why earth is died ?

 

Earth exhaled, and the ‘Great Dying’ began

Gases from deep in Earth’s crust are implicated in the planet’s worst extinction event.

Earth’s biggest mass extinction was triggered by the release of gases from the planet’s own crust.

Some 252 million years ago, enormous amounts of lava poured out of volcanoes in Siberia, along with volatile gases such as chlorine and bromine. The gases depleted the ozone layer, allowing dangerous levels of ultraviolet radiation to reach Earth’s surface. As a result, more than 90% of all marine species went extinct, an event known as the Great Dying.

Scientists have been unable to account for the precise source of the volatiles. A team led by Michael Broadley at the French National Centre for Scientific Research in Vandoeuvre-Lès-Nancy compared Siberian rocks that formed before the eruption with others that formed from cooling lava after the eruption. The older rocks contained levels of chlorine, bromine and iodine high enough to deplete most — or even all — of the globe’s ozone layer. Those gases rose, with the lava, from deep in Earth’s crust.

Eruptions that tap buried volatiles are more likely to cause a global environmental crisis than those that don’t.