Unfortunately, Lanakila, Walt Brown's explanation leaves a lot to be desired (to put it mildly). Below are my comments on his explanation at
http://creationscience.com/onlinebook/Limestone2.html#1016860:
ABSTRACT: Too much limestone exists on earth to have been formed, as evolutionists claim, by present processes (from marine animals, such as shelled creatures and corals). Most limestone was deposited as the subterranean water violently escaped to the earths surface during the flood. Simultaneously, fresh carbon, needed to rapidly reestablish plant life buried during the flood, was released into the biosphere.
We'll see if he proves this.
Limestone, sometimes called calcium carbonate (CaCO3), accounts for 10-15% of all sedimentary rock. Any satisfactory explanation for sedimentary layers and the worlds fossils they contain must also explain the enclosed limestone layers and limestone cement. This requires answering two questions rarely asked and perhaps never before answered.
OK.
What is the origin of the earths limestone? Remarkably, earths limestone holds more calcium and carbon than todays atmosphere, oceans, coal, oil, and living matter combined.
Not surprising, really, considering that all but the tiniest fraction of the shell-bearing organisms that ever lived are now dead. Walt also left a very important item out of his list. The Earth's crust holds far more calcium and carbon than all of the limestone.
A simple, visual examination of limestone grains shows that few are ground-up sea shells or corals, as some believe.
And how exactly does one recognize a shell or coral once it has been ground up to micron size, anyway?
How were sediments cemented to form rocks? Specifically, how were large quantities of cementing agents (usually limestone and silica) produced, transported, and deposited, often quite uniformly, between sedimentary grains worldwide?
Traditional geology says that limestone was formed on the bottom of oceans. In that case, the ocean itself would serve just fine as an agent to transport cementing agents.
Answering these questions in the context of the hydroplate theory will answer another question: What was the source of the carbon dioxide (CO2) needed to reestablish vegetation after the flood? Remember, preflood vegetation was buried during the flood, most of it becoming our coal, oil, and methane deposits.
I don't understand why this is a problem with flood geology anyway, but I'll take his word for it.
I'll skip this section since it is largely correct. One note, though -- acid rain is caused by sulfur dioxide, not carbon dioxide. The "acid" in acid rain is actually sulfuric acid. Much stronger stuff.
A Scenario. Lets suppose that before the flood the subterranean chamber contained some CO2 and a large amount of limestone, perhaps lining the chambers walls.
WAIT A MINUTE! He is supposed to be explaining the origin of limestone, and he starts be saying "Let's suppose...the subterranean chamber...contained a large amount of limestone". Pardon me while I stop laughing.
Any gaseous CO2 was quickly squeezed into solution by the great pressure from the weight of the crust above the chamber. The subterranean water therefore was acidic, and some of the solid limestone dissolved until the available CO2 was consumed in the reaction written above.
CO2 is only a tiny percent of the Earth's atmosphere. Any acidity due to dissolved CO2 would be extremely small. The amount of calcium carbonate in solution would therefore also be tiny.
As this subterranean water escaped to the earths surface during the flood, the waters pressure dropped drastically, so CO2 gas and microscopic, milky-white particles of limestone came out of solution. The escaping water scoured out the relatively soft limestone. Considerable CO2 entered the atmosphere, and tiny limestone particles spread throughout the flood waters.
"Considerable CO2 entered the atmosphere" I'll say. Noah and the residents of his ark would all be dead.
Superimposed on this general pressure decrease were extreme pressure fluctuations from waves and water-hammer action. (See page 218.) Within each tiny volume of liquid, limestone could precipitate as the pressure suddenly dropped. An instant later, a nearby pressure jump dissolved other limestone. The turbulent conditions caused carbon atoms to jump back and forth from one side of the above equation to the other. Therefore, much limestone was precipitated throughout the escaping flood waters.
If in fact the atoms were "jumping back and forth", then the equation is in equilibrium and nothing will precipitate.
The solubility of limestone in the escaping water also decreased, because water pressure dropped enormously. Therefore, some limestone precipitated without releasing CO2. Later, liquefaction sorted all precipitated particles into more uniform layers of limestone. (See pages 151163.)
First, water pressure has only a minor effect on solubility. Second, using Brown's own chemical equation, it is impossible for limestone to precipitate without also releasing CO2. He can't have the chemical equation apply when he wants it to and not apply when he doesn't want it to.
Surface waters, especially oceans, are huge reservoirs of CO2. Oceans, lakes, rivers and ground water hold 50 times more CO2 than our atmosphere. Any excess CO2 that enters the atmosphere eventually causes CO2 elsewhere to dissolve in surface waters. In other words, an approximate balance exists between the amount of CO2 in the atmosphere and in surface waters.
OK.
Sediments, eroded during the initial stages of the flood, settled through the flood waters all over the earth. After most of these waters drained into the newly formed oceans, limy (alkaline) water filled and slowly migrated through pore spaces between sedimentary particles.
I thought all the lime had precipitated as limestone? Now some of it didn't? Walt can't have his cake and eat it, too.
Plentiful amounts of CO2 in the atmosphere after the flood provided the necessary food to help reestablish plants, including forests, on the earth. As plants grew and removed CO2 from the atmosphere, surface waters released additional CO2, thereby precipitating more limestone. Limestone that precipitated between loose sedimentary grains cemented them together into rocks.
Of course at this point there is so much CO2 in the atmosphere that everyone on the ark is long dead.
Tiny particles of precipitated limestone are excellent cementing agents when near-saturation conditions exist. Smaller and more irregular particles of limestone readily dissolve; larger particles grow, sealing cracks and gaps. Precipitation within a closely packed bed of sediments (cementation) occurs more readily than precipitation outside the bed.
So I guess the original question about how sedimentary rocks were cemented wasn't such a big deal after all, eh?
All in all, this is laughably bad "science".