- It is slow change .
- Ex- change in level of the earth .
- It is sudden change .
- Ex -earthquake activities
I. Earth Movements
(i) Vertical (up and down) movements cause faulting of the crustal rocks.
Features produced : Plateaus; block mountains (horsts); basins; some types of escarpment.
(ii) Lateral (sideways) movements cause folding of the crustal rocks.
Features produced - fold mountains; rift valleys; horsts; block mountains
II. Volcanic Eruptions
(i) External (lavas reach the Earth’s surface)
Features produced : lava plains and plateaus; volcanic cones; geysers
(ii) Internal (lavas solidify in the crust)
Features produced : dykes; sills; batholiths; laccoliths
|Core of Earth|
(i) Weathering (the break-up of rocks by alternate heating and cooling; chemical actions, and the action of living organisms).
Features produced : soil; earth pillars (by rain action)
(ii) Erosion (the break-up of rocks by the action of rock particles being moved over the Earth’s surface by water, wind and ice).
Features produced : valleys; peneplains; cliffs, river and coastal terraces; escarpments (in) Transport (the movement of rock particles over the Earth s surface by water, wind and ice)
(i) By water (river or sea)
Features produced : flood plains; levees; alluvial fans; deltas; beaches; lake plains; marine alluvial plains
(ii) By Ice (ice sheets and valley glaciers)
Features produced : boulder clay plains; out-wash plains; moraines; drumlins; eskers
(iii) By Wind
Features produced : loess plains; sand dunes
(iv) By living organisms (e.g. coral) features produced : coral formations
(v) By Evaporation and Precipitation -Features produced : salt deposits
(vi) Of Organic Matter- Features produced : coal deposits