The Prehistoric Sea Beneath Luhačovice — The Source of the Healing Springs

The sea that was here millions of years ago

Anyone standing today by the Luhačovice springs and tasting the salty Vincentka water would hardly imagine that the remains of an ancient ocean lie hidden beneath their feet. The Luhačovice mineral waters did not come into being by chance—their story begins tens of millions of years ago, at a time when the warm Tethys Sea lapped at the shores of what is now the White Carpathians.

During the late Mesozoic and early Cenozoic eras (roughly 100 to 20 million years ago), the vast Tethys Sea covered a large part of Central and Southern Europe. Over millions of years, layers of sand, clay, and calcareous mud—sediments that geologists today call flysch—accumulated on its floor. The characteristic alternation of harder sandstone and softer claystone layers is still visible today on the exposed rock faces in the valleys around Luhačovice.

What is flysch and why is it so important

Flysch rocks form the geological foundation of the entire White Carpathians region and the adjacent Luhačovice Zálesí. Luhačovice lies in the western part of the Carpathians, specifically in the so-called Račany Unit of the Magura Flysch. This unit is characterized by thick layers of sedimentary rocks that formed in a deep-sea environment.

Flysch sediments have one key property: they contain 20 to 25 percent carbonate cement—the remains of marine organisms and dissolved minerals. It is precisely this cement that is one of the sources of the minerals found in Luhačovice’s waters today.

How Minerals Get into the Water

The process of mineral water formation is complex and takes thousands of years. Simplified, it can be broken down into several steps:

Salt (NaCl) from marine sediments. Flysch rocks contain so-called fossil marine waters—remnants of original seawater trapped in the pores of the rocks. These “fossilized” waters are rich in sodium chloride, or table salt, which gives the Luhačovice springs their characteristic saltiness.

Carbon dioxide (CO₂) from the Earth’s depths. Deep beneath the Carpathian flysch, at depths of 25 to 30 kilometers, carbon dioxide is formed. It rises to the surface along tectonic faults—cracks in the Earth’s crust. As CO₂ penetrates the flysch rocks, it dissolves minerals within them and enriches the water. The result is a sparkling mineral water saturated with minerals.

Iodine and bromine from organic remains. Tertiary sediments also contain the remains of marine organisms, from which trace elements such as iodine, bromine, and fluorine are released. It is precisely this elevated iodine content that distinguishes Luhačovice’s waters from many other European mineral springs.

Tectonic faults — the path from the depths to the surface

The mere presence of minerals in the rocks would not be enough. For a spring to form, there must be a path through which water can rise from the depths to the surface. In the vicinity of Luhačovice, this role is fulfilled by a system of tectonic faults—deep cracks in the Earth’s crust that formed during the folding of the Carpathians.

Geologists refer to the so-called Luhačovice spring structure—a specific arrangement of faults and strata that allows deep groundwater to rise precisely in the spa valley. The intersection of two or more fault lines creates areas where the Earth’s crust is most permeable, and it is precisely there that the most abundant springs emerge.

Why Luhačovice?

There are hundreds of mineral springs in Europe, but few places offer such a unique combination of conditions as Luhačovice. There are three key factors:

First, thick flysch sediments rich in marine minerals provide the raw material. Second, deep tectonic faults extending into the Earth’s mantle ensure a supply of carbon dioxide. And third, the specific geometry of the faults in the Luhačovice valley allows the water to rise to the surface.

The result is cold hydrogen carbonate-chloride-sodium acidulous water—that is, water richly saturated with carbon dioxide, with a high content of sodium, chlorides, and hydrogen carbonates, enriched with iodine, bromine, and other trace elements. Such a combination is rare on a pan-European scale.

Comparison with other mineral springs

Similar iodine-rich mineral waters can be found, for example, in Govora, Romania, or at certain Italian spas. Unlike thermal springs (such as those in Karlovy Vary, where the water is heated by volcanic activity), the waters in Luhačovice are cold—their temperature at the surface ranges from 10 to 12 °C. It is therefore not a volcanic phenomenon, but a result of the unique geological structure of the Carpathian flysch zone.

What Science Says

Among others, Michal Zádrapa devoted a detailed study to the Luhačovice springs in his 2014 bachelor’s thesis, completed at VŠB — Technical University of Ostrava. The thesis clearly summarizes the hydrogeological conditions of the area and the history of the springs’ use for spa purposes. Further information on the geology of the Moravian Carpathians is provided by the moravske-karpaty.cz portal.

For visitors to Luhačovice, this conveys a single message: when you taste Vincentka or Ottovka, you are drinking water that has traveled a journey spanning millions of years—from an ancient sea, through deep layers of rock, along tectonic faults, all the way to the surface of the spa valley. It is one of the most remarkable geological stories in Central Europe.

Other articles in the series: The Oldest Residents of Luhačovice · The Serényi Family · Antonín Václavík and the Luhačovice Zálesí