Faithfree, a question.

[Gawdzilla Sama]

Would the composition of limestone be noticeably different if it were laid down in a few weeks instead of over a very long time?

[Tyrannical]

Sediment layers would look different if done over a short period versus a long period. There are probably real world examples of fast versus slow sediment deposit layers.

I'm not thinking that would convince too many creationists anyways.

[Faithfree]

Would the composition of limestone be noticeably different if it were laid down in a few weeks instead of over a very long time?

Maybe not chemically different, but the way limestone is deposited can leave clear evidence in it's internal structures and microstructures, as Tyrannical suggests. A good example is provided by some ancient reef deposits I have worked on. The reef core is composed of lots of organisms and other limestone particles that grow or accrete upward on layers below in an orderly way that must take a long time to form (you can calibrate that by looking at modern reefs). But around the steep reef margins there are beds of limestone that formed very rapidly ('geologically instantaneous') due to collapse of the reef edge or when big storms wash large volumes of fine lime sediment off the reef into the depths. The resulting layers are all limestone but quite different to the expert.

[Gawdzilla Sama]

Would the composition of limestone be noticeably different if it were laid down in a few weeks instead of over a very long time?

Maybe not chemically different, but the way limestone is deposited can leave clear evidence in it's internal structures and microstructures, as Tyrannical suggests. A good example is provided by some ancient reef deposits I have worked on. The reef core is composed of lots of organisms and other limestone particles that grow or accrete upward on layers below in an orderly way that must take a long time to form (you can calibrate that by looking at modern reefs). But around the steep reef margins there are beds of limestone that formed very rapidly ('geologically instantaneous') due to collapse of the reef edge or when big storms wash large volumes of fine lime sediment off the reef into the depths. The resulting layers are all limestone but quite different to the expert.

So it would be fairly easy for a geologist to determine if the limestone was laid down by a rapid sedimentation (ie, a flood)? Gotcha. And, of course, we have fossil sea critters in the trillions, and the endless generations didn't go through their life cycles in a few weeks.

[Faithfree]

Would the composition of limestone be noticeably different if it were laid down in a few weeks instead of over a very long time?

Maybe not chemically different, but the way limestone is deposited can leave clear evidence in it's internal structures and microstructures, as Tyrannical suggests. A good example is provided by some ancient reef deposits I have worked on. The reef core is composed of lots of organisms and other limestone particles that grow or accrete upward on layers below in an orderly way that must take a long time to form (you can calibrate that by looking at modern reefs). But around the steep reef margins there are beds of limestone that formed very rapidly ('geologically instantaneous') due to collapse of the reef edge or when big storms wash large volumes of fine lime sediment off the reef into the depths. The resulting layers are all limestone but quite different to the expert.

So it would be fairly easy for a geologist to determine if the limestone was laid down by a rapid sedimentation (ie, a flood)? Gotcha. And, of course, we have fossil sea critters in the trillions, and the endless generations didn't go through their life cycles in a few weeks.

Yep that's it. Unless the limestone has been totally recrystallized (which can destroy its original structure), in most cases there should be evidence of how it was deposited. Most limestone weren't deposited rapidly. Even where rapid deposition can be demonstrated, it is usually the case that individual rapidly deposited beds are separated by other beds that formed slowly (i.e. overall slow rate of accumulation). We see this happening today, and we can see it in the rock record.

[Gawdzilla Sama]

Are the rapid deposits limited in area or can they cover large areas?

[Thinking Aloud]

It's worth adding that most limestone isn't "sediment" in the sense of stuff washed out to sea, it's dead stuff. However it forms, you have to take into account the length of time it would have taken the living stuff to form in the first place.

(Can I just add "ooliths" because it's such a nice word?)

[Gawdzilla Sama]

It's worth adding that most limestone isn't "sediment" in the sense of stuff washed out to sea, it's dead stuff. However it forms, you have to take into account the length of time it would have taken the living stuff to form in the first place.

(Can I just add "ooliths" because it's such a nice word?)

Yeah, the skeletons of trillions of tiny sea creatures would take trillions of tiny sea creatures living out their lives and dying.

On the other hand, when I used this against a creationist they just said "Well, you know time passed faster during the flood, right?)

[Mysturji]

It's worth adding that most limestone isn't "sediment" in the sense of stuff washed out to sea, it's dead stuff. However it forms, you have to take into account the length of time it would have taken the living stuff to form in the first place.

(Can I just add "ooliths" because it's such a nice word?)

Yeah, the skeletons of trillions of tiny sea creatures would take trillions of tiny sea creatures living out their lives and dying.

On the other hand, when I used this against a creationist they just said "Well, you know time passed faster during the flood, right?)

E=MCfuckoff

[Gawdzilla Sama]

It's worth adding that most limestone isn't "sediment" in the sense of stuff washed out to sea, it's dead stuff. However it forms, you have to take into account the length of time it would have taken the living stuff to form in the first place.

(Can I just add "ooliths" because it's such a nice word?)

Yeah, the skeletons of trillions of tiny sea creatures would take trillions of tiny sea creatures living out their lives and dying.

On the other hand, when I used this against a creationist they just said "Well, you know time passed faster during the flood, right?)

E=MCfuckoff

The explanation was "Well, we know that a "day" was actually a geological age, so 40 days would be 40 billion (sic) years.)

[Faithfree]

Are the rapid deposits limited in area or can they cover large areas?

The most widespread rapidly-formed deposits are produced by turbidity currents (http://en.wikipedia.org/wiki/Turbidity_current). If the source area of the turbidity current has lime sediment, then the deposited bed will be a limestone (limestone turbidite: http://en.wikipedia.org/wiki/Turbidite). These currents can deposit a bed over hundreds of square miles of the deep sea floor within hours - but it will be thin, and in the geological record it will be separated by slowly deposited beds and/or time gaps. If you have a thick rapidly-formed limestone deposit it will almost certainly be of only local extent (e.g. from the collapse of a steep reef margin).

[Tyrannical]

In The Beginning, the Lord God did a whole bunch of amazingly complicated things. Of course all of this gave Moses a terrible headache, so God decided a more simpler parable was in order

[Faithfree]

Are the rapid deposits limited in area or can they cover large areas?

The most widespread rapidly-formed deposits are produced by turbidity currents (http://en.wikipedia.org/wiki/Turbidity_current). If the source area of the turbidity current has lime sediment, then the deposited bed will be a limestone (limestone turbidite: http://en.wikipedia.org/wiki/Turbidite). These currents can deposit a bed over hundreds of square miles of the deep sea floor within hours - but it will be thin, and in the geological record it will be separated by slowly deposited beds and/or time gaps. If you have a thick rapidly-formed limestone deposit it will almost certainly be of only local extent (e.g. from the collapse of a steep reef margin).

Here's a website about limestone turbidites, but it may well be unintelligible to the layman: http://www.mcz.harvard.edu/Departments/ ... tm#gravity
Just remember - the individual beds are deposited very quickly, but very infrequently - net result is slow sedimentation rate.

[Gawdzilla Sama]

It was.

[Thinking Aloud]

And then there's Derbyshire.