During summer holidays a friendly advice and recommendation led us to this geological quite special place and rock formation near the Isar meadows of Lower Bavaria in the small village of Usterling. The location is called Wachsender Fels, (i. e. growing rock) but this self-enlarging boulder is not situated within a stalactite cave but just outside at the end of a hillside.
The growing rock with an age of ca. 5,000 years has today a length of 40 m and a height of 5 m, each year 1-2 cm are added by the very small water runnel flowing down on its crest. The fluid from a nearby karst spring contains a lot of soluted limestone and carbon dioxide. As soon as the water reaches the surface the carbon dioxide begins to leave the fluid and the limestone is being deposited down on the rock.
We luckily reached the site late in the afternoon when the last sunbeams of the day touched and transformed the rock for a very short time to a real sculpture. A few moments later this unexpected appearance rapidly dissolved again with the approaching sun-set. A wooden stairways leads visitors easily to the beginning of the growing rock.
The German geological term for this kind of rocks is steinerne Rinne (i. e. stony runnel) but an equivalent scientific term in English seemingly does not exist for this more seldom rock formation near karst hills and mountains.