In Romania, an area full of strange rocks called trovants can swell and grow like mushrooms after being exposed to rainwater.
Rocks are inanimate objects. They are not living creatures. They have no biological processes and cannot breathe, reproduce or move. At least, this is what we all know.
However, a special type of stone in Romania is a complete exception; they “behave” like a living organism. Trovant is completely immobile during the dry season and remains in place without changing size. But when the rainy season comes, the stones seem to come alive, increase in size and even move.
Researchers suspect these unusually spherical rocks were formed by unusually intense and prolonged seismic activity of the middle Miocene period. Shock waves created by large earthquakes compact sandy sediments and condense limestone cement into spherical clumps – often called trovants.
What causes these rocks to grow, move and reproduce?
Trovants are very diverse in size and shape; some can fit in the palm, while many stone blocks are taller than a person’s head, even up to 4.5 m. Of the more than 100 trovants recorded in at least 20 locations, several blocks were excavated after the sand bed around them was quarried.
Strange rocks in Romania that can swell and grow like mushrooms after rain are a mysterious phenomenon that has attracted much attention from the scientific community. These rocks are related to a geological phenomenon in the area. Trovants comprise a core of hard rock and sand or gravel that forms around it. These unique structures can only develop in highly porous sand accumulations and sandstone deposits cemented by calcium carbonate-rich water.
Calcium carbonate is essential in the formation of trovants, and it also plays a vital role in causing rocks to grow in response to rainwater. After each heavy shower, trovants absorb minerals from the rainwater, then naturally combine with chemicals already in the rock, creating reactions and internal pressure. This pressure causes the rock to grow from its center to its edges and multiply at a deposition rate of about 4-5 cm per 1000 years.
Some trovants are permanently attached to the ground below via solid stone bases, such as the “Old Ladies” block at Ulmet. Their unusual bulging shape comes from ancient origins. This stone was found in the Romanian village of Costesti.
The word trovant means “cement sand”. This type of rock is formed of sand that appeared millions of years ago on Earth. The earthquakes that created this strange rock happened 6 million years ago.
Trovant stones appear with smooth and angular shapes, often cylindrical, nodular or spherical. Trovants develop these inconsistent shapes as they “grow” and “reproduce” due to the irregular secretion of “cement”. You can see these stones grow from just a few millimeters in size and grow up to 10 meters.
But it is not only their structure and ability to grow and reproduce that makes trovant rocks unique. They can also move from one place to another. And if that’s not enough, they also have root-like extensions and age rings visible when you cut the stone. However, until now, scientists have been unable to explain these unique features.
The fantastic thing is that during and after every rain, Trovants stones in Costesti village grow like mushrooms. The rocks keep growing and bulging strangely. Trovant stone only thrives when there is rainwater. They usually are only 6 to 9 mm in size, but when water enters, they swell up to 6 to 10 meters. Some rocks even move. Cut the stone in half and see the rings of veins inside like a tree trunk.
Visually, it can be seen that trovants combine the characteristics of a plant with a rock, so it is unclear whether they should be classified as living organisms. But whether they are alive or not, these growing stones provide a majestic sight – a must-see when visiting Romania’s Valcea District.
Inside the trovants are hard rock cores; outside is a shell made of sand. However, the swelling phenomenon of trovants is explained by some scientists to mean that underneath the rock crust is a high mineral content. When the rock surface gets wet, this mineral begins to pressure the outer layer of sand and causes the rock to begin to swell.
Different small shapes: oval or rough-like pimples appear on the surface of the stone slabs. This is a concretion with sedimentary sand or rock particles bonded together by calcium carbonate. “Some are made from sandstone, others from gravel. In geological terms, they can be called grindstones and conglomerate rocks,” said Florin Stoican, representative of Buila-Vanturarita National Park.
There is little research on the origin of the “growing stones” in Romania, but many theories have been put forward. According to the International Geological Congress in Oslo 2008, “Trovant” is considered a type of “sandstone concretion”. According to the hypothesis at the congress, the Romanian Trovant has a magnetic texture reflecting paleodynamic (paleoseismic) conditions and corresponding to specific sand deposit compositions (especially carbonates). Accumulates in the sand and appears during significant seismic shocks.
Strange rocks in Romania are said to have been born after earthquakes 6 million years ago. Sand reservoirs are created after the successive sedimentation of materials brought by rivers. Gravity, geological shock, solution cohesion (especially surface tension) and adhesion strength between sand particles and liquid are believed to be involved in this process.