Untitled Flashcards Set

Hadean Eon

The earliest eon of Earth's history (about 4.6 to 4 billion years ago); considered 'informal' as no rocks remain from this time.

Archean Eon

Lasted from about 4 billion to 2.5 billion years ago; characterized by the cooling of Earth’s crust and formation of solid rock.

Solar Nebula Hypothesis

Explains the formation of the solar system as a giant cloud of gas and dust collapsing under gravity.

Early Earth

Described as a molten mass with extreme heat and an atmosphere primarily composed of carbon dioxide and nitrogen.

Zircon minerals

Ancient minerals that have provided evidence of Early Earth conditions, dated around 4.4 billion years old.

Komatiites

Volcanic rocks formed from very high-temperature lava, indicating a hotter Earth in its early history.

Partial melting

Occurs when only part of a rock melts, crucial for magma formation and Earth's crust development.

Shields

Large, stable areas of ancient exposed rock on the Earth's surface.

Oceans' origin hypotheses

Include Outgassing (volcanic water release) and Comet/Asteroid Impacts (water delivery from space).

Early Earth atmosphere

Consisted of carbon dioxide, nitrogen, water vapor, methane, and ammonia; lacked free oxygen.

Miller-Urey experiment

A 1953 experiment that simulated early Earth conditions, forming amino acids, supporting the origins of life theory.

Evidence for early life

Includes chemical, sedimentary, and fossil evidence, such as amino acids and stromatolites.

Oldest fossil evidence

About 3.5 billion years old, consisting of stromatolites formed by microbial mats.

Cratons

Stable, ancient cores of continents, containing both shields and platforms. foundation of continent.

What is komatiite?

Komatiites are volcanic rocks that indicate past high temperatures in Earth's mantle.

What was the atmosphere of Early Earth like?

The early atmosphere likely contained carbon dioxide, nitrogen, and was devoid of oxygen.

How is the Moon thought to have formed?

The Moon formed from debris after a Mars-sized body collided with Earth.

What are shields and platforms?

Shields are stable rock areas; platforms are sedimentary rock layers covering shields.

What evidence supports the existence of early life?

Chemical, sedimentary, and fossil evidence like amino acids and stromatolites supports early life existence.