A huge asteroid is usually thought to be the only culprit for the extinction of dinosaurs, but that may not be the only cause,media New Atlas reported. After analyzing fossil shells from that period, scientists concluded that the Earth’s system was already under pressure before the impact, as volcanic eruptions could heat the ocean and raise mercury levels to dangerous levels.
Technically, dinosaurs were victims of climate change – but the question was what triggered it. After an asteroid hit Earth, most species became extinct as a result of the attendant climate change. Such an impact would trigger a large amount of dust particles that would hover in the atmosphere for years, in addition to acid rain that increased the acidity of the ocean. At the same time, dust clouds block sunlight for months, killing many plants. These factors prevent most living things on Earth from continuing to survive.
But while the story of an asteroid impact is considered the most important hypothesis, it is not the only one. Another major competitor is the massive volcanic eruption, most likely those that formed India’s Dedryn shield. It is one of the largest territorial shields in the world and covers an area of about 500,000 square kilometers. The eruption began about 66 million years ago and lasted about a million years. During this time, it will release large amounts of carbon dioxide, which will lead to significant climate change.
Now, researchers at the University of Michigan have found evidence to support the effects of india’s Dedrydin shield eruption. By studying fossil mollusc shells about 66 million years ago, the team found evidence of warming oceans and higher levels of mercury — both symptoms of volcanic eruptions.
The fossil shells were collected from Antarctica, the United States, Argentina, India, Egypt, Libya and Sweden. By analyzing the isotope composition of the carbonates, the team was able to determine the temperature of the water at the time the shells formed, and to calculate the mercury content in the water. Importantly, these markers appeared in the fossil record before the impact.
Kyle Meyer, lead author of the study, said: “For the first time, we can see the unique effects of the Dedrynoor eruption on the climate and the environment by analyzing a single material. Surprisingly, the same samples showed the highest mercury concentrations, similar to those in places where mercury was heavily contaminated in modern industrial industries, when the temperature of the sea suddenly warmed. “
It is clear that mercury should be avoided in the environment, but is usually found in highly polluted areas around power plants and mines. For comparison, the team examined the mercury in modern clam shells collected from an industrial site in Virginia and came up with similar readings.
Sierra Petersen, co-author of the study, said: “Human fishing is prohibited in modern premises due to high mercury levels. “So imagine the environmental impact of mercury pollution levels that have been around the world for tens to hundreds of thousands of years. “
The researchers didn’t point out that the asteroid impact didn’t happen – instead, they said both could contribute. Asteroid impacts may have accelerated climate change caused by volcanic eruptions. The team says studying these markers could help us better understand ancient climate change events.
The study was published in the journal Nature Communications.