The K/T boundary. The intermediate claystone layer contains 1000 times more
iridium than the upper and lower layers. It is the boundary between Cretaceous and
Tertiary Periods. The rock is from
Wyoming, USA.
The Cainozoic (Cenozoic) is the current geological era. It began 66 million years ago and continues today. Before it was the Mesozoic.
During the Cainozoic the continents moved into their present positions. The climate started warm, but cooling continued steadily. Finally ice ages occurred.
The word Cainozoic is derived from Greek kainos = "new", and zoe = "life". 'Cainozoic' may be spelled 'Cenozoic'. It has three periods, and the periods are split into stages.