Ordovician tagged posts

Zircones. Credit: Anders Lindskog

Sustained meteorite bombardment. Some 470 million years ago, during the middle part of the geological period known as the Ordovician, an asteroid collision took place somewhere between Mars and Jupiter. The collision caused an explosion that sent a cascade of meteorites towards Earth. The heavy bombardment of Earth continued for millions of years, and even today some 20% of all meteorites that reach Earth originate from this asteroid break-up. At the same time Earth witnessed the greatest rise in marine biodiversity since the origin of multicellular life...