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[Monty Fowler]

Since the subject of fire sites on Niku has come up again, is it possible to get a little more detail about what was found at the ones at the 7 Site as far as possible date or origin?

Fire Feature M, for instance, which was excavated in 2001, did have a radiocarbon sample analyzed but the only information in Ameliapedia is that it was "recent." From what I know and understand about radiocarbon dating, it's possible to get it at least a little closer than that, specifically in this case, pre- or post-1955 since it's in the Pacific. What exactly did the analysis report say?

LTM,
Monty Fowler, TIGHAR No. 2189 EC

[Ric Gillespie]

From what I know and understand about radiocarbon dating, it's possible to get it at least a little closer than that, specifically in this case, pre- or post-1955 since it's in the Pacific. What exactly did the analysis report say?

You seem to know more about radiocarbon dating than the University of Waikato Radiocarbon Dating Laboratory.  Their report is attached.

[Monty Fowler]

Interesting report, more for what it doesn't say than what it does.

LTM,
Monty Fowler, TIGHAR No. 2189 EC

[Ric Gillespie]

Interesting report, more for what it doesn't say than what it does.

What do you mean?  Seems pretty clear to me.

[Jennifer Hubbard]

Does this report mean that the sample was approximately 15.3 to 27.2 years old in 2002, or is that not what those numbers mean? Is the 98.5 a confidence or an age?

Otherwise, it just seems to indicate that the sample was within 200 years old?

[Ric Gillespie]

Otherwise, it just seems to indicate that the sample was within 200 years old?

That is correct.

[Martin X. Moleski, SJ]

The difficulties of using carbon dating have been discussed in earlier incarnations of the Forum.


Date:         Sat, 5 Feb 2000 17:44:10 EST
From:         Ken Feder
Subject:      Carbon dating

Radiocarbon dating would not be of any help here for two primary reasons:

1. the error factor is far too great; even with the most precise method available, accelerator mass spectrometry, we're still talking decades and

2. Even if the error factor wasn't an issue, the Niku materials are just way too recent for carbon dating. The half life of radiocarbon (carbon-14) is 5,730 years. 1939 is only 61 years ago (just a little more than 1% of the halflife).

Since radioactive decay is a statistical phenomenon, that's simply not enough time; so little of the c-14 has decayed, an accurate estimate of age based on how much has decayed would be impossible. The major radiocarbon labs tell you that anything less than a couple of hundred years old is simply too young (and anything much over 40,000 or 50,000 years is too old, though dates up to 70,000 are theoretically possible).

Ken Feder

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From Ric

Thanks Ken.  Oh well.  Hey, anybody ever wonder what really happened to Helen of Troy?

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From Randy Jacobson

Carbon dating is not precise down to a year or two, and the technique is not particularly well regarded for times less than 100 years of age.


I found this exchange by using the friendly search tool.  The link to the FST is hidden under a tab at the top of every page in the Forum, labeled "Search."

[Monty Fowler]

I was just curious about the "recent" labeling, that was not one I was familiar with.

So based on that, Fire Feature M could have come from Amelia and Fred the castaways. Or the US Coast Guard LORAN guys. Or the Niku residents when they were clearing that part of the island for coconut planting. Maybe the US Navy survey guys. Or a completely undocumented visit.

Still, it's interesting as part of the totality of that particular part of the island.

LTM,
Monty Fowler, TIGHAR No. 2189 EC

[Ric Gillespie]

I was just curious about the "recent" labeling, that was not one I was familiar with.

There is no "recent" labeling.  The term used is "modern" and it means within the past 200 years.

So based on that, Fire Feature M could have come from Amelia and Fred the castaways. Or the US Coast Guard LORAN guys. Or the Niku residents when they were clearing that part of the island for coconut planting. Maybe the US Navy survey guys. Or a completely undocumented visit.

Obviously.
The same is true of all of the "fire features" at the Seven Site unless the site was inhabited greater than 200 years ago. 
BTW, there are probably not nearly as many "fire features" at the site as we originally mapped.  At the time, we counted every discovery of ash or  piece of charcoal as a separate "fire feature," but it there has been a lot of disturbance to the site over the years and it seems more than likely that ash and charcoal got scattered around.  There are really only a very few places where concentrations of ash, charcoal, burn-damaged fish bones and birds bones confirm the presence of a campfire.

Still, it's interesting as part of the totality of that particular part of the island.

Especially when you have all the information. For example, in one campfire we found two broken bottles, both American and both dating from the pre-war period.  The bottoms of the bottles were melted but the upper portions were not heat-damaged, creating the impression that the bottles had originally stood upright in the fire.  Nearby was a length of wire twisted in such a way as to allow someone to hold a bottle upright.  It certainly looks like someone was boiling water.  The pre-war American bottles could have been beach-combed by anybody but neither the colonists nor the Coasties had any need need to boil water.

[Monty Fowler]

Interesting take on the bottles. Was that Tom King's impression?

LTM,
Monty Fowler, TIGHAR No. 2189 EC

[Ric Gillespie]

Interesting take on the bottles. Was that Tom King's impression?

Yes. It's kind of a no-brainer.

[Monty Fowler]

Professional first impressions count for a lot out in the field. I well remember the Knob That Wasn't episode, although that did make for some interesting historical detective work.

Discounting all the little "bits" of charcoal and whatnot, how many fire features does TIGHAR now think are located at the 7 Site, and are they grouped in any coherent way?

LTM,
Monty Fowler, TIGHAR No. 2189 EC

[Ric Gillespie]

Discounting all the little "bits" of charcoal and whatnot, how many fire features does TIGHAR now think are located at the 7 Site, and are they grouped in any coherent way?

I'm not sure.  I haven't looked at that for some time.  Been busy with other stuff.