Have you ever wondered where limestone forms? Or how civilization has used it for thousands of years? Limestone has a storied history because of its commonality and valuable physical properties. Its origins are a mixture of history, science, innovation, and creativity.
What is the origin of limestone? Limestone is a common sedimentary rock that contains more than 50% calcium carbonate. Although it comes in many different forms, its origins can be traced back to either chemical or biochemical processes that occurred in the geological past, often tens to hundreds of millions years ago.
When marine organisms die, they accumulate on the ocean floor. Their soft organic parts decay, leaving only their exoskeletons, which break down over long periods. These sediments are transformed into bioclastic limestone when carbonate cement fills the gaps between the shell fragments. This process happens in warm, tropical waters and is called tropical bioclastic limestone. In cooler waters at mid to high latitudes, it’s called temperate bioclastic limestone.
When reef-building corals congregate in large numbers, the structure preserves itself as it transforms into tropical limestone reef rock.
Converting shell sediments into solid rock consists of many steps. First, the increasing weight of accumulating sediment compacts the shell fragments slowly. Compaction forces the pieces together, limiting the space between them and driving out the contained water. The fragments are gradually fused together. Finally, more compression and burial can cause some alteration or recrystallization of the calcite to make the rock even harder.
Some limestones form from marine and other waters with a lot of calcium carbonate. If forces remove carbon dioxide from this water, calcium carbonate will likely occur. For example, the rock found along tropical beaches is limestone that forms this way. Some limestones also form in freshwater environments near caves, springs, and lakes.
If a body of limestone is squeezed and deformed by heat and pressure over time, it changes into recrystallized limestone or marble. Marble is hard, polishable, and often used for building and sculpture.
Limestone gets its name because the sediment releases lime when burned.
Humankind has used limestone for thousands of years, from the Egyptian pyramids to Roman road construction to modern-day industries.
Here’s a brief timeline of limestone and its many uses.
Egyptians extensively quarried the limestone deposits flanking Egypt’s River Nile to supply building materials for constructing pyramids and temples. The Great Pyramid of Giza, the oldest and largest of the three pyramids in the Giza pyramid complex, consists of about 2.3 million limestone blocks averaging one cubic meter in size and weighing 2 to 3 tons each.
Between 300 BCE and 200 CE, the Romans improved the technology for making lime and lime mortar. A cement made from slaked lime mixed with volcanic ash was found near Pozzuoli at Naples Bay and hardens both in the air and underwater.
Scientists discovered a lime mortar floor from 7,000 BCE in Yiftah El, Israel. Hydrated lime made up the floor, which is created by heating limestone and adding water.
At the end of Emperor Augustus’s reign, the Roman Empire divided itself into over 100 provinces connected by over 350 roads. Builders used lime cement to hold roading stones together as a base core and filler.
Scholars generally agree that the end of the Roman Empire in Europe was the start of the Dark Ages. During the political and social upheaval, the application of limestone and lime in major construction diminished. Some believe this was because of the loss of technology and knowledge from disease, illiteracy, and war.
King Henry III ordered the whitening of the Great Tower of London inside and out. Workers likely used a slaked limestone mixture or whitewash to paint the tower’s stonework. How exactly does limestone whiten? Over some time, calcium carbonate crystals form, displaying a bright white surface.
Workers carried out restoration efforts on the Great Wall during the Ming Dynasty (1368 to 1644). This restoration involved using vast amounts of lime mortar to cement the wall’s countless miles of stonework.
A total of 5 billion tons of limestone are used annually in steel production, cement production, agriculture, and construction. Many products extracted straight from limestone, like calcium carbonate, have many applications.
For example, in 1926, Waldo Semon developed a method for transforming PVC material into a more useful form. He discovered a way to plasticize PVC by mixing it with additives like calcium carbonate, which is made by crushing limestone, considerably expanding its economical application.
Adrian Pilkington and Kenneth Bickerstaff developed a float glass technique in the 1950s in which silica, sodium carbonate, and lime are first heated to an extremely high temperature to create soda-lime glass. Then, people can transform the molten glass into plate glass after floating it over a bed of molten tin.
To transition from acid to alkaline manufacturing processes, the paper-making industry must replace filler additions like kaolin clay with PCC, a type of calcium carbonate. Limestone is the primary raw material used in the production of PCC.
With our quarry in Pontotoc, Oklahoma, Pontotoc Sand & Stone is in a perfect position to provide the crushed limestone you need for your next job. If you aren’t sure what you need, we’re here to help you find the ideal limestone product for your specific application.
Contact Pontotoc Sand & Stone today.