Dating Pollen

Pollen grains, the male microgametophytes of seed plants (angiosperms and gymnosperms), are widely distributed in the environment and accumulate in a range of sedimentary environments including lakes, bogs, caves, floodplains, and the deep oceans. While some components of pollen grains such as the generative nucleus degrade quickly in the environment, the resilient pollen wall can be preserved for thousands to millions of years. The widespread distribution and high preservation potential of pollen grains underline the value of ancient or “subfossil” pollen not only as a tool for reconstructing past vegetation history and environmental change (see palynology), but also as a sample material for radiocarbon dating. The wide variety of deposits that have been successfully dated from pollen include peats, lake sediments, aeolian deposits, packrat middens, and Pleistocene ice-wedge casts. Key advantages of pollen as a dating material are that it may be present in deposits where plant macrofossils are scarce or lacking, and it can be identified in terms of the source vegetation, unlike bulk material where the provenance is unknown.