Summary
Highlights
Around 250 million years ago, a massive mantle plume formed in Siberia, leading to the eruption of the Siberian Traps. This volcanism released enormous amounts of CO2, burning carbonaceous rocks and causing significant global warming, ocean anoxia, and acidification. This event, known as the 'Great Dying,' resulted in the extinction of over 90% of all species, marking the largest mass extinction in Earth's history.
Following the Great Dying, life quickly recovered, leading to the Mesozoic Era, known as the age of dinosaurs. Dinosaurs evolved around 240 million years ago and dominated the Earth. Mammals also evolved during this era, though later, and were overshadowed by the dinosaurs. Recent discoveries suggest dinosaurs may have been warm-blooded, allowing them to be more active.
The most significant tectonic event of the Mesozoic was the breakup of Pangea, starting around 180 million years ago. This led to the formation and widening of the Atlantic Ocean. Along the western coast of North America, convergent forces caused ongoing mountain building and volcanism, responsible for uplifting the Rocky Mountains, which began forming about 80 million years ago.
The Mesozoic Era concluded with a catastrophic asteroid impact near the Yucatan Peninsula. The impact caused immediate devastation, including a thermal pulse, hurricane-force shockwaves, tsunamis, and ejected molten fragments that reheated the Earth's surface. These events obliterated life near the impact site, but the long-term consequences proved even more devastating worldwide.
The asteroid impact's long-term effects included dust particles blocking sunlight, causing months of darkness and a global winter that disrupted photosynthesis and food chains. The vaporization of evaporite rocks released CO2, leading to global warming for hundreds of thousands of years, and sulfuric acid rain. This rapid environmental shift caused the extinction of around 80% of all species, including all dinosaurs, paving the way for the mammal-dominated Cenozoic Era.