Canary Islands PAU Geology & Env Sci cheat sheet

Earth's layered structure by composition: continental crust (granitic, ~30-70 km thick), oceanic crust (basaltic, ~5-10 km), mantle (peridotite, to ~2900 km), and core (Fe-Ni); by rheology: lithosphere (rigid, ~100 km), asthenosphere (partially molten, plastic), mesosphere, and core.

Seismic discontinuities mark layer boundaries: Mohorovičić (crust-mantle), Gutenberg (~2900 km, mantle-core), and Lehmann (~5150 km, inner-outer core); S-waves cannot pass the outer core, proving it is liquid.

Isostasy: Airy model (crustal roots support topography; thicker crust floats higher) and Pratt model (density variations at constant depth); post-glacial rebound is isostatic evidence.

Plate tectonics: lithospheric plates move over the asthenosphere driven by mantle convection, slab pull, and ridge push. Divergent boundaries create oceanic ridges and rift valleys; convergent boundaries form subduction zones, trenches, volcanic arcs, and fold mountains; transform boundaries produce strike-slip faults.

Wilson cycle: continental rifting → ocean opening → subduction → continental collision → suture zone; the Canary Islands are intraplate volcanic islands on Jurassic oceanic crust, not at a plate margin.

Magmatic processes: partial melting of mantle peridotite produces basaltic magma (decompression melting at ridges, flux melting at subduction zones); Bowen's reaction series orders crystallization from olivine/pyroxene (high T) to quartz/muscovite (low T); fractional crystallization and assimilation drive magma differentiation.

Igneous rock classification: plutonic (coarse-grained, e.g. granite, gabbro) vs volcanic (fine-grained, e.g. rhyolite, basalt); silica content controls viscosity - high-silica magmas are viscous and explosive, low-silica magmas are fluid and effusive.

Metamorphism: contact (thermal) metamorphism around intrusions produces hornfels; regional metamorphism produces foliated rocks (slate → schist → gneiss) with increasing P-T; index minerals (chlorite, biotite, garnet, staurolite, kyanite, sillimanite) map metamorphic grade.

Canary Islands volcanism: hotspot/plume-related alkaline magmatism (basanites, phonolites, trachytes); shield-building basaltic stages followed by felsic explosive phases; the islands show an age progression from Fuerteventura/Lanzarote (oldest) to El Hierro (youngest).

Weathering types: physical (freeze-thaw, salt crystallization, thermal expansion, unloading) and chemical (hydrolysis, oxidation, carbonation/dissolution, hydration); chemical weathering is fastest in warm, humid climates, physical weathering in cold/arid climates.

Karst in the Canary Islands forms from dissolution of basaltic and sedimentary rocks; salt weathering from marine spray is a dominant mechanical process on coastal cliffs.

Erosion agents: water (rills, gullies, sheet wash), wind (deflation, abrasion), ice (glacial plucking, abrasion), gravity (mass wasting: rockfalls, landslides, debris flows); volcanic islands show rapid erosion by barrancos (dry ravines) and coastal undercutting.

Transport: bed load (traction, saltation), suspended load, and dissolved load; competence and capacity of a stream depend on velocity; sorting and rounding increase with transport distance.

Sedimentary structures as environmental indicators: cross-bedding (dunes, rivers), graded bedding (turbidites), ripple marks (shallow water), mud cracks (subaerial exposure), bioturbation (benthic activity).

Sedimentary environments: continental (fluvial, eolian, glacial, lacustrine), transitional (deltas, beaches, tidal flats, lagoons), marine (shallow shelf, reef, deep sea). Facies change laterally and vertically with sea-level change.

Diagenesis: compaction, cementation, recrystallization, and lithification convert sediment to sedimentary rock; sedimentary rocks preserve fossils and record depositional conditions.

Transgression/regression sequences: fining-upward successions record transgression (sea-level rise); coarsening-upward successions record regression; unconformities (angular, disconformity, nonconformity) mark gaps in the record.

Canary coastal and aeolian systems: dune fields (Maspalomas, Corralejo) built by trade winds; marine terraces record Quaternary sea-level changes and tectonic uplift.

Stratigraphic principles: superposition (older below), original horizontality, lateral continuity, cross-cutting relationships (younger features cut older), inclusions (fragments are older than host), and faunal succession.

Relative dating uses lithostratigraphy, biostratigraphy (index fossils), and sequence stratigraphy; absolute dating uses radiometric methods (U-Pb, K-Ar, Rb-Sr, C-14 for young organic material).

Geological time scale eras: Precambrian (~4600-541 Ma), Paleozoic (541-252 Ma), Mesozoic (252-66 Ma), Cenozoic (66 Ma-present); major extinctions at end-Ordovician, end-Devonian, end-Permian (largest), end-Triassic, and end-Cretaceous (K-Pg).

Fossils: body fossils (shells, bones) and trace fossils (tracks, burrows); preservation requires rapid burial and anoxic conditions; index fossils are widespread, abundant, and short-ranging (e.g. ammonites, trilobites, graptolites).

Canary Islands geology: oceanic island volcanism since the Miocene (~20 Ma); Fuerteventura and Lanzarote oldest, El Hierro and La Palma youngest; submarine and subaerial volcanic sequences, intrusive complexes (Fuerteventura basal complex), and marine sedimentary intercalations record sea-level and volcanic history.

Fossil content of the Canaries is sparse because of volcanic terrain; marine fossiliferous sediments (e.g. Las Palmas, Gran Canaria) and aeolianites preserve Quaternary fauna.

Unconformities and correlation: angular unconformity (tilted older beds below flat younger beds), disconformity (erosion surface between parallel beds), nonconformity (sedimentary over igneous/metamorphic basement).

Paleomagnetism and magnetic reversals in oceanic crust record sea-floor spreading and provide a global chronostratigraphic framework.

Mass extinctions and stratigraphic boundaries: K-Pg boundary marked by iridium anomaly and impact ejecta (Chicxulub); end-Permian linked to Siberian Traps volcanism and anoxia.

Mineral identification: color, streak, luster, hardness (Mohs scale 1 talc-10 diamond), cleavage, fracture, crystal habit, specific gravity, and reaction to acid (calcite effervesces).

Silicate structures: isolated tetrahedra (olivine), single chains (pyroxene), double chains (amphibole), sheets (mica, clay), frameworks (quartz, feldspar); silicate minerals dominate the crust.

Common rock-forming minerals: quartz, feldspars (orthoclase, plagioclase), micas (biotite, muscovite), amphibole (hornblende), pyroxene (augite), olivine, calcite, dolomite, gypsum, halite, hematite, magnetite.

Igneous rocks by texture and composition: basalt/gabbro (mafic), andesite/diorite (intermediate), rhyolite/granite (felsic); glassy (obsidian), vesicular (pumice, scoria), pyroclastic (tuff, ignimbrite).

Sedimentary rocks: clastic (conglomerate, sandstone, shale), chemical (limestone, dolostone, chert, evaporites), organic (coal); grain size and sorting indicate transport energy.

Metamorphic rocks: foliated (slate, phyllite, schist, gneiss) and non-foliated (marble, quartzite, hornfels); protolith and P-T conditions determine mineral assemblage.

Bowen's reaction series and magma evolution: fractional crystallization produces more felsic residual melts; assimilation and magma mixing modify composition; partial melting of crust produces granitic magmas.

Canary volcanic rocks: basanites, tephrites, phonolites, trachytes, rhyolites; alkali basalt series typical of intraplate oceanic islands; pyroclastic deposits and lava tubes (e.g. Cueva de los Verdes) record eruptive styles.

Rock cycle: igneous, sedimentary, and metamorphic rocks transform through melting, weathering/erosion, deposition/lithification, and metamorphism; plate tectonics drives the cycle.

Hazard vs risk: hazard is the probability of a dangerous event; risk = hazard × exposure × vulnerability; risk management reduces exposure and vulnerability, not just hazard.

Volcanic hazards: lava flows, pyroclastic flows and surges, ash fall, lahars, volcanic gases, and sector collapse; Canary Islands hazards include basaltic fissure eruptions (e.g. Tajogaite 2021, La Palma), ash disruption, and lava flow damage.

Seismic and landslide hazards: earthquakes from volcanic and tectonic activity; volcanic island landslides (e.g. Güímar and Orotava valleys, Tenerife) can generate tsunamis; rockfalls common on steep barrancos.

Coastal hazards: erosion, cliff retreat, storm surges, and sea-level rise; dune and beach systems (Maspalomas, Corralejo) are dynamic and vulnerable to human pressure.

Natural resources: volcanic rocks as aggregates, pozzolans, and building stone; groundwater in volcanic aquifers (galerías and pozos in the Canaries); geothermal potential; solar and wind energy.

Geological maps: scale, legend, strike and dip symbols, contour lines, and lithological units; cross-sections are constructed perpendicular to strike using apparent dips and thicknesses.

Cross-section rules: younger units on top (superposition), faults and folds shown by offsets and curvature, unconformities drawn as wavy lines, and thicknesses preserved unless tectonically modified.

Three-point problems: determine strike from two points of equal elevation and dip direction/dip angle from a third point; use structure contours to project units in the subsurface.

Hazard mitigation in the Canaries: volcanic monitoring (IGN, INVOLCAN), evacuation plans, land-use planning on lava flow paths, and coastal setback lines.

Atmospheric composition: N2 ~78%, O2 ~21%, Ar ~0.93%, CO2 ~0.04%; variable water vapor, aerosols, and ozone; layers: troposphere (weather), stratosphere (ozone layer), mesosphere, thermosphere, exosphere.

Temperature decreases with altitude in the troposphere (lapse rate ~6.5 °C/km) and increases in the stratosphere due to ozone absorption of UV.

Atmospheric circulation: Hadley, Ferrel, and Polar cells; trade winds (NE in the Northern Hemisphere) driven by subtropical highs; the Canary Islands lie in the trade-wind belt with a semi-permanent Azores High.

Canary climate: subtropical, mild temperatures year-round, low rainfall, high humidity on windward slopes; the 'mar de nubes' (sea of clouds) forms on north-facing slopes due to the trade-wind inversion; rain shadow on south slopes.

El Niño-Southern Oscillation (ENSO) and North Atlantic Oscillation (NAO) affect rainfall variability in the Canaries; Saharan dust intrusions (calima) affect air quality and marine productivity.

Greenhouse effect: CO2, CH4, N2O, and water vapor absorb outgoing infrared radiation; anthropogenic emissions have raised CO2 from ~280 ppm (pre-industrial) to over 420 ppm.

Climate change impacts in the Canaries: sea-level rise, coastal erosion, increased heat waves, drought, changes in trade-wind patterns and cloud cover, and shifts in marine ecosystems.

Climate proxies: ice cores, tree rings, sediment cores, corals, and speleothems record past climate; the Canaries' marine sediments record Saharan dust and upwelling history.

Ozone depletion: CFCs release chlorine that destroys stratospheric ozone; the Montreal Protocol phased out CFCs; the ozone hole forms over Antarctica in spring.

Water cycle: evaporation, transpiration, condensation, precipitation, infiltration, runoff, and groundwater flow; residence times vary from days (atmosphere) to millennia (deep groundwater, oceans).

Ocean dynamics: surface currents driven by winds and Coriolis effect (gyres); thermohaline circulation driven by temperature and salinity differences; upwelling brings nutrient-rich water to the surface.

Canary Current: a cool, southward-flowing eastern boundary current with coastal upwelling, moderating temperatures and supporting rich fisheries; it interacts with the Canary Islands' climate.

Tides: caused by gravitational pull of the Moon and Sun; spring tides at new/full moon, neap tides at quarter moons; tidal range varies with coastal geometry.

Waves: generated by wind; wave height depends on wind speed, duration, and fetch; waves break when depth is about 1.3 times wave height; longshore drift moves sediment along the coast.

Coastal processes: erosion (hydraulic action, abrasion, attrition, solution), transport (longshore drift), and deposition (beaches, spits, tombolos); sea-level change and storms drive coastal evolution.

Groundwater in volcanic islands: aquifers in fractured basalt and pyroclastic layers; Canarian water management uses galerías (horizontal tunnels) and pozos (wells); overexploitation causes salinization and water-table decline.

Water quality: eutrophication from nutrient runoff, salinization from seawater intrusion, and pollution from agriculture and wastewater; desalination supplies water in the Canaries.

Coastal management: beach nourishment, groynes, breakwaters, and dune restoration; integrated coastal zone management balances development and conservation.

Soil formation factors (Jenny): parent material, climate, organisms, relief, and time (CLORPT); soil profile horizons O, A, E, B, C, R.

Volcanic soils (andisols) in the Canaries are fertile, rich in minerals, and derived from basalt and ash; they support agriculture (bananas, vines, tomatoes) but are vulnerable to erosion on steep slopes.

Island biogeography: species richness depends on island area, isolation, and habitat diversity; the Canaries are a biodiversity hotspot with many endemic species (e.g. Canary Island pine, dragon tree, laurel forest).

Laurel forest (laurisilva) is a relict Tertiary ecosystem found on humid north-facing slopes (Garajonay, Anaga); it is a key conservation priority.

Endemic fauna: Canary Island lizard, laurel pigeon, Bolle's pigeon, and numerous invertebrates; invasive species (e.g. feral cats, rats, rabbits) threaten endemics.

Conservation tools: protected areas (national parks: Teide, Caldera de Taburiente, Garajonay, Timanfaya), Natura 2000 network, and species recovery plans; UNESCO biosphere reserves cover several islands.

Ecosystem services: provisioning (water, food), regulating (climate, erosion control), cultural (tourism, recreation), and supporting (soil formation, nutrient cycling).

Threats to island biodiversity: habitat loss from tourism and urbanization, invasive species, climate change, and overexploitation of water and coastal resources.

Soil erosion and desertification: steep slopes, sparse vegetation, and intense rainfall events cause erosion; terracing and reforestation are traditional and modern conservation measures.

Environmental impact assessment (EIA): identifies, predicts, and mitigates impacts of projects; steps include screening, scoping, baseline study, impact prediction, mitigation, and monitoring.

Pollution types: air (particulate matter, NOx, SO2, ozone), water (nutrients, heavy metals, hydrocarbons), soil (pesticides, salinization), and noise; the Canaries face air quality issues from Saharan dust and traffic.

Waste management hierarchy: prevention > reuse > recycling > recovery (energy) > disposal (landfill); the Canaries generate high waste volumes due to tourism.

Marine pollution: plastics, microplastics, and oil spills threaten Canary marine ecosystems; wastewater discharge affects coastal water quality.

Sustainable development: balances economic, social, and environmental needs (Brundtland definition); UN Sustainable Development Goals (SDGs) provide a framework; the Canaries face tension between tourism growth and resource limits.

Renewable energy in the Canaries: wind and solar potential; reliance on imported fossil fuels; energy transition and storage challenges on islands.

Circular economy: designs out waste and pollution, keeps materials in use, and regenerates natural systems; applies to tourism, agriculture, and water management.

Environmental legislation: EU directives (EIA, Habitats, Water Framework), Spanish national laws, and Canary Islands regional regulations protect habitats and regulate waste and water.

Indicators of sustainability: ecological footprint, carbon footprint, water footprint, and carrying capacity; tourism carrying capacity is a key issue for the Canary Islands.