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 are folded or bent. The folded rock may fracture, producing lines of weakness. These weaknesses or faults are exploited by rivers and other agents of erosion, and are more easily broken down than unfractured rock.', copy:'(Image © Garret Nagle)'});)
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In geology, a deformation (bend) in beds or layers of rock. Folds are caused by pressures within the Earth's crust resulting from plate-tectonic activity. Rocks are slowly pushed and compressed together, forming folds. Such deformation usually occurs in sedimentary layers that are softer and more flexible. If the force is more sudden, and the rock more brittle, then a fault forms instead of a fold.
Folding can result in gentle slopes or mountain chains such as the Rocky Mountains and the Alps. They can be eroded to form escarpments, giving rise to an undulating topography.
If the bend of the fold is arched up in the middle it is called an anticline; if it sags downwards in the middle it is called a syncline. The line along which a bed of rock folds is called its axis. The axial plane is the plane joining the axes of successive beds.
© Research Machines plc 2008. All rights reserved. Helicon Publishing is a division of Research Machines plc.
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atmosphere (earth science)
basalt
calcium carbonate
calcium hydroxide
carbon cycle
carbon dioxide
carbonate
cementation
chalk (rock)
chemical weathering
coastal erosion
conglomerate (geology)
continental drift
core (earth science)
crust
earthquake
erosion
evaporation
exfoliation
extrusive rock
fault
fertilizer
fold
fossil
freeze–thaw
global warming
gneiss
granite
gravel
greenhouse effect
helium
igneous rock
intrusive rock
krypton
lava
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lithosphere
magma
mantle
marble
metamorphic rock
metamorphism
mineral
neon
nitrate
nitrogen
nitrogen cycle
ocean
oxygen
physical weathering
plate
plate tectonics
plutonic rock
pollution
Precambrian era
rock
rock cycle
sandstone
schist
seafloor spreading
seawater
sediment
sedimentary rock
shale
silica
slate
soil
volcano
water
water cycle
water pollution
weathering
basalt
calcium carbonate
calcium hydroxide
carbon cycle
carbon dioxide
carbonate
cementation
chalk (rock)
chemical weathering
coastal erosion
conglomerate (geology)
continental drift
core (earth science)
crust
earthquake
erosion
evaporation
exfoliation
extrusive rock
fault
fertilizer
fold
fossil
freeze–thaw
global warming
gneiss
granite
gravel
greenhouse effect
helium
igneous rock
intrusive rock
krypton
lava
limestone
lithosphere
magma
mantle
marble
metamorphic rock
metamorphism
mineral
neon
nitrate
nitrogen
nitrogen cycle
ocean
oxygen
physical weathering
plate
plate tectonics
plutonic rock
pollution
Precambrian era
rock
rock cycle
sandstone
schist
seafloor spreading
seawater
sediment
sedimentary rock
shale
silica
slate
soil
volcano
water
water cycle
water pollution
weathering
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