Canary Islands PAU Geology & Env Sci key terms

The state of gravitational balance in which rigid outer layers of the Earth float on the denser mantle beneath. Thicker or lighter crust rides higher, so mountain ranges have deep roots and ocean basins sit lower.

The cool, rigid outer shell of the Earth made of crust plus the uppermost mantle. It is broken into tectonic plates that move over the weaker, slowly flowing asthenosphere below.

A hot, partially molten and mechanically weak layer of the upper mantle beneath the lithosphere. It deforms slowly by creep, allowing tectonic plates to slide and enabling isostatic readjustment.

Slow circulation of hot rock inside the mantle driven by heat escaping from the deep Earth. Rising and sinking limbs transfer heat and provide the main driving force for the motion of tectonic plates.

The unifying theory that the lithosphere is divided into plates that move relative to each other. Their divergence, convergence and lateral sliding explain earthquakes, volcanoes, mountain belts and ocean formation.

A convergent boundary where one lithospheric plate sinks beneath another into the mantle. It generates deep earthquakes, volcanic arcs, trenches and magma through fluid-induced melting of the mantle wedge.

A long-lived, fixed zone of upwelling hot mantle that melts the base of the overriding plate, producing chains of volcanoes. As the plate moves, older volcanoes are carried away and become extinct.

A broad, gently sloping volcano built by repeated eruptions of low-viscosity basaltic lava that flows far before solidifying. The Canary Islands and Hawaii are classic examples of this volcanic form.

A large, roughly circular depression formed when a volcano collapses or explodes after magma is emptied from its chamber. It is much wider than a crater and may later fill with water or new lava.

A fast-moving, ground-hugging avalanche of hot gas, ash and rock fragments erupted from a volcano. It travels at high speed and high temperature, making it one of the deadliest volcanic hazards.

The process by which a cooling magma changes composition as early-formed minerals crystallise and are removed, leaving the remaining melt richer in silica and other incompatible elements. It produces varied rock types from one parent magma.

A dark, fine-grained volcanic rock rich in iron and magnesium and low in silica. It forms most oceanic crust and the lava of Canary Island shield volcanoes, often with a porphyritic or vesicular texture.

The solid-state change of a pre-existing rock in response to heat, pressure or chemically active fluids. New minerals and textures develop without the rock melting, producing rocks such as schist, gneiss and marble.

A planar layering or alignment of platy minerals, such as mica and chlorite, that develops in many metamorphic rocks under directed pressure. It gives rocks like slate and schist their tendency to split.

The original, unmetamorphosed parent rock from which a metamorphic rock formed. Knowing the protolith helps interpret the metamorphic history, for example limestone becoming marble or shale becoming slate.

The in-place breakdown of rock and minerals at or near the surface by physical, chemical and biological processes. It produces regolith and dissolved ions but does not itself remove material.

The removal and wearing away of rock, sediment or soil by moving agents such as water, wind, ice or gravity. It is distinct from weathering, which only breaks material down in place.

The movement of loose particles by flowing water, wind, ice or gravity. Grain size, density and current energy determine whether material is carried in suspension, by saltation, rolling or dragged along the bed.

A specific setting of deposition, such as a beach, delta, reef, dune field or deep-sea fan, characterised by particular energy, water depth and organisms. Each environment leaves a recognisable set of structures and grain features.

The branch of geology that studies the order, age and correlation of layered rocks. It uses lithology, fossils and physical markers to reconstruct sequences of events and build the geological time scale.

A fossil species with a wide geographic range and a short geological lifespan, used to date and correlate rock layers. Its presence in two distant beds suggests they formed at about the same time.

Determining the order of geological events without assigning numerical ages, using principles such as superposition, cross-cutting relationships and fossil succession. It establishes which rocks or structures are older or younger.

A vertical profile drawn across a map that shows the arrangement of rock units and structures beneath the surface. It is constructed from map data, dip measurements and borehole information to reveal subsurface geometry.

A natural process linked to volcanic activity that threatens people, property or infrastructure, such as lava flows, ash fall, pyroclastic flows, lahars or gas emissions. Risk depends on hazard, exposure and vulnerability.

The probability that earthquake shaking of a given intensity will occur in a region within a stated time period. It is assessed from fault activity, historical seismicity and local ground conditions.

The fraction of incoming solar radiation reflected back to space by a surface or the planet as a whole. Ice and snow have high albedo, oceans and dark soils low, so albedo changes affect climate.

The warming of a planet's surface because certain atmospheric gases absorb outgoing infrared radiation and re-emit it downward. Human-added gases such as carbon dioxide and methane strengthen this effect.

A long-term shift in average climate conditions or their variability, caused by natural factors or human emissions. It includes rising temperatures, altered rainfall, sea-level rise and more frequent extremes.

A large, roughly circular system of surface ocean currents driven by prevailing winds and deflected by the Coriolis effect. Gyres redistribute heat between the tropics and higher latitudes and concentrate floating debris.

The upward movement of cold, nutrient-rich deep water toward the ocean surface, often caused by winds pushing surface water offshore. It sustains highly productive fisheries and influences coastal climate.

The apparent deflection of moving fluids and objects caused by the Earth's rotation. It turns motion to the right in the Northern Hemisphere and to the left in the Southern, shaping winds and ocean currents.

The zigzag movement of sediment along a coast as waves approach at an angle, carrying material up the beach and back down. It builds spits and bars and causes gradual beach migration.

The layer of weathered mineral particles, organic matter, water and air at the Earth's surface that supports plant growth. Its character depends on parent rock, climate, organisms, relief and time.

A species that occurs naturally only in a defined area and nowhere else. Island endemics, such as many Canary Island plants and lizards, are especially vulnerable to habitat loss and invasive species.

The variety of living organisms at genetic, species and ecosystem levels. High biodiversity supports ecosystem stability and resilience, and is a key conservation target on islands.

A non-native organism introduced to a new area that spreads and causes ecological or economic harm. On islands they often outcompete native and endemic species that evolved without such competitors.

A formal process that predicts the likely environmental effects of a proposed project before it is approved, and identifies ways to avoid, reduce or compensate for harm. It supports informed planning decisions.

Development that meets present needs without compromising the ability of future generations to meet theirs. It balances economic growth, social wellbeing and environmental protection, a delicate issue on resource-limited islands.

The introduction of substances or energy into the environment at levels that harm living things or degrade natural systems. It includes air, water, soil and noise pollution from human activities.