This is the online edition of In the Beginning: Compelling Evidence for Creation and the Flood, 8th Edition (2008), by Dr. Walt Brown. It is designed to be read online.
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The Origin of Limestone
SUMMARY: Too much limestone 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. Before the flood, supercritical water steadily dissolved certain minerals in the subterranean chamber’s floor and ceiling. The floor and ceiling became increasingly porous and spongelike,1 allowing even deeper dissolving. As explained on pages 118–119, rising temperatures in the chamber caused more and more limestone (and salt) to precipitate onto the chamber floor. During the flood, the escaping subterranean water swept the precipitated limestone up to the earth’s surface.
Limestone2 and similar minerals account for 10–15% of all sedimentary rock.3 Any satisfactory explanation for the world’s fossils and sedimentary layers 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, most 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. If that solution then seeps into a cave, evaporation and loss of CO2 will reverse the reaction and precipitate limestone, 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 expressed 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 44 grams of CO2 that escape the solution, 100 grams of limestone precipitate and the reaction moves back to the left. Little temperature change occurs with either reaction.6
A Scenario. Supercritical water (SCW) readily dissolves certain minerals and other solids. [See pages 118–119.] As temperatures rise or as pressures drop in the SCW, these dissolved substances precipitate as “snow.” In the years before the flood, tiny limestone particles precipitated to the subterranean chamber floor as the temperature in the SCW steadily rose. During the flood, the pressure in the escaping water rapidly dropped, so more limestone precipitated and CO2 gas escaped. Simultaneously, 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 172–183.]
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.
Plentiful amounts of CO2 in the atmosphere after the flood provided the necessary “food” to help reestablish earth’s vegetation, including forests. 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. 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.