Miocene

The Miocene Epoch is a period of time that extends from about 5 million to 24 million years before the present. As with other older geologic periods, the rock beds that define the start and end are well identified, but the exact dates of the start and end of the period are slightly uncertain. The Miocene was named by Sir Charles Lyell. The name means roughly "less recent" and refers to the essentially modern mammalian faunas. The Miocene follows the Oligocene Epoch and is followed by the Pliocene Epoch. The Miocene is the fourth epoch of the Tertiary Era.

The Miocene boundaries is not set at an easily identified worldwide event but rather at regional boundaries between the warmer Oligocene the relatively cooler Miocene and the even cooler Pliocene.

The Miocene faunal stages from youngest to oldest are:

1. Aquitanian
2. Burdigalian
3. Langhian
4. Serravallian
5. Tortonian
6. Messinian

Continents continued to drift toward their present positions. Of the modern geologic features, only the land bridge between South America and North America was absent. Climates remained moderately warm although slow global cooling that eventual led to the Pleistocene glaciations continued. Mountain building took place in Western North America and Europe. Both continental and marine Miocene deposits are common worldwide with marine outcrops common near modern shorelines. Well studied continental exposures occur in the American Great Plains and in Argentina.

Both marine and continental fauna were fairly modern. Recognizable wolves, horses, beaver, deer, camels, crows, ducks, owls, whales, etc existed in the Miocene. Only in isolated South America and Australia did widely divergent fauna exist.

See also: Geologic Time Scale

Referenced By