In Romania there is an area full of weird rocks, called trovants, capable of swelling and growing like … mushrooms after being exposed to rainwater.
The small town of Costesti in Romania is home to large curved pebbles called trovants. They have long been the object of attraction for the curiosity of the local population with their strange shape, their ability to generate, grow and move like a living being.
Trovants are available in a wide variety of sizes and shapes, some fit in the palm of the hand while many are taller than the head, even up to 4.5m. Of the more than 100 trovants recorded in at least 20 sites, several rocks were dug up after the sand surrounding them was extracted.
The strange stone in Romania that has the ability to swell and grow like mushrooms after the rain is a mysterious phenomenon that is attracting a lot of scientific attention. These rocks are linked to a geological phenomenon in the region.
In fact, a few trovants are attached to the ground below by a hard rock base, like the “Old Ladies” block in Ulmet. Their unusual bulge comes from ancient origins.
This rock is located in the Romanian village of Costesti. The word trovants means “cement sand”. This rock is formed from a type of sand that appeared millions of years ago on Earth. In fact, the earthquakes that create this strange rock happened 6 million years ago.
The rocks kept growing and swelling strangely. What is amazing is that during and after every rain the Trovants rocks of the village of Costesti sprout like … mushrooms. The rocks kept growing and swelling strangely. Trovants only grow when there is rainwater. Normally they are only 6-9mm, but when there is water, they swell up to 6-10 meters. Some stones even know how to move. Cut the stone in half and there are internal veins like a tree.
After heavy rains, the rocks began to “come to life”. Inside the Trovante rock are cores of hard rock, the outside is a crust formed of sand. However, the phenomenon of bulging of the rock trovants is explained by some scientists that under the rocky crust there is a high content of minerals. When the surface of the rock gets wet, this mineral begins to put pressure on the outer sand layer and causes the mass to swell. Various small cubes: oval or rough, like imperfections, appear on the face of the stones. It is a form of concretion with grains of sand or sedimentary rock bound together by calcium carbonate. “Some are sandstone, some are gravel. In geological terms, they can be called abrasive and agglomerated,” said Florin Stoican, representative of Buila-Vanturarita National Park.
People call them growing rocks. The researchers found no difference between Trovants and the surrounding sand. Therefore, they suspect that the sphere formed due to the unusually intense and prolonged seismic activity of the Middle Miocene. The shock waves emitted by the compacted sand deposits of the Earth and concentrate the limestone cement to form spherical rocks.
Over time, these elements eroded the loose sandstone around them, exposing denser rocks.
When exposed to heavy rain, their calcium carbonate can melt and gradually form the outer circumference of the rock over time. Not much is known about this process, but it is believed to have only occurred at about 4-5 cm for over 1,200 years.
The surrounding sandstone layers have layers that indicate the area was an ancient marine environment where basal rocks and sediments formed, as well as bivalve and gastropod fossils. seen in some Trovants.
