Chronology of Lake Bonneville, 30,000 to 10,000 yr B.P.

• 368 radiocarbon ages from outcrops and shorelines have been compiled in this update.
• New ages should be placed in the context of hundreds of ages that have already been obtained.
• This compilation provides data for many different sub-disciplines of Quaternary science.
• Ages for organic materials limit the time of lake occupation at particular altitudes.
• In some cases carbonate ages show contamination from radiocarbon reservoirs or young carbon.

368 radiocarbon ages between 30 and 10 cal ka for samples collected from outcrops and shorelines from the Lake Bonneville basin have been compiled for this paper. Samples include 1. organic materials from sources outside the lake, such as wood, charcoal, plant fragments from emergent aquatics, and dispersed wetland organics, and 2. carbonate materials deposited in the lake, such as mollusk shells, tufa, charophyte debris, ooids, and marl. In general, organic materials provide rather than precise ages for lacustrine events, but their interpretation is less complicated than interpretation of results from carbonate samples. The data set shows evidence of contamination of different carbonate samples with both younger carbon and older carbon. For example, a radiocarbon reservoir at certain places within the lake during the middle transgressive phase accounts for ages of mollusk shells that are older than basal wood ages at similar altitudes. The large number of ages permits an accurate reconstruction of the lake chronology; conflicts between ages can be detected and reliable ages can be meaningfully integrated in interpretations. If fewer ages were available, the chronology might look simpler, but its accuracy would be unknown.