Pangaea believed to be the main cause of the shrinking of lysocline areas. The third cause of this extinction event that can be attributed to northern Pangaea is the beginnings of anoxic ocean environments, or oceans with very low oxygen concentrations. The mix of anoxic oceans and ocean acidification due to metal loading led to increasingly acidic oceans, which ultimately led to the extinction of benthic species. Pangaea Pangaea or Pangea () was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from earlier continental units approximately 335 million years ago, and it began to break
Gondwana resulted in the Uralian orogeny and Laurasia. Pangaea was finally amalgamated in the Late Carboniferous-Early Permian, but the oblique forces continued until Pangaea began to rift in the Triassic. In the eastern end collisions occurred slightly later. The North China, South China, and Indochina blocks rifted from Gondwana during the middle Paleozoic and opened the Proto-Tethys Ocean. North China docked with Mongolia and Siberia during the Carboniferous–Permian, followed by South China. The Cimmerian blocks then rifted from Gondwana to form the Palaeo-Thethys and Neo-Tethys oceans in the Late Carboniferous, and docked with Asia during the Triassic and Jurassic. Western Pangaea