For about 90 million years, our planet has beencompletely different. In the so-called Cretaceous period, which will be discussed in this article, huge dinosaurs walked on the surface of the earth, and volcanoes erupted much more often and stronger than now. Since a lot of water vapor and carbon dioxide got into the atmosphere of our planet during volcanic eruptions, a strong greenhouse effect appeared on Earth. Water vapor and carbon dioxide covered our planet like a plastic bag and did not allow the incident sunlight to reflect back into space. As a result, the planet was almost always warm, and even in the now cold Antarctica, the average air temperature was about 13 degrees Celsius. And this means that it did not have as much snow and ice as it is now. Or maybe there were rainforests?
Earth in the time of the dinosaurs
Scientists already have good reason to believethat during the time of dinosaurs in Antarctica, relatively warm rivers flowed and tall trees grew. In 2017, the crew of the German research vessel Polarstern decided to go to the ice-covered Amundsen Sea and drill a deep hole at its bottom. Thus, they wanted to find soil samples from the Cretaceous period, since having studied their composition they could very well find the remains of ancient plants. Upon reaching the place, they drilled a hole at the bottom of the sea 30.7 meters deep. A core was extracted from it, whose age was about 88 million years. These are just the times of the Cretaceous period, which was interesting to researchers.
Core Is a rock sample that was mined fromdeep holes on the surface of the earth. By studying the extracted materials, scientists can determine the climate that reigned in ancient times, as well as recognize the species of ancient plants.
Ancient plants in Antarctica
Studying ancient soil, scientists led byProfessor Johann P. Klages actually found the fossilized remains of plant roots, as well as their pollen. By comparing these remains with the roots and pollen of modern plants, they were able to find out that conifers, ferns, and even plants with flowers grew on the territory of ancient Antarctica. At the moment, we can say with confidence that 90 million years ago in Antarctica grew:
- Conifers of the Podocarpaceae familythat are found today in South America and Africa;
- Conifers of the Araucariaceae familyfound in Australia and the islands of New Guinea;
- A huge amount of fern, including the Cyatheaceae family, which today includes 514 species;
- Flowering plants of the genus Beaupreawhose closest relatives are African proteas.
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It turns out that millions of years ago it’s now coldAntarctica was a territory covered with lush, green vegetation. Scientists also believe that rivers with fresh water flowed between the forests - did the trees need to eat something? In words and images of artists, ancient Antarctica is presented as a hot, tropical place. But in reality, the climate by modern standards was not so comfortable, because the average air temperature clearly did not exceed 13 degrees Celsius. It was a little nicer only in the summer, when the air was heated to 18.5 degrees. It is also known that in ancient Antarctica it rained quite often - the average annual rainfall was 1120 millimeters, when as in modern Moscow, about 707 millimeters fall annually.
Interesting fact: in the days of dinosaurs, the day was only 23.5 hours. About where 30 minutes of time disappeared, read in this material.
In addition to being formed under the influence oferupted greenhouse-effect volcanoes, trees growing in Antarctica contributed to an increase in air temperature. The fact is that dense vegetation did not allow sunlight to bounce off the surface of the Earth, and the forest territories of Antarctica seemed to attract heat. The ability of forests, water, sand, snow and other surfaces of our planet to reflect sunlight is called land albedo. Plant forests have low albedo, so intheir clusters are relatively warm climate. And the snow and ice have high albedos, so modern Antarctica reflects a lot of sunlight, does not retain heat and is a rather cold place.
Forests existed in Antarctica several dozenmillion years and most likely disappeared 70 million years ago. Then the location of the continents on our planet began to change, which undoubtedly affected the activity of volcanoes. As a result of changes in volcanic activity, sea level and many other innovations, the air temperature on our planet began to fall and in places reached -45 degrees Celsius.
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Today we know Antarctica as covered in snow andice desert, on which live except for penguins and scientists. But something strange is happening today with the icy continent, because recently the air temperature in some of its areas has risen to 18.3 degrees Celsius, just like in the days of dinosaurs. Climate change is transforming the appearance of Antarctica and it is impossible to call it a crystal clear and white spot on our planet. Look at satellite photos - brown earth is already visible on the mainland. We live in unpredictable times and who knows, maybe in a couple of decades tropical forests will reappear in Antarctica?