weathering and mass movement Flashcards
what is weathering
weathering is the breakdown of rocks and soil
what are the types
- chemical weathering
2. mechanical weathering
what is erosion
the breaking down of rocks and soil and the transportation of the eroded materials moving water,moving wind,moving ice
what is mechanical weathering
breaks up rocks into small pieces by putting pressure on the rock eg. freeze thaw action
what is chemical weathering
when rocks are dissolved because of a chemical reaction eg.carbonation
what is carbonation
carbon dioxide mixes with rainfall to form a weak carbonic acid
what happens (carbonation)
weak carbonic acid reacts with the the calcium carbonate and dissolves the rock
how does it pass through
because limestone is a permable rock (sedementry)
how is limestone pavement formed
rainwater falls onto limestone and passes through the joints carbonation makes the joints wider by dissolving the calcium carbonate these gaps are called grikes blocks left are called clints
caves
the swallow holes can widen to become caves and caverns
explain stalactites
as the water seeps through the limestone it carries dissolved limestone this eventually reaches the roof the drops slowly evaporate and leave behind small deposits of pure limestone called calcite.
what is stalagmites
if it falls to the ground it evaporates and leaves deposits of calcite directly below the stalactites this froms upside down icicle shapes called stalagmites
gradient
refers to the steepness of the slope
water content
water can make regolith heavier moves down slope faster water can also act as a lubricant movement easier
mudflows
occur when soil and regolith become saturated
