Exercises: Landform shaping

Define and order the four stages of the cycle of action of an external agent: erosion, weathering, deposition, and transport.

State four external agents of landform shaping and name a characteristic landform for each, indicating whether it is erosional or depositional.

What is karst topography, on what type of rock does it develop, and what chemical process explains it? Give an example of a surface karst feature and a subterranean one.

Relate each agent to the landform it produces and briefly explain the mechanism: glacier (U-shaped valley), river (meander), wind (dune), and waves (cliff).

Explain step by step how a delta forms at the mouth of a river and indicate what condition must be met for the delta to advance rather than be eroded by the sea.

Differentiate between physical and chemical weathering, describing two processes of each type (for example freeze-thaw weathering, thermal shattering, dissolution, or oxidation) and the climate in which each is most effective.

The Chihuahuan Desert displays a landscape of flat-topped hills (mesas) and gullies on clay. Explain which external agent dominates this landform shaping, why clay erodes so quickly, and what role the sparse vegetation plays.

Profiles A and B in the diagram correspond to cross-sections of two valleys in a mountain massif that hosted Quaternary glaciers.

1. a) A civil engineering project claims that the slopes of profile B are safer against rockfalls than those of profile A because it features a flat trough floor. Technically refute this idea by analysing how glacial overdeepening and postglacial stress release (decompression) affect the mechanical stability of vertical rock walls.
2. b) If a river with a high discharge establishes itself at the bottom of valley B after the complete retreat of the ice, predict and conceptually draw how its cross-profile will transform over tens of thousands of years.
3. c) Deduce what geomorphological and bathymetric differences would exist between both valleys if a marine transgression floods their mouths: which one will give rise to a ria and which one to a fjord? Justify the typical presence of a shallow bedrock threshold (lip) at the mouth of one of them.

Analyze how climate change can modify landform processes along the Mexican coastline, considering sea-level rise, changes in rainfall patterns, and storm frequency.