Earth Sciences and Mineralogy Lecture Flashcards

Vocabulary flashcards covering core concepts in Earth Sciences, astronomy, mineralogy, seismic wave behavior, and planetary structure based on the lecture notes.

Earth Sciences

A field of study that combines biology, physics, and chemistry to understand how the Earth works

Hypothesis

A testable idea based on observation

Scientific Theory

A hypothesis that is supported by a large body of scientific evidence or proof

Scientific Law

A description of what nature does under certain conditions, usually expressed as mathematical equations

Law of Universal Gravitation

A law stating that gravity is an attractive force between two particles or objects

• $F = G \frac{m_1 m_2}{r^2}$.

Big Bang Theory

A theory stating that 13 billion years ago, all matter and energy in the universe was packed into an infinitely small point before rapidly expanding outward

Matter

Anything that has mass and volume

Energy

The ability to do work

Kinetic Energy

The energy of moving matter.

Potential Energy

Stored energy

Atom

The smallest unit into which matter can be easily divided

Element

Atoms that have a particular number of protons and can exist in different states of matter

Density

A measure of how much mass is packed into a particular volume

• $\text{Density} = \frac{\text{Mass}}{\text{Volume}}$.

Nuclear Fusion

hydrogen and helium combine to form stars

• heavier elements up to iron (26)

Supernova

An exploded star capable of forming elements heavier than iron (atomic number $26$)

Nebular Theory

a swirling flat disc of spinning material —> volatile materials = move outward and refractory materials = move inward —> creation of planet

Volatile Materials

Swirling gases close to the Sun that easily evaporate and move outward during early solar system formation.

Refractory Materials

Materials that melt at higher temperatures and move inward toward the center during planet formation.

Differentiation

melted materials separated by density, creating the different layers of the earth

Mineral

A naturally occurring, inorganic solid with a definable chemical composition and an orderly, fixed 3D crystalline pattern.

Synthetic Mineral

A manufactured substance that looks like an actual mineral but does not occur naturally.

Amorphous Solid

A solid structure, such as glass, that lacks an orderly 3D repeating crystalline pattern.

Crystal

A single, continuous crystalline solid bound by flat surfaces/ crystal faces.

Crystal Lattice

A three-dimensional repeating pattern of regularly spaced atoms.

how minerals can form

1. solidification of melting

2. precipitation from water solution (dissolved ions bond together to create crystals)

3. solid state diffusion

4. biomineralization

5. precipitation directly from gases (around volcanoes)

Biomineralization

living organisms cause minerals to precipitate

Solid State Diffusion

The movement of atoms/ ions through a solid under different amounts of pressure

Silicate Minerals

Minerals consisting of silicon bonded to $4$ oxygen atoms in a silica tetrahedron, making up $92\%$ of Earth's minerals.

Chondrites

Undifferentiated meteorites that have not been melted or separated into distinct layers

Achondrites

Meteorites that have undergone melting, crystallization, and differentiation on larger bodies

Primary Waves (P-waves)

• Longitudinal seismic waves

• fastest

• pass through both solids and liquids

Secondary Waves (S-waves)

• Transverse/ horizontal seismic waves

• travel only through solids

S-wave Shadow Zone

The zone on the far side of earth —> outer core is liquid

P-wave Shadow Zone

Restricted areas bc refraction at solid-to-liquid density boundaries

• moves faster in solids, slower in liquids

state of earth’s layers

• inner core = solid

• outer core = liquid

• lower mantle = solid that can easily deform

• upper mantle = solid'

• crust = solid

Mohorovičić Discontinuity (Moho)

P-waves suddenly accelerate $5\text{--}10\,km$ beneath the surface —> clue that mantle is solid

Oceanic Crust

basalt, mafic, density of $3.0\,g/cm^3$ , rich in Fe and Mg

Continental Crust

granite, felsic, $5\text{--}70\,km$ thick, density of $2.7\,g/cm^3$ , rich in Al, K, Na

Mantle Xenolith

A fragment of mantle rock carried up to the Earth's crust inside magma

Lithosphere

crust and upper mantle, brittle

Asthenosphere

lower mantle, can flow/ deform (low viscosity), ductile

Viscosity

resistance to flow

Archimedes' Principle

object displaces its own weight of liquid —> how lithosphere floats atop the ductile asthenosphere

three main heat sources of Earth's interior:

1. original accretion,

2. planetary differentiation

3. radioactive decay

Radioactive Decay

Earth's primary internal heat source, caused by unstable atoms breaking down and releasing thermal energy

Bowen's Reaction Series

A sequence organizing eight igneous mineral groups based on the temperatures and chemical conditions at which they crystallize from magma.

• discontinuous series

• continuous series

discontinuous series

• crystallization temp

  • more mafic —> higher temp, olivine at highest

  • more felsic —> lower temp, quartz at lowest

• elemental composition —> changes Si:O ratio/ crystal structure

  • mafic —> rich in Fe, Mg, Ca (harder, heavier)

  • felsic —> rich in Si, Al, O (softer, lighter weight)

continuous series

• higher temp —> rich in Ca⁺²

• lower temp —> rich in Na⁺¹

balances chemical formula/ charges

mafic rocks

• forms first

• rich in Fe, Mg, Ca

• denser

• dark color

• higher crystallization temp

felsic rocks

• forms later

• rich in Si, Al, O

• less dense

• light color

• lower crystallization temp

extrusive igneous rocks

rocks that from from LAVA (above surface), cools faster, smaller crystals

intrusive igneous rocks

rocks that form from MAGMA (below surface), cools slower, larger crystals

how rocks melt (how we get magma)

1. flux melting

2. decompression melting

3. heat transfer melting

flux melting

mixing CO₂ with hot rock to lower its melting temp

decompression melting

decreasing pressure in mantle while maintaining the same temp

heat transfer melting

heat rises on surrounding rocks —> melted surrounded rocks

fractional crystallization

to get mafic rocks: early-crystallizing mafic minerals (olivine) cool and separate first, leaving behind a residual magma that becomes progressively more felsic.

partial melting

to get mafic rocks: melting of only a portion of solid rock —> richer in felsic components than the original source rock

intrusion

where melted rock cools: magma forces its way into existing rock beneath earth’s surface —> different shapes

classifying igneous rocks

1. how big are the crystals (large = intrusive, small = extrusive)

2. chemical composition (felsic or mafic, color diff, density diff)

3. glassy igneous rock classification (cooled super fast —> no crystals, air bubble vesicles)

theory of tectonic plates

earth is divided into plates that move/ collide into each other

continental drift

theory that continents move over time bc of tectonic plates

expanding earth theory

continents are moving apart bc earth is getting bigger

contracting earth theory

earth is shrinking, casing wrinkles in the crust —> mountain ranges

land bridges theory

landmasses were connected during periods of lower sea levels —> species migrating

evidence of continental drift

1. similar fossils found in different continents

2. matching geological units/ mountain ranges

3. glacial striations

Marie Tharp and Bruce Heezen

researchers that analyzed the ocean floor using sonar and found mountain ridges —> where new ocean floor is created

• ocean floor = thin closer to ridges, thicker farther away —> proof of sea floor spreading

paleomagnetism

certain rocks have magnetite that react to earth’s magnetic pole —> tells us where poles were when rock was formed —> proved magnetic reversals happened throughout time

magnetic stripping

new crust forms at mid ocean ridges with records of the magnetic polarity as it forms