Buckingham Palace is one of the world's most recognizable buildings, having served as the home and administrative headquarters of British royalty for centuries. Over in the United States, the Pentagon is instantly recognizable as the headquarters of the Department of Defense, while the Empire State Building is one of New York City's iconic landmarks. These three buildings and others have something in common, according to a new study— they were all constructed, at least in part, from a material called oolitic limestone, which contains microbes that lived hundreds of millions of years ago.
Oolitic limestone is described by the University College London as a carbonate rock that consists mainly of particles known as ooliths and roughly the same size as sand grains. These particles have concentric rings of calcium carbonate (CaCO3) and are evenly distributed, making it easy to cut and sculpt, while still being hard and durable enough. This makes it an ideal building material in its various forms, with Portland limestone being one of the better-known examples.
While the UCL website noted that ooliths, which are also known as ooids, were created by sand grains or seashell fragments that rolled on the seafloor and formed layers of sediment over time, the new study published in the journal Scientific Reports disputes this theory, stressing instead that they were made of concentric layers of even smaller, mineralized microbes. This suggests that Buckingham Palace, the Pentagon, and other buildings made from oolitic limestone essentially have microscopic fossils that might have existed as far back as 340 million years ago, possibly even predating the dinosaurs.
In a statement quoted by Phys.org, study co-researcher Dr. Bob Burne, an honorary professor from the Australian National University, stressed that man had long known about oolitic limestone as a strong and lightweight building stone, well before the material was used in the construction of some of the world's most famed buildings.
"Mississippian oolite found in Indiana in the U.S. has been used to build parts of the Pentagon in Virginia and parts of the Empire State Building in New York City. Jurassic oolite in England has been used to construct Buckingham Palace and much of the City of Bath, the British Museum, and St Paul's Cathedral."Explaining the mathematical model he and his colleagues used in their new study, co-author Murray Batchelor, also from ANU, said that the model was inspired by a separate one developed in 1972 to explain the growth of certain brain tumors. The new model, he noted, could explain why layers of oolitic limestone accumulate in a concentric fashion, while also "[predicting] a limited size of ooids."
The new paper doesn't just provide an interesting look at one of the key materials used in the construction of Buckingham Palace and other well-known structures, the researchers said. According to Batchelor, studying oolitic limestone could also help people have a better understanding of how climate change had an impact on Earth through the years.