TW_N19 Geotrail Laas

Stop 1: The Laas Mill – Symbol of fertility

For a village to arise, two basic living conditions must be present: water and fertile soils.

The motto above the door to the Laas mill reminds us of the latter. Soils have much to do with geology because they consist almost entirely of minerals and rocks. On them everything was grown that humans needed to live. Not only food crops but also raw material plants like flax for fabric production. Forest soils provided the indispensable construction and fuel wood.

Among the food crops, grain was one of the most important, but it had to be ground into flour with abrasive-resistant stones. These were also found near Laas: the red breccias resistant due to their quartz content.

But the mill was not used only to grind grain into flour. Between 1880 and 1930 it also operated threshing and fodder-cutting machines at the neighboring farms. The mill is the last in a series of mills, sawmills, and forges that once lined up on the Laas brook.

Stop 2: The debris flow – Fear and dread

The beautiful cultural landscape does not immediately reveal that its formation was associated with fear and dread for the villagers. You stand here on an alluvial fan, a typical valley landscape feature. It originates point-like from a ditch and fans out downstream. Over the years, loose rock material accumulates in these ditches, which then moves during heavy rainfalls as a debris flow seeking its way down.

Villages in the Gail valley were repeatedly swept over by such debris flows. Houses were buried and the landscape devastated. Clearing the fields was laborious because heavy stones had to be removed. Mostly they were piled into stone heaps or stone walls.

In 1878, retaining walls were built above the residential blocks at the mountain foot to protect Laas.

Stop 3: The waterworks – Enough water thanks to desert

Water is indispensable alongside soil for the existence of a village. And Laas has it in abundance. On one hand because of the climate, as the Gail valley is one of the regions with the highest precipitation in Carinthia. But the geology also contributes by providing high-quality spring water.

The peaks of the Gailtal Alps around Laas are made up of limestone and dolomite rocks. Thanks to their many fractures, they absorb precipitation water and lead it deep into the mountain. On its way down, the mountain water encounters the poorly water-permeable red sedimentary rocks, rocks formed in a desert. This sealing layer forces the water to emerge. The spring line, along which one spring after another gushes from the mountain, runs along the entire Laas mountain. Without this seal, the water would flow away inside the mountain. Then the Gailtal Alps near Laas would not be the good spring water sources they are.

The first central water supply for Laas was built in 1922. The water reservoir bears witness to this. Previously, the inhabitants obtained their water from central village or farm wells.

Stop 4: The petrified trees of Laas – an underrated treasure

If humans cannot derive an immediate practical benefit from a natural formation, it tends to remain unnoticed - even if it is extremely valuable for science.

This was the case for the petrified tree of Laas, the largest plant fossil in Austria. It was uncovered around 1930 during rock blasting and initially used only by local children as a spectacular playground. Only in the 1940s did geologists learn of the trunk, and only in 1968 was it declared a natural monument. Since then, several other petrified trees have been found in Laas.

The 280-million-year-old tree proves that already in the Permian era trees up to 30 meters high grew. They had a widely branched crown but were not true conifers yet, rather their precursors, the cordaites. The scientific name of the tree is Dadoxylon schrollianum. What has been preserved is not the wood itself, but its pores filled with quartz. From the arrangement of the trees in the sandstone rock - lying here tangled - it can be concluded that they did not grow here but were washed to their current location.

Stop 5: Slag – turquoise and jade

In the gently babbling brook, among red rocks, glassy turquoise to jade-green stones sometimes sparkle. More often one finds dark and bubbly rocks like those expected near volcanoes. Along the Geotrail, they give the first hint that humans have always tried to make life easier and more comfortable by using raw materials.

In fact, these are artificial smelting residues (slag) generated during the extraction of metals from ores in a nearby blast furnace plant. Slag appears glass-like because it cools quickly. It has no time to form crystals but solidifies like glass into an unstructured (amorphous) mass. The colorful hues come from different metal salts. The bubbly cavities form due to gases produced during the smelting process and initially trapped in the slag.

Slag was and is used as insulating and bulk material (e.g., road gravel) and in the cement industry.

Stop 6: The blast furnace plant – shine and glamour

One of the most important raw materials for humanity is iron because high-quality weapons and robust tools can be made from it. It was mined in the Gailtal and Karnisch Alps and was a guarantor of prosperity. Two mining operations were also operated very close to this location.

The blast furnace plant of Laas, due to its good state of preservation, provides a clear picture of a smelting hut of the early 19th century. The blast furnace was put into operation in 1817, but due to unprofitability was shut down again in 1847. The facility is dominated by the forester's house with the attached, towering blast furnace. Behind it stretches the impressive coal pile, from which the blast furnace was charged with ore and charcoal from above via a wooden bridge. The doubly executed roasting oven, with which the ore was desulfurized, is unique in its kind in Austria. On average, 140 tons of pig iron were produced annually in Laas.

The forester's house even served as a film set in the 1950s. With the film crew for the Heimatfilm “Die Försterbuben,” a touch of glamour came to the still predominantly rural Gail valley.

Stop 7: The Pittersburg – old castle on young rock

As everywhere, humans had to protect themselves from the hardships of nature and enemies by erecting wooden or stone buildings. Wooden constructions naturally offered little protection against hostile attacks, which is why stone was preferred for fortifications and castles.

Of the three main rock groups around Laas, the garnet mica schists at the bottom, the limestones at the top, and the red mainland deposits in between, only the latter two were used as building and utility stones. And of course not only for the castle! They were used for house and garden walls, mortars, millstones, and even cannonballs for the storming of the Pittersburg. The mica schists were not used due to their schistose structure and low strength.

The Pittersburg was built on a striking limestone ridge. It is with about 245 million years the youngest rock that is hiked along the Geotrail. The first documentary mention of the castle dates back to 1252. From the 16th century, decay began. The remains of a cistern, a keep, and the zwinger wall have been preserved.

Stop 8: The village church – unexpected things

Stone art of unexpected quality can be admired in the late Gothic filial church of St. Andreas. This cultural achievement was possible because on one hand there was enough money for excellent craftsmen, as the Pittersburg near Laas was home to wealthy administrators for centuries. They initiated the construction of the church. On the other hand, the material for stonemasonry was found locally: the fine-grained, easy-to-process red Laas sandstone. The church was built between 1510 and 1535 under the direction of Bartlmä Firtaler.

Stone carving reached its highest perfection at the sacristy portal, whose door also preserves a late Gothic lock and fittings. The little stone figures high up on the buttresses decorated with cross flowers on the outside wall are bizarre. The stones around the west and south portals, with its late Gothic iron-studded door, were also elaborately worked. Particularly enchanting in the church is also its lierne and star rib vault with its delicate painted floral tendrils.