Stegosaurus lived in the Cretaceous Period

Cretaceous Period (144-65 million years ago)

The Cretaceous Period is the period 144-65 million years ago. It was shaped by the rule of large carnivorous dinosaurs and a sudden extinction of the dinosaurs at the end of the Cretaceous period, when a meteorite probably hit the earth.

Our present day continents are forming

During the Cretaceous Period, the former supercontinent Pangea finally breaks up into the continents as we know them today. The Tethys is becoming increasingly narrowed between North Africa and Europe. The climate cooled down a little and was no longer sufficient for reef formation by corals, which require a constant temperature of at least 20 ° C. Large parts of Germany are initially flooded, but in the course of the Cretaceous the ocean withdraws from Germany.

The lone is created

With the retreat of the sea over southern Germany, the creation of the Lonetal begins. The surface of the earth in our area bulged over a large area, at that time southern Germany was located on an area of ​​this bulge inclined to the south or southeast. The apex of this vault was in the area of ​​today's Rhine Valley, from there the masses of water flowed off to the south or southeast, depending on their gradient. This drainage system formed large rivers, including the Lone. The headwaters of the Lone are likely to have been located in the Black Forest or even further to the west. This Urlone was hardly comparable with today's little river. Rather, it should have been a mighty river that flowed into the Tethys far to the south, on what is now the northern edge of the Alps. A Danube as we know it today, into which the Lone could have flowed, did not yet exist at that time.

Reign of the dinosaurs

On land, new species of dinosaurs appear in the Cretaceous Period, including the most well-known species such as the Tricaterops, Tyrannosaurus Rex and the Velociraptor.

Giant pterosaurs dominated the skies of the Cretaceous Period. These included the ornithocheiros, with a wingspan of 12 meters and a body length of 2.5 meters, probably the largest airborne creature that ever populated our earth.

Perhaps the greatest changes occurred in the plant kingdom: flowering plants spread increasingly and became the most common plant species by the end of the Cretaceous Period.

Mammals led a largely shadowy existence at this time, they were mainly small, nimble nest predators, such as the Didelphodon, which fed on dinosaur eggs.

Life in the sea could hardly have been less dangerous than on land. Giant mosasaurs, up to 17 meters long, carnivorous marine reptiles were at the top of the marine food chain. Archelon, a nearly 5 meter tall giant tortoise, also lived in the seas of the Cretaceous period, but despite its size, it was by no means safe from the predators of the time, which in addition to the mosasaurs also included sharks.

Illustration: Mosasaur

The end of a dynasty

65 million years ago, the dinosaurs suddenly died out on land and in the water. The question of the cause of extinction is one of the most common questions in paleontology. It is likely that climate change has contributed to the extinction of many species. The earth was cooling noticeably at this time, and a drop in sea level may have reduced the dinosaur habitats, especially the shallow water areas.

In addition, there was an accumulation of volcanic eruptions at the end of the Cretaceous period, which should at least have led to local changes in the atmosphere.

The second and most frequently cited theory is the so-called "impact theory". It is believed that a large meteorite impact caused the dinosaurs to die out. Huge clouds of dust could have darkened the atmosphere for months or even years and ultimately deprived the animals of that time of their livelihood.

The sudden mass extinction at the end of the Cretaceous however paved the way for the success story of mammals in the next geological period - and thus also prepared the stage for the development of humans.

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