Paper 3 · June 2023 · Fluvial Geomorphology
The drainage on the Masembura extract forms a branching, tree-like pattern with tributaries joining at acute angles across the whole sheet. Name this pattern and state what it indicates about the underlying rock.
ARadial, indicating a central volcanic cone or dome from which all the streams flow outward down its flanks.
BTrellis, indicating alternating bands of hard and soft rock which the tributaries follow along the strike.
CDendritic, indicating uniform, structurally undeformed rock of even resistance, which a granite plateau provides.
DDeranged, indicating a surface recently disorganised by glacial deposition with no established drainage lines.
Explanation
A dendritic pattern develops where no structural line steers the streams, so they simply take the steepest available route: uniform rock of even resistance, exactly what the granite plateau of the extract offers. A trellis pattern requires alternating hard and soft bands, and a radial pattern requires a dome or cone.
Derived from ZIMSEC Advanced Level Geography 6037/3 Paper 3 Practical Test, June 2023 session, Q2