A.D. Tropical Environment - Landforms Flashcards
What is hydrolysis?
the breaking down of rocks by chemical reactions with water
-maximised efficiency by higher temperature
What is exfoliation?
mechanical process of weathering where there is less moisture available
- change between night and day temperatures heat the rock
- the rock conducts heat poorly which stresses the outer layer which peals off
How are tors formed + example?
piles of rock strongly jointed
- closer joints are more susceptible to hydrolysis
- top soil gets weathered away
- further apart joints are vertical and high up causing core stones to balance on each other
- exfoliation causes rocks to break off - clitter
- freeze thaw weathering forms them into a round shape
- Kenya, Dartmoor
How are inselbergs and bornhardts formed?
- triggered by a volcanic process where lava hardens forming a body of hard rock inside soft rock
- the inferior rock has strong and tight jointing
- outer has spaced joints and is easily eroded by wind and water
- overtime, exhumation exposes the hard rock-forming an inselberg
- inselberg eventually experiences magical collapse or gets exfoliated
What are the characteristics of a bornhardt?
Sugarloaf Mountain
- they are granite domes
- steep sides
- not necessarily found in tropical climate
- sheet jointing - parallel erosion to the surface of the ground
- some vegetation
How are Karst Landscapes formed?
formed from organic matter under the sea - sea shells
in areas of tectonic uplift or vertical erosion in rivers
Karstification - when water interacts with limestone, dissolving the depressions between rocks
Carbonation- Calcium Carbonate reacts with rain water forming Carbonic Acid that reacts with minerals in the rocks and weathers them down
Percolation
What are cockpits?
type of Karst landscape where depressions get eroded by solution
vegetation can grow on top
Where are tower Karsts common?
- in areas of less tectonic uplift
- low relief
- water table high
Why do sink holes or blue holes form?
- solution, carbonation cause lines of weakness in rock
- a steep sided, deep and wide hole will form
- eventual ceiling collapse
- water level rises and fills up sink holes forming blue holes
How did the Dragon Hole form?
- Ice Age in South East China Sea:
- water levels were much lower than now
- glacial runoff and carbonation dissolved limestone forming sink holes and caverns
- some caverns’ ceilings collapsed and got filled with water from rising sea levels
