Geology Exam 1 Set

Geology

The scientific study of the processes that occur on Earth, its evolution and past events, and predictions of Earth's future.

Importance of Geology

the formation of Earth's landscapes, exploration of natural resources, mitigating geologic hazards, understanding environmental change, and the evolution of Earth and other planets.

Earth Systems

Interacting components of Earth including the Geosphere, Atmosphere, Hydrosphere, and Biosphere.

Natural Resources

Materials from the Earth like petroleum, natural gas, coal, and rare earth elements, vital for energy and industry.

Rare Earth Elements (REE)

Mined from geologic formations and used in various applications such as magnets, catalysts, polishes, metallurgy, batteries, and glass.

Geologic Hazards

Natural dangers related to Earth's processes, such as volcanoes, earthquakes, tsunamis, floods, hurricanes, and landslides.

Climate Change

Significant and lasting changes in weather patterns over periods ranging from decades to millions of years, studied by geologists to predict future trends.

Science

A body of knowledge related to the study of natural phenomena and the application of the scientific method.

Scientific Method

A systematic approach involving gathering facts through observation, formulating hypotheses, and testing those hypotheses.

Theory of Plate Tectonics

A major scientific theory explaining the movement of Earth's lithospheric plates, supported by observations like the fit of continents and similar fossil distributions.

Hypothesis

A statement designed to explain a set of observations, which must be able to explain existing observations, predict new ones (testable), and be falsifiable.

Theory (Scientific)

A well-tested and widely accepted view that scientists agree best explains certain observational facts, considered the strongest scientific statement, yet provisional.

Nebular hypothesis

The bodies of our solar system evolved from a rotating cloud of gas and dust, known as the Solar Nebula.

Solar Nebula

A rotating cloud of gas (Hydrogen and Helium) and dust (from dead stars) from which our solar system evolved.

Protoplanets

Asteroid-sized bodies that formed from the repeated collisions and coalescence of dust particles during the solar system's formation.

Differentiation of the Earth

A process where increased temperatures in the early Earth led to melting and chemical separation of components, with metals sinking towards the center and rocky materials rising towards the surface.

Crust

The outermost compositional layer of the Earth.

Mantle

The compositional layer below the crust, making up 82% of the Earth's volume.

Core

The innermost compositional layer of the Earth, primarily composed of iron and nickel, with a density of approximately 11g.

Lithosphere

The stiff, rigid sphere of rock composed of the crust and the uppermost mantle.

Asthenosphere

A moveable, weak sphere in the upper mantle, characterized by high temperatures.

Moho (Mohorovicic discontinuity)

The boundary that separates the Earth's crust from the mantle.

Continental Crust

A component of the Earth's crust characterized by low density and being generally thick.

Oceanic Crust

A component of the Earth's crust that is generally thin.

Weathering

The alteration of rocks at or near the Earth's surface.

Igneous Rocks

Rocks formed from the crystallization of magma.

Extrusive Igneous Rocks

Igneous rocks that form when lava is extruded and solidifies at the Earth's surface.

Intrusive Igneous Rocks

Igneous rocks that form when magma intrudes and solidifies below the Earth's surface.

Sedimentary Rocks

Rocks formed from either detrital or chemical sediments.

Metamorphic Rocks

Rocks formed from the solid-state alteration of pre-existing rocks due to increased temperature, increased pressure, or chemical changes.

Principle of Uniformitarianism

The concept that the geological processes which have shaped the Earth in the past are fundamentally the same as those operating today.

Continental Drift

The hypothesis that all the continents had once fit together to form a supercontinent and has subsequently drifted apart to their present positions.

Evidence Supporting Continental Drift

Geometric fit of the continents, fossil matches, geologic matches (e.g., matching mountain ranges), and paleoclimatic evidence (e.g., glacial striations).

Harry Hess

Known as the 'Father of seafloor spreading'.

Seafloor Spreading Hypothesis

Sea floor forms at mid-ocean ridges, seafloor is consumed at trenches, and the process is driven by convection flow in the mantle.

Plate Tectonics

A model explaining how the Earth works; a collection of ideas that explain the observed motion of Earth's outer shell through mechanisms like subduction and seafloor spreading, which generate Earth's major features.

Lithosphere

The outermost shell of the Earth, consisting of a rigid layer composed of the crust and upper mantle.

Asthenosphere

A weak, partly melted portion of the mantle upon which the lithosphere sits.

Divergent Boundary

Where plates move apart, resulting in the upwelling of material from the mantle to create new seafloor (new crust).

Convergent Boundary

Where plates move towards one another, resulting in the subduction (consumption) of oceanic lithosphere into the mantle (destroying crust).

Transform Boundary

Where plates slide past each other without the production or destruction of lithosphere.

Ocean-continent Convergent Boundary

Involves the subduction of denser oceanic crust and lithosphere beneath continental crust, creating ocean trenches and volcanic arcs away from the plate boundary.

Continent-continent Convergent Boundary

Occurs when two continental crusts collide due to their buoyancy, leading to the formation of large mountain masses.

Slab-pull

A force driving plate motion where oceanic crust, as it is subducted, pulls the tectonic plate behind it.

Ridge-push

A gravity-driven force that results from the elevated position of a mid-ocean ridge, pushing the plates away from the ridge.

Mantle convection

The constant movement of material in the mantle, representing a shear force that contributes to driving plate motion.

Mineral

Naturally occurring, generally inorganic, solid, with an ordered internal molecular structure and a definite chemical composition.

Rock

A naturally occurring consolidated mixture (or aggregate) of minerals.

Element

A substance that cannot be decomposed into a simpler substance by ordinary chemical or mechanical means; the basic building blocks of minerals.

Atom

The smallest individual particle that retains the properties of an element.

Nucleus

The central region of an atom, consisting of protons and neutrons.

Proton

A positively charged particle found in the nucleus of an atom.

Neutron

A particle with no charge found in the nucleus of an atom.

Electron

A negatively charged particle that orbits the nucleus of an atom.

Valence Electrons

Electrons located in the outermost 'shell' of an element.

Atomic Number

The number of protons in an atom, which determines what element the atom is.

Atomic Mass (Weight)

The sum of protons and neutrons in an atom.

Isotopes

Atoms of the same element that exhibit variation in their mass number due to a different number of neutrons.

Ion

An element with an electrically charged atom, resulting from the loss or gain of an electron.

Cation

A positively charged atom (ion).

Anion

A negatively charged atom (ion).

Octet Rule

Atoms gain, lose, or share electrons in order to obtain a full valence shell (typically eight electrons).

Chemical Bond

A strong attractive force that links atoms together.

Compound

Two or more elements bonded together.

Ionic Bond

A chemical bond where atoms gain or lose outermost (valence) electrons to form ions, which then attract one another.

Covalent Bond

A chemical bond where atoms share electrons, generally stronger than ionic bonds.

Metallic Bond

A chemical bond where valence electrons are free to migrate among atoms.

Mineral Formation Processes

Crystallization of molten rock, precipitation of minerals from solution, and biological processes.

Polymorphs

Minerals with the same chemical composition but different crystalline structures (different packing of atoms).

Crystal Form

The external expression of a mineral's internal ordered molecular structure.

Luster

The appearance of a mineral in reflected light, categorized as metallic or nonmetallic.

Color

A generally unreliable property for mineral identification, as it can vary due to impurities or slight changes in composition.

Streak

The color of a mineral in its powdered form, obtained by rubbing it across an unglazed porcelain plate.

Hardness

A mineral's resistance to abrasion or scratching, measured using the Mohs scale of hardness.

Mohs Scale of Hardness

A relative scale used to measure the hardness of minerals, from 1 (softest) to 10 (hardest, diamond).

Cleavage

The tendency of a mineral to break along planes of weak bonding, producing smooth, flat surfaces.

Fracture

The absence of cleavage when a mineral is broken, resulting in an irregular or uneven surface.

Specific Gravity

The measure of a mineral's density (weight relative to an equal volume of water).

Oxygen (O)

The most abundant element in Earth's crust (47% by weight), and the only anion listed among the most abundant.

Silicon (Si)

The second most abundant element in Earth's crust (28% by weight), which forms covalent bonds with aluminum.

Aluminum (Al)

The third most abundant element in Earth's crust (8% by weight), which forms covalent bonds with silicon.

Silicates

A major mineral group characterized by the (SiO4)-4 anionic complex (silica tetrahedron); they constitute approximately 92% of Earth's crust due to the abundance of Si and O.

Carbonates

A major nonsilicate mineral group characterized by the (CO3)-2 anionic complex, exemplified by calcite, limestone, and dolomite.

Halides

A major nonsilicate mineral group characterized by halogen anions like (Cl)-2 or F-1, exemplified by halite (salt) and fluorite.

Oxides

A major nonsilicate mineral group characterized by the O-2 anion, exemplified by magnetite and hematite, and are often economically important.

Sulfides

A major nonsilicate mineral group characterized by the S-2 anion, exemplified by pyrite and galena.

Sulfates

A major nonsilicate mineral group characterized by the (SO4)-2 anionic complex, exemplified by gypsum (main component of drywall).

Native Elements

A major mineral group consisting of minerals composed of a single element, such as copper or gold.

Phosphates

A major nonsilicate mineral group characterized by the (PO4)-3 anionic complex, exemplified by apatite (found in teeth and bones).

Silica Tetrahedron

The fundamental building block of silicates (SiO4)-4, composed of four oxygen atoms surrounding a central silicon atom, held by strong covalent bonds.

Isolated Tetrahedron Silicates

A silicate structure where individual silica tetrahedra are bonded together by intervening cations (ionic bonds), as seen in minerals like olivine.

Single Chain Silicates

A silicate structure formed by a continuous chain of covalently bonded silica tetrahedra, with cations linking the chains, as seen in pyroxene.

Double Chain Silicates

A silicate structure formed by two parallel single chains of silica tetrahedra covalently bonded together, as seen in amphiboles like hornblende.

Sheet Silicates

A silicate structure where silica tetrahedra are connected continuously from end to end, forming flat sheets, as seen in biotite and muscovite.

Framework Silicates

A silicate structure forming a 3-D network where all silica tetrahedra are interconnected, as seen in quartz and feldspar.

Cleavage

The tendency of a mineral to break along specific planes of weakness, often characteristic of its internal atomic structure (e.g., silicate structure).

Mafic Minerals

Dark-colored silicate minerals rich in iron (Fe) and magnesium (Mg), including olivine, pyroxene, amphibole, and biotite.

Felsic Minerals

Light-colored silicate minerals, typically rich in framework silicates like feldspar and quartz, including muscovite, plagioclase, orthoclase, and quartz.

Olivine

A mafic silicate mineral with the formula (Mg,Fe)SiO4, characterized by an isolated tetrahedron silicate structure.

Pyroxene

A mafic silicate mineral with the formula (Mg,Fe)SiO3, characterized by two cleavage planes and a single chain silicate structure.