I. Phanerozoic Eon Project Outline
A. Paleozoic Era(541 million to 252 million years ago)
- Cambrian Period
- Ordovician Period
- Tremadocian Epoch(Early Ordovician)
- Floian Epoch(Early Ordovician)
- Dapingian Epoch(Middle Ordovician)
- Darriwilian Epoch(Middle Ordovician)
- Sandbian Epoch(Late Ordovician)
- Katian Epoch(Late Ordovician)
- Hirnantian Epoch(Late Ordovician)
- Silurian Period
- Devonian Period
- Carboniferous Period
- Permian Period
B. Mesozoic Era(252 million to 66 million years ago)
- The Phanerozoic Eon is the span of geologic time extending about 541 million years from the end of the Proterozoic Eon (which began about 2.5 billion years ago) to the present.
- The Paleozoic Era is the earliest and the longest of the Phanerozoic eras, lasting from 541 to 251.902 million years ago.
- Dinosaurs ruled the Earth in the mighty Mesozoic Era
- 64 million years after dinosaurs went extinct, modern humans emerged in the Cenozoic era
- In the U.S., scientists divide the Carboniferous Period into two parts: the earlier Mississipian (359.2 million to 318.1 million years ago) and the later Pennsylvanian (318.1 million to 299 million years ago).source
- During the Ordovician, the southern continents were collected into Gondwana. Gondwana started the period in equatorial latitudes and, as the period progressed, drifted toward the South Pole.
- The Taconic orogeny, a major mountain-building episode, was well under way in Cambrian times. In the early and middle Ordovician, temperatures were mild, but at the beginning of the Late Ordovician, from 460 to 450 Ma, volcanoes along the margin of the Iapetus Ocean spewed massive amounts of carbon dioxide, a greenhouse gas, into the atmosphere, turning the planet into a hothouse