Toarcian turnover
The Toarcian turnover, alternatively the Toarcian extinction, the Pliensbachian-Toarcian extinction, or the Early Jurassic extinction, is the wave of extinctions that marked the end of the Pliensbachian age and the start of the Toarcian age of the Early Jurassic epoch, 183 million years ago.
The Toarcian turnover was most strongly affected marine life, notably mollusks, radiolarians, foraminifera, calcareous nannoplankton, brachiopods, ostracods, crinoids, crustaceans, marine reptiles, and fish. Its reach was global in extent, as evidenced by research in Europe, Africa, Japan, South America, and North America. Evidence points to a warming climate, the spread of anoxia in the oceans, and ocean acidifcation as the probable cause of these marine extinctions, linked in turn to the massive volcanism of the Karoo-Ferrar eruptions that occurred at this time. The Toarcian turnover was the seventh-largest mass extinction in Earth's history.
