The Siberian Traps (Russian: ДибиŃŃŠŗŠøŠµ ŃŃŠ°ŠæŠæŃ, romanized:Ā Sibirskiye trappy) are a large region of volcanic rock, known as a large igneous province, in Siberia, Russia. Large volumes of basaltic lava covered a large expanse of Siberia in a flood basalt event. The massive eruptive event that formed the traps is one of the largest known volcanic events in the last 500 million years. The eruptions continued for roughly two million years and spanned the PermianāTriassic boundary, or PāT boundary, which occurred around 251.9 million years ago. The Siberian Traps are believed to be the primary cause of the PermianāTriassic extinction event, the most severe extinction event in the geologic record. Subsequent periods of Siberian Traps activity have been linked to smaller biotic crises, including the Smithian-Spathian, Olenekian-Anisian, Middle-Late Anisian, and Anisian-Ladinian extinction events. Today, the area is covered by about 7Ā millionĀ km (3Ā millionĀ sqĀ mi) of basaltic rock, with a volume of around 4Ā millionĀ km (1Ā millionĀ cuĀ mi).