Earth Science

Earth's Surface, Rocks & Minerals, Fossils, Plate Tectonics, 'Air, Weather, & Climate', Water, Energy Resources

Crust

• The outermost layer of the Earth, varying in thickness from about 5 km (oceanic crust) to about 30 km (continental crust).

• Composed mainly of silicate rocks and minerals.

• Divided into tectonic plates that float on the semi-fluid asthenosphere below.

Mantle

• Located beneath the crust, extending to a depth of approximately 2,900 km.

• Composed of solid silicate rocks that are semi-fluid due to high temperatures and pressure, allowing for slow convection currents.

• Divided into the upper mantle (which includes the asthenosphere) and the lower mantle.

Lithosphere

The rigid outer layer of the Earth, consisting of the crust and the uppermost part of the mantle, extending down to about 100 km.

Asthenosphere

The semi-fluid layer beneath the lithosphere, characterized by its ability to flow slowly, which allows tectonic plates to move over it.

Lower Mantle

The deeper layer of the mantle, extending from about 660 km to 2,900 km, composed of more solid rocks under immense pressure, with increased density compared to the upper mantle.

Outer Core

• Lies beneath the mantle and extends from about 2,900 km to 5,150 km deep.

• Composed primarily of liquid iron and nickel.

• Responsible for generating Earth’s magnetic field through the motion of molten metals.

Inner Core

• The innermost layer, extending from about 5,150 km to the center of the Earth at approximately 6,371 km deep.

• Composed of solid iron and nickel, with temperatures reaching up to 5,700 K.

• Despite the high temperatures, the inner core remains solid due to immense pressure.

Magnetic Field

• The Earth's magnetic field is generated by the movement of molten iron and nickel in the outer core, which creates electric currents.

• This magnetic field extends beyond the Earth’s surface, forming a protective shield called the magnetosphere, which deflects solar wind and cosmic radiation.

• The magnetic field is crucial for navigation (as seen with compasses), affects satellite communications, and protects living organisms from harmful effects of solar radiation.

Paleontologists

Scientists who study fossils.

Trace Fossiles

Fossils showing the activities of organisms, not body parts,
Ex: Footprints, nests, burrows, droppings

Weather

• The state of atmosphere at given location.

• Everyday conditions (temperature & precipitation)

Climate

• Average weather conditions over periods of time.

• Factors of change: altitude, terrain, latitude, bodies of water.

Temperature Climate Zone

• Has most of the world’s population.

• Factors of change: humidity & temperature

Air mass

• Large body of air with the same temperature and humidity althroughout.

• Always moving.

Air pressure

Force of air exerts on Earth’s surface.

Arctic Air Mass

Very cold, near Arctic & Antarctic areas.

Polar Air Mass

Less cold, areas slightly pass polar regions.

Tropical Air Mass

Somewhat warm, tropical areas.

Equational

Very warm, near equator.

Maritime

Formed over water (humid).

Continental

Formed over land (dry).

Front

Boundary between air masses.

Warm Front

Warm air mass moves into an area where cooler air mass has been = cools & condenses into stratus clouds → light rain = warm & humid (after)

Cold Front

Cold air mass moves into warm area, warm air rises & cools = cumulonimbus clouds & thunderstorms = cool & less humid (after)

Stationary Front

2 different air masses meet, does not combine/move into each other = stratus clouds & light rain

Secluded Front

Between the area 2 fronts meet, warm moving between 2 cold = thunderstorms, tornadoes, less humid

Pressure Systems

When there are changes in air pressure.

High-pressure System

Area with higher air pressure than the air around it.

Low-pressure System

Area with lower air pressure than the air around it.

Tropical Climate

Warmest, near/around equator, high humidity & lots of rainfall, plant & animal life.

Dry Climate

Varying temperature, low humidity & rainfall, few plants & animals.

Temperate Climate

4 seasons, winters & summers, moderate rainfall, lots of plants & animals.

Continental Climate

Past Temperate, 4 seasons, mid-summers & harsh winters, moderate rainfall, lots of plants & animals.

Polar Climate

(When the distance from equator increases, the cold temp does the same) Near both poles, cold, little precipitation, dry, few plants & animals.

Climate Change

Long-term shifts in temperatures and weather patterns, primarily driven by human activities.

Fossils

• “Time capsules”

• The preserved evidence of living things long ago.

• Involved sedimentary rocks (metamorphic & igneous could destroy not preserve)

Permineralization

Water seeps into organic material (from living thing/s), minerals dissolved in water are left behind in the material, material beaks down until only the materials remained (with sediment around it) = forming fossil in rock

Mold

The leftover impression/pattern from the absent organism on a rock.

Cast

Sediment (rock) filling the mold.

Body fossil

Fossilized part of an ancient living thing.

Evaporation VS. Boiling

• Both turns liquids to gases.

• Evaporation is slower & occurs to molecules of surface.

Water Cycle Process

The water cycle is the continuous movement of water on, above, and below Earth's surface, driven by solar energy and gravity. Key processes include evaporation/transpiration (liquid to vapor), condensation (vapor to clouds), precipitation (rain/snow/hail), and collection (runoff/infiltration).

Groundwater

Water stored underground, formed when water forms through layers & emerges to surface (other bodies of water).

Resource

Material used to support the needs of living things.

Renewable Resources

Resource that is naturally replenished, cannot run out.

Ex: Sunlight, wind, plants

Non Renewable Resources

Resource that take a long time to replenish, may run out.

Ex: Oil, coal, plastic, gold, copper

Aristotle (Geology — Earthquakes)

Theory proposing opposing winds within the cavernous Earth.

Democritus (Geology — Earthquakes)

Theory proposing water forcing its way into Earth through rain.

Geodynamo

• Iron swirls the magnetic field → electric fields → strengthens fields through increasing with another field

• How Earth maintains magnetic field

Bullen Discontinuity

Division between outer & inner cores.

Rock

A naturally occurring solid substance with one or more minerals & materials, not man-made.

Igneous rocks

• Formed from lava/magma (hot molten rock cools & hardens).

• Deep within Earth/surface.

• Smoother compared to tropical types.

Intrusive

“Plutomic rocks”, beneath surface

Extrusive

“Volcanic rocks”, on surface

Sedimentary rocks

• “Nature’s Storytellers” (preservation)

• Develop from the gathering & compassion of layers of small particles that solidifies into rocks (sand, mud, flora, fauna).

Weathering

Human intervention/natural process (physical/chermical/biological) breakdown of rocks (particles).

Erosion

The transport (movement away from source) of rock particles by water, wind, and ice.

Deposition

Settling of particles (environment of deposition - where they settle/deposit), now forming layers

Compaction

The layers compress together.

Lithification

Transformation to solid rock through cementation (binds particles).

Clastic Sedimentary

From compaction of fragments of a rock/other minerals.

Chemical Sedimentary

From precipitation of minerals from solution (evaporation/chemical reactions).

Organic Sedimentary

• From organic materials (plants, debris, shell).

• Often contain fossils & traces about the past environments.

• Takes longer to form (hundreds of years).

Metamorphic

• “Shape-shifters”
  Forms when existing rocks (sedimentary/igneous)

Metamorphism

Undergo changes by heat, pressure, or fluid (chemical).

Regional Metamorphism

• Large scale pressure & heat.

• Tectonic plate movements.

• Results in schist & gneiss.

Contact Metamorphism

• Heated by magma/lava.

• Heat changes patterns.

Hydrothermal Metamorphism

When the hot fluids circulate through rock → chemical reactions → alters the rock/s minerals

Dynamic Metamorphism

• Intense pressure & mechanical deformation.

• Plates move together.

• Sheer stress & low temperature.

Foliated Metamorphic rocks

Layered appearance from the composition.

Non-foliated Metamorphic rocks

Scattered/randomly oriented appearance.

Minerals

• Naturally formed elements/chemical compound with a crystalline structure.

Physical Properties

Aspects of a material that can be observed.

Color

• First property noticed in minerals.

• May be misleading (due to impurities).

Streak

• Color of the powdered form of the mineral.

• By rubbing the mineral across an unglazed porcelain plate (“streak plate”).

• Can be different from the Color.

Luster

• How a mineral reflects light.

• Metallic, glassy, pearly, dull.

Hardness

• Resistance to scratches.

• Measured with a “Mohs Scale”.

Cleavage

Tendency to break (flat planes).

Fracture

Breaking in an irregular way (no smooth planes).

Specific Gravity

Ratio of mineral/s density (mass), the weight.

Chemical Composition

• Easy to observe.

• Has specific taste,

• Elements that make up the structure.

• To identify and understand the properties & uses.

Reactivity with Acids

• Helps with identification.

• Dropping dilute hydrochloric acid on mineral = fizzing (carbon dioxide)

Xenoliths

Rocks brought to surface from upper mantle.

Seismic waves

Vibrations through Earth.

Seismologists

Study waves & earthquakes, can measure body waves & get information about Earth’s interior.

Earthquakes

Releases energy & produces seismic waves that go through the layers.

Focus

Location where the burst occurs.

Epicenter of earthquakes

Line drawn from the location of focus.

Track epicenters

Predict location of faults.

Surface waves

Throigh shallow crust, causes destruction.

Love Waves (Surface)

Waves wiggle (side to side) through surface, “snake”

Rayleigh Waves (Surface)

Waves roll along the surface in waves

Body Waves (Surface)

Waves that go through Earth’s interior.

P-waves (Surface)

• Compressional-like “primary” sound waves, the fastest type.

• Travels through mantle to the other side of Earth.

S-waves (Surface)

• Shear waves, wave motion (bounce not roll).

• Through solid rock, dissipate at the core.

Seismometers

Instruments sensitive to/that record Earth’s vibrations to measure S & P Waves.

Low-velocity Zone

100 km (depth), transition from strong/brittle to weak/ductile rocks, boundary between Lithosphere & Asthenosphere.

Asthenosphere

• Most ductile area of mantle.

• Tectonic plates move across it.

• Earthquakes & volcanoes occur at plate boundaries.

• Mantle convection.

• Below the lithosphere.

Lower Asthenosphere

2 increases in seismic activities: 410 km & 660 km (Transition Zone: area between these areas).

Mesosphere

• Increase in seismic velocities.

• Ultra low velocity zone.

• Below Asthenosphere.