What does T2 of WJEC A-Level Geology cover?

T2, Geological Map Applications, is one of the two compulsory Geological Themes at A2 and is assessed directly in the practical component. It covers the interpretation of geological maps: reading dip and strike from outcrop patterns, applying the rule of Vs where outcrops cross valleys, recognising horizontal, dipping, folded, faulted and unconformable strata, constructing a geological cross-section from a map, and reconstructing the full sequence of geological events of an area.

What is the rule of Vs?

The rule of Vs describes how the outcrop of a dipping bed bends into a V where it crosses a valley. For beds dipping less steeply than the valley, the V points in the direction of dip, so the apex shows which way the bed dips. A wide, open V means a gentle dip and a tight V means a steeper dip. Horizontal beds follow the contours exactly, and vertical beds run straight across the valley regardless of the topography.

How do you recognise an unconformity on a map?

An unconformity appears as a single geological boundary that cuts across, or truncates, the outcrops or structures of the older rocks beneath it. Along its length the beds above the unconformity rest on different older units, and typically the lower beds are tilted or folded while the upper beds are more uniform. It records a period of uplift and erosion between the two sets of rocks, so everything below it is older than the beds above.

How is a geological cross-section constructed?

First draw a topographic profile along the section line by plotting the height where each contour crosses it, keeping the vertical scale equal to the horizontal to avoid exaggeration. Then transfer the geological boundaries and faults from the map onto the profile, project the beds below the surface at the dip read from the map (from symbols or the rule of Vs), keeping them parallel and of constant thickness, draw the faults, folds and any unconformity, and finally label the beds in order.

How is the sequence of geological events reconstructed?

Using the dating principles. Superposition gives the order of deposition, with the lowest bed oldest. Cross-cutting relationships place faults, dykes and intrusions after the beds they cut. Unconformities record uplift and erosion, with everything below older than the beds above and any truncated structures predating them. Inclusions are older than their host. Folding is dated by the beds it affects and the unconformity that truncates it, and the events are assembled into an ordered history.

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WJEC A-Level Geology T2 Geological Map Applications: a deep dive on map interpretation and cross-sections

A deep-dive WJEC and Eduqas A-Level Geology guide to T2, Geological Map Applications. Covers reading dip and strike and the rule of Vs, recognising horizontal, dipping, folded, faulted and unconformable strata, constructing a geological cross-section, and reconstructing the full sequence of geological events of an area, with exam-style worked questions.

Generated by Claude Opus 4.814 min readWJECUpdated 2026-06-16

Reviewed by: AI editorial process; not yet individually human-reviewed

Jump to a section

What T2 actually demands
Reading the map
Building the section
Reconstructing the history
Check your knowledge

What T2 actually demands

T2 is a practical skill, assessed directly in Component 1, and it rewards method. Examiners want you to read structure from an outcrop pattern, construct a clean cross-section, and reconstruct a history justified at every step by a dating principle. It is the place where the structures of G2 and the dating principles of F3 are applied to real maps.

Each skill has a dot-point page with worked questions; this overview connects them.

Reading the map

Strike is the horizontal direction on a bedding plane and dip the downward slope at right angles to it. The rule of Vs reads dip where a bed crosses a valley: horizontal beds follow the contours, dipping beds make a V pointing in the dip direction, and vertical beds run straight across. Horizontal strata give outcrops parallel to contours, folds give symmetrical repeated bands, faults give offset or cut-out beds, and an unconformity truncates the older structures beneath it.

Building the section

A cross-section is built by drawing the topographic profile (vertical scale equal to horizontal), transferring boundaries and faults, projecting beds at the correct dip, and drawing folds, faults and unconformities.

Reconstructing the history

The sequence of events follows from superposition (lowest oldest), cross-cutting relationships (the cutter is younger), unconformities (recording uplift and erosion) and inclusions, with folding dated by the beds it affects and the unconformity that truncates it.

Check your knowledge

Attempt these under timed conditions, then check against the solutions.

Define dip and strike. (2 marks)
State how the rule of Vs gives the direction of dip. (1 mark)
How does the outcrop of a horizontal bed relate to the contours? (1 mark)
State the first step in constructing a cross-section. (1 mark)
Why should the vertical scale equal the horizontal scale? (2 marks)
State the principle that places a fault after the folding it cuts. (1 mark)

Sources & how we know this

WJEC Eduqas A-level Geology specification — WJEC Eduqas (2017)