A white mineral composed of calcium carbonate common in limestone rocks. See Limestone Properties
Calcrete
A duricrust of dried up calcite. SeeDuricrust
Caldera
A large depression formed when super eruptions blows and collapse the flanks of a volcano. SeeVolcanoes
canyon
See gorge.
carbonation
A type of chemical weathering were acidulated water containing carbon dioxide reacts with limestone rocks containing caclite (calcium carbonate) turning it into calcium bicarbonate.
castle kopje
An inselberg with balanced rocks on top of each other forming a castle appearance. See Granitic Inselbergs
chalk
A white and soft sedimentary rock composed of calcite (calcium carbonate) and formed from dead organic matter such as sea creatures and plants.
chemical weathering
Weathering by means of reactions between rock and different elements such as water and acids. See Chemical Weathering
chelation
The weathering of rocks by acids released from decayed organic matter. See Chemical Weathering
cinder cone
A small volcano which mainly extrudes fragmented lava (scoria)
The troughs found on a limestone pavement formed when carbonated water attacks and deepens vertical joints.
cockpit
Star shaped depressions separating conical hills in a limestone terrain formed when water attacks lines of weakness.
Cohesion
The ability of particles to strongly stick together resisting movement.
Colluvium
Debris washed down at the foot of a slope
conical karst
In a karst topography water attacks lines of weakness leaving behind conical and circular hills.
composite cone
A cone shaped and catastrophic volcano which mainly generates ash and pyroclastic materials. See Volcanoes
concordant
Small volcanic intrusions (plutons) running across the bedding planes of large volcanic plutons. See Plutonic Forces
convergent boundary
A catastrophic plate boundary between oceanic and continental, oceanic and oceanic or continental and continental plates that collides generating volcanic activities, mountains and earthquakes. See Plate Boundaries
continent
The land area of a plate consisting of sial. See Plate Tectonics
continental crust
The outermpst continental section consisting of sial which is more thicker than the oceanic crust. See Plate tectonics
continental shelf
The extended part of a continent into the ocean.
corestone
Small to medium sized circular rocks constituting saprolite of deep weathered profile. See Deep weathering
A circular blowout left on top of a volcano when an eruption occurs. See Volcanoes
crust
The outermost layer of the earth.
cumulo-dome
A dome shaped volcano that extrudes viscous, less runny lava that quickly solidifies.
D
Debris
All loose weathered or eroded material found on the surface.
Deep weathering
The weathering of underground rocks by water and humic acids that percolate through the soil.
dip
The angle made by a stratum with the horizontal surface.
divergence boundary
A plate boundary where plates split (move apart) creating an opening that oozes magma to the top.
dome
A more folded anticline.
duricrust
A hard layer(crust) found on top of hills or plateaus made from mineral precipitation.
dike/dyke
An often small discordant pluton that runs across existing rocks
diorite
A coarse grained igneous rock consisting of quartz, feldspar and hornblende.
dolerite
A dark, medium coarse grained igneous rock that forms many sills and dykes.
dry valley
A dried up valley with traces of prior water flow that percolated down a limestone. See karst landscape
dwala
A low lying basal surface exhumed from underground by the stripping of regolith. See Granitic inselberg
E
earthquake
A sudden movement in the earth's crust caused and triggered by plate movements and volcanoes. See
endogenic
Denoting all processses occurring internally the earth's surface.
epicenter
The area on the ground, above the focus, where an earthquakes first hits. See earthquakes.
etchplanation
The weathering of underground rocks producing deep regolith which is then stripped away revealing weathered rocks as inselbergs. See Inselberg Formation
exfoliation
A type of physical weathering were a rock's outer layer peels off caused by repeated expansion and contraction by insolation. See Physical Weathering
exhumation
The stripping away of regolith revealing underground basal surfaces or piling boulders as inselbergs.
Exogenic
Denoting all processes occurring on or out of the earth's surface.
A gently sloping extension of a plateau or hill (inselberg). See Inselbergs
permeable
Allowing water to pass through
pervious
See permeable.
Peneplain
According to W.M Davis, this represents the last stage of erosion characterised by a levelled land surface. See Slope Evolutional Theories
polje
A near steep sided valley with a flat floor found in a karst landscape. See Karst Landscape
ponor
See sinkhole
porphyry
A rock, usually igneous, with coarse grains interbedded in a fine groundmass (small grains)
pressure release
A physical weathering type where underground rocks are subjected to differential pressures and temperatures on the surface causing them to develop cracks running parallel to the surface.
Q
quartz
A crystal shiny mineral mostly native to igneous rocks such as granite.
R
rainsplash
The process whereby raindrops dislodge and erode soil grains on a surface. See Slope processes
rectilinear slope
The middle transportation unit of a slope where the gradient is constant. See Slope Profiles
recumbent fold
Extremely folded rocks forming a "Z like" pattern. See Folds
regolith
All the unconsolidated debris covering the bedrock below the earth's surface. See Deep weathering
reverse fault
A fault where the downthrow slides up the upthrow. See faults
rills
Tiny streams created by running water along slopes
rivulet
See rill
rift valley
A downthrow (valley/graben) which slides down between two fault lines. See Rift Valley
rockfall
A mass movement where weathering, water or earth movements collapse rock boulders along a scarp. See mass movements
runoff
Water running down a slope as overland flow or throughflow. Runoff encompasses all types of water flow. See Slope Processes
S
sandstone
A hard sedimentary rock cemented with fragments of quartz and sand.
salt crystallisation
A type of physical weathering where salts within rock cracks expand causing the eventual disintegration of the rock. See physical weathering.
saprock
The first deep weathered layer consisting of boulders. See deep weathering.
saprolite
A deep weathered layer comprising of weathered corestones. See Deep weathering
scarp
A steep and resistant rock face uncovered by debris found on the edges of plateaus, valleys and or inselbergs. Also called scarp.
schist
A coarse grained metamorphic rock.
scree
Pile of weathered or eroded material covering a slope.
sedimentary rock
A rock type formed from grains of other rocks or remains of dead plants and animals.
shale
A fine clay sedimentary rock.
sheetwash
A type of overland flow where water moves unconcentrated collecting soil in the path. See Processes on slopes
sial
Denoting chemical composition of the continental crust
sill
A discordant pluton (intrusive feature) running horizontally to existing sedimentary rocks. See plutons.
slicrete
A duricrust of silica.
sima
Denoting chemical composition of the oceanic crust.