(ORDO NEWS) — In some parts of the United States, giant piles of boulders can be found that make distinct musical sounds when struck with a hammer.
Voiced rocks, also known as lithophonic rocks (also used in idiophonic musical instruments called lithophones) are rocks that resonate like a bell when struck. In the US, you can find them in Ringing Rocks Park, Bucks County, Pennsylvania, and Pluto, Montana.
It is not known how these stones got their musical abilities, but it is believed that a combination of the composition of these particular rocks and how this pile of stones formed may contribute to this unique quality.
Previously, several scientists became interested in ringing rocks. However, none of them was able to formulate a reliable theory about the ringing ability of rocks or the formation of boulder fields.
In 1965, geologist Richard Faas of Lafayette College in Easton, Pennsylvania, took some rocks to his lab for testing and found that when struck, the rocks emit a series of sounds at frequencies lower than the human ear can hear.
He came to the conclusion that in these special rock fields, audible sound is obtained only because these stones interact with each other. Although Faas’s experiments explained the nature of the sounds, they did not reveal the mechanism in the breed that created them.
More than a dozen ringing rock boulder fields have been identified in the Pennsylvania and New Jersey area, but unfortunately, most of them are either privately owned or have been destroyed by urban development.
There are currently three places north of Philadelphia that are easily accessible to the public: Ringing Rocks County Park, Stony Garden, and Ringing Hill Park.
Ringing boulder fields in southeastern Pennsylvania and New Jersey are a type of felsenmeer (a German term meaning “sea of rocks”).
These barren block fields occur in periglacial environments where stable rock outcrops are exposed with a slope of less than 25°.
Frost breaks the top of the rock, and the slight slope of the terrain allows fine weathering materials to be washed away. The accumulation of snow and ice often lifts and turns boulders, leaving a significant free space between them.
In the 1960s, a Rutgers University professor conducted an informal experiment in which he cut boulders of ringing rock from Bucks County Park into thin slices and then measured them for shape change.
He found that the sound-producing stones showed a characteristic expansion or “relaxation” within 24 hours of being cut, indicating that the rock was under internal stress.
The professor noticed that the sounding stones were usually found closer to the middle of the boulder fields, where they did not come into contact with the soil and the shade of the surrounding trees. The scientist is sure that the ability to ring is a direct result of internal stresses.
Contact us: [email protected]