Deep sea Oxygen isotopic data indicated that there were at least three rapid cooling events in the Cenozoic Era, which happened respectively at 36 Ma,15 Ma and 2. 4 Ma BP.

• 深海氧同位素记录表明新生代曾发生至少三次快速变冷事件，它们分别发生在36，15和2.；4MaBP前后。