Neoproterozoic

The final era of the Proterozoic Eon, spanning approximately 1,000 to 539 million years ago. It includes major episodes of global glaciation and the emergence of complex animal life.

Snowball Earth: The hypothesis that Earth experienced episodes of near-global glaciation. Neoproterozoic deposits record glaciations severe enough to motivate this hypothesis.
Proterozoic: The eon of geologic time preceding the Phanerozoic, from about 2.5 billion to 539 million years ago. The Neoproterozoic is its final era.
International Commission on Stratigraphy: The scientific body that standardizes the global geologic time scale and its boundaries. Its chart formalizes the Neoproterozoic’s periods and their dates.
Snowball Earth hypothesis: A scientific hypothesis that Earth was almost entirely covered by ice during ancient glaciations. Neoproterozoic glacial deposits provide its most prominent geological test.
Sturtian glaciation: A Neoproterozoic ice age that lasted roughly 717 to 660 million years ago. It was one of the era’s two major Cryogenian glaciations.
Geologic time scale: The system that organizes Earth's history into nested eons, eras, periods, and smaller intervals. It places the Neoproterozoic between the Mesoproterozoic and Phanerozoic.
Global Boundary Stratotype Section and Point: A designated geological section that defines the boundary of a unit on the geologic time scale. The Ediacaran base is fixed at a stratotype in South Australia.
Cap carbonate: A carbonate rock layer that commonly overlies Neoproterozoic glacial deposits. Its placement above glacial sediments records abrupt postglacial ocean and climate change.
Marinoan glaciation: A severe Cryogenian ice age that ended about 635 million years ago. Its deposits preserve evidence for ice reaching low latitudes.
Tonian: The earliest period of the Neoproterozoic, spanning about 1,000 to 720 million years ago. It begins the era and precedes the Cryogenian.

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MesoproterozoicCompared with: It follows the Mesoproterozoic and contains major glaciations and early animal diversification.