Geologic Time and Earth Processes

Flashcards covering key terms and definitions related to geologic time, Earth processes, and seismic activities.

Geologic Time

Earth's history spanning 4.55 billion years; vast time scale making human history a small fraction.

Uniformitarianism

The principle that present processes help interpret past geological events.

Radiometric Dating

A method to determine the age of rocks using the decay of radioactive isotopes.

Half-life

The time required for half of the parent isotopes in a sample to decay.

Parent Isotope

The original radioactive isotope that undergoes decay.

Daughter Isotope

The stable product that results from the decay of a parent isotope.

Superposition

A principle stating that in an undeformed sequence of sedimentary rocks, the oldest layers are at the bottom.

Original Horizontality

The concept that sedimentary layers are deposited horizontally; tilting occurs afterward.

Mass Movement

The downslope movement of rock, soil, or debris due to gravity, which shapes the land.

Glacier

A permanent mass of ice that moves downslope under the influence of gravity.

Seismic Waves

Vibrations caused by the release of energy during an earthquake; includes body waves and surface waves.

Epicenter

The point on the Earth's surface directly above the focus of an earthquake.

Intraplate Earthquake

An earthquake that occurs within tectonic plates, away from plate boundaries.

Liquefaction

A phenomenon where saturated soil behaves like a liquid during shaking, causing instability.

Erosion

The process by which rock and soil are worn away and transported by natural forces such as wind or water.

Fossil Succession

A principle stating that fossils found in rock layers can help determine relative ages.

Tension

A type of stress that acts away from each other, causing rock to stretch.

What is condensation?

Condensation is the process where water vapor cools and changes back into liquid water, forming clouds.

What is precipitation?

Precipitation is any form of water, such as rain, sleet, or snow, that falls from clouds to the Earth's surface.

What happens during evaporation?

Evaporation is the process where liquid water is heated and transforms into water vapor.

What is collection in the water cycle?

Collection is the process where water gathers in bodies like rivers, lakes, and oceans after precipitation.

What role do plants play in the water cycle?

Plants contribute to the water cycle through a process called transpiration, where they release water vapor into the air.