The world during the start of the Cainozoic
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
The Cainozoic (Cenozoic) is the present geological era. The word is derived from Greek kainos = "new", and zoe = "life". The era covers the period from 66 million years ago to the present. It started after the Cretaceous–Tertiary extinction event, which saw the demise of the last non-avian dinosaurs and the end of the Mesozoic Era.
During the Cainozoic the continents moved into their present positions. The climate started warm, but global cooling continued steadily, and finally ice ages occurred. On land, the Cainozoic is the era of mammals, and of birds and flowering plants. Grassland became a major habitat, and aquatic mammals took over the roles of predatory reptiles like the mosasaurs and plesiosaurs. As a result, the ecological landscape of the Cainozoic has become quite different from the Mesozoic.
The Cainozoic is spilt down into three periods, and the periods are split into stages.
Previously, what is now the Cainozoic was divided into two periods, the Tertiary and the Quaternary. The Tertiary corresponded to the Palaeogene+Neogene. Now, the term 'Tertiary' is not used officially ('deprecated').
- ↑ Cohen K.M; Finney S. & Gibbard P.L. 2013. International Chronostratigraphic Chart. International Commission on Stratigraphy. 
- ↑ Levin, Harold L. 2005. The Earth through time. 8th ed, Wiley, N.Y. Chapter 4: The fossil record.
- ↑ International Commission on Stratigraphy  There are alternate spellings for some terms: the prefix 'Palaeo' is written 'Paleo' in American English. both versions are correct. 'Cainozoic' may be spelled 'Cenozoic'.