The Great Dying's Engine
Around 252 million years ago, the Earth's crust split open across what is now Siberia, initiating the largest known volcanic event in the last 500 million years. This was not a typical mountain volcano; it was a large igneous province known as the Siberian Traps. For roughly two million years, fissures in the ground poured out immense volumes of basaltic lava, covering an area of about 7 million square kilometers. The total volume of erupted material is estimated at around 4 million cubic kilometers, enough to cover the entire United States in magma a kilometer deep.
The eruptions occurred across the Permian-Triassic boundary and are considered the primary cause of the most severe extinction event in Earth's history. Today, this region, particularly the Putorana Plateau, displays the geological aftermath. The landscape is characterized by step-like hills formed by layers of solidified flood basalt, which is where the name "traps" originates—from the Swedish word "trappa" for stairs. The lava flows are thousands of meters thick in some places, a record of a planetary catastrophe.
A Planet pushed to the brink
The Siberian Traps eruptions released a mixture of gases into the atmosphere. As magma surged through the Earth's crust, it intruded into the Tunguska sedimentary basin, which was rich in coal, carbonate, and evaporite deposits. The intense heat from the magma baked these deposits, combusting massive quantities of coal and organic matter. This process released billions of tons of carbon dioxide, methane, and sulfur dioxide.
The consequences were global. Greenhouse gases caused lethal warming, with equatorial ocean temperatures potentially exceeding 40°C (104°F). Sulfur dioxide led to intense acid rain, while the absorption of CO2 by the oceans caused severe acidification and anoxia (a lack of oxygen). This cascade of environmental changes proved fatal for most life. Up to 96% of all marine species and 70% of terrestrial vertebrate species perished in the Great Dying. The event fundamentally altered Earth's evolutionary course, removing existing species and creating ecological space for new life forms, including the eventual rise of the dinosaurs.