Earth Science Reviewer: Earth's History, Geological Processes, and Natural Resources

Vocabulary-style flashcards covering the major concepts of Earth's history, geological time, tectonics, soil properties, and the water cycle as presented in the Earth Science Reviewer.

Age of the Earth

The Earth is approximately $4.6 \times 10^9$ years old.

Relative Dating

The process of placing events or rocks in chronological order without knowing their actual age.

Absolute Dating

Determines actual ages using radiometric dating, which involves the decay of radioactive isotopes.

Principle of Original Horizontality

The principle stating that sedimentary layers are originally deposited horizontally.

Principle of Superposition

The principle stating that in undisturbed layers, the oldest rocks are at the bottom.

Principle of Cross-cutting Relationships

A feature that cuts across rock layers is younger than the layers it cuts.

Principle of Inclusions

The principle stating that rock fragments included in another rock are older than the host rock.

Eon

The largest unit of geologic time, such as the Phanerozoic or Precambrian.

Era

A major division within an eon, such as the Paleozoic, Mesozoic, or Cenozoic.

Period

A subdivision of an era, such as the Cambrian, Jurassic, or Quaternary.

Epoch

The smallest common unit of geologic time; a subdivision of a period, such as the Pleistocene or Holocene.

Hadean Eon

The eon occurring $\text{~} 4.6-4.0 \times 10^9 \text{ years ago}$ characterized by Earth's formation, meteorite bombardment, and collision with Theia.

Archean Eon

The eon occurring $\text{~} 4.0-2.5 \times 10^9 \text{ years ago}$ where Earth cooled and prokaryotes like cyanobacteria (stromatolites) appeared.

Proterozoic Eon

The eon occurring $\text{~} 2.5-0.54 \times 10^9 \text{ years ago}$ seeing the appearance of eukaryotes, soft-bodied animals, and the formation of the ozone layer.

Phanerozoic Eon

The eon from $\text{~} 541 \times 10^6 \text{ years ago}$ to the present, known for "visible life" and fossilized hard body parts.

Paleozoic Era

The era known as "Ancient Life," including the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian periods.

Mesozoic Era

The era known as the "Age of Dinosaurs / Reptiles," including the Triassic, Jurassic, and Cretaceous periods.

Cenozoic Era

The era known as the "Age of Mammals," starting from $65.5 \times 10^6 \text{ years ago}$ to the present.

Pleistocene Epoch

The epoch within the Quaternary Period known as the Great Ice Age, where earliest humans appeared.

Anthropocene

An unofficial epoch describing significant human impact on Earth's climate and ecosystems.

Internal Geological Processes

Processes occurring inside Earth driven by heat from Earth's interior, including plate tectonics and volcanism.

External Geological Processes

Processes occurring on Earth's surface driven by water, wind, ice, and gravity, including weathering and erosion.

Orogeny

The process of mountain building due to plate collision.

Divergent Boundary

A plate boundary where plates move away from each other, creating mid-ocean ridges and rift valleys.

Convergent Boundary

A plate boundary where plates move toward each other and collide, forming trenches and mountain ranges.

Transform Boundary

A plate boundary where plates slide horizontally past one another, causing earthquakes such as along the San Andreas Fault.

Weathering

The breaking down of rocks into smaller pieces via physical, chemical, or biological means.

Erosion

The movement or transport of sediments by natural agents like water, wind, ice, or gravity.

Deposition

The dropping of sediments in a new location, forming features like deltas and beaches.

Renewable Resources

Resources that can be replaced naturally within the time the supply is used, such as solar energy and water.

Non-renewable Resources

Resources that cannot be replaced in a short period as they take millions of years to form, such as fossil fuels.

Pacific Ring of Fire

A region with over $450$ volcanoes where the Philippines is located, contributing to rich metallic mineral deposits.

Soil Composition

Soil typically consists of $45\%$ mineral particles, $5\%$ organic matter (humus), $25\%$ water, and $25\%$ air.

Loam

An ideal soil type for most plants that holds moisture well, drains well, and allows good air access to roots.

O Horizon

The upper layer of soil containing organic materials like leaves and decomposed matter, including humus.

A Horizon

Also known as topsoil; it is rich in organic material and is the site of seed germination.

C Horizon

The layer consisting of broken bedrock with little to no organic matter.

Desertification

Land degradation in arid or semi-arid regions resulting from drought and overgrazing.

Salinization

The buildup of salt in soil from over-irrigation as water evaporates and leaves salts behind.

Hydrologic Cycle

The continuous circulation of water driven by solar radiation, involving stages like evaporation and precipitation.

Transpiration

The process by which plants release water vapor through their stomata.

Infiltration / Percolation

The process where water seeps into the soil to replenish groundwater and aquifers.

Watershed

An area of land where all runoff drains into a common outlet like a river, lake, or ocean.

Eutrophication

A pollution process where excess nutrients cause algal blooms, leading to oxygen depletion and dead zones.

Point-source Pollution

Pollution originating from a single identifiable source, such as a factory pipe.