Geomorphology: Earth Movements, Plate Tectonics, Rocks and Landforms
Geomorphology: Earth Movements, Plate Tectonics, Rocks and Landforms
This domain tests endogenic and exogenic processes, plate tectonics, the rock cycle and the landforms each produces. Expect diagram-free explanations and cause–effect sequences.
Core rules and concepts
- Endogenic movements build relief: diastrophic movements are epeirogenic (vertical, broad uplift/subsidence) or orogenic (horizontal compression, folding and faulting); volcanism and earthquakes also belong here.
- Exogenic processes wear relief down: weathering, mass wasting, erosion, transport and deposition by water, wind, ice and waves.
- Wegener's continental drift proposed Pangaea and Panthalassa, later split into Laurasia and Gondwana, with evidence from coastlines, fossils, rocks and glacial deposits.
- Hess's sea-floor spreading explained drift: new crust forms at mid-ocean ridges and is destroyed at trenches.
- Plate boundaries: divergent (constructive, ridges), convergent (destructive, trenches and fold mountains), transform (conservative, shear).
- Rocks: igneous (intrusive/extrusive), sedimentary (layered, fossils) and metamorphic (heat/pressure), linked in the rock cycle.
Worked example
The Himalayas formed where the Indian plate moved north into the Eurasian plate at a convergent boundary. Marine sedimentary rocks of the Tethys Sea are now high peaks, and folding plus thrusting explains the range. The plates still converge, so the range rises and earthquakes are frequent. Naming the boundary type earns the explanation marks.
Traps
Divergent boundaries create crust; transform boundaries neither create nor destroy it. Epeirogenic is vertical, orogenic horizontal. A fault is not a fold. Do not call the Deccan Traps sedimentary; they are basaltic lava flows.