Geology Lecture 1 Review: Earth Systems, Solar System, and Plate Tectonics

Vocabulary flashcards covering fundamental geology concepts including Earth system science, the rock cycle, planetary formation, interior Earth layers, continental drift, and plate tectonics.

Hypothesis

A tentative or untested explanation that typically requires additional data to prove or disprove it.

Theory

A well-tested and widely accepted view that the scientific community agrees best explains certain observational facts.

Earth System Science

An approach that views Earth as a system composed of interacting spheres—the lithosphere, atmosphere, hydrosphere, and biosphere—that exchange matter and energy with one another.

Open System

A system in which both matter and energy flow freely into and out of the system, such as a leaf or an ocean.

Closed System

A system in which energy can move freely in and out, but matter does not enter or leave.

Igneous Rocks

Rocks formed from the cooling and solidification of magma or molten rock, with examples including granite and basalt.

Sedimentary Rocks

Rocks derived from sediment created by weathering of pre-existing rocks or crystallization of minerals from seawater, which are deposited in layers, buried, and lithified.

Metamorphic Rocks

Rocks formed by altering pre-existing igneous, sedimentary, or metamorphic rocks through the driving forces of increased heat and pressure.

Rock Cycle

A geologic model demonstrating that any rock type can change into another rock type under appropriate conditions.

Plane of the Ecliptic

The common geometric plane within which all planets in the solar system align as they revolve around the Sun.

Terrestrial Planets

The four inner planets closest to the Sun (Mercury, Venus, Earth, and Mars), characterized as small, rocky bodies consisting of an iron core surrounded by a silicate mantle.

Jovian Planets

The outer giant planets (Jupiter, Saturn, Uranus, and Neptune), consisting of a solid rocky core surrounded by layers of frozen or liquid hydrogen, helium, methane, and ammonia.

Solar Nebula

A giant cloud of gases and dust existing over $4,500,000,000$ years ago that contracted and rotated to form the solar system.

Planetesimals

Asteroid-sized bodies formed within the cooling solar nebula as condensed solid particles collided and coalesced.

Planetary Differentiation

The process during early planetary formation where internal materials softened and separated into layers based on density, causing heavy metals like iron to sink to the core while lighter materials formed the crust.

Asthenosphere

A weak layer of ultramafic mantle rock (peridotite) located in the upper mantle below the lithosphere, which is partially molten ($1\text{--}3\times 10^{-2}$ or 1\text{--}3\text{\textpercent} partial melt) and allows the lithosphere to glide across it.

Lithosphere

The rigid outer layer of Earth composed of the crust and the solid upper portion of the mantle that glides across the underlying asthenosphere.

Continental Drift

A hypothesis proposed by Alfred Wegener in $1915$ stating that modern continents were once joined in a supercontinent named Pangaea before breaking apart and drifting to their present locations.

Normal Polarity

A magnetic orientation where Earth's magnetic lines of force leave the magnetic South pole and enter the magnetic North pole, matching Earth's present magnetic field.

Reverse Polarity

A magnetic orientation opposite to Earth's present field, where magnetic lines of force leave the magnetic North pole and enter the magnetic South pole.

Polar Wander Paths

Apparent trajectories showing movement of the magnetic poles over geologic time, which actually reflect the drifting of continents rather than physical movement of the poles.

Mid Ocean Ridges

Undersea mountain ranges located along divergent plate boundaries where rising magma creates new oceanic lithosphere as tectonic plates spread apart.

Black Smokers

Deep-sea hydrothermal hot springs located along mid-ocean ridges that erupt hot, mineral-rich seawater.

Transform Fault

A plate boundary oriented parallel to the direction of seafloor spreading where tectonic plates slide horizontally past one another without constructing or destroying lithosphere.