Cenomanian-Turonian boundary eventとは 意味・読み方・使い方

The Cenomanian-Turonian boundary event, also known as the Cenomanian-Turonian extinction event, the Cenomanian-Turonian anoxic event, and referred to in Europe as the Bonarelli Event, was the latter of two anoxic extinction events early in the Late Cretaceous period. The event occurred approximately 91.5 ± 8.6 million years ago, and brought about the extinction of the ichthyosaurs and pliosaurs. Although the cause is still uncertain, the result starved the Earth's oceans of oxygen for nearly half a million years, causing the extinction of approximately 27 percent of marine invertebrates. This global environmental disturbance increased atmospheric and oceanic temperatures. Boundary sediments show an enrichment of trace elements, and contain elevated 613C values.