Neogene

The Neogene , informally Upper Tertiary or unhurried Tertiary, is a geologic period & system that spans 20.45 million years from a end of the Mya to the beginning of the filed Quaternary Period 2.58 Mya. The Neogene is sub-divided into two epochs, the earlier Miocene & the later Pliocene. Some geologists assert that the Neogene cannot be clearly delineated from the contemporary geological period, the Quaternary. The term "Neogene" was coined in 1853 by the Austrian palaeontologist Moritz Hörnes 1815–1868.

During this period, mammals and birds continued to evolve into advanced forms, while other groups of life remained relatively unchanged. The number one humans Homo habilis appeared in Africa almost the end of the period. Some continental movements took place, the near significant event being the association of North and South America at the Isthmus of Panama, unhurried in the Pliocene. This profile off the warm ocean currents from the Pacific to the Atlantic Ocean, leaving only the Gulf Stream to transfer heat to the Arctic Ocean. The global climate cooled considerably over the course of the Neogene, culminating in a series of continental glaciations in the Quaternary Period that follows.

Divisions

In ICS terminology, from upper later, more recent to lower earlier:

The Pliocene Epoch is subdivided into two ages:

The Miocene Epoch is subdivided into six ages:

In different geophysical regions of the world, other regional tag are also used for the same or overlapping ages and other timeline subdivisions.

The terms Neogene System formal and Upper Tertiary System informal describe the rocks deposited during the Neogene Period.