RE: [asa] radiometric question

Hi Bernie,

The site, keep in mind, is on the opposite end of the theological spectrum,
which is one reason I thought it might be of interest since it digs a little
deeper into the possible role of the ICR players. They do a fair job of
pointing out why there is error in assuming that K-Ar (1.26 billion year
half-life) would work at all with the Mt. St. Helen's samples, but you'll
have to do better than me to get an accurate view of this. Admittedly, the
test does appear to be a common one for igneous rock tests, which is
obviously important for volcanic sampling.

The NAiG site mentions that the testing lab used by ICR is no longer doing
K-Ar and, apparently, were clear that the tests were only accurate if the
samples were not younger than 2 million years. K-Ar is for dating the
oldest things, not the youngest.

I'm just no qualified to give a fair answer to your question, but others
here can, I'm confident.

Coope

From: asa-owner@lists.calvin.edu [mailto:asa-owner@lists.calvin.edu] On
Behalf Of Dehler, Bernie
Sent: Tuesday, November 04, 2008 2:03 PM
To: asa@calvin.edu
Subject: RE: [asa] radiometric question

Hi Coope- that was an interesting link. I read something in that link that
wasn't clear to me, though. I could see a YEC saying that we weren't there
when many volcanoes erupted, so let's pretend we didn't know when Mt. St.
Helens erupted and see what the radiometric results reveal. Your link said
this:

Without properly referencing
<http://www.noanswersingenesis.org.au/museumintro.htm> Bartelt et al.'s
report,
<http://www.answersingenesis.org/home/area/magazines/docs/v23n3_radio_dating
_rubble.asp> Swenson comments on one of the many criticisms of Austin's
'research':

'One critic said that Dr Austin should not have sent young samples to the
dating laboratory because it potentially puts "large error-bars on the
data." By this reasoning, the method could not be used on any rocks, since,
if we did not see the rocks form, how would we know whether they are young?'

 This is the old YEC 'only eyewitnesses can provide accurate histories'
scam. Obviously, Swenson, like many YECs, fails to realize that scientists
can successfully unravel past events without witnessing them. Forensic
scientists frequently send criminals to prison without eyewitness testimony.
To be exact, the recent hideous actions of the Washington DC area (USA)
sniper(s) illustrate how
<http://www.cbsnews.com/stories/2002/10/21/eveningnews/main526391.shtml>
unreliable eyewitnesses can be and how important forensic science is in
solving crimes and stopping killers.

I don't think the answer was very good. or the analogy of forensic science.
For example, I guess if Mt. St. Helens had erupted 300 years ago- before our
written history, we would get back very wrong old dates, correct? So in
this case, we only know it is incorrect because we actually know when Mt.
St. Helens erupted?

In another post response Dr. Campbell said:

"For example I know exactly what living mollusks would be very likely to
give very old shells and modern bodies or vice versa with 14C. If a land
snail lives on old limestone rocks, it's going to get a significant amount
of the carbonate for the shell from the rock, and it will be old relative to
the body. Mollusks that feed on chemosynthetic bacteria that use old
hydrocarbons as an energy source are going to have old carbon in their
bodies, but form the shell from reasonably modern carbonate in seawater."

If you are trying to date the shells from animals that lived a few hundred
or thousand years ago, how would you know their environment? There's no way
to know what they fed on way back then, correct?

.Bernie

  _____

From: asa-owner@lists.calvin.edu [mailto:asa-owner@lists.calvin.edu] On
Behalf Of George Cooper
Sent: Tuesday, November 04, 2008 10:27 AM
To: asa@calvin.edu
Subject: RE: [asa] radiometric question

Bernie,

You might enjoy this site regarding the K-Ar testing of Mt. St. Helens.

http://www.noanswersingenesis.org.au/mt_st_helens_dacite_kh.htm

Coope

From: asa-owner@lists.calvin.edu [mailto:asa-owner@lists.calvin.edu] On
Behalf Of Dehler, Bernie
Sent: Tuesday, November 04, 2008 11:36 AM
To: asa@calvin.edu
Subject: [asa] radiometric question

I went to talk origins to learn about radiometric dating, and was happy to
see it referred to this ASA article:

"Radiometric Dating - A Christian Perspective"
 <http://www.asa3.org/ASA/resources/Wiens.html>
http://www.asa3.org/ASA/resources/Wiens.html

I have a question. It says:

14. A young-Earth research group reported that they sent a rock erupted in
1980 from Mount Saint Helens volcano to a dating lab and got back a
potassium-argon age of several million years. This shows we should not trust
radiometric dating.

There are indeed ways to "trick" radiometric dating if a single dating
method is improperly used on a sample. Anyone can move the hands on a clock
and get the wrong time. Likewise, people actively looking for incorrect
radiometric dates can in fact get them. Geologists have known for over forty
years that the potassium-argon method cannot be used on rocks only twenty to
thirty years old. Publicizing this incorrect age as a completely new finding
was inappropriate. The reasons are discussed in the Potassium-Argon Dating
section above. Be assured that multiple dating methods used together on
igneous rocks are almost always correct unless the sample is too difficult
to date due to factors such as metamorphism or a large fraction of
xenoliths.

Let me ask a clarifying question. Suppose a YEC takes a rock from Mt. St.
Helen's and asks for a date due to radiometric dating. I assume various
dating methods will be used. will they get the correct recent date? I
didn't see a clear, blunt, answer.

.Bernie

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Received on Tue Nov 4 15:42:54 2008