The Earth "got angry" and it took 2 million years to recover.

In recent days, the volcano on Hongahaapai Island in the South Pacific island nation of Tonga has erupted violently several times and triggered tsunamis, posing a serious threat to the local area and surrounding areas.

This mosaic photo shows: a satellite image of Tonga's Hongaha Apa'i Island taken by the Worldview02 satellite on April 11, 2021 (left) and a satellite image of the island after the volcanic eruption taken by the Gaofen-1 satellite on January 17, 2022. The orange curve is the original outline of the island marked according to geographic coordinates. Xinhua News Agency (Photo courtesy of Xinhua News Agency Satellite News Laboratory)

Volcanic eruptions cause mass extinction? It happened 200 million years ago

200 million years ago, there was also a huge volcanic eruption, which was much more powerful than the Tonga volcano eruption. It not only brought about a huge climate change, but also caused a mass extinction, causing more than half of the earth's creatures to disappear. What caused this "catastrophe" in the history of evolution?

Image source: Xinhua Viewpoint

Recently, an international team led by China University of Geosciences (Wuhan) and Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences, found strong evidence that volcanic eruptions were the main cause of environmental upheavals and species extinction at the time. The relevant results have been published in the international authoritative journal Nature Communications.

Schematic diagram of forest fires caused by volcanic eruptions 200 million years ago. Drawn by Yang Dinghua from the Institute of Paleontology and Anthropology, Chinese Academy of Sciences

Since mercury can be transported over long distances in the atmosphere, it is very likely to be preserved in large areas of land and sea strata, and therefore can be used as a good indicator to track traces of volcanic activity.

In recent geological studies, mercury has been widely used to indicate ancient volcanic records in Earth's historical sediments.

The research team targeted the East Asian region located on the eastern margin of the Tethys Ocean at that time, and selected two continuously developed Triassic and Jurassic stratigraphic sections representing high latitudes (Haojiagou in the Junggar Basin of Xinjiang) and mid- and low-latitudes (Xuanhan area of ​​the Sichuan Basin), and carried out analysis and research using a variety of methods, including organic carbon isotopes, mercury concentrations and isotopes, chemical alteration indices, and clay minerals.

The stratigraphic sections involved in this study: Photo of the Haojiagou section in the Junggar Basin, Xinjiang. Photo courtesy of China University of Geosciences (Wuhan)

The stratigraphic sections involved in this study: Photos of the Xuanhan section in the Sichuan Basin. Photo courtesy of the Institute of Paleoanthropology and Anthropology, Chinese Academy of Sciences

The results showed that the mercury content in these strata increased significantly, the carbon isotope values ​​fluctuated, and the clay minerals indicating weathering also changed. Since volcanic activity is the most important natural source of mercury in geological history, such results prove that volcanic eruptions not only affected a wide range, but also led to a series of climatic and ecological changes.

It takes 2 million years to recuperate

Wang Yongdong's team from the Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences, has been paying attention to whether there are records of volcanic activity, such as volcanic ash, in the geological sediments at the turn of the Triassic and Jurassic periods in the Sichuan Basin in South China.

He said that this mass extinction is one of the five mass extinctions in the history of the Earth. For decades, scientists have put forward various speculations on the cause of this extinction. Volcanic eruptions are considered to be an important cause, but the extent of its impact has been difficult to determine.

Combining previous geological studies, researchers finally roughly restored the mass extinction scene 200 million years ago:

At that time, a "supervolcano" on land continued to erupt for nearly 600,000 years, forming a large-scale magma deposit across North America and Pangaea. The volcano emitted huge amounts of carbon dioxide and methane into the atmosphere, causing carbon dioxide concentrations to reach about 10 times the current level. The increasing greenhouse gases caused climate warming, ocean hypoxia, seawater acidification, and increased continental weathering. This process lasted for about 2 million years. A large number of organisms were unable to adapt to the drastic changes in the environment and eventually disappeared from the earth.

"However, this mass extinction also provided room for other organisms to develop. Dinosaurs appeared soon after, starting their journey of dominance that lasted for more than 100 million years," said Shen Jun, the first author of the paper and a researcher at China University of Geosciences (Wuhan).

Volcanoes are adjustments to the Earth's interior.

It is also a warning to humans about "excessive activities"

Some volcanoes have erupted before human history but are no longer active and are called "dead volcanoes."

There are about 2,000 known "dead volcanoes" on Earth. Throughout human history, volcanoes that are still active or erupt periodically are called "active volcanoes", and a total of 523 "active volcanoes" have been discovered.

What are some famous volcanic eruptions on Earth?

Famous volcanic eruptions on Earth

Volcanic Eruption

How to reduce losses?

Volcanic eruptions are one of the ways of releasing energy induced by adjustments within the earth, which far exceeds the ability of humans to interfere with. Therefore, volcanic eruptions are inevitable.

However, there are often signs before a volcanic eruption, such as gas eruptions, earthquakes, and increased geothermal heat. This is because as the underground magma rises, part of the rock mass will break and sink or rise upward, forming deformation. Severe cases will cause earthquakes, which are called "volcanic earthquakes."

At present, volcano monitoring technology is divided into three categories internationally, namely volcanic earthquake monitoring, volcanic deformation monitoring and volcanic gas monitoring.

Most seismometers that monitor volcanic activity are located within 1 to 15 km of the crater. Obtaining a baseline of background seismic activity recorded over many years and inferring possible precursory activities have become the main tools for predicting volcanic eruptions.

Scientists are making substantial progress monitoring Mount St. Helens, thanks to satellite data that can detect tiny movements, ground sensors that track molten rock deep underground and gas-sniffing devices that can be flown on drones over the boiling mountain.

Thanks to the increase and upgrade of monitoring equipment, scientists have successfully predicted the timing of many volcanic eruptions in the past 40 years.

However, how to infer the situation deep underground by looking at data such as gas emissions and surface shape, that is, the personality of each volcano - unique properties and structure, has become a new challenge for volcanologists. Volcanic systems are complex and hidden, so volcanic forecasts are not as good as weather forecasts.

Therefore, people should pay attention to relevant information and government arrangements in a timely manner and live away from volcanoes if feasible.

Human beings should have a deep understanding of the earth and live in harmony with it. This is the most effective, lowest-cost and least-harmful "fire prevention and disaster reduction" measure.

Related paper information:

https://doi.org/10.1038/s41467-022-27965-x

refer to:

China Science Daily (2022-01-19, Page 4, original title: "How the Earth Adjusts Itself After a Volcanic Eruption")

Expert: Wang Yongbin, PhD, University of Chinese Academy of Sciences, Associate Professor, School of Earth Sciences, Yunnan University

Comprehensive sources: Xinhua Viewpoint, Science and Technology Daily, China Science Daily, Science Popularization China, etc.