Walk-about through space and time

History and evolution of our earth



Walk-about through space and time

Walk-about through space and time

Over the course of millions of years the region that is today Carinthia gradually shifted from a position near the south pole to its present location on the globe. This ‘walk-about’ was associated with repeated changes in climatic and geological conditions, frequently resulting in the region lying below sea level. Geoscientific methods shed light on the climate, geography and environmental conditions in past epochs, while plant and animal fossils allow us fascinating insights into the history and evolution of our planet. Humankind did not appear until very much later, and was then still very much part of the natural cycle of life, and as such dependent on the climate and migratory pattern of prey animals.

Carinthia at the south pole

Five hundred million years ago, in the early Palaeozoic, the region that is present-day Carinthia lay below sea level near the south pole. For around 150 million years the Earth was in an interglacial period with considerably higher temperatures than today that was interrupted only once, for about 30 million years, by an ice age. In the Carinthian limestones from this period one finds fossils of various types of marine life, including corals, which are typical of shallow, warm seas.

Early marine predators

Elongated fossils are evidence of early sea dwellers that were related to today’s squid and octopuses. On contrast to the latter, however, they had a shell, made of aragonite that fossilized into calcite. These orthoceras (‘straight-horns’) could grow up to a length of eight metres and were the largest marine predators of their time. 

How do we know … how old fossils are?

An undisturbed sequence of rock strata enables researchers to determine the age of fossils (biostratigraphy). The rule of thumb is: the deeper, the older. More exact information as to their age can be made using the naturally-occurring radioactive isotopes in the rock. Here the rule is: the further back in time, the less precise the results will be.

Carinthia emerges

Towards the end of the Palaeozoic era, around 300 million years ago, the supercontinent Pangaea formed. The region of today’s Alps lay on its eastern coast near the Equator. After a lengthy interglacial a colder period began with intermittently extensive regions of glaciation, that did not, however, affect the equatorial regions. In Carinthia, finds from this time include fossils of a diverse flora from warm and wet as well as dry habitats, and the earliest traces of land vertebrates (early reptiles) from Austria, typical of a dry and warm region with seasonal rainfall.

Giant trees

Around 330 million years ago (in the Carboniferous) giant horsetails as well as sigillaria and scale trees flourished in this region. The commonest finds are remains of leaves from these giant trees; only rarely are large trunk fossils preserved like that from the Gail Valley displayed here.

How do we know ... the geographical position of a particular region in the past?

Certain sedimentary rocks can allow us to draw conclusions about the prevailing climatic conditions during their formation. Red sandstones indicate an arid, desert-like environment with seasonal rainfall, found for example near the Equator. Two hundred and ninety million years ago in the present-day Gail Valley two different early reptiles left their tracks one after the other in the red sand of a wide, desiccating river landscape.

When rocks form, magnetic constituents such as iron align themselves with the earth’s magnetic field. This also yields clues to their former geographical position.

Submersed once again

Around 220 million years ago the supercontinent Pangaea began to break up again and the regions where the Alps would eventually arise sank in shallow tropical seas north of the Equator. Once again there was an interglacial period with no ice sheets in the polar regions that lasted for more than 200 million years. Molluscs with spiral shells called ammonites flourished and are emblematic of the Mesozoic.

Giants of the seas

Small and large marine reptiles lived in the shallow tropical sea, including Shastasaurus carinthiacus, which grew to a length of several metres. Although only a few of its ribs and vertebrae have been preserved as fossils they nonetheless give us a unique insight into life during the Triassic.

How do we know … what extinct animals looked like and how they lived?

The bodily structure of extinct animals and the rock in which they are embedded can supply information about how they lived and the environment they inhabited. The small ‘flipper lizard’ Neusticosaurus was an agile swimmer that preyed on fish. For this it developed large eyes and a set of teeth that bent outward slightly to seize its prey. Fossils have been found in limestones, a chemical sediment that forms predominantly in warm shallow lagoons and marine areas. The fossilized remains of fish are also occasionally found in these limestones.

A gap in time

While the present-day Alps are hard to miss, their formation led to the rocks of the Jurassic and the Cretaceous – and thus around 135 million years of the Earth’s history – being almost completely lost in Carinthia. Fossils from this time are found at only a very few sites in Carinthia.  

On water and land

In the Cenozoic, which began around 65 million years ago, Carinthia had almost reached its present-day position on the globe and was largely continental. However, it was flooded by the sea another two times, as attested by fossils of marine creatures such as molluscs, sea urchins and corals. When the sea finally retreated, swamp forests and bush swamps spread out near the coasts. Here early species of elephant, rhinoceros, apes and other tropical animals lived, as the climate was considerably warmer than today.

Prehistoric elephants in the Lavant Valley

Around eighteen million years ago the prehistoric elephant Gomphotherium migrated from Africa to Europe. Alongside characteristic molars with rounded cusps these herbivorous giants also had two pairs of tusks in the upper and lower jaw, very much in contrast to the elephants found today. 

How do we know … what the environment looked like and how cold or warm it was at any given time?

Certain rocks and plant and animal fossils can tell us about the climatic conditions of earlier times. Apes, rhinoceroses and elephants lived and still live in warm regions, and leaf shapes are also different from those in colder areas. Bogs need moist to wet climatic conditions to form. Peat forms in anaerobic conditions, later turning into lignite (soft coal) and then hard coal.

The Carinthian forest ape Dryopithecus carinthiacus lived 12.5 million years ago in a swamp forest in the present-day Lavant Valley. As the ‘first Austrian’ he had similar problems to today’s humans: a love of sweet fruit caused a large hole to develop in one of his molars.

Cold times

In the Cenozoic the climate started to cool. Currently we are in a warmer phase of the present ice age that began around 2.7 million years ago with the glaciation of both polar regions and during the course of which the Alps were almost entirely covered in glaciers four times. The Drau glacier, for example, once extended from the Grossglockner mountain to Griffen, and the Klagenfurt basin lay under a layer of ice that was more than 600 metres thick. Despite the cold a variety of animals adapted to live on the dry tundra bordering the glaciers.

Ice age inhabitants

A distant relative of today’s elephant, the woolly mammoth evolved during the last ice age around 750,000 years ago. Consuming up to 250 kg of grass daily, these herbivores affected the landscape in that they regulated the vegetation of the tundra. Their bones and tusks are not only very large but also very long-lasting and are thus regularly found.

How do we know … which areas were covered by glaciers in the ice age?

While the tremendous forces exerted by the glaciers have left numerous traces on the subsurface, the remains of ice age inhabitants such as mammoths or woolly rhinoceroses are only found in areas that were free of ice. In winter, ice age cave bears, which were considerably larger than today’s brown bears, sought shelter in the ice-free areas in caves, where their bones have been preserved over the millennia. The tiny bones of unborn young that died with their mother in the cave have also been found occasionally.

Neanderthals in Griffen

The earliest known traces of human settlement in what is today Carinthia are around 40,000 years old and derive from the Neanderthals of the Palaeolithic. At that time, small groups of hunters and gatherers occasionally pushed forward into the periphery of the Alps. A small cave system in the south-east part of the hill on which Griffen Castle stands was used repeatedly by these people for temporary shelter. Finds in the outer cave include the remains of fire pits, simple stone tools and the bones of prey animals such as wisent, steppe bison, reindeer, deer and horse.

Inhabitants of the Karavanks

In the Potočnik cave in the Eastern Karavanks, Stone Age hunters found a sheltered site to make camp at 1,700 m above sea level. The more than hundred bone arrow or spear heads found there are typical of the time around 35–30,000 BCE. The stone tools – in particular scrapers and knives – were used to cut up meat and prepare skins. Fragments of ochre indicate that body-painting was practised. Unconnected with human use of the cave, bears also hibernated here. However, they were only occasionally hunted and killed.

Griffen Stone Age hunters

Excavations at the dripstone cave at Griffen revealed traces of a later Stone Age encampment dating from around 10,000 BCE. By now freed from their carapace of ice, the Alps were home to wild animals and the humans that hunted them.

Most of the tools for cutting, scraping and drilling together with the weapons consist of brown chalcedony. A few flakes of rock crystal probably came from the Saualm or Koralm mountain ranges. Hornstone was also present as a raw material. The bones of ibex and reindeer are evidence of the animals hunted.

Surviving in the high mountains

Near the Waidegger Höhe peak in the Gail Valley traces of Stone Age hunters (c. 7,000–4,500 BCE) were found at an elevation of 1,850 m above sea level. These hunters set up summer encampments in the mountains at crossing places, by lakes and streams or under the shelter of overhanging rock walls or large boulders. Rock crystal was used alongside hornstone and flint to make the blades for weapons and tools such as the scraper found at the Waidegger Alm that served to work the skins of hunted animals, for example ibex, chamois and marmots.

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