We all know that water on Earth is the source of life, and there is no life without water. However, water can also sometimes be a cause of disaster, especially when it comes in the form of torrential rains, which can cause great damage and threat to humans and other living things. There was once a heavy rain on Earth that lasted for more than 2 million years, will such weather still occur in the future?
According to scientists, there was indeed a 2 million-year-long global or localized wet event in Earth's history, known as the Carney Flood Event, which occurred during the Carney period in the middle of the Triassic period, about 2 years ago3.4 billion to 23.2 billion years ago. This event caused climate change and changes in biodiversity on Earth, and was the biggest trigger for the Triassic mass extinction, bringing great crises and challenges to life on Earth.
The discovery of the Carney flood event originated from an expedition by the British geologist Rafael in the 80s of the last century. At that time, he examined the rock formations of the Triassic in some parts of Europe and found some unusual features. In the rock layers of the Carney period, the soils exhibit the typical characteristics of tropical humid climates, i.e., organic and fluvial soils; The vegetation is characterized by hygroscopic pollenology that is more suitable for humid climates; Siliceous detritals enter the basin due to increased weathering of the land and increased runoff; Amber was widespread in geological layers during this period. These features suggest that the climate of the region changed abruptly from arid to humid during this period, and that the wetness did not last for a short time (in terms of geological time scales).
Rafael's discovery caught the attention of other geologists, who found similar features in different areas, thus confirming the existence of a Carney flood event. In the Sichuan Basin of China, the humid climate of the Carney period has also been found. Far across the ocean, in Texas, USA, alluvial sediments from the Carney period, such as sandstone, conglomerate, and mudstone, have also been found. These findings suggest that the Carney flood event is a wide-ranging geological event that may involve global or partial climate change.
So why did the Earth suddenly become unusually wet during this period? There are two main hypotheses, one related to large-scale volcanic eruptions, and the other related to plate tectonics and orogeny.
The first hypothesis is that the Carney flood event was caused by a large-scale volcanic eruption in Langoria (present-day western Canada). This eruption occurred on 23.4 billion years ago, a large amount of carbon dioxide was produced, which caused global warming, accelerated the atmospheric water cycle, and caused a surge in rainfall.
The evidence for this hypothesis is that carbon dioxide levels were indeed relatively high during the Carney period, and that the formation of volcanic rock formations in Langoria was similar to that of the Carney period. However, there are some problems with this hypothesis, such as the large error in the dating of volcanic eruptions, and the unclear extent and duration of volcanic eruptions.
The second hypothesis is that the Carney flood event was caused by plate tectonic movements and orogenic movements. This hypothesis suggests that the Carney flood event was a regional climate disturbance that occurred mainly in the western part of the Tethys Sea and was associated with the formation of new mountain ranges by the Cimmerian orogeny.
The Cimmerian orogeny was caused by the closure of the eastern branch of the Tethys Sea, which led to the beginning of the uplift on the southern side of the European continent, forming a series of mountain ranges. These mountains maintain a strong pressure gradient between the ocean and the continent, which creates the monsoon.
As a result, the summer monsoon is intercepted by the mountains, producing heavy rainfall, which explains the transition from sediments in the western Tethys Sea to a humid climate. The evidence for this hypothesis is that both the monsoon characteristics of the Carney period and the timing of the formation of the mountain range coincide with the Carney flood event.
However, there are some questions about this hypothesis, such as whether the monsoon is strong and widespread enough to cause global or partial climate change, and whether the formation of mountain ranges is related to volcanic activity.
In conclusion, there are still many controversies about the causes of the Carney flood event, which may involve the combined effect of multiple factors, and more evidence and analysis are needed to solve the problem.
Regardless of the cause of the Carney flood event, its impact and significance are enormous, it may have changed the ecological and geological environment on Earth, promoted the evolution and rise of some species, and may also lead to the extinction of some species, and may even be the prelude to the Triassic mass extinction.
The Carney flood event made it difficult for some organisms that had been adapted to arid climates to survive, while some organisms that had adapted to humid climates gained a survival advantage.
A large number of tropical rainforest plants began to go extinct on a large scale because these plants could not adapt to excessive water and low temperatures, and also lost their symbiotic relationship with other organisms. But the Carney flood event also contributed to the expansion of ferns, as these plants can grow in or near water, and are also resistant to low temperatures.
Carney flood events may also have altered the Earth's geological environment, altering some previously stable terrain and revealing some otherwise inconspicuous terrain.
For example, the Carney flood event may have led to the disappearance of some deserts as they were washed and eroded by large amounts of rain, forming new rivers and lakes. Conversely, the Carney flood event may have contributed to the formation of some mountain ranges as a result of plate tectonic and volcanic activity, which may have been associated with the Carney flood event. For example, the Karni flood event may have contributed to the formation of the Himalayas, as these mountains were caused by the collision of the Indian and Eurasian plates, which may have been associated with the Karni flood event.
Without the Carney flood event, there would not be such a species-rich earth now, under the influence of the event, the Triassic ushered in a mass extinction, bringing great crises and challenges to life on earth. The Triassic mass extinction was the worst extinction event in Earth's history, occurring at the end of the Triassic period, about 2 years ago5.1 billion years ago, it caused the extinction of about 95% of all species on Earth. Many scientists believe that the global climate instability caused by the Carney flood event caused some species to become extinct due to climate change and the disruption of the food chain, and the extinction of these species may have laid the groundwork for the later Triassic mass extinction, which plunged life on Earth into a deep crisis.
There are still many difficult questions and confusions in the study of Carney flood events, but they are enough to warn us that human activities will lead to climate warming and increased rainfall on the earth, which will lead to new flood events. This question is worth pondering!