Canary Islands PAU Geology & Env Sci flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Mohorovičić discontinuity

The boundary between Earth's crust and mantle, marked by an abrupt increase in seismic wave velocity; it lies about 5-10 km beneath oceans and 30-70 km beneath continents.

Isostasy

The state of gravitational equilibrium in which Earth's lithosphere floats on the denser asthenosphere; Airy and Pratt models explain how crustal thickness and density support topography.

Bowen's reaction series

The sequence in which minerals crystallize from cooling magma, from olivine and calcium plagioclase at high temperature to quartz, muscovite, and potassium feldspar at low temperature.

Slab pull

The force driving plate motion in which a dense subducting oceanic plate sinks into the mantle at a convergent boundary, pulling the rest of the plate behind it.

Hotspot volcanism

Volcanism caused by a mantle plume rising beneath a plate, forming volcanic islands or chains as the plate moves over the fixed hotspot, as in the Canary Islands and Hawaii.

Karst weathering

Chemical dissolution of soluble rocks such as limestone, dolomite, and gypsum by acidic water, producing caves, sinkholes, and underground drainage systems.

Graded bedding

A sedimentary structure in which grain size decreases upward within a bed, typically deposited by a turbidity current or other waning flow.

Cross-bedding

Inclined layers within a sedimentary bed formed by migration of dunes or ripples; it indicates the direction of sediment transport and the depositional environment.

Barranco

A steep-sided, usually dry ravine or gully cut into volcanic terrain by episodic flash floods; common in the Canary Islands and other arid volcanic regions.

Diagenesis

The set of low-temperature physical and chemical changes, including compaction and cementation, that convert loose sediment into sedimentary rock after deposition.

Principle of superposition

The stratigraphic principle stating that in an undisturbed sequence of sedimentary rocks, the oldest layers lie at the bottom and the youngest at the top.

Index fossil

A fossil species that is widespread, abundant, and short-ranging in time, used to correlate rock layers and define biostratigraphic zones.

Angular unconformity

An unconformity in which tilted or folded older strata are overlain by younger, flat-lying layers, indicating a period of deformation and erosion.

K-Pg boundary

The stratigraphic boundary about 66 million years ago marking the end-Cretaceous mass extinction, associated with the Chicxulub impact and an iridium anomaly.

Radiometric dating

A method of absolute dating that uses the decay of radioactive isotopes (such as U-238, K-40, or C-14) to calculate the age of rocks or organic remains.

Mohs hardness scale

A relative scale from 1 (talc) to 10 (diamond) ranking minerals by their resistance to scratching; used in hand-sample mineral identification.

Silicate tetrahedron

The basic structural unit of silicate minerals, consisting of one silicon atom surrounded by four oxygen atoms; it links into chains, sheets, or frameworks.

Fractional crystallization

The process by which early-formed minerals are removed from a cooling magma, changing the composition of the remaining melt toward more felsic compositions.

Foliation

A planar arrangement of mineral grains in metamorphic rocks, produced by directed pressure; it includes slaty cleavage, schistosity, and gneissic banding.

Tephra

Fragmental volcanic material ejected during explosive eruptions, classified by size as ash, lapilli, or bombs; it forms pyroclastic deposits and tuff.

Risk equation

Risk equals hazard multiplied by exposure and vulnerability; it expresses the potential for loss from a natural event and guides hazard management decisions.

Strike and dip

Strike is the compass direction of a horizontal line on a bedding plane; dip is the angle and direction of maximum inclination of that plane.

Three-point problem

A geological mapping method that uses the elevations of a planar unit at three points to determine its strike, dip direction, and dip angle.

Lahar

A volcanic mudflow or debris flow formed when water mixes with loose volcanic ash and debris; it can travel far downstream and is a major volcanic hazard.

Trade winds

Prevailing easterly winds in the tropics, blowing from subtropical high-pressure belts toward the equator; they shape the climate of the Canary Islands.

Mar de nubes

A persistent layer of low cloud on windward slopes of the Canary Islands, formed when moist trade winds are trapped beneath a temperature inversion.

Calima

A weather phenomenon in the Canary Islands in which Saharan dust and hot, dry air are carried westward, reducing visibility and air quality.

Thermohaline circulation

A global ocean circulation driven by differences in water temperature and salinity, which control density and cause deep-water formation and slow overturning.

Upwelling

The rise of cold, nutrient-rich deep water to the ocean surface, often caused by offshore winds; it supports high marine productivity, as in the Canary Current.

Longshore drift

The movement of sediment along a coastline by waves approaching at an angle, causing a net transport in the direction of the prevailing wave approach.

Andisol

A fertile soil formed from volcanic ash, rich in minerals and organic matter; common in the Canary Islands and important for agriculture.

Laurisilva

A humid subtropical laurel forest found on north-facing slopes of the Canary Islands, a relict Tertiary ecosystem protected in Garajonay and Anaga.