Andalusia PAU Geology and Environmental Sciences cheat sheet

Plate boundaries: divergent (ridges, normal faults, basaltic tholeiitic magmatism), convergent (subduction: calc-alkaline andesitic-granitic arcs; collision: crustal thickening, nappes), transform (strike-slip, no volcanism).

Lithosphere thickness controls subduction style: old, cold, dense oceanic lithosphere subducts steeply; young, buoyant lithosphere gives shallow subduction and flat-slab segments.

Mantle melting is triggered by decompression (ridges, rifts), volatile addition (subduction fluids lower peridotite solidus) or heat addition (hot spots, mantle plumes).

Bowen's reaction series: discontinuous branch olivine→pyroxene→amphibole→biotite; continuous branch Ca-plagioclase→Na-plagioclase; both converge to K-feldspar, muscovite, quartz.

Metamorphic facies by P-T: zeolite and greenschist (low grade), amphibolite (medium), granulite (high T, low P), blueschist (high P, low T, subduction), eclogite (very high P, mafic).

Metamorphic index minerals in pelites: chlorite→biotite→garnet→staurolite→kyanite→sillimanite with rising temperature; kyanite/sillimanite/andalusite polymorphs distinguish baric type.

Deformation: brittle (faults, joints, breccia, cataclasite) above the brittle-ductile transition; ductile (folds, foliation, mylonite) below it; stress types are compressional, tensional and shear.

Folds: anticline (oldest rocks in core, limbs dip away), syncline (youngest in core); plunging folds give V-shaped outcrop patterns; fault types: normal (extension), reverse/thrust (compression), strike-slip (shear).

Wilson cycle: continental rifting → ocean opening → subduction → collision → suturing; ophiolites mark fossil oceanic crust and suture zones mark former oceans.

Mineral definition: naturally occurring, inorganic, crystalline solid with a definite chemical composition (or limited solid solution) and ordered atomic structure.

Physical properties for identification: hardness (Mohs 1 talc to 10 diamond), cleavage (number of planes and angles), lustre (metallic/non-metallic), streak, colour, density, crystal habit, reaction with dilute HCl (calcite).

Silicate framework: isolated tetrahedra (olivine), chains (pyroxene single, amphibole double), sheets (micas, clays), frameworks (quartz, feldspars, zeolites); non-silicates include carbonates, sulphides, oxides, halides, sulphates.

Igneous classification by silica and colour index: felsic/granitic (quartz + K-feldspar, light, viscous, explosive), intermediate/andesitic, mafic/basaltic (pyroxene + Ca-plagioclase, dark, fluid, effusive), ultramafic (olivine, peridotite).

Texture records cooling history: phaneritic (slow, plutonic), aphanitic (fast, volcanic), porphyritic (two-stage), glassy/obsidian (very fast), vesicular/pumice (gas-rich), pyroclastic (explosive fragmentation).

Sedimentary rocks: clastic (conglomerate, sandstone, shale by grain size), chemical (limestone, dolomite, gypsum, halite, chert), organic (coal, some limestone); grain rounding, sorting and cement record transport and diagenesis.

Sedimentary structures: cross-bedding (current direction), graded bedding (turbidites, fining upward), ripple marks (oscillation vs current), mud cracks (subaerial exposure), bioturbation.

Metamorphic textures: foliated (slate, phyllite, schist, gneiss by increasing grade) and non-foliated (marble from limestone, quartzite from sandstone, hornfels from contact metamorphism).

Rock cycle links the three families: melting produces magma, weathering-erosion-transport-deposition-diagenesis produces sedimentary rock, heat/pressure/fluids produce metamorphic rock.

Stratigraphic principles: superposition, original horizontality, lateral continuity, cross-cutting relationships, inclusions, faunal succession; unconformities are angular, disconformity or nonconformity.

Relative time units (eons-eras-periods-epochs) versus chronostratigraphic equivalents (eonothem-erathem-system-series); absolute ages from radiometric dating (U-Pb, K-Ar, Rb-Sr, 14C for the last ~50 ka).

Geological time scale key boundaries: Cambrian explosion ~541 Ma, end-Permian mass extinction ~252 Ma (~90% marine species), end-Cretaceous ~66 Ma (Chicxulub impact, dinosaurs), Pleistocene-Holocene boundary ~11.7 ka.

Index fossils are short-ranging, widespread, facies-independent: ammonites (Mesozoic), graptolites (Ordovician-Silurian), trilobites (Palaeozoic), foraminifera and calcareous nannofossils (Mesozoic-Cenozoic).

Fossilisation requires rapid burial, hard parts, anoxic conditions and low diagenetic alteration; preservation types: permineralisation, moulds and casts, amber, carbonisation, trace fossils (ichnofossils).

Biostratigraphy uses biozones and first/last appearance datums; magnetostratigraphy uses polarity chrons; chemostratigraphy uses isotope excursions (e.g., δ13C negative shift at PETM).

Plate reconstructions use palaeomagnetism (apparent polar wander, sea-floor magnetic stripes), hotspot tracks and faunal provinciality; Pangaea assembled ~320-250 Ma and broke up from ~200 Ma.

Sequence stratigraphy: transgressive-regressive cycles controlled by eustasy, subsidence and sediment supply; lowstand, transgressive and highstand systems tracts bounded by sequence boundaries.

Mineral deposit classes: magmatic segregation (chromite, Ni-Cu sulphides), porphyry (Cu-Mo-Au), hydrothermal veins (Au, Pb-Zn), skarn, VMS/SEDEX (Zn-Pb), placer, lateritic (bauxite, Ni), evaporites.

Energy resources: conventional oil and gas in structural/stratigraphic traps sealed by caprock; coal rank peat→lignite→bituminous→anthracite with rising maturity; unconventional shale gas, tight gas, tar sands, gas hydrates.

Aquifer properties: porosity (storage) versus permeability (transmissibility); confined aquifers have potentiometric surface and artesian flow; over-abstraction causes water-table decline, land subsidence and saline intrusion.

Mass-movement classification by material and velocity: falls, topples, slides (rotational/translational), flows (debris, mud, earthflow), creep; triggers are rainfall, earthquakes, undercutting and slope loading.

Landslide susceptibility factors: slope angle, lithology and structure (clay, schistosity dipping out of slope), weathering, vegetation loss, water content, seismic shaking; mitigation via drainage, retaining walls, anchors, revegetation.

Flood hazard: return period T and exceedance probability P = 1/T per year; factors include rainfall intensity, catchment area, soil permeability, urbanisation (increased runoff), floodplain occupancy.

Volcanic and seismic hazards: pyroclastic flows, lahars, ash fall, lava flows, gas; earthquakes described by magnitude (logarithmic energy) and intensity (damage, modified Mercalli); tsunamis from submarine rupture or flank collapse.

Geological map reading: contours give topography, boundaries give dip direction (V-rule: outcrop V points downstream for gentle dip), strike and dip symbols, fold axes, faults (barbs on downthrown side), cross-sections.

Atmospheric layers: troposphere (weather, lapse rate ~6.5 °C/km), stratosphere (ozone layer absorbs UV), mesosphere, thermosphere, exosphere; pressure decreases exponentially with altitude.

Earth's radiation budget: incoming shortwave, reflected (albedo), absorbed, outgoing longwave; greenhouse gases absorb and re-emit longwave radiation, raising surface temperature.

General circulation: Hadley, Ferrel and Polar cells; trade winds, westerlies, polar easterlies; Coriolis deflection (right in Northern Hemisphere, left in Southern); ITCZ and subtropical highs.

Hydrological cycle fluxes: evaporation, transpiration, condensation, precipitation, runoff, infiltration, groundwater flow; residence times longest in oceans and glaciers, shortest in atmosphere.

Ocean circulation: surface currents driven by winds and Coriolis (gyres, Gulf Stream), thermohaline circulation driven by temperature and salinity (deep water formation in North Atlantic).

Rock weathering and soil formation: physical (freeze-thaw, salt, thermal), chemical (hydrolysis, oxidation, carbonation), biological; soil profile O-A-B-C-R, controls: climate, parent material, relief, organisms, time.

Carbon cycle: reservoirs atmosphere, ocean, biosphere, soils, fossil fuels, carbonate rocks; fluxes include photosynthesis, respiration, ocean uptake, volcanic degassing, anthropogenic combustion.

Landscape systems: drainage basins as sediment routing systems (erosion, transport, deposition); base level, graded profiles, knickpoints; aeolian, glacial, fluvial and coastal processes shape relief.

Air pollutants: primary (SO2, NOx, CO, particulates, hydrocarbons) versus secondary (ozone, PAN, sulphuric and nitric acid); PM2.5 and PM10 classified by aerodynamic diameter.

Photochemical smog forms under sunlight when NOx and volatile organic compounds react, producing ozone; tropospheric ozone is a pollutant while stratospheric ozone is protective.

Acid deposition: SO2 and NOx oxidise to H2SO4 and HNO3, lowering rain pH below 5.6; impacts on soils (base cation leaching, aluminium mobilisation) and freshwater biota; mitigation via desulphurisation and catalytic converters.

Eutrophication: excess nitrogen and phosphorus cause algal blooms, oxygen depletion (hypoxia), fish kills; sources are fertilisers, manure and wastewater; mitigation via nutrient-stripping and buffer strips.

Water quality indicators: BOD5, COD, dissolved oxygen, nitrates, phosphates, heavy metals (Pb, Cd, Hg, As), hydrocarbons, coliforms; EU Water Framework Directive uses ecological and chemical status.

Soil pollution: heavy metals, pesticides, hydrocarbons, salinisation and acidification; remediation by excavation, soil washing, bioremediation, phytoremediation, permeable reactive barriers.

Greenhouse gases ranked by contribution: CO2 (fossil fuel combustion, land-use change), CH4 (livestock, rice, landfills), N2O (fertilisers), fluorinated gases; global warming potential per molecule far higher for CH4 and SF6.

Waste management hierarchy: prevention, reuse, recycling, recovery (energy), disposal; landfill leachate and biogas (CH4) require collection and treatment.

Environmental Impact Assessment (EIA) stages: screening, scoping, baseline study, impact prediction, mitigation, Environmental Impact Statement, public consultation, monitoring; Strategic Environmental Assessment applies to plans and programmes.

Sustainability concept: meeting present needs without compromising future generations; three pillars environmental, social and economic; indicators include ecological footprint, carbon footprint, HDI.

Protected areas and Natura 2000 network (Special Protection Areas under Birds Directive, Special Areas of Conservation under Habitats Directive) conserve habitats and species.

Risk definition: Risk = hazard × exposure × vulnerability; hazard is the probability of a damaging event, vulnerability the susceptibility to damage; risk management combines prevention, mitigation, preparedness and response.

Coastal and fluvial risk management: setback lines, dune and wetland restoration, floodplain zoning, dams and levees (may increase downstream risk if they fail), early warning systems.

Renewable versus non-renewable resources: solar, wind, hydro, geothermal, biomass are renewable if use rate does not exceed regeneration; fossil fuels and minerals are finite.

Climate change adaptation and mitigation: mitigation reduces emissions (renewables, efficiency, carbon capture), adaptation reduces vulnerability (early warning, resilient infrastructure, crop change).

Environmental legislation framework in Spain and Andalusia: state laws on EIA and water, Andalusian laws on protected natural areas and integrated pollution prevention; precautionary and polluter-pays principles.

Reading a geological map: identify legend units, topographic base, fold and fault symbols, dip-strike notation; interpret the geological history from oldest to youngest event.

Cross-section construction: project boundaries to section line, use dip angles and thickness, respect apparent versus true dip (true dip is steepest, perpendicular to strike).

Structural contour maps: contour lines of a marker horizon; V-shape opening downstream indicates dip direction; closed contours indicate dome (older inside) or basin (younger inside).

Isopach and facies maps show thickness variation and lateral change; isochron maps show equal time surfaces; these aid resource exploration and basin analysis.

Reserve classification: resources versus reserves (proved, probable, possible); cut-off grade and stripping ratio determine economic viability of a deposit.

Hazard maps: landslide susceptibility, flood return-period zones, seismic hazard (PGA maps), volcanic hazard zones; used in land-use planning and emergency plans.

Groundwater vulnerability maps (DRASTIC-type) combine depth to water, recharge, aquifer media, soil, topography, impact of vadose zone and hydraulic conductivity.

Mine and quarry impacts: acid mine drainage from sulphide oxidation, tailings dams, dust and noise; restoration includes slope stabilisation, topsoil replacement and revegetation.

Field test sequence: observe lustre and colour, test hardness against fingernail (2.5), copper coin (3.5), steel knife (5.5), glass (5.5-6), streak on unglazed porcelain, then cleavage and acid reaction.

Quartz versus calcite versus feldspar: quartz (hardness 7, conchoidal fracture, no cleavage, no acid reaction), calcite (hardness 3, rhombohedral cleavage, effervesces in HCl), feldspar (hardness 6, two cleavages at ~90°, pearly faces).

Gypsum versus halite: gypsum (hardness 2, flexible, tabular), halite (hardness 2.5, cubic cleavage, salty taste); both are evaporites but differ in solubility and structure.

Mafic versus felsic identification: mafic rocks are dark, dense, rich in pyroxene, olivine and Ca-plagioclase; felsic rocks are light, less dense, rich in quartz and K-feldspar.

Sandstone classification: quartz arenite (well sorted, mature), arkose (feldspar-rich, arid granite source), greywacke (matrix-rich, turbidite); maturity increases with rounding, sorting and quartz content.

Limestone versus dolomite: limestone reacts vigorously with dilute HCl; dolomite reacts weakly or only when powdered; dolomitisation involves Mg replacing Ca during diagenesis.

Foliated rock sequence by grade: slate (microscopic mica, slaty cleavage), phyllite (sheen), schist (visible micas, garnet), gneiss (banded light and dark minerals).

Ore mineral identification: sulphides are metallic, dense, often coloured streak (pyrite black, chalcopyrite greenish-black, galena grey); oxides such as magnetite are magnetic and hematite gives red streak.

Mineral formula and class recognition: silicates contain SiO4 tetrahedra; carbonates contain CO3 (calcite CaCO3, dolomite CaMg(CO3)2); sulphates contain SO4 (gypsum CaSO4·2H2O, barite BaSO4).