABSTRACT
Microflora (bacteria and fungi) distributions in several paleosols from Mount Kenya, East Africa, provide important information about contamination of buried soil horizons dated by radiocarbon. High counts of bacteria and fungi in buried soils provide evidence for contamination by plant root effects or ground water movement. Profiles with decreasing counts vs. depth appear to produce internally consistent and accurate radiocarbon dates. Profiles with disjunct or bimodal distributions of microflora at various depths produce internally inconsistent chronological sequences of radiocarbon dated buried surfaces. Preliminary results suggest that numbers up to 5 × 102g−l for fungi and 5 × 103g−1 for bacteria in buried A horizons do not appear to affect the validity of 14C dates. Beyond this threshold value, contamination appears to produce younger dates, the difference between true age and age increasing with the amount of microflora contamination.
