radiometric dating fossils

How is the carbon-14 used in radiometric dating in fossils?

I need to know now.

It isn’t very often, at least not directly.

14C is only good back to 50,000 years or so, and only good for things that contain carbon (most fossils don’t)

For a good overview of dating techniques (and incidentally a rebuttal of theological and pseudo-scientific objections to them), by a former Los Alamos physicist, see

Wiens, R.C. (2002). Radiometric Dating - A Christian Perspective,
http://www.asa3.org/ASA/resources/WIENS.html

If ink doesn’t work, cut and paste and join up

http://www.asa3.org/ASA/

resources/WIENS.html

Using M & M’s to Demonstrate Radiometric Dating

dating fossils

What radiometric dating techniques are used to date human fossils?

I am already aware of Carbon-14 Dating. What are the dating techniques available for dating human fossils that are older than 50,000 years?

Actually, radiocarbon dating is accurate out to about 60,000 years, 75,000 for scientists who really push it (they push it because the C-14 margin of error is very small). Archaeologists consider it good enough to be considered an absolute dating technique due to the a fore mentioned reasonably small margin of error.

Still, the earliest known fossils of modern humans are about 200,000 years old. Hominid fossils, representing ancestral human species, are even older. In the cases of the 200,000 old fossils, potassium-argon radiometric dating is used.

Finally, genetic investigations are used to follow the development of our ancestral hominid species, though this genetic data can be very difficult to come by.

Dating the oldest fossils

dating using radioactive decay

How is radioactive decay used to date fossils?

How is radioactive decay used to date fossils?

Thanks! =)

Radiocarbon dating is used for organic remains up to about 50 or 60 thousand year. After that radio-isotope comparison (Potassium-Argon) dating methods are used for fossils by looking at the igneous rocks surrounding the sedimentary rocks in which they are found.

http://en.wikipedia.org/wiki/Radiocarbon_dating

http://www.suite101.com/article.cfm/paleontology/38275

Radioactive Decay Simplified

dating christian perspective

What is your view of online dating websites from a Christian perspective?

Anything else you would like to add?

Personally, I’m just not into that, but I have a few friends who are in successful relationships/marriages who met their significant others online. If you are thinking about joining a dating site, I would suggest something like eHarmony. This site is pretty safe, and it goes into great depths in finding people you are compatible with.

Kevin Ellerbe Sex Dating & Relationships Part 1

radiocarbon dating fossils

How can we be sure of the age of extremely old fossils? Radiocarbon dating is only accurate to 60,000 years?

I asked in this question how scientists knew that Amoebas evolved 2 billion years after the earliest life forms:
http://answers.yahoo.com/question/index;_ylt=Arn1WLXeBYEYtFm7k1NO7VPsy6IX;_ylv=3?qid=20070910134244AAEVHks

Alot of the answers said it was from fossil evidence…

But I have to ask how are these fossils dated? Is it Carbon-14 dating? Because we’re talking about fossils supposedly billions of years old… how do we know this?

http://en.wikipedia.org/wiki/Radiocarbon_dating#Computation_of_ages_and_dates

Well, we are never sure. We just have the best conclusion we can draw from the evidence.

There are other forms of dating that work well beyond the age at which C-14 dating no longer works.

Below is a really good article about radiometeric dating.

I think that some of the evidence about fossil evolution comes from molecular clock data: that is, we use fossils and DNA to tell us how long it takes to accumulate a certain number of DNA changes, and then we figure out how many relavent changes there are between amoebas and other organisms, and we extrapolate how long ago the last common ancestor was.

Evidence of evolution from fossil record

dating methods geology

explain about the methods of dating in geology?

OK, first geography is NOT geology *sigh*

Look up carbon dating; you can either tell by the degradation of carbon or by basic layering (what’s on the bottom is older than what’s on the top).

9 of 12- Young Earth Evidence (Geologic Column)- Billy Crone

dating timelines

The Panic Years by Doree Lewak

dating fossils methods

How accurate is carbon dating? What is the most accurate method of dating fossils, rock etc., or manuscripts.?

the carbon dating method is not used to determine the age of fossils or rocks. Carbon 14 has a relatively short half-life, which makes it useful only to date once-living organisms that are known or suspected to be less than about 40-50 thousand years old. But there are many other isotopes that can be used to date rocks and the fossils found within them, and the process works the same way. Also, the correct isoptope must be used to test the age of the object. Some isotopes have a very, very long half-life, and those isotopes can only be used to test objects that are, of course, very old. Use that same isotope to date a rock that just left the mouth of a volcano two weeks ago, and you will get a false reading. And vice versa.

Isotopic dating methods rely on the constant rate of decay from radioactive isotopes into daughter elements. When scientists test a rock, they draw a conclusion of it’s age.

This conclusion is based upon carefully designed and conducted experiments that compare the ratios in rock samples of parent elements to daughter elements ( some of which would have been from radioactive decay of the parent, some of which may have been present in the sample at the time of formation). Since radioactive decay is known to occur at a constant rate, the age of a rock can be determined from the ratio of the parent element to the daughter element. The concerns about these dating methods were exactly the same that creationists continue to raise - presence of the daughter element at the time the rock was formed and possible loss / gain of either the parent or daughter element at some point in the history of the rock. For this reason, the tests were designed to account for those possibilities.

Initial daughter element can often be accounted for by either measuring the amount of an isotope of the daughter element (the ratio of isotopes are almost always constant). Another possibility is (as in the case of the potassium - argon - K-Ar method) that because the daughter element is gaseous, it would escape from the rock when the rock was molten. Once the rock cooled, the gaseous daughter would be trapped in the rocks crystal structure and could no longer escape. By experimentation, scientists have determined which rocks are suitable for various dating techniques. For K-Ar, for example, igneous rocks are good candidates for testing because they formed directly from molten magma and have a simple history. Metamorphic rocks do not work well because heating events in their history have allowed the escape of Argon (daughter element) and thus will indicate an age too young for the sample. Sedimentary rocks do not work because they are made up of a mixture of deposits of many other types of rocks, each of which would point to a different age. At any rate, scientists have devoted a great deal of effort to determining exactly which dating methods are appropriate for which types of rocks.

The other problem to avoid when dating rocks is the possibility that changes to the rock have caused loss or gain of either the parent or daughter element - this would lead to a false date (too old if parent element were lost, too young if daughter element were lost). I know of two methods that have been designed that can account for this possibility - isochron dating and the uranium-thorium-lead discordia / concordia method (actually three independent age calculations for one sample). Both of these methods have internal checks for the possible loss / gain of elements to the rock.

Creationists want the world to think that geologists just grab a rock and throw any old radiometric test at it and poof - there’s the age of the rock. Reality is far more complex. If you examine the extensive research in the field of geochronology, you will see that one of the most important criteria in dating a sample lies in choosing an appropriate dating method for the sample. From G. Brent Dalrymple (see below):

One of the principal tasks of the geochronologist is to select the type of the material used for a dating analysis. A great deal of effort goes into the sample selection, and the choices are made before the analysis, not on the basis of the results. Mistakes are sometimes made but are usually caught by the various checks employed in the well-designed experiment. That is why you might have various ages for a certain rock, until all the tests are in and all of the checks have been completed.

The most compelling argument for an age of the earth of 4.5 billion years are the large number of independent tests that have been used to confirm this date. These tests have been performed on what are thought to be the earth’s oldest surviving rocks, meteorites, and moon rocks. These tests have consistently given the same ages for each of these objects.
Examples include:

The Earths Oldest Rock’s
Description Technique Age (in billions of years)

Amitsoq gneisses (western Greenland) Rb-Sr isochron 3.70 +- 0.12
Amitsoq gneisses (western Greenland) 207Pb-206Pb isochron 3.80 +- 0.12
Amitsoq gneisses (western Greenland) (zircons) U-Pb discordia 3.65 +- 0.05
Amitsoq gneisses (western Greenland) (zircons) Th-Pb discordia 3.65 +- 0.08
Amitsoq gneisses (western Greenland) (zircons) Lu-Hf isochron 3.55 +- 0.22
Sand River gneisses (South Africa) Rb-Sr isochron 3.79 +- 0.06

These are the oldest of the rocks dated on the earth so far (as of 1997). These are metamorphic rocks and thus have had some of their “history” lost - metamorphosis fully or partially resets the radiometric ages of rocks pointing to younger ages than the true age of the original rock. Older rocks may have been lost due to erosion or have not yet been discovered. Or they could have been destroyed by the subduction from plate tectonics.

For many more examples of the consistancy of dating the same rocks with multiple methods, see Consistent Radiometric Dates by Joe Meert, a Geologist at the University of Florida. Dr. Meert’s examples not only show that multiple radiometric methods come up with consistent dates for samples from the same locations, but that these results are also consistant with the paleomagnetic signature of the rocks, the position where the rocks would be expected to be (due to continental drift) at the time they were formed, and the cooling curves for the rocks. (Cooling curves deal with the fact that the different radiometric isotopes become “frozen” in the rocks at different temperatures. The higher the closure temperature for an isotope, the older the rock will be as dated by that isotope.) All of this consistancy rules out all of the arguments creationists attempt to make against radiometric dating techniques.
http://www.gate.net/~rwms/AgeEarth.html

Scientists also use geological principals to give relative dates to gelogical strata. http://homepage.usask.ca/~mjr347/prog/geoe118/geoe118.039.html, http://www.indiana.edu/~ensiweb/lessons/varves.html

Last but not least, scientists also use the Paleomagnetism studies of the ocean floor, which chronicles many polar shifts during the changing history of the ocean floor, to determine the age of the earth. A similar process happens in rock particles that are laid down as sedimentary rock, although the accruacy of this method of dating is not as accurate. It is still useful, however, in conjunction with other methods.

All of these methods, used independently, give the same approximate age of the earth; 4.56 billion years. They also give correlating dates of rocks when the proper methods of sampling are used.

In the case of fossils, scientists can date the geological strata in which the fossil is found. Determine when the layer of sediment was laid down, and you can know the date of the fossil that was buried in it.

For a detailed explaination of the dating method for manuscripts, visit http://www.skypoint.com/~waltzmn/MSDating.html and http://scriptorium.lib.duke.edu/papyrus/texts/manuscripts.html.

10 of 12- Young Earth Evidence (Geologic Column)-Billy Crone

dating of rocks

How are Index fossils helpful in in dating rocks and in reconstructing the Earth’s geologic history?

Basically what an index fossil is, is an animal that is found in an area and only existed for a certain time period. Because it only existed in a certain time period, you know that if you find this animal in a rock formation that the rocks were formed during that time period (assuming there were no geological disturbances like an earthquake or something).

That Handsome Devil-Dating Tips

dating fossils wiki

How did they date the fossils in the geologic column?

http://en.wikipedia.org/wiki/Charles_Lyell

The fossils had already been arranged in the geologic column by the time Charles Lyell wrote his book (Principles of Geology early 1800s).

Charles Darwin took a copy of his book with him on The Beagle.

They didn’t have our sophisticated dating tools back then.

I think they did it by size. The smallest ones were first. They were 550 million years old. The next size up were next, and so on and so on . . .

but the dinosaurs couldn’t come before humans so they had to adjust their scale for that.

Evolution and the age of Earth

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