JCE Geography cheat sheet

JCE Geography - Core Reference

• Plate boundaries: divergent (constructive) plates move apart and create new crust at mid-ocean ridges; convergent (destructive) plates collide, producing subduction zones, deep trenches and volcanic arcs; transform (conservative) plates slide past each other, generating shallow-focus earthquakes with little or no volcanism.

• Rock cycle: igneous rock crystallises from magma or lava; sedimentary rock forms by compaction and cementation of deposited sediment; metamorphic rock forms when pre-existing rock is altered by heat and/or pressure without melting.

• Weathering vs erosion: weathering is in-situ breakdown of rock (physical, chemical, biological); erosion is the transport of the broken material by water, wind, ice or gravity. Deposition follows when transport energy falls.

• River long profile and processes: erosion dominates the upper course (vertical erosion, V-shaped valleys), transport and lateral erosion dominate the middle course (meanders, floodplains), deposition dominates the lower course (deltas, levees).

• Coastal processes: hydraulic action, abrasion, attrition and solution erode; longshore drift moves sediment along the coast in the direction of the dominant wave approach. Constructive waves build beaches, destructive waves remove them.

• Population dynamics: natural increase = birth rate − death rate; net migration = immigration − emigration; total population change = natural increase + net migration. Rates are normally expressed per 1,000 people per year.

• Urbanisation: the proportion of a population living in urban areas rises fastest in low- and middle-income countries; push factors (rural poverty, land pressure) and pull factors (jobs, services) drive rural-to-urban migration.

• Development indicators: GDP per capita measures average income only; the Human Development Index combines life expectancy, education (mean and expected years of schooling) and GNI per capita, each scored 0–1 and averaged geometrically.

• Map skills: a scale of 1:50,000 means 1 cm on the map equals 50,000 cm (500 m) on the ground; contour lines join points of equal height, and closely spaced contours indicate steep slopes.