One thing mysterious occurred practically half a billion years in the past that triggered one of the vital essential modifications within the historical past of life on Earth. Instantly, there was an explosion of species, with the biodiversity of invertebrate animals rising from a really low degree to one thing much like what we see as we speak. The preferred rationalization for this “Great Ordovician Biodiversification Event” is that it was a results of an uncomfortably sizzling Earth cooling and finally heading into an ice age.

However what really triggered the change in temperature? In our new paper, published in Science Advances, we present that its onset coincided precisely with the largest documented asteroid breakup within the asteroid belt in the course of the previous two billion years, brought on by a collision with one other asteroid or a comet. Even as we speak, virtually a 3rd of all meteorites falling on Earth originate from the breakup of this 150 kilometer-wide asteroid between Jupiter and Mars.

Following this occasion, monumental quantities of mud would have unfold by way of the photo voltaic system. The blocking impact of this mud might have partly stopped daylight from reaching the Earth – resulting in cooler temperatures. We all know that this concerned the local weather altering from being kind of homogeneous to changing into divided into local weather zones – from Arctic circumstances on the poles to tropical circumstances on the equator. The high diversity among invertebrates, together with inexperienced algae, primitive fish, cephalopods and corals, got here as an adaptation to the brand new local weather.

Swedish sea ground

Our proof comes from detailed research of sea ground sediments of Ordovician age (485m-443m years in the past) uncovered at Kinnekulle in southern Sweden and Lynna River close to St. Petersburg in Russia. In a quarry at Kinnekulle, we discovered greater than 130 “fossil meteorites” – rocks that fell on Earth within the historical previous, which turned embedded in sea ground sediments and had been preserved similar to animal fossils.