AMS RADIOCARBON DATING OF QUATERNARY INSECTS

Thanks to these advances in reliable radiocarbon dating, we are now in a position to date a high density of insect fossils for multiple research purposes, namely paleoenvironmental reconstructions.

This raises the significance of RLB as a study site because:

•Despite its enduring significance as one of North America’s premier Late Pleistocene localities, there remain critical gaps in our understanding of its biotic history and paleoenvironment. These in turn affect inferences concerning climate, habitat, entrapment events, shifting biological communities, and whether RLB has any significance for understanding larger events, such as the timing and agency of the megafaunal extinctions.


•While RLB is justly famous for its diversity of vertebrates and birds, these species are often insensitive environmental indicators because they are highly mobile or migratory. Other, much more meaningful taxa for purposes of paleoenvironmental reconstruction, such as insects, are under-examined, or have not been collected and interpreted according to modern methods.

• Rigorously studied and dated Late Quaternary paleoenvironmental reconstructions from Ranch La Brea (RLB) and the greater Los Angeles Basin are scarce. We use data from AMS radiocarbon dated insect fragments to infer local climates over the past 50,000 years. Our results indicate: 1) Quaternary insect remains can be located with great accuracy in radiocarbon time, and 2) well-dated and documented climate indicator beetle species are sensitive proxies for environmental change in the Los Angeles Basin

©2017 Anna R. Holden