Limestone Layers and the Flood

In this context, they are talking about fossils of life forms much larger than the tiny fossils and fossil fragments that make up the bulk of the chalk. In other words, within the matrix of microfossils, larger fossils are found, but the are generally sparce.It is my understanding, that most limestone is directly or indirectly of biogenic origin, even though much of it may not be recognisable as being fossils or fossil fragments. Much is larger carbonate fragments broken down to become mud.Re: Walt Brown - He may have some scraps of good info to offer up, but I have also seen a fair amount of his "science" that is more in the category of being "bad science fiction". You may wish to do a forum search for "Walt Brown", if you wish a place to specificly discuss his thoughts. If you have Microsoft Excel, you may wish to consult and search the forum topic database I post online.Mooseps. My cat Hiss sends your cat a meow!

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Professor, geology, Whatsamatta U
Evolution - Changes in the environment, caused by the interactions of the components of the environment. "Do not meddle in the affairs of cats, for they are subtle and will piss on your computer." - Bruce Graham

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"The modern conservative is engaged in one of man's oldest exercises in moral philosophy; that is, the search for a superior moral justification for selfishness." - John Kenneth Galbraith

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"I know a little about a lot of things, and a lot about a few things, but I'm highly ignorant about everything." - Moose

All limestones are carbonate rocks, although not all carbonate rocks are limestones. The principle mineral of limestone is Calcium carbonate (CaCO₃).Saying carbonate limestone is like saying muddy mudstone or sandy sandstone.Moose

Source for quoted material: Limestone - WikipediaThere are special names for some calcite rocks formed by non-biogenic precipitation of CaCO₃. and Of course, vein calcite is also very common. I would regard such an not so much as being a rock (even though it is) as to being a secondary mineral deposit.I think that a rock description with mode of formation is more important than putting a specialized name on it.BTW, the same Wika source contained: I bring this up, because somewhere earlier a much higher figure was used. While is some areas the limestone percentage may indeed be quite high, I suspect that overall the 10 percent figure is pretty good. After all, limestones are pretty minor in the preCambrian, which is a big chunk of sedimentary rocks.Another NAPOTM brought to you by...Moose

I think you have asked some questions that do have answers, but the science behind the answers is fairly specialized and complex. Others seem to have covered your questions fairly well, without going so far as to write out the vast details of the processes.The one item seemingly not covered was: Now, this is getting into mantle chemistry considerations, which is a complex item in itself. My far from expert comments:That may or may not be an accurate statement about what volcanic gasses are. Some types of volcanos are not very "gassy" - Example, the basaltic volcanos of Hawaii. Others may be more "gassy" - Example, the more silica rich volcanos such as Vesuvius and Mt. Saint Helens. To get into this further would be to get rather heavily into magmatic evolution theory, which is very off-topic here.Anyhow, there is a CO₂ component in the mantle. It tends to get concentrated in the residual magma as the various minerals crystalize out because Carbon (C) does not fit into the crystal structures of common minerals (or even uncommon minerals?).Again, all this is getting pretty deep into igneous rock formation theory (igneous petrology), so I will go no further (expecially since I'm already working the fringes of my personal knowledge).Critiques from the other geologists welcome, although igneous petrology considerations probably should go to a new topic.MooseTo all - See terminology you don't understand? Let me remind you of the existence of the forums Geology Glossary.This message has been edited by minnemooseus, 03-19-2006 02:56 PM

The above quoted goes a bit too far. While, as best I know, there is indeed broad agreement that the majority of limestones are of direct or indirect biological origin, there are always details and specific occurances to be debated.Also, I think there's sometimes a strong tendancy for geologists and other scientists to go "devils advocate". Question and debate conclusions even though you actually do agree with the conclusions. Maybe it's just a professional version of "everyone loves a good argument".I find it mighty surprising that you would make a statement such as the above.Moose