Transcript Age-depth modelling workshop

Basic age-modelling
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Find ages for dated and undated depths
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E.g., linear interpolation, regression, spline (gaps)
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Choose which one looks nicest...
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How treat point estimates? (mid/max, multimodal)
Bayesian age-modelling
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Bayesian = combine data with other info
 14C
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dates and depth info
stratigraphical ordering / position
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e.g., wiggle-match dating
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Constraints on e.g. likely accumulation rates
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Other dates, e.g. pollen events, 210Pb (…)
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Outlier analysis
Usually done by millions of simulations
Wiggle-match dating
Outlier analysis
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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
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Extract OxCal directory to C:\Program Files
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Open .../OxCal/Index.html in Firefox
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R_Date( “test”, 2450, 50);
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Save file, run
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Run examples from manual
Bpeat
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Extract Bpeat.zip somewhere
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Open R there (or change dir)
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source(“Bpeat.R”)
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SetCore(“MSB2K”,2)
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TestRun()
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FinalRun( 0.1 ) # just a short run...
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DepthChron()
The future of Bpeat: Bacon
Bacon
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Muscles and fat – robust, yet flexible
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Floppy/crusty – flexibility can be adapted
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Can be cut to your liking – hiatuses
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Cured – Bpeat bugs repaired
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MacBacon – multi-platform
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Pigs are smart – combine prior info + new data
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Pigs can fly – workshop in Mexico
Age-modelling … your own data?
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Try the different software pieces
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What are best settings for your site?
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Do you agree with the age estimates?
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Differences between approaches