Text/Zhang Weicheng
About 202 million years ago, a massive volcanic eruption occurred on Earth, and the gas and dust emitted by the volcano obscured the sun for a long time, causing a long winter. That event led to the Triassic mass extinction, which wiped out three-quarters of the planet's species, including many large reptiles. However, the dinosaurs were lucky enough to survive, overcoming the cold and ushering in the warm Jurassic and Cretaceous periods, which survived until 65 million years ago. So, what kind of cold "volcanic winter" did the dinosaurs experience, and how did they survive that severe cold?
Pangea was formed about 300 million years ago as a result of tectonic plates that brought together most of the Earth's landmass
Volcanic eruptions in the Triassic
Dinosaurs appeared about 230 million years ago, when the Earth had bid farewell to the Paleozoic Era and entered the Triassic period of the Mesozoic Era, which was the first epoch of the Mesozoic Era, which began 252 million years ago and ended 201 million years ago. By the middle and late Triassic periods, primitive dinosaurs and the most primitive mammals had already lived on Earth, and there were aquatic reptiles such as ichthyosaurs in the sea. It was the dawn of the dinosaur era, and the dinosaurs were still relatively weak, far from reaching the level of dominating the animal world.
The Triassic Earth was very different from today, because all the landmasses were connected together and were a supercontinent. This supercontinent was formed about 300 million years ago and is known as the "Pangea" or "Pan-Continent". By the late Triassic, the magmatic activity of the underground asthenosphere was extremely intense, and the tremendous pressure caused the "Pangea" to split and trigger a large-scale volcanic eruption, which lasted for a long time.
Volcanoes eject large amounts of toxic gases and carbon dioxide, which are diffused into the air, causing global temperatures to rise. This drastic temperature change destroyed most of the plants that survived the eruption, making it even more difficult for animals to survive, and many animals became extinct.
Large amounts of volcanic ash remain in the air after the eruptions stopped, and they have clouded the skies for years, sparsely reaching the Earth's surface, and global temperatures have dropped with it. When the heat from volcanic eruptions is depleted in the atmosphere, the Earth turns into winter. The "volcanic winter" has arrived, and it has led to the extinction of more flora and fauna.
Find evidence of "Volcanic Winter".
Dinosaurs were thought to be adapted to live in warm climates, and roughly speaking, they were adapted to the humid greenhouse environments of the Triassic. But scientists have shown that dinosaurs did suffer from a cold "volcanic winter", and they apparently managed to survive that period.
The study was done by scientists from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, and Columbia University in the United States. In their research, scientists have found that dinosaurs have weathered harsh winters. They found evidence of ice in the Junggar Basin in the northwestern part of the continent, rocks with dinosaur footprints. They published the finding in the July 2, 2022, issue of Science Advances.
It is often assumed that dinosaurs lived in dense tropical jungles all the time. During the late Triassic and early Jurassic, the Earth had very high levels of carbon dioxide, much of which dates back to volcanic eruptions. Many scientists believe that due to the high content of carbon dioxide, the earth at that time became very hot and humid, and the climate was relatively warm. Also, there is no evidence that there were any polar ice caps at that time. On the contrary, on the earth at that time, dense forests seemed to stretch all the way to the polar regions.
The Junggar Basin is located at high latitudes, during the Triassic period, where vast forests were thought to have grown, with numerous conifers and deciduous trees growing along giant ancient lakes. Dinosaurs must have lived there at one time, and this is because the footprints they left behind have been found, many of which have been preserved in the sandstone formed at the bottom of the lake.
But was the climate really so suitable for dinosaurs? New research tells us more. This information suggests that despite the high levels of carbon dioxide in the atmosphere, the winters there are still harsh and cold, and the lake water may freeze, at least part of the lake will freeze, evidence of which lies in the rocks with dinosaur footprints.
Dinosaurs appeared about 230 million years ago
Triassic volcanic eruptions
Late Triassic
Feathers helped dinosaurs survive the winter
Scientists studied those rocks, and the size of the rock particles suggests that they are not sediments of local pristine lake mud. In other words, the rock was pushed here from somewhere else. Most likely, the lake water freezes the sand and gravel in the ice due to the cold weather. When the weather warms up and the ice drifts, the sand and gravel will take a "ride" on the ice and drift with the ice to another place. As the ice floes melt, they are deposited into new areas. These new sediments are different from the original sediments at the bottom of the lake, and they are evidence of the freezing phenomenon at that time.
During the Triassic period, volcanic eruptions left behind vast expanses of lava covering up to 7 million square kilometers across Africa, Europe and the Americas. This suggests that the magma eruption intermittently spanned at least tens of thousands of years, perhaps even 1 million years. This could mean that "volcanic winters" occur over and over again, ranging from years or decades to hundreds of years. As a result, the team concluded that the cold's damage to flora and fauna may have spread all the way to the tropics, and that some reptiles that could not withstand the cold went extinct.
However, the dinosaurs survived because many species of dinosaurs at the time had warm "feathered coats". Fossil evidence suggests that dinosaurs possessed feathers, which is where they differed greatly from other reptiles of the time. The feathers were enough for the dinosaurs to survive the long winters of the late Triassic. These dinosaur survivors multiplied rapidly during the warmer Jurassic period, and it is possible that they migrated to other regions. There, the fragile "natives" have become extinct, and the vacant land left behind by the extinct reptiles has become a new habitat for the dinosaurs.
Scientists believe that feathers may have been just one of the many reasons why dinosaurs were able to survive the long winter of the late Triassic and that dinosaurs diversified and spread around the globe in the early Jurassic period, and that there should have been other reasons why dinosaurs were such a successful species.
In the Junggar Basin (red oval zone), scientists have found evidence of a cold winter at the end of the Triassic