Carbon 14 dating

[Administrator: This has come from another thread. As a general rule we request that posts are not comprised of a cut and paste from another site. We prefer discussion among the participants here with referencing or shorter quotes from outside sources. Thank you.]

TULPJE

http://www.wels.net/sab/frm-qa.html

 

RADIOCHEMIST

There are several mistakes of fact in the quoted text posted by
Tulpje. I will take the last portion of his post first. The following
is what Tulpje posted:

Sdve-Svderbergh's remarks were not made at a Nobel Symposium as
claimed above. I have studied how this particular quote has "evolved"
on the Internet and in fact have created a web page devoted to it, as
an example of how creationists distort quotations without bothering to
check them out before repeating them. The web page that discusses the
distortion and evolution of this particular quote is at the following
link:

http://www.ntanet.net/quote.html

At the above link, I discuss how the quote went through 3 generations
on Creationist sites with substantial changes in each generation.

Going on to another point in the post, the following quote appears:

The above claim is simply false. Recent research has not raised
serious questions about the assumptions which are the basis of radio-
carbon dating. In fact, it has been known for many years that
calibrations must be done to account for the fact that the amount
of radioactive carbon has not been entirely constant with time. These
calibrations and correction factors have been in place for several
decades and everyone knows it. I note also that the author of this
quote did not give a reference for his claim that "recent research"
has raised doubts on these issues.

The author of the quote mentions a number of other potential problems
which must be taken into account in C-14 dating but these are well
known to workers in the field and are easily dealt with. In other
words the potential problems mentioned are not as formidable as
the author implies. In fact, most of them have been effectively
dealt with and recognized more than 40 years ago.

RADIOCHEMIST

 

JOE MEERT

Three points

(1) No geology professor would make the claim that C-14 dated the earth
to
4.5 Ga. You should take better notes.

(2) Andrew Snelling (of Answers in Genesis) claims that a piece of
'wood' obtained from a Triassic sandstone yielded a C-14 age that was
much too young for it to be a Triassic deposit. In doing so, he claims
to have invalidated the C-14 dating method and the old earth time scale.

Intrigued, I decided to pursue this matter in a bit more detail. I
wrote to the head of Geochron Labs Radiocarbon group (Dr. Cherkinsky)
who responded to my inquiry with the following e-mail:

When Snelling was asked about this he seemed puzzled that an iron
concretion could give a radiocarbon age. This is not at all uncommon
and a cursory look at the literature would have given Snelling something
to think about when he noticed the iron present in the sample. The
first is Snellings description of the 'wood' impregnated with silica and
hematite. Hematite is an iron oxide (rust essentially). Snelling
adamantly maintains that the sample is wood from the Hawkesbury
Formation Indeed, carbonized wood and plant matter is reported from the
Hawkesbury Formation, but Snelling provides no detailed description of
possible subsequent alteration---with the exception of the 'impregnated'
sentence above. However, this alteration is probably the key to the
'dilemma'. It likely explains why Geochron labs identified it as an
iron concretion with structures resembling wood. The replacement of
wood by iron and silica would give it just that appearance. This
alteration immediately calls into question the use of C-14 dating on the
sample. There have been studies on iron concretions and 'dating' of
them. For example Bird et al. (1994, The Carbon Isotope Composition of
Organic matter occluded in iron nodules; Chem Geol, 114) states:

Interestingly, the sample run in that study gave d13C values typical of
organic material (as in the Snelling study) and the iron concretion also
gave radiocarbon dates due to contamination. For example, nodules in
the Bird et al. (1994) study gave d13C= -24 0/00. In this study (from
a different area of Australia), the nodules gave C-14 ages between
7470-1960 14C (before 1950). So, despite Snelling's incredulity about
how one obtains an age from iron concretions, the answer is with some
contamination. Therefore, although Snelling claims that cleaning would
remove all possible contaminants, the paper by Bird et al. (1994) shows
that this is not the case for iron concretions because they do not
remove microbial contamination as clearly demonstrated by the study.

Furthermore, it is this microbial contamination that is responsible for
the 'apparent age' of the sample. Snelling admits (in his article)
that the sample was altered (silica and iron-rich), the radiocarbon lab
manager-- whose specialty is C-14 dating of woody material-- states that
the sample appears to be a concretion and a study that shows quite
clearly how such samples can give 'dates' through contamination. Thus,
Snelling'w work does not refute C-14, but instead shows its use in
dating microbial contamination.

(3)The notion that C-14 dates are routinely (and uncritically) tossed
out
smacks of other accusations made on this board with respect to other
dating
methods. Can you provide real
evidence that C-14 dates are routinely tossed out?