Semester 1 notes

Theory of plate tectonics

Earth's outer layer (lithosphere) is made up of several large plates that are in constant, slow motion.

Continental drift

The theory that Earth's continents have moved over geological time relative to each other, appearing to have 'drifted' across the Earth's surface.

Tectonic plates

Massive, irregularly shaped slabs of solid rock, generally composed of both crust and upper mantle material, that make up Earth's lithosphere.

Lithosphere

The Earth's crust and the uppermost part of the mantle.

Asthenosphere

A semi-molten, highly viscous, and ductile region of the Earth's upper mantle, located below the lithosphere.

Fault

A planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements.

Earthquake

A sudden and violent shaking of the ground, sometimes causing great destruction, as a result of movements within the earth's crust or volcanic action.

Tsunami

A long high sea wave caused by an earthquake, submarine landslide, or other disturbance.

Plate Boundary

The edge where two or more tectonic plates meet, dynamic zones of significant geological activity.

Mid-Oceanic ridge

A submerged mountain range, formed by plate tectonics, where new oceanic crust is created as plates move apart.

Subduction Zone

A geological area where one tectonic plate slides beneath another, typically the denser oceanic plate sliding beneath a less dense continental plate.

Global warming potential

A measure of how much heat a greenhouse gas traps in the atmosphere compared to carbon dioxide (CO2) over a specific time period, typically 100 years.

Troposphere

The lowest layer of the atmosphere, where weather occurs and life can breathe.

Stratosphere

Contains the ozone layer and has less turbulent air than the troposphere.

Coriolis effect

Circulating air is deflected toward the right in the Northern Hemisphere and toward the left in the Southern Hemisphere.

El Niño Southern Oscillation (ENSO)

A recurring climate phenomenon characterized by periodic variations in sea surface temperatures and atmospheric conditions in the central and eastern tropical Pacific Ocean.

Ozone Layer

A region in the stratosphere with a high concentration of ozone (O3) that protects life on Earth by absorbing most of the sun's harmful ultraviolet (UV) radiation.

Weather

The state of the atmosphere at a place and time as regards heat, dryness, sunshine, wind, rain, etc.

Climate

The weather conditions prevailing in an area in general or over a long period.

Greenhouse gas

Gases in the atmosphere that absorb and emit radiant energy, contributing to the greenhouse effect.

Thermohaline circulation

A large-scale ocean circulation driven by differences in temperature (thermo) and salinity (haline) that affects global climate patterns.

Temperature inversion

An atmospheric condition where temperature increases with altitude, inverting the usual pattern of cooler air aloft.

Desertification

Gradual loss of fertility in arid areas due to climate change or overexploitation/erosion.

Erosion

Any process that removes rock/soil particles from one area and transports them to another area.

Humus

Brown/black organic material from decomposed matter; very nutrient-rich.

Loam

Soil that is a balanced mix of sand, silt, and clay, often considered ideal for productivity.