|Proposed redefinition(s)||850–541 Ma|
Gradstein et al., 2012
|Proposed subdivisions||Cryogenian Period, 850–630 Ma|
Gradstein et al., 2012
47°04′34″N 55°49′52″W / 47.0762°N 55.8310°W
|Upper GSSP ratified||1992|
The Neoproterozoic Era is the unit of geologic time from 1 billion to 538.8 million years ago.
It is the last era of the Precambrian Supereon and the Proterozoic Eon; it is subdivided into the Tonian, Cryogenian, and Ediacaran periods. It is preceded by the Mesoproterozoic Era and succeeded by the Paleozoic Era of the Phanerozoic Eon.
The most severe
The earliest fossils of complex
According to Rino and co-workers, the sum of the continental crust formed in the Pan-African orogeny and the Grenville orogeny makes the Neoproterozoic the period of Earth's history that has produced most continental crust.
At the onset of the Neoproterozoic the supercontinent Rodinia, which had assembled during the late Mesoproterozoic, straddled the equator. During the Tonian, rifting commenced which broke Rodinia into a number of individual land masses.
Possibly as a consequence of the low-latitude position of most continents, several large-scale glacial events occurred during the Neoproterozoic Era including the
These glaciations are believed to have been so severe that there were ice sheets at the equator—a state known as the "Snowball Earth".
Neoproterozoic time is subdivided into the Tonian (1000–720 Ma), Cryogenian (720–635 Ma) and Ediacaran (635–538.8 Ma) periods.
Russian regional timescale
In the regional timescale of Russia, the Tonian and Cryogenian correspond to the Late Riphean; the Ediacaran corresponds to the Early to middle Vendian. Russian geologists divide the Neoproterozoic of Siberia into the Mayanian (from 1000 to 850 Ma) followed by the Baikalian (from 850 to 650 Ma).
Russian timescale for Proterozoic. Neoproterozoic is equivalent to the time span from Late Riphean to Late Vendian.
The idea of the Neoproterozoic Era was introduced in the 1960s. Nineteenth-century paleontologists set the start of
A few of the early animals appear possibly to be ancestors of modern animals. Most fall into ambiguous groups of frond-like organisms; discoids that might be holdfasts for stalked organisms ("medusoids"); mattress-like forms; small calcareous tubes; and armored animals of unknown provenance.
These were most commonly known as
In addition to Ediacaran biota, two other types of biota were discovered in China. The Doushantuo Formation preserves fossils of microscopic marine organisms in great detail. The Hainan biota consists of small worm-shaped organisms.
The nomenclature for the terminal period of the Neoproterozoic Era has been unstable. Russian and Nordic geologists referred to the last period of the Neoproterozoic as the
However, in 2004, the International Union of Geological Sciences ratified the Ediacaran Period to be a geological age of the Neoproterozoic, ranging from 635 to 538.8 (at the time to 542) million years ago. The Ediacaran Period boundaries are the only Precambrian boundaries defined by biologic Global Boundary Stratotype Section and Points, rather than the absolute Global Standard Stratigraphic Ages.
- Boring Billion – Earth history, 1.8 to 0.8 billion years ago
- ^ a b c "Stratigraphic Chart 2022" (PDF). International Stratigraphic Commission. February 2022. Retrieved 22 April 2022.
- ^ Craig, J. (26 November 2015). "Global Climate, the Dawn of Life and the Earth's Oldest Petroleum Systems". Retrieved 15 March 2019.
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- USGS. Retrieved 22 April 2022.