Esame di Stato Geologo common mistakes
Esame di Stato Geologo · Understand the traps and how to avoid them.
Confusing the order of superposition with the order of deformation events when reconstructing a geological history, e.g. reporting folding as older than the sedimentary unit it folds, or listing metamorphism before the intrusion that caused it.
Candidates memorize individual relative-dating principles (superposition, cross-cutting, inclusion) as isolated rules and never practise assembling a full event sequence from a described outcrop; under time pressure they apply the principles in the order they remember them rather than the order the evidence requires.
What to do instead
Practise building event chains from written descriptions only: for each described relationship (folded bed, cross-cutting dyke, baked contact, unconformity) write the pair of events and the principle that orders them, then topologically sort the list. Always test the finished chain by asking which event each later event must postdate. Do at least ten such reconstructions covering angular unconformities, intrusive contacts with chilled margins, and fault-cut-by-fault cases.
Treating a stereographic projection as decoration: reading foliation and lineation orientations from a problem statement but then giving a bedding or fault-plane attitude that contradicts the plotted great circle or pole, or failing to distinguish apparent from true dip.
Structural geology is studied mostly as terminology, and candidates rarely practise the geometric operations (finding the intersection lineation of two planes, rotating about an axis, computing true dip from two apparent dips) that the exam expects to be done by hand or by mental construction.
What to do instead
Drill the standard constructions until they are automatic: true dip from two apparent dips, plunge and trend of the intersection of two planes, and the angle between a borehole and a plane. For each exercise, sketch the map pattern that the attitude implies and check consistency. Learn to sanity-check a great circle against its pole (90 degrees apart) before writing the answer.
Answering geotechnical questions with soil or rock classification names alone (e.g. 'it is a CL' or 'RMR 55') without linking the classification to the design parameter or verification the question actually asks for, and mixing up total and effective stress or drained and undrained conditions.
Candidates learn classification systems and correlations as lists and never work through a full calculation chain; they also carry over the wrong drainage assumption from one problem type to the next, which silently invalidates the numbers.
What to do instead
For every problem, write the drainage condition and stress regime explicitly before choosing parameters. Rehearse the chain classification to parameter to check: from index properties to compressibility or shear strength, from RMR or GSI to cohesion and friction, then to a bearing capacity or slope stability check. Practise computing effective stress profiles with a water table and verify that pore pressure is subtracted everywhere it should be.
Confusing permeability with transmissivity, or storativity with specific yield, and then using the wrong unit or the wrong parameter in Darcy's law, well-hydraulics equations and groundwater-balance calculations.
The formulas are memorized symbolically without dimensional reasoning, so the candidate cannot detect when a parameter is being used in the wrong place; the exam's numerical answers then come out off by orders of magnitude but are reported without a plausibility check.
What to do instead
Attach dimensions to every symbol in your formula sheet (k in m/s, T in m2/s, S dimensionless, Sy dimensionless) and do a unit check on every calculation. Work through at least one pumping-test analysis end to end, converting drawdown data to transmissivity and storativity and then interpreting what the values mean hydrogeologically. Practise converting between k and T for a stated aquifer thickness in both directions.
Classifying a rock by naming minerals present without applying the correct compositional or textural criteria for the classification scheme in use, e.g. calling a rock a granite when modal quartz is below 20 percent, or labelling a foliated metamorphic rock by its protolith rather than by its fabric and grade.
Candidates revise mineral lists and hand-specimen descriptions separately from the classification diagrams, so they never internalize the threshold values (QAPF fields, modal percentages, grain-size boundaries) that decide the name; they also confuse protolith names with metamorphic names.
What to do instead
Memorize the decisive thresholds as numbers, not adjectives: QAPF field boundaries for plutonic and volcanic rocks, the 20 percent quartz line, the boundaries between slate, phyllite, schist and gneiss, and the index minerals for each metamorphic grade. Practise naming rocks from modal percentages given as numbers, and for each name state the single criterion that would change the name if it shifted.
Identifying fossils or interpreting depositional environments from a single taxon or a single sedimentary structure, ignoring the assemblage, the facies association and the stratigraphic context, and therefore assigning a precise age or environment that the evidence cannot support.
Paleontology and sedimentology are revised as catalogue knowledge (index fossils, structure names) and candidates are rarely asked to weigh evidence; they therefore over-interpret a single data point instead of reasoning about what the assemblage as a whole permits.
What to do instead
For each exercise, list all available evidence first (lithology, sedimentary structures, fossils, geometry, vertical trends), then state the environment as a range with the discriminating evidence named. Practise distinguishing environments that share one feature, such as shoreface versus tidal flat, or turbidite versus storm deposit, by identifying the features that separate them. When giving an age, state the biozone or assemblage basis and the uncertainty it carries.
Producing a geological map or cross-section in which the cross-section is not a valid projection of the map: unit boundaries do not match at the section line, apparent dips are used as true dips, or thicknesses vary without a structural reason.
Cartography is treated as a drawing exercise rather than a geometric test of a structural model; candidates do not systematically transfer contacts from map to section or check the section back against the map, so internal inconsistencies go unnoticed.
What to do instead
Adopt a fixed workflow: mark the section line on the map, project every contact and fault intersection, convert apparent dip to true dip perpendicular to the section line, then draw the section and finally re-project it onto the map to test the fit. Include a legend, scale, north arrow and a written statement of the structural interpretation. Practise on synthetic maps with a known answer before attempting real ones.
Treating landslide, flood and seismic hazard as separate silos: computing a factor of safety for a slope without considering rainfall-induced pore pressure rise, or zoning seismic hazard without accounting for local site amplification and liquefaction susceptibility of the mapped units.
The exam domains are studied in separate blocks and candidates never practise multi-hazard reasoning; they also default to a static, dry slope model because that is the simplest formula they know, and they forget that the geological map itself carries the site-response information.
What to do instead
For every hazard problem, write the triggering and preparatory factors explicitly and re-run the calculation with the triggering condition applied: raise the water table or pore pressure for the slope, add site amplification for the seismic case, check liquefaction potential from grain size and water table depth. Practise producing a hazard statement that names the evidence, the model assumption and the residual uncertainty, and cross-check the hazard against the geological and geomorphological map units.
Answering legal and ethical questions from memory of the profession's general reputation rather than from the actual text: misstating who may sign what, the scope of the professional's responsibilities in a public works procedure, or the obligations attached to a contaminated-site certification.
Legislation and deontology are left to the last days of revision and read as prose rather than as operative rules; candidates also assume that technical competence alone determines responsibility and overlook the formal acts (signature, report, attestation) that create legal exposure.
What to do instead
Build a one-page table of the operative rules: who can be appointed for which type of incarico, what the professional must sign and what that signature attests, the sequence of obligations in a public procedure, and the duties of confidentiality, independence and conflict-of-interest disclosure. For each rule, write one concrete scenario in which it is breached and what the correct conduct would be. Revise this table alongside the technical domains rather than at the end.
Writing answers that list correct facts without answering the question asked: giving a general description of a geological process when the question asks for a quantitative estimate, a verification, or a professional judgement with stated assumptions and residual uncertainty.
Candidates prepare by accumulating content and are never trained to identify the command word in the question (describe, calculate, verify, assess, justify) and to shape the answer to it; under exam pressure they write everything they know about the topic and run out of time before reaching the part that carries the marks.
What to do instead
Before writing, underline the command word and the object of the question and draft a three-line skeleton: what is asked, the method or criteria used, the result with its uncertainty. Practise timed answers in which the first sentence states the answer and the rest justifies it. For numerical questions, always report the assumption set and a plausibility check on the result; for judgement questions, always state the residual uncertainty and the verification that would reduce it.