Another plateau-reversal question

[Ken Lawrence]

Dear Oxcal group,

I am assisting a colleague with modeling the radiocarbon assays from a North American archaeological site.  Like the recent communications regarding the calibration plateaus and reversals, some of the assays fall on an awkward reversal. 

The site is a kill and butchery area repeatedly used at least seven times over the last 3500 years and all of the samples are from individual bison.  The question of interest is if the four samples within the calibration reversal suggest one event or multiple events.  Since these are from a scattered bone bed there is no stratigraphic information. I have attempted several approaches of modeling (e.g., combining and V_Sequence) and I keep getting the sense that I am biasing the results.  Any guidance on what approach might be best?  

    

R_Date("Sample05",565,20);    

R_Date("Sample04",540,30);

R_Date("Sample03",510,15);

R_Date("Sample02",500,15);

 

Thanks in advance for your assistance,

Ken

[MILLARD, ANDREW R.]

 

 

R_Combine shows this set of dates is statistically indistinguishable on the radiocarbon scale: X2-Test: df=3 T=7.8(5% 7.8). Therefore they are also indistinguishable on the calendar timescale irrespective of whether they fall on a plateau or not. They could represent one event between AD 1406 and 1429, or several events spread over the early 14^th and early 15^th centuries.

 

Best wishes 

Andrew 

-- 

Dr. Andrew Millard 

Associate Professor of Archaeology,

Durham University, UK 

Email: A.R.M...@durham.ac.uk  

Personal page: https://www.durham.ac.uk/staff/a-r-millard/ 

Dunbar 1650 MOOC: https://www.futurelearn.com/courses/battle-of-dunbar-1650 

 

 

From: 'Ken Lawrence' via OxCal <ox...@googlegroups.com>
Sent: 15 June 2025 21:32
To: OxCal <ox...@googlegroups.com>
Subject: Another plateau-reversal question

 

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[Ken Lawrence]

Thanks Andrew.  That matches with what I had suspected.  I just wanted some more experienced input.

 

Truly appreciate the assistance.

Ken

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