Proterozoic Eon and Earth History

These flashcards cover major geological and biological concepts from the Proterozoic Eon, including significant events, organisms, and climatic processes.

Proterozoic Eon

A geological eon that occurred from about 2.5 billion to 541 million years ago, marked by the formation of supercontinents and significant tectonic activity.

Supercontinent

A giant landmass composed of multiple continental plates joined together; notable examples include Columbia, Rodinia, and Pannotia.

Ediacaran Fauna

An assemblage of early multicellular, soft-bodied organisms that lived between 635 to 541 million years ago, showcasing early stages of animal life.

Banded Iron Formations (BIFs)

Sedimentary rocks formed from the precipitation of iron oxides, significant for understanding the oxygenation of Earth's atmosphere.

Great Oxygenation Event

A major event occurring around 2.4 billion years ago when Earth's atmosphere became rich in oxygen, largely due to cyanobacteria.

Snowball Earth

Hypothetical global glaciation events in Earth's history, where the planet's surface was entirely or nearly entirely frozen.

Albedo

The measure of reflectivity of Earth's surface; higher albedo from ice can lead to cooling, contributing to a positive feedback loop in climate.

Feedback Loop

A process where a system responds to an initial change and amplifies or diminishes that change; important in understanding climate dynamics.

Forcings

External factors that influence the climate system, such as volcanic CO₂ emissions, which can initiate warming trends.

Glacial Dropstones

Rocks that have been transported by glacial ice and deposited in sediment, serving as evidence of past glacial activity.

Cap Carbonates

Sedimentary deposits that overlie glacial deposits and indicate rapid climatic warming following glaciation.

Greenhouse gases

Gases that trap heat in Earth's atmosphere; a reduction in these gases can trigger global cooling.