Proterozoic Eon

Proterozoic Eon

Lasted from 2.5 billion to 542 million years ago.

Laurentia

Large continent formed by sutured Precambrian provinces.

Rodinia

Supercontinent formed during the Grenville Orogeny.

Paleoproterozoic Era

First era of the Proterozoic, 2.5 - 1.6 billion years ago.

Mesoproterozoic Era

Second era, 1.6 to 1.0 billion years ago.

Neoproterozoic Era

Last era before Paleozoic, 1.0 billion to 542 million years ago.

Great Oxidation Event

Significant rise in atmospheric oxygen levels.

Huronian Glaciation

First ice age, occurred 2.4-2.3 billion years ago.

Varangian Glaciation

Glaciation event 850-600 million years ago.

Banded Iron Formations

Indicate ancient photosynthesis and oxygen production.

Gunflint Chert

Contains fossil remains of prokaryotic organisms.

Midcontinent Rift

Abandoned oceanic rift in Lake Superior region.

Grenville Orogeny

Major orogeny associated with Rodinia's formation.

Shunga Event

Accumulation of organic matter, petroleum generation.

Wopmay Belt

Evidence of rifting and ocean basin opening.

Trans-Hudson Belt

Records Wilson Cycle events in sedimentation.

Copper Mineralization

Native copper found in Keweenawan basalt.

Mount Rogers Formation

Sediments deposited during failed rifting attempt.

Catoctin Formation

Basaltic lava flows formed during Iapetus Ocean opening.

Epicontinental Seas

Shallow seas covering continental shelves.

Orogens

Mountain belts formed by tectonic activity.

Prokaryotes

Single-celled organisms, including ancient cyanobacteria.

Tillites

Conglomerates formed from glacial debris.

Varves

Seasonal sedimentary layers indicating glacial activity.

Phosphorites

Rocks containing high concentrations of phosphate.

Continental Flood Basalts

Extensive volcanic rock formations from eruptions.

Epicontinental Deposits

Sediments from shallow marine environments.

Glacial striations

Scratched and grooved pebbles and boulders from glaciers.

Glacial dropstones

Rocks released from melting icebergs into sediments.

Varved clays

Layered clays from glacial lake deposits.

Snowball Earth

Term for widespread Neoproterozoic glaciation.

Varangian glaciation

Formal name for the late Proterozoic ice age.

Plate tectonics

Geological processes influencing Earth's climate.

Atmospheric CO2

Greenhouse gas contributing to global warming.

Photosynthetic organisms

Organisms that convert CO2 into oxygen.

Cyanobacteria

Photosynthetic prokaryotes forming stromatolites.

Limestones

Calcium carbonate rocks associated with glacial deposits.

Eukaryotes

Organisms with complex cells and sexual reproduction.

Acritarchs

Single-celled eukaryotic microfossils from Neoproterozoic.

Metazoans

Multicellular animals with organized tissues.

Ediacara fauna

Soft-bodied multicellular organisms from Neoproterozoic.

Trace fossils

Fossils indicating organism activity, like burrows.

Cloudina

Earliest known organism with a calcium carbonate shell.

Small Shelly Fauna

Fossils with hard parts appearing in Neoproterozoic.

Oxygen oases

Marine areas with sufficient oxygen for life.

Vendoza

Proposed taxonomic category for Ediacara organisms.

Unconformity

Gap in geological record between rock layers.

Mazatzal orogeny

Mountain-building event involving granite intrusion.

Belt Supergroup

Thick sequences of Neoproterozoic sedimentary rocks.

Eukaryotic cell size

Typically larger than 60 microns in diameter.

Neoproterozoic glaciation

Period of extensive glacial activity around 600 my.

Cambrian sedimentary rocks

Rocks overlying Neoproterozoic units in Grand Canyon.

Stromatolites

Layered structures formed by cyanobacterial mats.