# Uncertainty in tree ring wiggle match

19 views

### Helene

May 4, 2022, 6:37:03 AMMay 4
to OxCal

Dear list members,

I hope you can help me with what is the best way to introduce an uncertainty in the gap of a wiggle match.

I have an object where counting the exact number of rings between the C-14  samples proves very challenging.

How do I best introduce this uncertainty in the code?

Thank you for any help and best wishes,

Helene Svarva

### Christopher Ramsey

May 4, 2022, 6:44:01 AMMay 4
to OxCal group
Helene

There is some information on this at:

https://c14.arch.ox.ac.uk/oxcalhelp/hlp_analysis_oper.html#deposit

I think the best method probably is:

Sequence()
{
Boundary("Start");
Interval(N(10,5));
R_Date("A",2023,20);
Interval(N(10,5));
R_Date("B",1961,20);
Interval(N(10,5));
R_Date("C",1999,20);
Interval(N(10,5));
R_Date("D",1966,20);
Interval(N(10,5));
R_Date("E",1954,20);
Interval(N(10,5));
R_Date("F",1936,20);
Interval(N(10,5));
R_Date("G",1948,20);
Interval(N(10,5));
R_Date("H",1925,20);
Interval(N(10,5));
Boundary("End");
};

The difficulty comes if you have some gaps that are definite and others that are not. Neither this nor V_Sequence will work with zero errors. The error can be set to be 1 year though which works for most things. These methods are more often used for varves etc.

A completely different approach would be to use a P_Sequence with z set to be the cumulative ring count. This might be more suitable for species where ring counts are very variable.

Best wishes

Christopher
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