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Author Topic:   Chalk takes millions of years to form
Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 6 of 57 (713268)
12-11-2013 12:27 PM
Reply to: Message 5 by ringo
12-11-2013 11:54 AM


Well, not really. It takes a few decades to get to the ocean floor. The reason accumulation is so slow is that coccolithophores aren't very big and there aren't that many of them. Nor could there be, since they photosynthesize and so need to be near the surface and not overshadowed by loads of other coccolithophores.
Historical Geology/Calcareous ooze - Wikibooks, open books for an open world
Edited by Dr Adequate, : No reason given.
Edited by Dr Adequate, : No reason given.

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Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 9 of 57 (713271)
12-11-2013 12:31 PM
Reply to: Message 8 by Faith
12-11-2013 12:29 PM


A Floodist like me would hypothesize that the cliffs were like any of the thick strata anywhere on the earth, the result of the transportation by water of already-formed already-existent particles to their current location, and that before the Flood conditions were such that it didn't take so long for them to accumulate anyway. Any reason why this isn't possible?
So millions of years' worth of calcareous ooze formed in the two thousand years before the Flood?
Edited by Dr Adequate, : No reason given.

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Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


(1)
Message 10 of 57 (713272)
12-11-2013 12:33 PM
Reply to: Message 3 by Stile
12-11-2013 11:43 AM


Re: Chalkland Islands
No.
But I do have a chalk-question, and you are now the appointed chalk-expert. So here it is:
This geological chalk you're talking about. Is it the same as colloquial chalk? Like the stuff used by teachers in classrooms on chalkboards?
If so, is there any "chalk shortage" coming about from all the teachers using it up... what with it taking so long to make more, anyway.
Just wondering.
Blackboard chalk, French chalk, billiard chalk, tailors' chalk and the chalk used by weightlifters are not chalk. It's like the Great Granite Swindle all over again.
Edited by Dr Adequate, : No reason given.

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Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 11 of 57 (713275)
12-11-2013 12:40 PM
Reply to: Message 7 by New Cat's Eye
12-11-2013 12:28 PM


If chalk is calcium carbonate, and calcium carbonate is hard water scale, then the fact that I can get hard water scale on my showerhead in the order of weeks seems to suggest that it does not take millions of years for chalk to form.
Chalk isn't just any old calcium carbonate, it's calcium carbonate made out of coccoliths.
IIRC, this was first discovered by Thomas Henry Huxley ("Darwin's Bulldog").

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Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


(1)
Message 15 of 57 (713279)
12-11-2013 1:56 PM
Reply to: Message 14 by Tangle
12-11-2013 1:44 PM


There's no such thing as the creationist response to any given fact they need to explain away. We'll have to see what Faith has to say about it.

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Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


(1)
Message 19 of 57 (713288)
12-11-2013 5:04 PM
Reply to: Message 16 by Faith
12-11-2013 3:07 PM


Another reference on the subject refers to creationist Snelling saying that conditions of the Flood would have caused the coccoliths to "bloom," which is an explanation I've run across before, but what those conditions were wasn't part of that article.
Coccoliths bloom in real life, it doesn't produce the amount of sediment required. Though it is pretty.
Would coccoliths like that?
Well the problem, as I've explained, is that they need sunlight. This places an upper limit on the number of coccolithophores you can have at one time, because once the surface is covered with coccolithophores, you can't have any more coccolithophores under that, because they'd be in the shadow of the coccolithophores on top. So the "ideal conditions" for coccolithophores is not having too many coccolithophores.
As for the problem with transporting existing coccoliths that you expressed, because they would have been hardened into rock as they are in the cliffs, I keep seeing them described as "calcareous ooze" which doesn't sound like rock.
They start off as calcareous ooze, which lithifies by compaction and recrystallization.
Edited by Dr Adequate, : No reason given.

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Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 24 of 57 (713301)
12-11-2013 7:21 PM
Reply to: Message 22 by Faith
12-11-2013 6:02 PM


The amount of sunlight available should depend on the size of the area they cover. What area of sea floor would they need to cover to produce an amount that could build the chalk cliffs or all the chalk formations on earth?
Lots. Have a look at this map for starters.
The green bits are calcareous ooze. Let's call that about 10% of the sea floor. A quick look round the Internet shows that these deposits vary in thickness from tens to hundreds of meters. Let's call it an average of 25 meters, which is extremely conservative. If all that was spread out on the ocean floor, then, that would be a thickness of 2.5 meters. Now based on sediment traps, the rate of deposition is between 1 and 5 centimeters per thousand years. Call it 5 everywhere (again, favoring you rather than me). So being generous all round, that would be 50,000 year's worth of sediment if the whole of the ocean surface was dedicated to the production of coccolithophores and foraminiferans, which it isn't. That's before we get onto the actual rocks, and before we consider whether even a magic flood could sweep up the ooze into neat zones which just happen to correlate perfectly with the places that the calcareous-ooze-forming organisms happen to live in at present.

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