Laboratory procedures may not be fully able to remove the contaminants.Perhaps the most vexing problem in some outcrop studies are pervasive tiny rootlets from modern plants.A varve sequence might also have events in it of known calendar age, such as beds from flood events or volcanic ash layers that have historic records associated with them.
C ages from terrestrial plants avoid some problems with other materials.
Bulk sediment samples and samples of aquatic plants or animals such as the carbonate shells of clams, snails, and ostracodes may yield ages that are too old because of how carbon was fixed by the organism and the potential for the incorporation of “old” carbon from a water body.
Bacow, who has a deep appreciation for community spirit.
Over the past 25 years, she has brought the public and private sectors together in unlikely collaborations to revitalize countless communities.
The most reliable ages are from fossils that got their carbon directly from the atmosphere.