Below is the online edition of In the Beginning: Compelling Evidence for Creation and the Flood, by Dr. Walt Brown. Copyright © Center for Scientific Creation. All rights reserved.

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[ The Fountains of the Great Deep > The Origin of Limestone ]

The Origin of Limestone

SUMMARY: Too much limestone¹ exists on earth to have been formed, as evolutionists claim, by present processes on the earth’s surface, such as the accumulation of pulverized corals and shells. Had that happened, so much carbon dioxide (CO2) would have been released that all of earth’s surface waters and atmosphere would have become toxic hundreds of times over.

Before the flood, supercritical water in the subterranean chamber steadily dissolved certain minerals in the chamber’s floor and ceiling, making them increasingly porous and spongelike.² This allowed even deeper dissolving. As explained on pages 124–125, rising temperatures in the chamber caused more and more limestone to precipitate (out salt) onto the chamber floor. During the flood, the escaping subterranean water swept the precipitated limestone up to the earth’s surface.

About 20% of all sedimentary rock is limestone.³ Any satisfactory explanation for the world’s sedimentary layers and fossils should also explain the enclosed limestone layers and limestone cement. This requires answering two questions, rarely asked and perhaps never before answered:

1. What is the origin of the earth’s limestone? Remarkably, earth’s limestone holds a thousand times more calcium and carbon than today’s atmosphere, oceans, coal, oil, and living matter combined. A simple, visual examination of limestone grains shows that few are ground-up seashells or corals, as some believe.

2. 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? Especially perplexing has been finding the source of so much silica and the water to distribute it. Geologists call this “the quartz problem.”⁴

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 coal, oil, and methane.

Limestone Chemistry. Limestone, sometimes called calcium carbonate (CaCO₃), is difficult to identify by sight, but is quickly identified by the “acid test.” If a drop of any acid, such as vinegar, is placed on limestone or a rock containing limestone, it will fizz. The acid combines with the limestone to release fizzing bubbles of CO₂ gas. As you will see, limestone and CO₂ gas are intimately related.

Another common chemical reaction involving limestone begins when CO₂ dissolves in water, forming a weak acid (carbonic acid). If that slightly acidic solution seeps through ground containing limestone, limestone will dissolve until the excess CO₂ is consumed. (This is how limestone is hollowed out, forming limestone caves and voids that can produce sinkholes.) If that solution then seeps into an existing cave, evaporation and loss of CO₂ will reverse the reaction and precipitate the limestone in the solution, often forming spectacular stalactites and stalagmites.

A third example of this basic reaction is “acid rain.” With the increase in atmospheric CO₂ in recent decades, especially downwind from coal-burning power plants, CO₂ dissolves in rain, forming “acid rain.” Acid rain can harm vegetation and a region’s ecology if not neutralized, for example, by coming into contact with limestone.

Finally, limestone sometimes precipitates along the coasts of some eastern Caribbean islands, making their normally clear coastal waters suddenly cloudy white. Studies of this phenomenon have shown that limestone precipitates when CO₂ suddenly escapes from carbonate-saturated groundwater near the beach.⁵

These four examples are described by the following reversible chemical reaction.

      

In other words, when liquid water [H₂O (l)] containing dissolved (or aqueous) CO₂ [CO₂(aq)] comes in contact with solid limestone [CaCO₃(s)], the limestone dissolves and the chemical reaction moves to the right. Conversely, for every 100 grams of limestone that precipitate, 44 grams of CO₂ escape the solution and the reaction shifts back to the left. Little temperature change occurs with either reaction.⁶

Production of Earth’s Limestone. Supercritical water (SCW) readily dissolves certain minerals and other solids. [See pages 124–125.] As SCW’s temperature steadily rose in the preflood subterranean chambers, more and more substances dissolved in the water such as: sodium, chlorine, calcium, carbon, oxygen, copper, aluminum, and iron. Later, as the temperature rose further, they precipitated as salt (NaCl), limestone (CaCO₃), and various ores—a process in SCW called “out-salting.” Thick deposits of these mushy solids accumulated on the preflood subterranean chamber’s floor.

Today, when limestone forms at the earth’s surface, the released CO₂ enters the biosphere—the atmosphere, soil, and surface waters of the earth. Before the flood, vast amounts of limestone steadily precipitated onto the subterranean chamber floor, but the released CO₂ was confined to the chamber, unable to escape into the biosphere. That CO₂ again dissolved in subterranean water and was used to dissolve more minerals in the chamber’s ceiling and floor. Therefore, earth’s preflood limestone was produced without the obvious life-extinguishing problem described in Table 8 and the paragraph that follows it.

Here’s another way to look at the preflood production of limestone. The chemical equation above states that to form one molecule of limestone, one molecule of CO₂ must also come out of solution. In the subterranean chamber, that CO₂ went immediately back into the solution, so that CO₂ molecule was used over and over. No net CO₂ was emitted.

During the flood, pressure in the escaping water rapidly dropped, so some additional limestone precipitated and a relatively small amount of CO₂ gas escaped into the biosphere. Simultaneously, enormous amounts of limestone sediments on the chamber floor were swept up to the earth’s surface, where liquefaction sorted the limestone particles into more uniform layers. [See pages 197–213.]

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 ocean basins, limy (CO₂-rich) water filled and slowly migrated through pore spaces between sedimentary particles.

After the flood, plentiful amounts of CO₂ in the atmosphere provided the necessary “food” to help reestablish earth’s vegetation, especially forests. As plants grew and removed CO₂ from the atmosphere, surface waters could release additional CO₂ into the atmosphere, thereby precipitating more limestone. (A balance is always maintained between the amount of each specific gas in the atmosphere and the concentration of that gas in earth’s surface waters.⁷) Limestone that precipitated between loose sedimentary grains cemented them together into rocks. Earth’s surface waters are still huge reservoirs of CO₂. Oceans, lakes, rivers, and groundwater hold 50 times more CO₂ than our atmosphere.

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.

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