Montefarle

Hi I'm having a debate with my fundie classmate over evolution and he keeps bringing up the topic of carbon dating as if it were the only evidence leading toward evolution. Is all carbon dating incorrect or is it only specific types? And if carbon dating is completely ineffecient is there an alternative?

Nat

Carbon dating is an extremely effective method of judging the age of organic materials that are up to 50,000 year old. Beyond that, measurement of with carbon dating is tough due to too little residual carbon-14.

Geologists, who are usually working with material far older than 50,000 year, typically use potassium-argon, uranium-lead, or argon-argon radio-isotope dating methodologies. These are very effective at determining the ages of rocks up to billions of years old.

Neither of these tools, however, provided evidence for the Theory of Evolution - they are simply dating methodologies and are used to determine the approximate age of the Earth (estimated to be about 4.5 billion years old).

Cheers

Nat

Montefarle,

I recommend you go check out the TalkOrigins archives for some detailed papers discussing the evidence for evolution as well as many refutations of the oft used fallacious (and often downright dishonest) arguments of creationists.

<a href="http://www.talkorigins.org" target="_blank">TalkOrigins - click here</a>

Dr.GH

There are also a number of non-decay based methods such as thermo-remnant magnetism, thermo-luminescence, electron spin resonance, fission-track, dendrochronology, lake and glacial varve counting, and amino acid racemization. Each method has it's own data requirements, strenghts and weaknesses. Noteably, these methods cross-correlate very well.

[ October 02, 2002: Message edited by: Dr.GH ]</p>

Neruda

here's an idea: ask him how carbon dating works.

gravitybow

Here are two <a href="http://www.chepd.mq.edu.au/boomerang/teaching.www/java/carbdate.htm" target="_blank">JavaScript Carbon 14 Dating Calculators</a> you may want to try out. You can see that at 50,000 years, there's about a quarter of a percent of the isotope left.

Tim Thompson

Creationists are forever decrying the supposed weaknesses of radiometric dating, but rarely for any good reason. See my own <a href="http://www.tim-thompson.com/radiometric.html" target="_blank">Radiometric Dating Resource List</a>. There is a section on radocarbon dating, and also several give and take responses to creationist critiques of radiometric dating.

One of the more humorous aspects of all this is that creationists so often go after carbon dating, even though it really isn't all that reliable beyond about 50,000 years (although I think one can push to about 80,000 years with the newer techniques). The million & billion year figures come from the longer time frame methods, like the U/Th decay chain (and others).

Also, as someone else already mentioned, there are other methods that aren't strictly radiometric. I did write a short piece on <a href="http://www.tim-thompson.com/luminescence.html" target="_blank">luminescence dating</a>, which shows comparisons with radiometric dating.

ps418

Carbon dating works wonderfully, in most contexts. The best way to demonstrate that it works is by comparing 14C dates to independently-determined ages for the same deposits. For example, check out Figure PE-5 in <a href="http://www.cio.phys.rug.nl/HTML-docs/Verslag/97/PE-04.htm" target="_blank">Kitagawaa and van der Plicht, 2000. 45.000 YEAR VARVE CHRONOLOGY FROM JAPAN</a>, which compares 14C ages and varve count ages from a Japanese lake. The agreement is not perfect, but it is very good.

My article on <a href="http://www.geocities.com/earthhistory/tcn.htm" target="_blank">cosmogenic nuclide dating</a> explains a bit about how this particular method works, and has several examples of comparisons between cosmogenic nuclide dates and 14C and luminescence dates.

Montefarle

Thanks guys you've been really helpful!