Physical Geology and Geomorphology
Physical Geology and Geomorphology examines the processes that shape the Earth's surface and the landforms they create. The exam tests endogenic versus exogenic processes, weathering and mass wasting, and landform recognition in fluvial, glacial, aeolian and coastal environments.
Core rules and concepts
- Weathering is in-situ breakdown; erosion involves transport. Chemical weathering includes hydrolysis (feldspar to clay), oxidation (iron staining) and carbonation (limestone solution).
- River stages: youth has V-shaped valleys and rapids; maturity has meanders, ox-bow lakes and floodplains; old age has deltas and broad plains. The end product is a peneplain.
- Glaciers produce cirques, arêtes, horns, U-shaped valleys, hanging valleys and moraines; drumlins and eskers are depositional.
- Wind produces deflation hollows, yardangs, barchans (crescent, horns downwind) and seif dunes (longitudinal).
- Coasts show wave-cut platforms, sea caves, stacks, spits and tombolos.
- Drainage patterns: dendritic on uniform rock, trellis on folded strata, radial on domes, centripetal in basins.
Worked example
A question describes a crescent dune with horns pointing downwind and asks its name and wind direction. Reasoning: the crescent shape with horns downwind is a barchan; the gentle stoss slope faces the wind, so wind blows from the stoss side toward the steep lee side. If the stoss slope is western, the wind is westerly.
Traps
Do not label a V-profile valley as glacial; rivers cut V profiles. Distinguish barchan from seif by horn orientation. Answers about 'weathering' fail if the question asks for erosion or transport.