mechanical (freeze thaw), chemical(acid rain), and biological
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mechanical..
when water freezes it expands by 10%, causing stresses within the rock. when the ice melts, water seeps deeper within the crack. after repeated cycles of this, fragments of rock might break off
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chemical
rain water = slightly acidic, when rain falls on rocks such as limestone, a chemical reaction takes place, causing the rock to weaken and break down
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biological
the roots of growing plants can wides cracks in cliff rocks, burrowing animals and nesting birds on cliff faces can also cause the rock to weaken and break up
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Mass movement.. what types
rock falls, slumping and sliding
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rock falls
when pieces suddenly fall off from a cliff that has been weathered or undercut
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slumping
often occurs after long periods of rainfall - rain seeps through soil and permeable rock such as sandstone. -at the junction where permeable rock meets impermeable rock such as clay, the saturated rock slumps and slips
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sliding
similar to slumping but along a flat surface usually a bedding plane. large amounts of soil and rock move downslope rapidly
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Other cards in this set
Card 2
Front
mechanical..
Back
when water freezes it expands by 10%, causing stresses within the rock. when the ice melts, water seeps deeper within the crack. after repeated cycles of this, fragments of rock might break off
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