Andalusia PAU Geology and Environmental Sciences key terms

The theory that Earth's rigid outer shell is broken into large plates that move over the weaker mantle, explaining earthquakes, volcanoes, mountain building and the distribution of continents and oceans.

A convergent boundary where one lithospheric plate sinks beneath another into the mantle, producing deep ocean trenches, volcanic arcs and frequent powerful earthquakes.

A boundary where two plates move apart, allowing magma to rise and form new oceanic crust; expressed on land as rift valleys and on the seafloor as mid-ocean ridges.

A boundary where two plates move towards each other, causing subduction or continental collision and producing fold mountains, thrust faults and intense seismic activity.

A strike-slip fault where two plates slide horizontally past one another without creating or destroying crust; motion is parallel to the fault and generates shallow earthquakes.

The process at mid-ocean ridges where magma rises, solidifies and pushes older oceanic crust sideways, creating new lithosphere and recording magnetic reversals in stripes.

Molten or partially molten rock generated in the mantle or lower crust; its composition and gas content control whether an eruption is fluid and quiet or explosive.

Magma that has reached the surface and flows or is ejected from a volcano; rapid cooling produces fine-grained or glassy volcanic rocks.

A curved chain of volcanoes formed above a subducting slab, where fluids released from the sinking plate trigger melting in the overlying mantle wedge.

The solid-state change of a rock's mineral assemblage and texture in response to increased temperature, pressure or chemically active fluids, without bulk melting.

A planar layering in metamorphic rocks produced by the parallel alignment of platy minerals or by segregation into light and dark bands under directed stress.

A set of mineral assemblages that form under a defined range of temperature and pressure, used to infer the conditions a metamorphic rock experienced.

The original, pre-metamorphic rock from which a metamorphic rock developed; its bulk composition strongly constrains which new minerals can form.

A bend in layered rock produced by compression; an upward arch is an anticline and a downward trough is a syncline, with limbs dipping away from or towards the axis.

A dip-slip fault where the hanging wall moves down relative to the footwall, typically formed under extension and responsible for rift valleys and basin formation.

A low-angle reverse fault where the hanging wall is pushed up over the footwall, shortening the crust and stacking rock sheets during compression.

A fault with mainly horizontal displacement parallel to its strike, either dextral or sinistral, common along transform plate boundaries.

The continuous set of processes by which igneous, sedimentary and metamorphic rocks are created, altered, destroyed and recycled through melting, weathering, erosion and burial.

Rock formed by the cooling and crystallisation of magma or lava; slow cooling underground gives coarse grains, rapid cooling at the surface gives fine grains or glass.

Rock formed from compacted and cemented sediment, chemical precipitates or organic remains; commonly layered and the main archive of fossils and past environments.

Rock whose minerals and texture have been changed in the solid state by heat, pressure or fluids, often showing foliation, recrystallisation or distinctive index minerals.

A relative scale from 1 (talc) to 10 (diamond) ranking minerals by their resistance to scratching, used as a simple field identification tool.

The tendency of a mineral to break along flat planes determined by weak bonds in its crystal structure; described by number of directions and angles between them.

Layers of sedimentary rock, distinguished by composition, grain size or colour, that originally accumulated horizontally and are bounded by bedding planes.

The principle that in an undisturbed sequence of layered rocks, each layer is younger than the one below and older than the one above.

A fossil species with a wide geographic range but a short geological time span, used to correlate rock layers and establish relative ages.

The branch of stratigraphy that divides and correlates rock successions using their fossil content, especially the first and last appearances of diagnostic species.

Preserved evidence of past life, such as mineralised bones, shells, impressions, casts or traces, usually found in sedimentary rocks and used to date and interpret past environments.

Establishing the order of geological events without numerical ages, using superposition, cross-cutting relationships, inclusions and fossil succession.

Calculating the numerical age of a rock or mineral from the measured ratio of a radioactive parent isotope to its decay product and the known decay constant.

A permeable rock or sediment body that can store and transmit groundwater in usable quantities, bounded above or below by less permeable layers.

The upper surface of the saturated zone in an unconfined aquifer, whose level rises and falls with recharge, drought and pumping.

Nutrient enrichment of a water body, usually by nitrates and phosphates, causing algal blooms, oxygen depletion and loss of aquatic life.

The amount of dissolved oxygen consumed by microorganisms decomposing organic matter in a water sample, widely used as an indicator of organic pollution.

A vertical section through soil showing horizons from organic surface litter down to weathered parent material, reflecting climate, vegetation and drainage history.

The detachment and removal of soil particles by water or wind, accelerated by vegetation loss, steep slopes and poor farming practice, reducing fertility.

Warming of the lower atmosphere as gases such as carbon dioxide, methane and water vapour absorb outgoing infrared radiation and re-emit it towards the surface.

The fraction of incoming solar radiation reflected by a surface; snow and ice have high albedo, dark ocean and forest have low albedo, affecting local and global energy balance.

A natural process such as an earthquake, volcanic eruption, landslide, flood or tsunami that threatens life and property, with risk depending on hazard, exposure and vulnerability.

The expected loss from earthquakes in a given area, combining hazard probability with exposure of people and infrastructure and their vulnerability.

The point on the ground surface directly above the focus of an earthquake, where shaking is usually strongest and damage greatest.

The downslope movement of rock, soil or debris under gravity, often triggered by heavy rain, earthquakes or slope undercutting and worsened by deforestation.

A line on a topographic map joining points of equal elevation; spacing indicates slope steepness and closed loops mark hills or depressions.

A map showing the distribution, boundaries, age and structure of rock units at the surface, with symbols for dip, faults and folds.

Development that meets present needs without compromising the ability of future generations to meet theirs, balancing economic, social and environmental objectives.

A formal procedure that predicts the environmental effects of a proposed project before approval and proposes measures to avoid, reduce or offset them.

A natural resource replenished by natural processes at a rate comparable to or faster than human use, such as solar energy, wind, flowing water or sustainably managed forests.