Tim Thompson

I have never heard anything about Coelacanths, or any other fossil, being used in any way, shape, manner or form, for verification, or relative or absolute calibration of radiometric dates. I believe the statement that they were so used to be false. I also note that the creationist (who's name or identity I did not see), did not supply any specific examples or references. If he knows the statement to be true, then he must be able to produce a specific example, or a specific reference to a specific textbook. If he cannot do that, then it is just yet another example of yet another creationist, making wild claims that do not meet the respectable criteria of truth.

Radiometric dating, so far as I know, is in all cases based purely on the examination of radioactive samples. They are never "verified" or "calibrated" against any fossil. However, radiometric dating, like anything else, costs money. It is a common practice to use fossils as indicators of the age of a stratum, when that age has already been determined elsewhere, for that same stratum, by direct radiometric measurement. It seems likely that your creationist adversary has misunderstood this technique as a "verification", when in fact it is not.

I once again point interested observers towards my own <a href="http://www.tim-thompson.com/radiometric.html" target="_blank">Radiometric Dating Resource List</a>, which I believe to be the most complete such list online (it has not been updated for about 8 months, so feel free to report bum links & etc., or anything new that you think should be added). There are also several good books on the subject of radiometric dating, notably Dalrymple's The Age of the Earth, or Dickin's Radiogenic Isotope Geology.

tgamble

But if the fossils are found in more than one stratum, how can it be used to estimate the age of the one that it's in? dinosaurs are in the Triasic and Jurrasic (?) so if you found a dinosaur fossil how would you know which stratum it's in?

axe

seeing as I am being quoted or rather misquoted in this forum I thought I should at least reply to some of what is being said. I am not a creationist though I am a Christian who does believe God created everything wether it was through evolutionary means or other.

Point one I never ever in any of my posts said they used Coelacanths to Calibrate dates I said they used them in correlation with Radiometric dating before they found Coelacanths still existed. They believed them to be extinct so when a fossil of one was found they knew it to be at leats a few million years old. Most Archeologits now take that into account from what I have read. ( I am Not a Scientist and never claimed to be one I just love learning new things and don't mind being proven wrong.)
Dr GH did you actually read my posts or do you just like slagging people you don't know? easy targets are best I guess. I guess just because I question other peoples assumptions wether based on fact or not makes me a kook oh well at least I won't fall for just anyones lines. I like facts laid out for me in an understandable manner with clear proof. I haven't seen that yet from either the creationist side or archeological side as when I did the most research on the subjects a few years ago most archeologists did not agree on how certain Fossil layers should be categorized. ( again I am Not one I am just a curious guy.)
I have studied Cultural anthropology and cultural History wich is indirectly involved with Archeology but not on a degree level just as a way of expanding my understanding of people as well as Criminology out of SFU.


My point is that when I hear contradictory evidence even from within the accepted academics I will question everything including subjects brought up by "Creationists". If you want to slag me for wanting evidence I can understand I guess that makes you all intellectually superior so play on.

[ March 07, 2002: Message edited by: axe ]</p>

bluefugue

tgamble's original quote does not consist of your words?

graden1

I'm no expert, but as I understand it, the Triasic and Jurrasic had different types of dinosaurs. There were some species found only in the Triasic, and some found only in the Jurrasic. I don't recall which ones, though.

And I'm confident someone here will straighten this out for me if it's incorrect.

Thanx heaps,

Grady

tgamble

Axe, since I copied and pasted your entire post and gave a link to it, I fail to see where I quoted your out of context.

[ March 07, 2002: Message edited by: tgamble ]</p>

tgamble

See for yourself.

<a href="http://forums.sympatico.ca/WebX?14@31.nB9faZHKhqp^16694@.f038210/81" target="_blank">http://forums.sympatico.ca/WebX?14@31.nB9faZHKhqp^16694@.f038210/81</a>

John Solum

Hey tgamble,

as graden1 said, all dinosaurs aren't the same. There are Triassic dinosaurs like Coelophysis), Jurassic dinosaurs (like Allosaurus and Camarasaurus), and Cretaceous dinosaurs (like T. rex and Tirceratops).

However, not all fossils are equally good indicators of age since there are fossils that occur in rocks from a lot of different periods. In other words, if a particular fossil occurs in Triassic, Jurassic, AND Cretaceous rocks, then it's less useful as an indicator of age (in this example it's only possible to say the rock is Mesozoic in age - it's not possible to specify the period).

rockmom

Actually, coelacanths are not found in the fossil record after the Cretaceus. The species that are currently living do NOT live in areas where fossils form. Therefore they are not in the fossil record and are NOT the same species that are fossilized.

Coelacanths, the genus, are not an index fossil. An index fossil must be easy to recognize, common, geographically wide spread, and occur over a short span of strata. As a genus coelacanths do not meet this criteria, especially on the short span of strata. The genus Coelacanth was around for the entire Mesozoic. If a species of coelacanth is used as an index fossil, the discovery of another currently living species does not negate the value of the fossil species.

Actually, I did not misunderstand. He still misunderstands. He doesn't understand relative dating which is based on stratigraphy and paleontoloty/taphonomy. He does not understand radiometric dating methods.

The geologic time table is based on relative methods. The different periods and eras are based on the appearance and disappearance of index fossils in the strata. This work was started in the 19th century before Darwin.

In the 20th century, radiometric methods became available. Radiometric dating methods use measurements of radioactive isotopes such as uranium and their daughter products to determine a quantitative age for the rock in question. Generally igneous rocks are used for dating purposes.

At the end of the twentieth century, it became possible to use the accumulation of cosmogenic isotopes to date surfaces. This method is especially nifty since it can date surfaces from historic times through the potassium-argon range. Cosmogenic dating gives very good results that cross check with C-14 dates, Ur-Pb dates, and K-Ar dates.

Dr.GH

T.G.

I know Axe just followed you home. But, if he is going to stay I expect you to clean up after him.



ANyway, yeah Axe I read your posts (or tried to). Rarely would I ever mention basic things like grammer and spelling because these are life long weak points of mine as well. However, if I can not follow your writing to the extent that you indicate, then the problem is yours.

What does this mean?:

And this?:

I read it to mean that you still think that fossils are used to determin the quasi-calindrical dates from radiometric studies. They are not so used, they never have been so used, they can not be so used. Was that clear?

Axe, you have indicated that you have a criminology background, and so it is posible that you work in law enforcement. Speaking as a forensic scientist: Do you write your reports as poorly as you write these posts? I mean it. Even a report on a noninjury fender-bender written a poorly as your posts would get you fired (or if you were politically connected: sent to remedial english).

It is possible that you are playing dumb. If so; Knock it off. It is not cute.