65 million years ago the earth's atmosphere was contaminated with mercury


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If you think before the asteroid fell on our planet 65 million years ago, the life of the dinosaurs was beautiful and cloudless, then we must quickly disappoint you. According to a new study published in the journal Nature Communications, the earth's atmosphere was heavily contaminated with mercury even before the killer asteroid Chicxulub appeared. For many years, researchers have been arguing about the causes that led to the death of dinosaurs. While some blame the case of the asteroid for a high concentration of mercury in the Earth's atmosphere, others believe that the conditions on the planet are no longer suitable for life. But who is right?

Most likely, the dinosaurs died out as a result of a deadly series of random events.

Where does mercury come from in the earth's atmosphere?

The results of the study showed that strong volcanic eruptions began tens of thousands of years before the fall of an asteroid with a diameter of three kilometers on Earth. Scientists believe that lava could exacerbate the effects of a catastrophic event that claimed three quarters of the life on the planet. University of Michigan experts examined the composition of ancient petrified shells from around the world and observed an increase in mercury and carbon dioxide levels. According to the scientists, this is due to a series of volcanic eruptions that have caused traps to form on the Deccan Plateau (India) – one of the largest volcanic formations on our planet. Most of all, the outbreaks lasted about a million years. And what do you think caused the dinosaurs to die? You can share the answer and discuss the mass extinctions in the comments and with the participants in our telegram chat.

Model of the emission cycle of volcanic mercury.

As a result of the ongoing volcanism, a large amount of a toxic trace element – mercury – fell into the ocean. As a result, it was absorbed by the phytoplankton that the mollusks feed on. It is not surprising that the high concentration of toxic substances on land and in the oceans had a major impact on the climate and the environment. During the study, experts measured carbon dioxide and mercury levels in conch shells that were collected in India, Libya, Egypt, Sweden, the United States, Antarctica and other countries at different times, including today's Late Cretaceous and Pleistocene. The results showed that sudden warming occurred about 250,000 years before the mass extinction of the dinosaurs. This also coincides with a sharp rise in mercury around 68 and 70 million years ago, the most intense period of volcanic activity.

The extinct fossil oyster aged 66 to 72 million years. Agerostrea ungulata from Libya is shown.

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According to the Sciencealert.com portal, further analysis of deep sea residents is required to confirm the results. Nevertheless, it is already becoming clear today that the fossil marine flora and fauna represent a unique source of information about the mass extinction and the climate changes of the past. The study's authors believe that the same samples can avoid problems with mineral dating because they contain traces of chemical and climatic effects on the Earth's biosphere.