Valencian Community PAU Geology and Environmental Sciences common mistakes
Valencian Community PAU Geology and Environmental Sciences · Understand the traps and how to avoid them.
When asked to identify a rock from a hand-specimen description (grain size, mineralogy, texture, foliation), the candidate names the rock from a single feature, e.g. calling any dark fine-grained rock 'basalt' or any foliated rock 'schist', instead of applying the full textural and mineralogical key step by step.
Candidates memorise a handful of rock names with one visual cue attached and skip the classification procedure (grain size → mineral composition → texture → protolith or origin), so a single salient feature dominates the answer.
What to do instead
Practise a fixed decision routine for each rock group: for igneous rocks determine plutonic vs volcanic from crystal size, then silica/colour index and mafic minerals; for metamorphic rocks determine foliation type and index minerals; for sedimentary rocks determine clast size, sorting, rounding and cement. Write the routine out and apply it to ten described specimens before the exam.
On stratigraphy and geological-time questions, the candidate orders events by the alphabetical or numerical labels given rather than by the principles of superposition, cross-cutting relationships, original horizontality and faunal succession, and so places an intrusion or fault before the strata it cuts.
The principles are known as definitions but are not applied as an ordered algorithm; under time pressure the candidate reads the labels as a sequence and forgets that cross-cutting features postdate the units they affect.
What to do instead
For every relative-age exercise, list the events and then justify each arrow in the sequence with a named principle ('fault cuts B and C, therefore fault is younger than C'). Inclusions and unconformities must be explicitly dated. Do five practice sequences and state the principle for every step.
When explaining plate tectonics, the candidate describes convection currents as the sole and sufficient driver of plate motion and cannot link a specific boundary type to its seismicity, volcanism, topography and metamorphic signature.
Textbook summaries compress the driving mechanism into 'convection moves the plates', and boundary types are learned as separate lists rather than as one causal chain from mechanism to observable features.
What to do instead
Build a table with one row per boundary type (divergent oceanic, divergent continental, convergent ocean–ocean, ocean–continent, continent–continent, transform) and columns for stress regime, fault type, earthquake depth, magma source and composition, relief and metamorphic grade. Also learn slab pull and ridge push as the dominant forces, with mantle convection as the underlying context, not the direct cause.
In external-process questions the candidate conflates weathering with erosion, or describes transport and deposition without naming the agent and the energy change, e.g. saying 'the river deposits the material at the coast' without distinguishing bed load, suspended load and dissolved load or explaining why competence falls.
The process chain (weathering → erosion → transport → deposition → diagenesis) is memorised as a slogan, and each stage is learned in isolation, so the candidate cannot say what actually changes between stages.
What to do instead
For each agent (running water, wind, ice, gravity, waves) write a short chain naming the dominant process, the load type carried, the landforms produced by erosion and by deposition, and the reason deposition occurs (velocity drop, slope decrease, melting, evaporation). Use these chains to answer past-paper questions on river profiles, glacial valleys, dunes and deltas.
On climate questions the candidate treats the greenhouse effect as inherently a pollution problem, or confuses the natural greenhouse effect, the enhanced greenhouse effect and ozone depletion, and cannot separate climate variability (El Niño, NAO, solar cycles) from anthropogenic forcing.
Media framing merges 'greenhouse effect', 'global warming' and 'ozone hole', and the syllabus lists these as separate items that the candidate never contrasts explicitly.
What to do instead
Write three short definitions side by side: natural greenhouse effect (necessary, keeps mean surface temperature about 15 °C), enhanced greenhouse effect (increase in greenhouse gas concentrations from human activity), and stratospheric ozone depletion (chlorofluorocarbons, ultraviolet radiation, unrelated to warming). Then list internal variability mechanisms separately from external forcings, and practise classifying a given observation into the right category.
On hydrosphere questions the candidate describes the water cycle qualitatively but cannot reason about aquifer behaviour: they mislabel an unconfined aquifer as confined, confuse porosity with permeability, or predict that pumping always lowers the water table when the well is artesian.
Groundwater is taught with diagrams the candidate can label but not interpret, and the key distinctions (storage vs transmission, potentiometric surface vs water table) are never tested against a scenario.
What to do instead
Learn the pairs explicitly: porosity stores, permeability transmits; an unconfined aquifer has a water table, a confined one has a potentiometric surface and can flow without pumping. Practise with cross-section scenarios: given two wells and a pumping rate, state which aquifer responds, whether the spring dries up, and what happens to flow direction.
On geological-hazard questions the candidate treats hazard, vulnerability, exposure and risk as synonyms, and proposes generic responses ('raise awareness', 'evacuate') instead of matching the measure to the hazard (e.g. hazard maps and land-use zoning for mass movements, building codes and ground-movement monitoring for earthquakes, lahar warning and slope monitoring for volcanoes, floodplain zoning and upstream retention for floods).
The risk equation is memorised but not applied, and the candidate has no structured list of mitigation types (structural, non-structural, prediction, prevention), so answers default to vague social measures.
What to do instead
Learn risk = hazard × vulnerability × exposure and use it to structure every answer: state which factor the measure reduces. Keep a per-hazard list of prediction tools, structural measures and planning measures, and practise writing a three-part answer (assessment, mitigation, emergency response) for each hazard type.
On environmental-impact and pollution questions the candidate lists pollutants without identifying the pathway, the affected compartment (air, water, soil, biota) and the specific mitigation mechanism, or proposes 'recycling and raising awareness' for every problem, including eutrophication, acid rain and heavy-metal soil contamination.
Answers are written from general environmental vocabulary rather than from the mechanism of each problem, and the candidate does not distinguish prevention, treatment and restoration.
What to do instead
For each pollution case write four lines: source, pathway, receptor and effect, then the mitigation matched to the mechanism (e.g. eutrophication → reduce phosphorus and nitrogen inputs → tertiary wastewater treatment and buffer strips; acid rain → desulphurisation and catalytic converters; heavy metals → immobilisation, phytoextraction, soil removal). Learn the difference between prevention at source, end-of-pipe treatment and remediation.
On map, cross-section and data-interpretation tasks the candidate answers from the legend or a single data point instead of reading scale, orientation, contour values, strike and dip symbols and the full data series, and so gives a gradient, thickness or trend that is inconsistent with the information provided.
Practical work is often revised by reading rather than by doing, so the candidate has not internalised the order of operations for reading a geological map or a cross-section, and rushes to a conclusion from the most visible feature.
What to do instead
Adopt a fixed reading order: title and legend, scale, orientation, contours and spot heights, geological symbols, then structure. For gradients, calculate from two stated points and show the arithmetic. For cross-sections, transfer contacts and dips from the map before drawing. For graphs, describe the overall trend before quoting numbers. Practise one map and one cross-section per study session.
On minerals and geological resources the candidate identifies minerals by colour alone, or discusses resources only in terms of abundance, ignoring grade, reserve vs resource, and the environmental and economic factors that make a deposit exploitable.
Mineral identification is learned from photographs where colour is the most memorable cue, and economic geology is covered briefly, so the candidate lacks the concepts of ore grade, reserve classification and gangue.
What to do instead
Identify minerals using at least three properties: hardness (Mohs), cleavage or fracture, lustre, streak, and a diagnostic test such as effervescence with dilute acid for carbonates or magnetism for magnetite; state the properties you used in every answer. For resources, learn the resource/reserve distinction, the role of cut-off grade and price, and list the main environmental impacts of mining with their mitigation.