Earth Science Lecture Notes Flashcards

Vocabulary flashcards covering systems, geology, mineralogy, petrology, oceanography, and meteorology.

Absolute Dating

A method of determining exactly how long ago events in Earth history occurred, primarily using radioactive decay.

Absolute Instability

An atmospheric condition where the environmental lapse rate is steeper than the dry adiabatic rate, making bad weather and rising thermals likely.

Absolute Stability

An atmospheric condition where the environmental lapse rate is more shallow than the wet adiabatic rate, causing rising thermals to sink and making bad weather unlikely.

Accretion

The process by which planetesimals grow into larger planets through sticky collisions, converting kinetic energy into heat.

Active Continental Margin

A coastline characterized by intense geological activity, such as earthquakes and volcanoes, typically associated with subduction zones or transform faults.

Adiabatic Process

A thermodynamic process where no heat is exchanged between a system and its surroundings; in meteorology, it explains how air cools as it expands.

Aftershocks

Weaker seismic vibrations that occur several hours after a major earthquake as the rock releases remaining stored energy.

Air Mass

An enormous body of air with relatively uniform temperature and pressure at any given elevation; categorized as tropical, polar, maritime, or continental.

Albedo

(Inferred context) The reflectivity of a surface; mentioned via the necessity of wrapping an actinometer in black cloth to avoid reflecting solar radiation.

Antarctic Circumpolar Current

The strongest ocean current in the world, which flows unhindered around Antarctica, isolating it and contributing to global cooling.

Anticyclone

A high-pressure weather system where winds circulate outward (clockwise in the Northern Hemisphere) and air sinks and warms adiabatically.

Aphanitic Texture

A fine-grained igneous rock texture where crystals are too small to see with the naked eye, resulting from rapid cooling.

Aphelion

The point in Earth's orbit when it is furthest from the Sun ($152.5 \times 10^6\,km$), occurring around July 3rd.

Archipelago

A group or chain of islands, such as the Aleutian Islands or the West Indies.

Asthenosphere

The weak, partially molten layer of the mantle upon which the tectonic plates of the lithosphere float.

Atmospheric Pressure

The force exerted by the atmosphere per unit area; average sea-level pressure is $1013.25\,mb$ or $760\,mm\,Hg$.

Atomic Mass

The sum of the number of protons and neutrons in an atom's nucleus.

Atomic Number

The number of protons in the nucleus of an atom, which determines the element's identity.

Aurora

Curtains of light near the magnetic poles caused by solar wind particles colliding with atmospheric molecules; known as Borealis (North) and Australis (South).

Basalt

A dark, fine-grained (aphanitic) mafic igneous rock that is the primary component of the ocean basins.

Batholith

The largest type of pluton (intrusive igneous body), often forming the ancient core of a continent.

Bathymetry

The study and measurement of ocean depths below sea level.

Benthos

Marine organisms that live on or in the seafloor, such as clams and lobsters.

Binary System (Chemical)

(Inferred from minerals like Halite) A compound composed of two elements, such as $NaCl$.

Biogenic Sedimentary Rock

Rock formed from the lithification of organic matter and inorganic sediment, such as coal or chalk.

Biosphere

The totality of all life on planet Earth.

Bjørgvin Theory of Meteorology

The fundamental theory stating the atmosphere is divided into air masses that interact at boundaries called fronts.

Bowen Reaction Series

A progression describing the cooling order of minerals: mafic minerals crystallize first at high temperatures, while felsic minerals crystallize last.

Brackish Water

Water with a salinity significantly less than $35\text{\u2030}$, typically found where river water and seawater mix.

Brittle Deformation

The fracturing or breaking of rock when subjected to large forces in a short duration, resulting in faults.

Cation

A positively charged ion that has lost one or more electrons.

Cellular Respiration

The chemical reaction in cells: $C_6H_{12}O_6 + 6O_2 \rightarrow \text{energy} + 6CO_2 + 6H_2O$.

Centrifugal Force

A force caused by Earth's rotation that results in the Equator bulging outward, making the Earth an oblate spheroid.

Chemical Sedimentary Rock

Rock formed through the precipitation of minerals from water, such as limestone ($CaCO_3$).

Cinder Cone

A small, common type of volcano built from the accumulation of ejected pyroclastic materials (lahars).

Circle of Tangency

The line where a map projection's flat paper touches the Earth; accuracy is highest near this line.

Clastic Sedimentary Rock

Rock formed from the physical lithification of rock fragments (sediments), such as sandstone or shale.

Cleavage

The characteristic way a mineral breaks along flat planes of internal chemical weakness.

Closed System

A system that exchanges energy with its surroundings but does not exchange matter.

Cloud

A visible mass of water droplets or ice crystals formed when a thermal cools to its dew point.

Cohesion

The electrical attraction between water molecules due to water's dipolar nature, resulting in surface tension.

Conduction

The transfer of thermal energy through direct contact between objects.

Conformal Projection

A map that preserves the correct shapes of features but distorts their relative sizes.

Contact Metamorphism

The process where rock is changed into metamorphic rock primarily through intense heat from nearby magma.

Continental Drift

The early hypothesis proposed by Alfred Wegener that continents were once joined and have since moved apart.

Continental Effect

The phenomenon where inland areas experience extreme temperature variations due to the low heat capacity of land.

Continental Margin

The transition zone where the edge of a continent meets the ocean basin; includes the shelf, slope, and rise.

Convection

The transfer of heat by the physical movement of fluids (liquids or gases); drives tectonic plates and atmospheric weather.

Convergent Plate Boundary

A boundary where two tectonic plates move toward each other, leading to subduction or mountain building.

Coriolis Force

A fictitious force caused by Earth's rotation that deflects moving objects to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.

Craton

The ancient, stable interior of a continent, composed mainly of old batholiths.

Cyclone

A low-pressure weather system where winds circulate inward (counterclockwise in the Northern Hemisphere) and air rises and cools adiabatically.

Deep-Water Wave

An ocean wave in water deeper than its wave base ($\frac{1}{2}\lambda$), where speed depends only on wavelength.

Density

The ratio of an object's mass to its volume ($\rho = \frac{m}{V}$).

Dew Point

The specific temperature at which air becomes saturated ($100\%\,\text{relative humidity}$) and water vapor condenses into liquid.

Differentiation

The process by which a molten planet separates into layers of varying density, forming a core, mantle, and crust.

Dip-Slip Fault

A vertical or slanted break in rock where motion is up or down; necessary for forming fault mountains (horsts) and rift valleys (grabens).

Divergent Plate Boundary

A boundary where two tectonic plates move away from each other, allowing new rock to form from rising magma.

Ductile Deformation

The bending or folding of rock when subjected to small forces over a long duration.

Dynamic

A term describing a state of continuous change, used to characterize the Earth's systems.

Earth Science

The study of the Earth as an interrelated system involving geology, oceanography, meteorology, biology, and astronomy.

Earthquake

The sudden release of stored elastic potential energy in rock, causing intense seismic vibrations.

Echo Sounding

A technique using reflected sound waves to measure ocean depth ($\text{Depth} = \frac{1}{2} \times v \times t$).

Elastic Rebound

The mechanism by which compressed rock snaps back to its original shape, causing an earthquake.

Electromagnetic Radiation

Energy that travels as waves at the speed of light ($3.00 \times 10^8\,m/s$), including visible light, X-rays, and infrared.

Electron

A negatively charged subatomic particle that orbits the atomic nucleus.

Element

A substance composed of only one type of atom, defined by its atomic number.

Epicenter

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

Equatorial Countercurrent

A weak, warm surface current flowing west-to-east along the equator in opposition to the prevailing trade winds.

Equivalent Projection

A map that preserves the correct relative sizes of features but distorts their shapes.

Eustatic Change

A global change in mean sea level caused by factors like the melting of ice sheets or the thermal expansion of water.

External Energy Source

The Sun, which drives the Earth's hydrosphere, atmosphere, and most of the biosphere.

Extinction Level Event

A massive, sudden disappearance of lifeforms from the rock record, often caused by asteroid impacts.

Extrusive (Volcanic) Igneous Rock

Rock formed from the rapid cooling of lava on the Earth's surface, typically resulting in an aphanitic texture.

Fault Creep

The slow, continuous, and relatively safe movement of tectonic plates across a transform fault.

Felsic Igneous Rock

Igneous rock rich in silica/light silicates, characterized by light color, low density, and low melting temperatures (e.g., Granite).

Focus

The actual point within the Earth's crust where an earthquake originates.

Fold Mountains

Non-volcanic mountains formed by the horizontal compression and vertical folding of continental crust (e.g., Himalayas).

Food Web

A complex model of feeding relationships in an ecosystem, more accurate than a simple food chain.

Fossil Fuels

Energy sources formed from ancient life pressurized over millions of years, including coal, petroleum, and natural gas.

Frequency ($f$)

The number of wave cycles that pass a point per second, measured in hertz ($Hz$).

Front

The boundary between two different air masses; the site of most weather activity.

Geodesic

The shortest distance between two points on a sphere, which follows an arc of a great circle.

Geosphere

The solid part of the Earth, consisting of the crust, mantle, and core.

Geothermal Energy

The Earth's internal energy source, primarily generated by the radioactive decay of atoms.

Glassy Texture

An extremely fine-grained igneous texture formed by quenching (virtually instantaneous cooling), as seen in obsidian.

Great Circle

An intersection of a sphere and a plane that passes through the sphere's center; the largest possible circle on a sphere.

Greenhouse Effect

The process by which certain gases ($H_2O, CO_2$) trap heat in the atmosphere, keeping Earth habitable.

Groundmass

The small crystals in a porphyritic igneous rock that surround the larger phenocrysts.

Gyre

A large, circular system of ocean surface currents driven by prevailing winds and the Coriolis force.

Halocline

A layer in the ocean where salinity changes steeply with depth.

Hardness

A mineral's resistance to scratching, measured on the Mohs scale from 1 (Talc) to 10 (Diamond).

Heat Capacity

The amount of heat energy required to change the temperature of a substance; water has a high heat capacity.

Heat Index

An effective temperature combining real air temperature and relative humidity to quantify human discomfort.

Hotspot

An area of volcanic activity in the middle of a tectonic plate caused by a mantle plume.

Hydrothermal Metamorphism

Metamorphism caused by chemical reactions with minerals dissolved in hot water.

Hypsometry

The measurement of continental elevations above sea level.

Ice Age

A long period (millions of years) of cold global climate characterized by the presence of polar icecaps.

Igneous Rock

Rock formed from the crystallization of molten rock (magma or lava).

Index Fossil

A fossil of a species that lived for a brief, well-defined time period, used for relative dating of rock strata.