Earth Science – Modules 1-6 Vocabulary

A comprehensive set of vocabulary flashcards covering key terms and definitions from Earth Science Modules 1–6, including Earth system components, mineralogy, petrology, weathering, erosion, and related processes.

Earth Science

The study of Earth’s structure, properties, and processes.

Geology

Branch of Earth Science focused on Earth’s history, origin, and structure.

Meteorology

Scientific study of the atmosphere and weather.

Astronomy

Study of outer space, celestial bodies, and the universe beyond Earth.

Oceanography

Science dealing with the physical and biological aspects of the ocean environment.

Solar Nebular Hypothesis

Theory proposing the Solar System formed from a supernova-triggered rotating cloud of gas and dust.

Vortex Theory

Early idea that the Solar System originated from whirlpool-like motion producing circular orbits.

Collision Theory (Solar System)

Hypothesis that planets formed from material ejected after a collision between the Sun and a giant comet.

Kant-Laplace Nebular Theory

Model stating a collapsing nebula flattened and condensed into the Sun and planets.

Tidal Theory (Chamberlin-Moulton)

Concept that a passing star pulled material from the Sun, which later condensed into planets.

Lithosphere

Earth’s rigid outer layer; often called the crust.

Hydrosphere

All liquid-water components of Earth (oceans, lakes, rivers, groundwater).

Atmosphere

Gaseous envelope surrounding Earth that protects it from harmful solar radiation.

Troposphere

Lowest, thinnest atmospheric layer where weather occurs.

Stratosphere

Atmospheric layer containing the protective ozone layer.

Mesosphere

Middle layer of the atmosphere that burns up most incoming meteoroids.

Thermosphere

Hottest atmospheric layer; absorbs high-energy solar radiation.

Ecosphere (Exosphere)

Outermost atmospheric layer shielding Earth from meteors, asteroids, and cosmic rays.

Biosphere

Life-supporting zone of Earth where living organisms exist.

Mineral

Naturally occurring, inorganic, crystalline solid with an ordered atomic arrangement.

Luster

The way a mineral’s surface reflects light (metallic vs. non-metallic).

Hardness

A mineral’s resistance to being scratched (Mohs scale).

Color (Minerals)

Visible hue of a mineral; least reliable diagnostic property.

Crystalline Structure

External shape reflecting a mineral’s internal atomic arrangement.

Equant Crystal

Crystal whose three dimensions are approximately equal in length.

Elongate Crystal

Prismatic crystal that is longer in one direction.

Platy Crystal

Crystal that appears flattened like a plate.

Cleavage

Tendency of a mineral to break along flat, even planes.

Fracture

Irregular, uneven breakage of a mineral not along cleavage planes.

Magnetism (Minerals)

Ability of certain minerals (e.g., magnetite) to attract a magnet.

Reaction to Acid

Effervescence of carbonate minerals when exposed to dilute HCl.

Specific Gravity

Relative density: mineral weight divided by weight of an equal volume of water.

Silicates

Mineral group composed of silicon and oxygen, often with additional metals.

Oxides

Minerals consisting of oxygen bonded to metallic elements.

Sulfates

Minerals containing the sulfate ion (SO₄²⁻).

Sulfides

Minerals consisting of sulfur combined with metals.

Halides

Minerals formed from halogen ions (Cl⁻, F⁻) bonded to metals.

Carbonates

Minerals with carbonate ion (CO₃²⁻) plus metal cations.

Native Elements

Minerals composed of a single element in uncombined form (e.g., gold).

Phosphates

Minerals derived from the phosphate ion; often formed from mineral breakdown.

Mineraloid

Substance resembling a mineral but lacking a crystalline structure.

Igneous Rock

Rock formed by crystallization of molten material.

Extrusive Igneous Rock

Igneous rock that solidifies from lava at Earth’s surface.

Intrusive Igneous Rock

Igneous rock that crystallizes from magma beneath the surface.

Sedimentary Rock

Rock produced by lithification of sediments.

Clastic Sedimentary Rock

Sedimentary rock composed of compacted and cemented fragments of pre-existing rocks.

Organic Sedimentary Rock

Sedimentary rock formed from accumulated biological material (e.g., coal).

Chemical Sedimentary Rock

Rock precipitated from solution (e.g., limestone from CaCO₃).

Bioclastic Sedimentary Rock

Rock made of broken shell or skeletal fragments.

Metamorphic Rock

Rock altered by heat, pressure, and/or chemically active fluids.

Contact Metamorphism

Metamorphism caused by heat from nearby magma intrusion.

Burial Metamorphism

Metamorphism resulting from deep burial under accumulating sediments.

Regional (Dynamothermal) Metamorphism

Large-scale metamorphism associated with mountain-building and plate collision.

Hydrothermal Metamorphism

Alteration of rock by hot, mineral-rich fluids.

Heat (Agent of Metamorphism)

Energy source that drives recrystallization in rocks.

Pressure (Agent of Metamorphism)

Force that increases rock density and promotes new mineral growth.

Foliated Texture

Metamorphic texture showing banded or layered appearance.

Non-foliated Texture

Metamorphic texture lacking distinct layering.

Mechanical Weathering

Physical breakdown of rocks without chemical change.

Pressure-Release Fracturing

Expansion and cracking of rock after overlying material is removed.

Frost Wedging

Rock disintegration caused by repeated freeze-thaw of water in cracks.

Abrasion (Weathering)

Mechanical scraping of rock surfaces by particles carried by wind, water, or ice.

Organic Activity (Weathering)

Rock breakup due to plant roots, burrowing animals, or other biological actions.

Thermal Expansion and Contraction

Cracking caused by temperature-driven expansion and contraction of rock surfaces.

Chemical Weathering

Decomposition of rocks through chemical reactions altering mineral composition.

Dissolution

Chemical weathering where minerals dissolve into water.

Hydrolysis

Reaction of minerals with acidic water, forming new minerals like clay.

Oxidation

Chemical reaction of minerals with oxygen, often producing rust-colored oxides.

Carbonation

Reaction of CO₂-rich water with minerals, especially carbonates.

Glacial Erosion

Transport of rock particles incorporated within glacial ice.

Fluvial Erosion

Erosion by running water, subdivided into rain splash, sheet, and rill processes.

Rain Splash Erosion

Detachment of soil particles by impact of raindrops.

Sheet Erosion

Uniform removal of soil in thin layers by overland flow.

Rill Erosion

Formation of small channels as water concentrates during sheet flow.

Deflation (Aeolian)

Removal and transport of loose particles by wind.

Wind Abrasion

Erosive sculpting of surfaces by wind-blown particles.

Deposition

Exogenic process where transported sediments settle and accumulate.