Basic age-modelling

Find ages for dated and undated depths E.g., linear interpolation, regression, spline (gaps) Choose which one looks nicest... How treat point estimates? (mid/max, multimodal)

Bayesian age-modelling

Bayesian = combine data with other info 14C dates and depth info stratigraphical ordering / position

• e.g., wiggle-match dating Constraints on e.g. likely accumulation rates Other dates, e.g. pollen events, 210Pb (…) Outlier analysis

Usually done by millions of simulations

Wiggle-match dating

Outlier analysis

• Reasons: site, error, lab?• Give prior outlier probabilities to dates• Iteration i: is date within 2 lengths sd?• If not, label date and shift to fit• [Labelled / total] posterior outlier

prob.• No need to remove outliers!• Fit F: 1 – mean(posterior outlier prob.)

OxCal

• Extract OxCal directory to C:\Program Files

• Open .../OxCal/Index.html in Firefox

• R_Date( “test”, 2450, 50);

• Save file, run

• Run examples from manual

Bpeat

• Extract Bpeat.zip somewhere

• Open R there (or change dir)

• source(“Bpeat.R”)

• SetCore(“MSB2K”,2)

• TestRun()

• FinalRun( 0.1 ) # just a short run...

• DepthChron()

The future of Bpeat: Bacon

Bacon

Muscles and fat – robust, yet flexible Floppy/crusty – flexibility can be adapted Can be cut to your liking – hiatuses Cured – Bpeat bugs repaired MacBacon – multi-platform Pigs are smart – combine prior info + new

data Pigs can fly – workshop in Mexico

Age-modelling … your own data?

Try the different software pieces What are best settings for your site? Do you agree with the age estimates? Differences between approaches