ERTH2404 Lecture Notes Review

A set of vocabulary flashcards based on key concepts from the ERTH2404 lecture notes on permafrost, groundwater, and earth resources.

Permafrost

Ground (soil or rock) that remains at a temperature of 0°C or lower for at least two consecutive years.

Active layer

The near-surface layer of permafrost that thaws in summer and freezes in winter, usually 0.5 m to 2 m thick.

Suprapermafrost

The layer above the permafrost that includes the active layer and taliks.

Gelifluction

Mass movement linked to the thawing of the active layer, where saturated soil flows down slopes.

Solifluction

The slow flow of water-saturated soil down a slope due to thawing permafrost.

Thermokarst

Geological processes resulting from the thawing of permafrost containing ground ice, causing subsidence and landslides.

Hydrologic cycle

The continuous movement of water on, above, and below the surface of the Earth, operating for over 4 billion years.

Unsaturated zone

The zone near the Earth's surface where the soil pores contain both air and water; also called the vadose zone.

Saturated zone

The zone in which all spaces in a rock or soil are filled with water.

Recharge

The process of water seeping into an aquifer or saturated zone from the surface.

Aquitard

A geological formation that restricts the flow of groundwater from one aquifer to another.

Darcy’s Law

An equation describing the flow of groundwater through porous media, stating that flow velocity is proportional to the hydraulic gradient.

Hydraulic conductivity

A measure of how easily water can flow through a porous material or rock.

Permeability

The ability of a material to transmit fluids, affected by the size and connectivity of pores.

Aquifer

A geologic formation that can yield significant amounts of groundwater.

Groundwater discharge

The flow of groundwater to the surface, contributing to streamflow and lakes.

Cone of depression

An area around a well where the water table has been lowered due to excessive water extraction.

Saltwater intrusion

The movement of saline water into freshwater aquifers, often due to over-extraction of groundwater.

Fossil fuels

Natural fuels formed from the remains of living organisms, primarily including coal, oil, and natural gas.

Bitumen

A thick, viscous form of petroleum that is found in oil sands and requires special methods for extraction.