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Author Topic:   Validity of Radiometric Dating
hbgmysite 
Suspended Junior Member (Idle past 1875 days)
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From: NewYork
Joined: 07-20-2015


Message 196 of 207 (763052)
07-20-2015 4:05 AM
Reply to: Message 195 by 46&2
06-21-2015 3:09 AM


Re: Interested
Interesting, really.... I would like to know how one would determine that someone is certainly bankrupt in regards to morality apart from the Christian God?

Edited by hbgmysite, : No reason given.


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Phat
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Posts: 14760
From: Denver,Colorado USA
Joined: 12-30-2003
Member Rating: 1.2


Message 197 of 207 (832745)
05-09-2018 11:11 AM
Reply to: Message 68 by ringo
07-16-2014 1:06 PM


Re: why wiki may be a poor source
ringo writes:

Science depends entirely on disagreement. Scientists try to falsify their own hypotheses - if they don't, somebody else might do it for them and make them look bad.

Well we all disagree a lot around here. Maybe that makes us all scientists~!


Chance as a real force is a myth. It has no basis in reality and no place in scientific inquiry. For science and philosophy to continue to advance in knowledge, chance must be demythologized once and for all. –RC Sproul
"A lie can travel half way around the world while the truth is putting on its shoes." –Mark Twain "
~"If that's not sufficient for you go soak your head."~Faith
Paul was probably SO soaked in prayer nobody else has ever equaled him.~Faith :)

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ringo
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Posts: 18827
From: frozen wasteland
Joined: 03-23-2005
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Message 198 of 207 (832760)
05-09-2018 3:20 PM
Reply to: Message 197 by Phat
05-09-2018 11:11 AM


Re: why wiki may be a poor source
Phat writes:

Well we all disagree a lot around here. Maybe that makes us all scientists~!


No, it isn't the disagreement that makes science. It's trying to figure out which side of the disagreement - if either - is correct.

An honest discussion is more of a peer review than a pep rally. My toughest critics here are the people who agree with me. -- ringo

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Pollux
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Posts: 271
Joined: 11-13-2011


Message 199 of 207 (850873)
04-15-2019 9:51 PM


seamount and volcano chains
The correlation of dates of volcanoes in seamount chains and land based volcanoes with distance travelled from a hot spot is good evidence for the validity of RM dating. The H-E chain is a great example.

YEC can say only the "right"dates get published.

Does anyone here have references for relevant dates from the 60s and early 70s before plate tectonics was accepted? A date which was found after publication to be consistent with distance travelled would be quite telling.


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dwise1
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Member Rating: 5.7


Message 200 of 207 (850875)
04-15-2019 10:23 PM
Reply to: Message 199 by Pollux
04-15-2019 9:51 PM


Re: seamount and volcano chains
YEC can say only the "right"dates get published.

Not quite what you're asking for, but here's something that Glenn R. Morton wrote before his religious melt-down in which he examines John Woodmorappe's (pseudonym of a high school teacher, as I understand it) list of "bad dates" -- https://morton-yec-archive.blogspot.com/...age-of-earth.html. Basically, most of the "bad dates" that Woodmorappe presented ended up being too young, not "too old" as a YEC would want bad dates to be in order to reflect their false beliefs.

Edited by dwise1, : "reflect their false beliefs", not "reflect his false beliefs"


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Dredge
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Posts: 1295
From: Australia
Joined: 09-06-2016


Message 201 of 207 (881750)
08-28-2020 8:28 PM
Reply to: Message 3 by Chiroptera
11-24-2007 10:47 PM


You say:
"The fact is that all the other dating methods do give good collaboration of potassium-argon dating. The other radiometric methods involve very different parent chemical elements, different daughter elements, and different stages of intermediaries. All of these different method usual yield essentially the same ages for the same minerals and individual rocks, and different methods used in different parts of the world yield consistent dates when correlated with such things as index fossils."

I understand the sense of correlating the different dating methods with "index fossils", but how are the index fossils dated?


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dwise1
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Joined: 05-02-2006
Member Rating: 5.7


(1)
Message 202 of 207 (881756)
08-29-2020 12:50 AM
Reply to: Message 201 by Dredge
08-28-2020 8:28 PM


I understand the sense of correlating the different dating methods with "index fossils", but how are the index fossils dated?

By the strata that they are found in. Which are in turn dated by other methods such as igneous intrusion tie points.

The purpose of index fossils is to identify the particular layer you're looking at.


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NosyNed
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Posts: 8951
From: Canada
Joined: 04-04-2003


(4)
Message 203 of 207 (881761)
08-29-2020 9:56 AM
Reply to: Message 201 by Dredge
08-28-2020 8:28 PM


Index fossils
Index fossils aren't a dating method themselves and shouldn't be confused with that. They are just a short cut. So if you see a certain index fossil in a rock you have a pretty good idea of the time period.

It's like if you're a car nut. If you see big fins you can say it's about a 1960 plus or minus a couple of years. It's not definitive but you're going to be right a lot more than wrong.

In fact, if you're a car nut like me you can look at a car and guess it's date and make from things like headlights. The manufacturers followed certain styles and each one has a "look" that stays in the cars for decades. Which picks the make. The some detail picks which half decade you are looking at.

Just like index fossils it isn't a real "test" just makes life easier when you are out in the field. You might guess that a certain standstone should be Cretaceous but seeing a fossil in it that only existed in that era nails it down.

The index fossils are established when it is shown over time that the particular fossil has only ever been found in a reasonably narrow band of time as determined by "real" dating methods.

You also only pick as an index a fossil that is very common for the time period and easily identified.


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JonF
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Posts: 6171
Joined: 06-23-2003


(3)
Message 204 of 207 (881799)
08-30-2020 5:30 PM
Reply to: Message 203 by NosyNed
08-29-2020 9:56 AM


Re: Index fossils
Index fossils aren't a dating method themselves and shouldn't be confused with that.

Yup. They are a correlation method.

The formations in which index fossils are found usually cannot be directly absolutely dated by radiometric methods. But many of them can be closely dated by dating igneous layers above and/or below and/or piercing them. If 47 Mya igneous layer A is just above fossiliferous layer B and 52 Mya igneous layer C is just below B,then B is between 47 and 52 Mya.

Once any such fossiliferous layer has been dated, all layers with the same index fossils correlate and have the same date.

(One requirement for a good index fossil is the organism didn't exist for very long in geologic terms.)

Index Fossils

Edited by JonF, : No reason given.


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dwise1
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Posts: 4366
Joined: 05-02-2006
Member Rating: 5.7


(1)
Message 205 of 207 (881800)
08-30-2020 7:44 PM
Reply to: Message 204 by JonF
08-30-2020 5:30 PM


Re: Index fossils
(One requirement for a good index fossil is the organism didn't exist for very long in geologic terms.)

Index Fossils

To quote directly from that link you provided:

quote:
Keyed to the relative time scale are examples of index fossils, the forms of life which existed during limited periods of geologic time and thus are used as guides to the age of the rocks in which they are preserved.

The Wikipedia article, List of index fossils, used that same source and expanded on it:

quote:
Index fossils (also known as guide fossils or indicator fossils) are fossils used to define and identify geologic periods (or faunal stages). Index fossils must have a short vertical range, wide geographic distribution and rapid evolutionary trends. Another term, Zone fossil is used when the fossil have all the characters stated above except wide geographical distribution, they are limited to a zone and can't be used for correlations of strata.

Since limestone consists in part of the skeletal remains of marine organisms, I've assumed that they can at least serve to identify different limestones. But I haven't found any reference to that.


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Dredge
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Posts: 1295
From: Australia
Joined: 09-06-2016


Message 206 of 207 (881803)
08-30-2020 10:42 PM
Reply to: Message 204 by JonF
08-30-2020 5:30 PM


Re: Index fossils
I get the impression relative ages of strata are generally more relevant and useful to geologists than absolute ages.

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Pollux
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Posts: 271
Joined: 11-13-2011


(2)
Message 207 of 207 (881805)
08-31-2020 8:12 AM
Reply to: Message 206 by Dredge
08-30-2020 10:42 PM


Re: Index fossils
I think geologists are often very interested in getting accurate dates. One reads often a statement about high precision dating methods being used to refine the dating of events.
For instance careful work has been done to refine the order of the eruption of the Deccan Traps compared to the Chicxulub meteorite and the End-Cretaceous extinction. Also similarly to see the exact relation between the Siberian Traps eruptions and the End-Permian extinction.

A great amount was known about the order of fossils before RMD was available. Now they have been dated, knowing the fossil can give you the date without needing a RMD test.

An example of index fossils is the use of a succession of about 40 different ammonites to delineate time zones for about 40,000,000 years of the first half of the Cretaceous.


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