EAS Exam 1

Oceanology / Oceangraphy

The scientific study of the oceans, including their physical, chemical, geological, and biological aspects.

Ocean

A vast, continuous body of saline water occupying major depressions on Earth's surface.

Sea, Bay, Gulf

Peripheral, smaller bodies of salt water partially enclosed by land or shallower than the open ocean.

Oceanic / Ocean Basin

Referring to the deep open ocean; the deep depressions beneath ocean waters underlain by basaltic crust.

Percontinental Sea

A marginal sea located along the edge of a continent over the continental shelf.

Epicontinental Sea

A shallow sea extending onto the interior of a continent.

Continent

A large, continuous landmass composed primarily of thick, granitic continental crust.

Atmosphere

The gaseous envelope surrounding Earth.

Hydrosphere

All liquid, frozen, and vaporous water on or near Earth's surface.

Geolithosphere

The solid, rocky portion of the Earth

Crust

Earth's outermost solid layer, split into continental and oceanic types.

Moho

The seismic boundary marking the base of the crust and top of the mantle.

Gutenberg Discontinuity

The boundary separating the lower mantle from the liquid outer core.

Core

The central, metallic (iron-nickel) portion of the Earth.

Continental Crust

Low-density (~2.7 g/cm³), thick (30–50 km) crust primarily granitic in composition.

Oceanic Crust

High-density (~3.0 g/cm³), thin (5–10 km) crust primarily basaltic in composition.

Physical State

The mechanical behavior of matter controlled by temperature and pressure.

Outer Rigid Mantle

The uppermost, brittle portion of the mantle bonded directly to the crust.

Lithosphere

The brittle, solid outer mechanical layer comprising the crust and uppermost rigid mantle.

Asthenosphere

The weak, ductile/plastic region of the upper mantle where slow convective flow occurs.

Mesosphere

The solid, rigid lower mantle extending from the base of the asthenosphere to the outer core.

Outer Core

The molten/liquid iron-nickel layer responsible for generating Earth's magnetic field.

Inner core

The solid metallic center of Earth maintained in a solid state by extreme overburden pressure.

Atom

The basic unit of a chemical element.

Nucleus

The dense center of an atom containing protons and neutrons.

Proton, Neutron, Electron

Subatomic particles; protons are positively charged, neutrons are neutral, and electrons are negatively charged.

Electron Cloud

The region surrounding the nucleus where electrons orbit.

Element

A substance made of only one type of atom defined by its proton count.

Radioactivity & Radioactive Decay (Fission)

Spontaneous breakdown of unstable atomic nuclei, releasing energetic particles and radiogenic heat inside Earth.

Fusion

Nuclear reaction combining lighter atomic nuclei into heavier ones (the primary energy source of the Sun)

Geothermal Gradient

The rate at which temperature increases with depth inside the Earth.

Magnetosphere

The magnetic field region surrounding Earth that deflects energetic charged particles.

Plasma

Ionized gas consisting of free electrons and positive ions.

Polarity

The direction of magnetic orientation (North vs. South magnetic poles)

Solar Wind

A stream of charged particles (plasma) ejected from the Sun's upper atmosphere.

Curie Point

The critical temperature (~580°C for magnetite) below which magnetic minerals lock in the orientation of Earth's ambient magnetic field.

Polar Normal / Polar Reversal

Normal polarity occurs when magnetic north aligns with geographic north; reversal occurs when the magnetic poles switch positions.

Paleomagnetism / Remnant Magnetism

The permanent magnetic signature preserved in iron-bearing rocks as they cool below their Curie point.

Upwelling

The upward movement of warm, less dense mantle material or deep ocean water.

Downwelling

The sinking of colder, denser material (e.g., subducting slabs or cold surface waters)

Convection

Heat move from fluid

Advection

The lateral or horizontal transport of heat or matter via mass motion.

Convection Cell

A circular loop of moving material where warm fluid rises, cools, moves laterally, and sinks.

Lithospheric Plate

A rigid segment of the lithosphere floating and moving atop the asthenosphere.

Microplate / Macroplate

Small tectonic fragments versus major, continent-sized tectonic plates.

Conduction

Heat move from solid

Continental drift

Where countries can connect like a puzzle

Subduction

Rock breaking and sliding down

Subducted plate

Rock at bottom

overriding plate

stay up surface

Island arc

curve line on island