how old are rocks?

[RobdoR]

How do we know how old rocks are? Radio active materials right? You measure their decay.

Let's say a rock is 100 million years old. What does that mean? Does it mean that the rock flew out of a volcano 100 million years ago? If so, why was the radioactive material not decaying before then?

Please let me know if you have the answer. Because this is one of my main pillars of doubt keeping me from embracing evolution as a world view.

 

[SpaceYeti]

Radiometric dating. Compare the produced element to the radioactive element that produces it, compare the amount there is to the half-life of the radioactive product. Some products are, themselves, radioactive, so take that into account and look for those products and check the second element's half-life against that as well. This measures how long ago the rock was formed, in whatever manner it was formed (volcanic or otherwise, though I was under the impression volcanic rock did not contain radioactive material.

This all has nothing to do with evolution. Evolution is biology, this subject is geography, and rocks are not alive.

 

[Jennywocky]

I guess the OP was trying to say that he doesn't accept evolution yet because he's not convinced the world is that old and/or that he needs to have the dating system validated to him first.

 

[Jesse]

I think you were meant to say carbon dating as that which is applicable only to matter which was once living.

What use of discovering the age of rocks? Except to say they are more that 6000 years old. (Sarcasm)

 

[ProxyAmenRa]

There is a rough ratio of carbon 14 to carbon 12 in the atmosphere. As an organism engages in metabolic activity it ingests or absorbs carbon 14. When it dies it no longer ingests or absorbs carbon 14. The half life of carbon 14 is 5730 years. Using a mass spectrometer we can estimate the mass of carbon 14 in an object. The following equation can be used to determine the age of a fossil.

M=Aexp(-(1.209*10^(-4))*t)

M = amount at time t.
A = initial amount.

When t = 0, M=A
When t = 5720, M=(1/2)A

This is the general drift of estimating an age of an object by radioactive decay.

 

[Architect]

Its more than just half-life too, you also look for the presence of decay products. Uranium for example is a big atom that decays into daughters, ending up in lead. The quantities of said daughter material tell you how far along it is.

I'm unclear why this is your holdup to believe or not believe in evolution. If you want to believe in god you can as well suppose that he created the earth with partially decayed products in its crust. Why? Just to fool us I suppose.

Evolution is something else, we can see it in the laboratory for Pete's sake!

 

[Jennywocky]

Evolution is something else, we can see it in the laboratory for Pete's sake!

Well, more like a natural selection mechanism that works, at least...

 

[Latro]

C14 dating is NOT a useful method on geological time scales. The masses of C14 become too small, and the possibility of ionizing radiation influencing the data becomes too large. We have much better tools, such as potassium-argon dating, to handle things on geological time scales.

 

[Bird]

How do we know how old rocks are? Radio active materials right? You measure their decay.

Let's say a rock is 100 million years old. What does that mean? Does it mean that the rock flew out of a volcano 100 million years ago? If so, why was the radioactive material not decaying before then?

Please let me know if you have the answer. Because this is one of my main pillars of doubt keeping me from embracing evolution as a world view.

I really like rocks.


You should look into geology and chemistry to
answer your question.


In your op you're forgetting some important key
details such as the effects on certain "matters"
when heat is introduced. Likewise, a rock that
we see now that is billions of years old has been
decaying since day one of its existence, just because
it hasn't weathered completely away does not
mean that it has not underdone changes. A rock
must also be victim to the elements in order to
properly decay.

There are a lot of variables that should be considered,
I think.

 

[Artsu Tharaz]

You count how many rings they have.

I could be thinking of something else.

 

[SpaceYeti]

Well, more like a natural selection mechanism that works, at least...

Nope, full on evolution. Organisms with fast life cycles have reproduced into different groups which either would not or coul not reproduce, making them different species.

 

[SpaceYeti]

I guess the OP was trying to say that he doesn't accept evolution yet because he's not convinced the world is that old and/or that he needs to have the dating system validated to him first.

If the world is significantly younger than is generally acknowledged, that just means evolution happened faster than we think. The evidence for evolution is astounding (endiginous retroviruses, yo). the age of the Earth just let's us know a maximum amount of time in which it happened.

 

[gcomeau]

How do we know how old rocks are?

Like this:

http://duelingdogma.blogspot.com/2010/05/proving-evolution-post-1-dating-methods.html

(Writing those posts up has saved me so much time and effort over the years since...)

 

[ProxyAmenRa]

Like this:

http://duelingdogma.blogspot.com/2010/05/proving-evolution-post-1-dating-methods.html

(Writing those posts up has saved me so much time and effort over the years since...)

Thank you. I was wondering about how they calibrated the models.

 

[Da Blob]

There is a rough ratio of carbon 14 to carbon 12 in the atmosphere. As an organism engages in metabolic activity it ingests or absorbs carbon 14. When it dies it no longer ingests or absorbs carbon 14. The half life of carbon 14 is 5730 years. Using a mass spectrometer we can estimate the mass of carbon 14 in an object. The following equation can be used to determine the age of a fossil.

M=Aexp(-(1.209*10^(-4))*t)

M = amount at time t.
A = initial amount.

When t = 0, M=A
When t = 5720, M=(1/2)A

This is the general drift of estimating an age of an object by radioactive decay.

Yes but Carbon dating is based upon the rather ridiculous assumptions that there has Never been any variations in the amount of carbon in the atmosphere (such as that caused by smoke) and that there has Never been any variation in the ratio of Carbon 14 to Carbon 12 (such as what could be caused by a distant supernova's effluent temporarily increasing the amount of carbon 14)

The age of rocks is determined by velocity, because time is relative to velocity. The age of anything is determined by relative velocity, so if One was traveling fast enough (say twice the speed of light), all rocks could be seen as existing for just a short "Time" - say two or three weeks at our velocity...

 

[gcomeau]

Yes but Carbon dating is based upon the rather ridiculous assumptions that there has Never been any variations in the amount of carbon in the atmosphere

Wow, ALL those scientists who spent the last several decades doing exhaustive research on this sure are stupid never to have thought of something that obvious, don't you think? They should really just come to you and ask you to consult on this stuff so they get it right.


Oh wait, your statement is completely false and no such assumption is made. See my earlier link. Don't get your physics education from creationist websites.

The age of rocks is determined by velocity, because time is relative to velocity....

Which only has statistically significant effects at relativistic velocities, which no rocks on earth we're measuring the age of are travelling at.

...so if One was traveling fast enough (say twice the speed of light)...

Argh...

 

[ProxyAmenRa]

Yes but Carbon dating is based upon the rather ridiculous assumptions that there has Never been any variations in the amount of carbon in the atmosphere (such as that caused by smoke) and that there has Never been any variation in the ratio of Carbon 14 to Carbon 12 (such as what could be caused by a distant supernova's effluent temporarily increasing the amount of carbon 14

Ohh the wonderful world of calibration.

The age of rocks is determined by velocity, because time is relative to velocity. The age of anything is determined by relative velocity, so if One was traveling fast enough (say twice the speed of light), all rocks could be seen as existing for just a short "Time" - say two or three weeks at our velocity...

We should adjust our clocks to take into account relativity.

 

[Da Blob]

Wow, ALL those scientists who spent the last several decades doing exhaustive research on this sure are stupid never to have thought of something that obvious, don't you think? They should really just come to you and ask you to consult on this stuff so they get it right.
if I am incorrect about these assumptions, please prove it. I have been known to make mistakes and I will apologize for error

Oh wait, your statement is completely false and no such assumption is made. See my earlier link. Don't get your physics education from creationist websites.

Completely false? provide references please...

Which only has statistically significant effects at relativistic velocities, which no rocks on earth we're measuring the age of are travelling at.

Depends on the relative velocity of the Observer - doesn't it...

Argh...

As an aside (not meant to derail) There is an issue of determining exactly when homo sapiens appeared on this planet. There are some that believe that the first tool that separated man from beast was the manipulation of fire. It is a possibility that date could be determined by carbon dating. That is to say man as opposed to beast lived a smoky carbon-filled atmosphere caused by being around the The Fire a lot. There could be a gap in the fossil record that reflects this transition, for there should be a lot more carbon 14 in those remains of early man than in the media they are found in...

Interesting as well, is that the Bible was written for an audience whose understanding of physics was basically the states of matter: solid, liquid, gas and fire/energy. Fire was the only known source of Light, so the first part of Genesis could read "God separated the Fire from the Darkness and called it Good"...

The first man may have done likewise...


EDIT: there really is no explanation for this established fact

Most man-made chemicals are made of fossil fuels, such as petroleum or coal, in which the carbon-14 should have long since decayed. However, such deposits often contain trace amounts of carbon-14 (varying significantly, but ranging from 1% the ratio found in living organisms to amounts comparable to an apparent age of 40,000 years for oils with the highest levels of carbon-14)

 

[Bird]

We should adjust our clocks to take into account relativity.

YES.

 

[gcomeau]

Wow, ALL those scientists who spent the last several decades doing exhaustive research on this sure are stupid never to have thought of something that obvious, don't you think? They should really just come to you and ask you to consult on this stuff so they get it right.

if I am incorrect about these assumptions, please prove it. I have been known to make mistakes and I will apologize for error

Oh wait, your statement is completely false and no such assumption is made. See my earlier link. Don't get your physics education from creationist websites.

Completely false? provide references please...

See where I said "see my earlier link"? Try that.

Or, if you prefer a visual, try this:

http://en.wikipedia.org/wiki/File:Radiocarbon_dating_calibration.svg

That's a C14 calibration scale. See all the little jumps and spikes along that red line? That's the corrections being applied for variations in past concentrations of atmospheric carbon. Which is a really weird thing for them to be doing if they're assuming there aren't any variations, isn't it?

Which only has statistically significant effects at relativistic velocities, which no rocks on earth we're measuring the age of are travelling at.

Depends on the relative velocity of the Observer - doesn't it...

You do realize we're measuring the ages of rocks on earth right? Which you, the obsevrer, are also standing on and thus moving at the same velocity as?

EDIT: there really is no explanation for this established fact

Read this:

http://www.talkorigins.org/faqs/c14.html

 

[Mello]

HELLA OLD

 

[SpaceYeti]

Yes but Carbon dating is based upon the rather ridiculous assumptions that there has Never been any variations in the amount of carbon in the atmosphere (such as that caused by smoke) and that there has Never been any variation in the ratio of Carbon 14 to Carbon 12 (such as what could be caused by a distant supernova's effluent temporarily increasing the amount of carbon 14)

The age of rocks is determined by velocity, because time is relative to velocity. The age of anything is determined by relative velocity, so if One was traveling fast enough (say twice the speed of light), all rocks could be seen as existing for just a short "Time" - say two or three weeks at our velocity...

Actually, something traveling twice the speed of light would be traveling backwards in time (relative to us) at the same rate we're going forward in time. Unfortunately, that's not possible.

 

[EyeSeeCold]

I think it's rude to ask them this question.

 

[Melllvar]

would be traveling backwards in time (relative to us) at the same rate we're going forward in time.

You mean like conservatives?

 

[EyeSeeCold]

lmao

 

[SpaceYeti]

... Huh? Who are you talking to, about what?

 

[RobdoR]

Ok, I still don't have a satisfying answer so let me clarify.

When a rock is formed am I to assume that it has a certain ratio of un-decayed material, say Rubidium-87?

Here's a quote from the dueling dogma article:

Rubidium-87 decays into Strontium-87. When magma first cools into an igneous rock formation all parts of the rock will have the same ratio of strontium-87/strontium-86 because the isotopes are freely dispersing through the molten rock prior to that time.

This assumption seems reasonable, but I've never seen that assumption explained. Does all lava have known ratios? Has that ratio been constant over the life of the earth? These are my questions. If anyone has links, I would greatly appreciate it. Thanks.




The reason I mentioned evolution earlier is that the age of fossils are determined by their rocks, so the timeline of evolution is dependent on knowing when the rocks were formed.

And when I talk about evolution I'm using it in the sweeping world view sense. Evolution is not just natural selection. Evolution is the mainstream theory of natural history, an explanation of our existence.

 

[gcomeau]

Ok, I still don't have a satisfying answer so let me clarify.

When a rock is formed am I to assume that it has a certain ratio of un-decayed material, say Rubidium-87?

Here's a quote from the dueling dogma article:


This assumption seems reasonable, but I've never seen that assumption explained.

It's not an assumption, it's experimentally determined. And if you haven't seen it explained then I'm guessing when you got to this part of that post:

For further info on the various radiometric dating methods, and since (I believe) all the other participants in this discussion are Christians, I would highly recommend this page:

Radiometric Dating

You didn't click on the link since it answers your question in detail. I'll link it directly here:

http://www.asa3.org/ASA/resources/Wiens.html#page 6

Click on that, go down to the section on Rubidium Strontium dating, and you'll find lots of explanation that addresses your question.

 

[RobdoR]

you're right, my laziness won out. Thanks for the spoon feed

 

[SpaceYeti]

Rubidium-87 decays into Strontium-87. When magma first cools into an igneous rock formation all parts of the rock will have the same ratio of strontium-87/strontium-86 because the isotopes are freely dispersing through the molten rock prior to that time.

This assumption seems reasonable, but I've never seen that assumption explained. Does all lava have known ratios? Has that ratio been constant over the life of the earth? These are my questions. If anyone has links, I would greatly appreciate it. Thanks.

What would cause a newly formed rock to have an unequal disbursement of the elements which compose it?

The reason I mentioned evolution earlier is that the age of fossils are determined by their rocks, so the timeline of evolution is dependent on knowing when the rocks were formed.

There's two manners of dating, though. One of them is relativistic dating. The higher layers tend to be newer, the lower older. Using the fossils in them we can determine a progression of like fossils and use their similarity and relative age to determine progression still. If radiometric dating is consistently wrong, actual physical similarities in the fossils and older layers being lower would still happen, and could still determine relative age, even if we couldn't place a number of years on each layer/fossil. However, radiometric dating, of several different elements from each sampled rock, being tested in different experiments, remains notably consistent, so I don't know why we'd blow it off like that.

And when I talk about evolution I'm using it in the sweeping world view sense. Evolution is not just natural selection. Evolution is the mainstream theory of natural history, an explanation of our existence.

Evolution is not a world-view. It is the mainstream theory of natural history, sure. It makes to much sense to ignore, so that's understandable. It's also the manner in which humans appeared. It's either a general word for when something changes over time, or capitalized and this specific scientific theory.

 

[Da Blob]

See where I said "see my earlier link"? Try that.

Or, if you prefer a visual, try this:

http://en.wikipedia.org/wiki/File:Radiocarbon_dating_calibration.svg

That's a C14 calibration scale. See all the little jumps and spikes along that red line? That's the corrections being applied for variations in past concentrations of atmospheric carbon. Which is a really weird thing for them to be doing if they're assuming there aren't any variations, isn't it?




You do realize we're measuring the ages of rocks on earth right? Which you, the obsevrer, are also standing on and thus moving at the same velocity as?



Read this:

http://www.talkorigins.org/faqs/c14.html

Agreed! My information was outdated based on earlier work, although I still question the methodology of the calibration, how have they determined which carbon 14 variations were caused by production of carbon 14 in the atmosphere and which molecules were formed by radioactive decay or whatever, after an organism had died? I mean if one is using atmospheric carbon 14 as the basis for dating organic remains, how does a researcher tell the difference between carbon 14 molecules produced at different times by different sources and that produced in the atmosphere?

Also agreed! however, no one was alive at the time these rocks were formed and there is no objective means to determine the relative velocity of the Earth "billions of years ago". Of course the issue is that time and age are relative to an observation of such. There really is no single answer to "how much time has passed since such and such cosmic event happened" It really depends on whose time are we talking about...

 

[Anthile]

Agreed! My information was outdated based on earlier work, although I still question the methodology of the calibration, how have they determined which carbon 14 variations were caused by production of carbon 14 in the atmosphere and which molecules were formed by radioactive decay or whatever, after an organism had died? I mean if one is using atmospheric carbon 14 as the basis for dating organic remains, how does a researcher tell the difference between carbon 14 molecules produced at different times by different sources and that produced in the atmosphere?

Also agreed! however, no one was alive at the time these rocks were formed and there is no objective means to determine the relative velocity of the Earth "billions of years ago". Of course the issue is that time and age are relative to an observation of such. There really is no single answer to "how much time has passed since such and such cosmic event happened" It really depends on whose time are we talking about...

Why do you even bother with these threads? We all already know that no evidence, no matter how waterproof, will convince you otherwise. Da Blob will only accept answers and facts approved by Da Blob or people who agree with you.
This thread is about a rather simple, factual question and you chose to answer with a philosophical statement, which doesn't seem to mean anything. I judge the concluding ellipsis as a sign that not even you knew how to get out of that statement or maybe you simply got bored with your own inanity. We also know that you're not even remotely interested in a fair and balanced discussion regarding any topic that can be linked to science. It probably means that all time measurement is pointless and how awful atheists are. Grrr atheists. Yay theists.
Or something like that. I don't really care. It's kind of funny, because regarding your postings I couldn't care less but I have reached the point at which I have to put effort into expressing that fact with longwinded postings. Economists call that the 'rebound effect'. I don't think you care and neither do I.

 

[Da Blob]

Actually, I am beginning to wonder why i bother. I just get so tired of folks stating mere theories as if they were established fact. For example, the 'fact' that Carbon 14 was a constant was paraded for decades. However, it turns out that Carbon 14 is not a constant and there have been some recent efforts to 'calibrate' the variations which is, of course, impossible, as the variations had multiple, now unobservable, causes.

There is no science of the Past! How many times have I stated that fact? One can not experiment with the Past to prove hypothesis or theory.

Yet fools and egotists disregard this aspect of reality and treat their own speculations and articles of faith as if they were facts that were verifiable and had both internal and external validity...

Time is not defined, it is a mystery...

 

[Cogwulf]

Actually, I am beginning to wonder why i bother. I just get so tired of folks stating mere theories as if they were established fact. For example, the 'fact' that Carbon 14 was a constant was paraded for decades. However, it turns out that Carbon 14 is not a constant and there have been some recent efforts to 'calibrate' the variations which is, of course, impossible, as the variations had multiple, now unobservable, causes.

There is no science of the Past! How many times have I stated that fact? One can not experiment with the Past to prove hypothesis or theory.

Yet fools and egotists disregard this aspect of reality and treat their own speculations and articles of faith as if they were facts that were verifiable and had both internal and external validity...

Time is not defined, it is a mystery...

Scientists acknowledge it has limitations and can be inaccurate. But it is better than nothing. We don't say "we have a test that is accurate most of the time, but we just won't bother using it at all because there's a 5% chance it is wrong."
Furthermore, the fact that coal appears to be 40,000 years old is one of the reasons why it's believed that carbon dating is less accurate after about 20,000 years.


To scientists, being wrong can be important as being right. It seems to me that you think scientists are stating all of these things as facts, they don't. Scientific papers are full of questions, a good paper should have more questions than answers. Scientists are no longer trying to prove carbon dating right, they are looking for ways in which it is wrong.
And science isn't one Thing. It is lots of people doing lots of very different things. Science is science when we can cross reference findings and data made by different people doing different things in different places.

 

[gcomeau]

Actually, I am beginning to wonder why i bother. I just get so tired of folks stating mere theories as if they were established fact. For example, the 'fact' that Carbon 14 was a constant was paraded for decades.

You have to be kidding me. You complain about people presenting "mere theories" as facts while you run around spouting flat out falsehoods as facts. As you have been doing this entire discussion for example.

C14 dating was invented in 1949... wasn't published until 1952.

THIS is an image from a 1952 radiocarbon dating paper:

Now that's a validation curve... not a proper calibration curve, they didn't have enough data points to calibrate at high resolution properly back then and it obviously took a great deal of work to collect that data but they were not at any point "assuming" constancy of past concentrations of C14. They initially based that on an understanfing of the physics of how C14 is generated and then they checked it IMMEDIATELY and CONFIRMED it was close enough to constant to give decent estimates then went to work refining the numbers to improve that accuracy.

You know who was "parading for decades" that scientists just baselessly assumed atmospheric C14 concentrations were constant in the past... even though that was obviously untrue... and even though they were repeatedly informed this was untrue?

Creationists.

They peddled that crap year after year after year and they STILL do it to try and discredit evolution because they don't have any ability to deal with the reality.

However, it turns out that Carbon 14 is not a constant and there have been some recent efforts to 'calibrate' the variations which is, of course, impossible, as the variations had multiple, now unobservable, causes.

Oh for the love of whatever you consider holy... you JUST SAW the damn calibration curve. How do you think they generated it if you're now claiming it was impossible to do, drawing values out of a hat? Gave 1000 monkeys 1000 pens and waited for one of them to draw something that kinds looked nice?

You didn't read the information you were linked to at all did you? You didn't even make the attempt. You clearly prefer ignorance to knowledge if that knowledge contradicts what you want to believe.

There is no science of the Past! How many times have I stated that fact?

And here we go again, stating falsehoods as facts while getting outraged about people supposedly (bot not in reality) stating theories as facts.

 

[gcomeau]

Scientists acknowledge it has limitations and can be inaccurate. But it is better than nothing. We don't say "we have a test that is accurate most of the time, but we just won't bother using it at all because there's a 5% chance it is wrong."
Furthermore, the fact that coal appears to be 40,000 years old is one of the reasons why it's believed that carbon dating is less accurate after about 20,000 years.

No...

The fact that coal *sometimes* appears 40,000 years old is because *sometimes* that coal is mined from regions with higher concentrations of radioactive materials in the surrounding rocks which cause excess C14 to be generated in thecoal deposits.

http://www.talkorigins.org/faqs/c14.html

(The important part if you don;t ant to read the whole thing)

"So, the physicists want to find fossil fuels that have very little 14C. In the course of this work, they've discovered that fossil fuels vary widely in 14C content. Some have no detectable 14C; some have quite a lot of 14C. Apparently it correlates best with the content of the natural radioactivity of the rocks surrounding the fossil fuels, particularly the neutron- and alpha-particle-emitting isotopes of the uranium-thorium series. "

The reason C14 dating *used* to be considered innacurate over 20,000 years is because after that period of time the C14 has decayed to low enough levels that using older equipment it was hard to measure it accurately... and we didn't have a decent calibration scale that stretched that far back in time. Both of those situations no longer apply, C14 is currently considered accurate back to near 50,000 years.

 

[Cogwulf]

No...

The fact that coal *sometimes* appears 40,000 years old is because *sometimes* that coal is mined from regions with higher concentrations of radioactive materials in the surrounding rocks which cause excess C14 to be generated in thecoal deposits.

I just mean that for older samples, the levels of C14 are low enough to be affected by interference.

 

[gcomeau]

I just mean that for older samples, the levels of C14 are low enough to be affected by interference.

Fair enough...

 

[SpaceYeti]

In these cases, you might note that the coal's age is under-dated.