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Author Topic:   Geology- working up from basic principles.
Dr Adequate
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Posts: 16094
Joined: 07-20-2006
Member Rating: 9.0


Message 76 of 156 (419781)
09-04-2007 6:41 PM
Reply to: Message 72 by Ihategod
09-04-2007 4:55 PM


Re: Law of superposition (revisited)
I never changed my position, I just wasn't getting anywhere arguing in the face of opposition and religious devotion to the LoS. I still really can't imagine how this really applies to geology, all of the time without allowing variation. I don't see how it is a law, I do see how it can be a basic principle.

Well, it's a consequence of propositions such as "gravity is down", and "sediment comes from above", and "solid things don't pass through each other".

Try applying these insights to the histories of these bottles:

Of course, you will have to apply some "uniformitarian assumptions", such as that the laws of nature weren't violated during the formation of the layers.

Geology's really quite easy when you get the hang of it.

The vast majority of geological formations are?

Yet to be mentioned in this thread, young Padawan.

Edited by Dr Adequate, : No reason given.

Edited by Dr Adequate, : No reason given.

Edited by Dr Adequate, : No reason given.


This message is a reply to:
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Ihategod
Member (Idle past 4141 days)
Posts: 235
Joined: 08-15-2007


Message 77 of 156 (419845)
09-05-2007 1:41 AM
Reply to: Message 74 by iceage
09-04-2007 5:50 PM


Re: Law of superposition (revisited)
Thanks for helping out, I mean to extend this to everyone as I don't deem it necessary to respond in kind. I think I am beginning to understand how this works, as I was previously ignorant but due to the participation of you's guys I think we can move on. Much gratitude.
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NosyNed
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Posts: 8842
From: Canada
Joined: 04-04-2003
Member Rating: 6.7


Message 78 of 156 (419848)
09-05-2007 1:58 AM
Reply to: Message 77 by Ihategod
09-05-2007 1:41 AM


In your own words
It is generally a good idea to restate what you think you have grasped in your own words to check that you really have it.

Why don't you do that before moving on?


This message is a reply to:
 Message 77 by Ihategod, posted 09-05-2007 1:41 AM Ihategod has responded

Replies to this message:
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iceage 
Suspended Member (Idle past 4026 days)
Posts: 1024
From: Pacific Northwest
Joined: 09-08-2003


Message 79 of 156 (419849)
09-05-2007 2:07 AM
Reply to: Message 77 by Ihategod
09-05-2007 1:41 AM


Re: Law of superposition (revisited)
Thanks for the courteous response. Graciousness always provides a lesson for all.
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Ihategod
Member (Idle past 4141 days)
Posts: 235
Joined: 08-15-2007


Message 80 of 156 (419859)
09-05-2007 2:38 AM
Reply to: Message 78 by NosyNed
09-05-2007 1:58 AM


Re: In your own words
I understand how the Basics of Steno's principles are relative to geology for the most part. So I think The Matt can move on as I seem to be the only one holding this thread back. Thank you.
This message is a reply to:
 Message 78 by NosyNed, posted 09-05-2007 1:58 AM NosyNed has responded

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NosyNed
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Posts: 8842
From: Canada
Joined: 04-04-2003
Member Rating: 6.7


Message 81 of 156 (419881)
09-05-2007 9:23 AM
Reply to: Message 80 by Ihategod
09-05-2007 2:38 AM


Re: In your own words
I've thought many times that I had something nailed.... until I came to explain it to someone else :eek: .

Getting the basics down rock (intended) solid is important before moving on. They all build on each other.


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bdfoster
Member (Idle past 2990 days)
Posts: 60
From: Riverside, CA
Joined: 05-09-2007


Message 82 of 156 (419932)
09-05-2007 3:26 PM
Reply to: Message 80 by Ihategod
09-05-2007 2:38 AM


Re: In your own words
I'm curious Vashgun, whether you are ok with everething up through faunal succession, or just Steno's principles.
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Ihategod
Member (Idle past 4141 days)
Posts: 235
Joined: 08-15-2007


Message 83 of 156 (420686)
09-09-2007 12:54 AM
Reply to: Message 82 by bdfoster
09-05-2007 3:26 PM


Re: In your own words
Pretend I never interrupted please. I am ok with all of the basic principles thus far stated, and if I get confused, allow me the opportunity to ask you's guys questions. Thanks for being patient.
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The Matt
Member (Idle past 3653 days)
Posts: 99
From: U.K.
Joined: 06-07-2007


Message 84 of 156 (422743)
09-18-2007 5:24 AM


Stratigraphy and radiometric dating.
The principles we've covered so far are basically what were used to determine the order of the rock strata (particularly superposition and faunal succession/biostratigraphy). This wasn't simple or easy and it certainly didn't happen overnight, but with thousands of observations at thousands of localities a picture was built up of the extents of various formations and their relationships to one another.

So how do we test if we got the order correct? Radiometric dating.
Radioactive isotopes are generally unstable and over time decay from their 'parent element' to a more stable form, the 'daughter element'. We can measure the rate at which this decay happens* and work out what is known as the half life. This is the time it takes one half of the parent elements to decay, and it forms an exponential curve. After one half life is over, half of the parent element remains. After two, a quarter, three an eighth, four a sixteenth etc etc. We determine the age by measuring the ratio of parent to daughter elements and see how many half lives of known length this equates to. There are a number of different elements we can use for dating, many with different half lives. Those with shorter half lives are suitable for younger material, and those with longer half lives for older. Misusing them will give erroneous results, for example carbon14 is good up to about 70,000 years. Try to date palaeozoic coal with it and it will give you a younger date. Likewise potassium argon dating is only good on material over 100,000 yrs. Try to date lava that is practically still warm and again you'll get an incorrect result.

We can typically only date igneous material with most of these methods, however carbon dating is for biological material. Some metamorphic material may be dated with some techiques, but this will give the time of metamorphosis, not when the parent rock (rock that was metamorphosed) was formed.

Here is a very good resouce on radiometric dating which deals with a lot of misconceptions about it as well as explaining numerous techniques.

I don't want to dwell on this too much, but the point I'd like to make is that radiometric dating is an independent method that confirms the ordering of rocks as determined by other methods.

For some more evidence that this dating is valid, I'd like to borrow from this excellent thread by Loudmouth.

Loudmouth writes:

The Hawaiian islands and the Emporer seamounts are the direct cause of volcanic activity. It has been theorized that these formations all originated from one mantle plume. This same mantle plume is now responsible for the eruptions at Kilauea. Also, the Pacific plate, on which the seamounts and islands are part of, is moving northwest at about 8-10 cm/year as measured by GPS. So, as the Pacific plate moves over the hotspot, new islands will crop up in a line. The picture below shows the Hawaiian chain and the Emporer chain, with Kilauea being the last island on the right hand side:

Conventional geology, through the theory of tectonics, puts forth the following predictions:

1. The measured age of the seamounts will increase, in a linear fashion, as the distance from Kilauea increases.

(snip)

YEC theories, saying that these seamounts and islands were created within a short geologic time frame, put foth the following predictions:

1. There should be no linear correlation between the distance from Kilauea and the age of the islands or seamounts. This is because YEC's believe that such islands were made quickly, and not over millions of years. Also, they believe that K/Ar dating is not accurate. Therefore, no realtionship should be found between a faulty dating methodology and real life islands.

(snip)

AGE:

The age of the islands was measured using K/Ar dating. Now, if either the plate movement, radioactive decay rates, or the precision of the dating method were not reliable, then we should not see a linear relationship between the measured age of the islands/seamounts and their distance from the hotspot (ie Kilauea). However, there is a linear relationship as seen in this graph:

You can find the actual numbers for the graph here if you want to construct your own graph.

Going with the data, we can see that the Pacific plate moved about 5,000 km over a 65 million year span. If at any time the decay rates changed, then we should not see a linear relationship. Instead, there should be an abrupt change in the age/distance ratio. Also, if there was a great shift in the plate movement, this relationship also should not be linear.


(edited out material not relevant to this thread where (snip) is written)

It seems apparent that radiometric dating has confirmed that we have the order of rocks correct.

*Just to clarify, it's not possible to predict when an individual atom will decay (correct me if I'm wrong here someone), however in their millions they behave predictably. Picture unweighted dice. If I were to roll and told you to guess the outcome, it would be purely by luck if you were correct as its is essentially random, however if I were to roll it a thousand times, you could bet good money that any given number would be rolled approximately one sixth of the time.


Replies to this message:
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bdfoster
Member (Idle past 2990 days)
Posts: 60
From: Riverside, CA
Joined: 05-09-2007


Message 85 of 156 (424286)
09-26-2007 12:57 PM
Reply to: Message 84 by The Matt
09-18-2007 5:24 AM


Re: Stratigraphy and radiometric dating.
I know YECs have problems with radiometric dating. I think their objections are unreasonable. But that's another thread.

It seems apparent that radiometric dating has confirmed that we have the order of rocks correct.

But I think it's the other way around. The order of strata is well established by the stratigraphic principals you already mentioned, and I don't think need any confirmation from radiometric dating. But the consistancy of radiometric dating with stratigraphy is a confirmation of the former.


Brent
This message is a reply to:
 Message 84 by The Matt, posted 09-18-2007 5:24 AM The Matt has not yet responded

  
RAZD
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Posts: 19819
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 10.0


Message 86 of 156 (426443)
10-06-2007 6:40 PM
Reply to: Message 1 by The Matt
07-13-2007 7:50 AM


The first thing I would like to deal with is the law of superposition.

From Message 39

TheWay writes:

I wouldn't argue with you on the founding principles of geology. However, I am currently looking into creationwiki's claim on superposition. Perhaps you could input your opinion on THIS article?

From the article:

quote:
Superposition ignores the general case of sedimentation in moving water and most bodies of water have moving water. In moving water, sediment layers form horizontally. The process of sedimentation in moving water has been demonstrated in laboratory experiment. In these examples, thin layers of sediment built horizontally at a noticeable rate with these layers forming one on top of the other as the edge moved forward. There were other layers beneath them but the two on top were easier to watch. In fact it can be shown that Superposition goes against both experiments and observations in sedimentology.

Geneal case in moving water? I'm betting the "lab experiment" doesn't look anything like the graphic, but seeing as there is no reference to any paper on this "experiment" (or any reference to who performed it or where or when ... ) it is hard to discuss the actual data.

Enjoy.


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This message is a reply to:
 Message 1 by The Matt, posted 07-13-2007 7:50 AM The Matt has not yet responded

Replies to this message:
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JonF
Member
Posts: 4581
Joined: 06-23-2003
Member Rating: 4.5


Message 87 of 156 (426458)
10-06-2007 9:10 PM
Reply to: Message 86 by RAZD
10-06-2007 6:40 PM


I'm betting the "lab experiment" doesn't look anything like the graphic, but seeing as there is no reference to any paper on this "experiment" (or any reference to who performed it or where or when ... ) it is hard to discuss the actual data.

Dollars to doughnuts it's Berthault.

Claim CD240. Note that No Aswers in Genesis has moved; home.austarnet.com.au/stear must be replaced by noanswersingenesis.org.au. E.g. http://noanswersingenesis.org.au/henke_steno.htm.


This message is a reply to:
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jar
Member
Posts: 30936
From: Texas!!
Joined: 04-20-2004


Message 88 of 156 (432961)
11-09-2007 10:43 AM


Bump for Antioch's Fire
Start at Message 1 sir.


Aslan is not a Tame Lion
  
The Matt
Member (Idle past 3653 days)
Posts: 99
From: U.K.
Joined: 06-07-2007


Message 89 of 156 (433002)
11-09-2007 1:55 PM


Apologies for lack of input here- I'm rather snowed under with uni work at the mo but do intend to keep adding things in the future.
  
Kitsune
Member (Idle past 2412 days)
Posts: 788
From: Leicester, UK
Joined: 09-16-2007


Message 90 of 156 (516717)
07-27-2009 5:02 AM
Reply to: Message 8 by The Matt
07-23-2007 12:08 AM


Principle of Original Horizontality -- an exception?
Can anyone tell me if Walther's Law violates this principle? I understand that you "read" sediment deposited in this way from the bottom (oldest) up (youngest) -- but the strata themselves appear to be deposited laterally or even close to vertically. I've been looking at an illustration of this here.

A creationist keeps insisting that this must have "thrown" geologists when they were "inventing" the fossil record. (At the moment he also thinks that dating methods have been deliberately changed in order to reflect a fanciful ordering of fossils so I doubt if I'm going to get far with him, but I'm interested in learning about this sedimentation process.)

The video he cites, which appears to misrepresent Walther's Law, can be seen here (about halfway through -- first is the ol' polystrate-fossils-are-a-problem nonsense):

"Drama in the Rocks" part 1

Any information would be welcome, thanks.

Edited by LindaLou, : added link

Edited by LindaLou, : typo


This message is a reply to:
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Replies to this message:
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