Catalonia PAU Geology & Env Sci flashcards

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

Lithosphere

Rigid outer shell of Earth comprising the crust and uppermost mantle, broken into tectonic plates that move over the ductile asthenosphere.

Benioff–Wadati zone

Inclined zone of deep-focus earthquakes along a subducting slab at a convergent boundary, tracing the descending plate into the mantle.

Isostasy

Gravitational equilibrium whereby the lithosphere floats on the asthenosphere; thicker or less dense crust stands higher, as in Airy and Pratt models.

Anticline

Upward-arching fold whose limbs dip away from the axial plane; the oldest rocks crop out in its core.

Bowen's reaction series

Order of mineral crystallisation from cooling magma; olivine forms first and quartz last, and the reverse order governs weathering resistance.

Hjulström curve

Graph relating stream velocity to erosion, transport, or deposition of sediment particles of different sizes; fine clays need high velocity to erode.

Karst landscape

Terrain formed by chemical dissolution of soluble rocks such as limestone, producing dolines, caves, disappearing streams, and stalactites.

Soil horizon B

Subsurface soil layer of illuviation where clays, iron oxides, and humus accumulate after being leached from the overlying A horizon.

Angular unconformity

Erosion surface separating tilted or folded older strata from overlying horizontal younger beds, recording deformation followed by erosion and renewed deposition.

Index fossil

Fossil species with a short stratigraphic range and wide geographic distribution, used to correlate and date rock layers.

End-Permian extinction

Mass extinction about 252 million years ago, the largest in Earth history, eliminating roughly 90% of marine species, linked to Siberian Traps volcanism.

Radiometric dating

Absolute dating method using decay of radioactive isotopes with known half-lives, such as carbon-14 for recent material and uranium-lead for ancient rocks.

Mohs hardness scale

Ten-point relative scale from talc (1) to diamond (10) ranking mineral resistance to scratching, used in hand-specimen identification.

Foliation

Parallel alignment of platy minerals or compositional banding in metamorphic rocks, produced by directed pressure, as in slate, schist, and gneiss.

Acid mine drainage

Pollution formed when sulphide minerals in mine waste oxidise and generate acidic, metal-rich water that contaminates streams and groundwater.

Clastic sedimentary rock

Rock made of fragments of pre-existing rocks, classified by grain size as conglomerate, sandstone, siltstone, or shale.

Lapse rate

Rate at which air temperature falls with altitude in the troposphere, averaging about 6.5 degrees Celsius per kilometre.

Anticyclone

High-pressure system with subsiding air, diverging surface winds, and generally clear, stable weather with little precipitation.

Ice–albedo feedback

Positive climate feedback in which melting ice exposes darker surfaces that absorb more solar radiation, amplifying further warming and melt.

Milankovitch cycles

Variations in Earth's orbital eccentricity, axial tilt, and precession that alter solar insolation and drive glacial–interglacial climate cycles.

Aquifer

Permeable geological formation able to store and transmit groundwater in usable quantities; confined aquifers are bounded by impermeable layers.

Eutrophication

Nutrient enrichment of water bodies causing algal blooms, oxygen depletion, and loss of aquatic life, typically from agricultural or urban runoff.

BOD

Biochemical oxygen demand: oxygen consumed by microbes decomposing organic matter in water, used as an indicator of organic pollution.

Watershed

Land area drained by a river and its tributaries, bounded by topographic divides, functioning as the unit for water resource management.

Carrying capacity

Maximum population size an environment can sustain indefinitely given available resources, represented as K in the logistic growth model.

Trophic level

Position of an organism in a food chain, such as producer, primary consumer, or secondary consumer; energy transfer between levels is about ten percent.

Nitrogen fixation

Conversion of atmospheric nitrogen gas into ammonia by bacteria such as Rhizobium, making nitrogen available to living organisms in the nitrogen cycle.

Keystone species

Species whose removal disproportionately alters ecosystem structure and function, despite its low abundance, such as sea otters or wolves.

Environmental impact assessment

Structured process predicting environmental effects of a proposed project before approval, including scoping, baseline study, mitigation, and public consultation.

Risk equation

Risk is the product of hazard, exposure, and vulnerability; reducing any factor lowers overall risk from natural or technological hazards.

Polluter pays principle

Environmental policy principle requiring those who cause pollution to bear the costs of prevention, remediation, and damage compensation.

Floodplain zoning

Land-use planning tool restricting or conditioning development in areas prone to flooding, reducing exposure and economic losses from flood hazards.