science weathering n erosion Flashcards
Define Weathering
Weathering is the process by which rocks are chemically altered or physically broken down into smaller fragments
Define Mechanical Weathering
Physically breaking rocks into smaller fragments
Define Chemical Weathering
Rock is broken down or altered by chemical reactions
What is Frost Wedging?
Frost Wedging is physical weathering. It is when water collects in gaps and cracks in rocks. The water then freezes and expands, putting pressure on the rock and widening gaps. This process repeats itself continually widening cracks. An example is a pothole.
What is Abrasion?
Abrasion is physical weathering. It is when material is broken down by moving wind, water or ice. Rocks being propelled by wind water or ice scrape against each other and stationary rocks. They are small scratches and can remove a small amount of material, so this leaves behind a polished surface. Examples are glaciers rubbing against land masses and rivers running through rock.
What is Biological (physical)?
Physical Biological Weathering can be both physical and chemical. Organisms can physically break rocks. Examples are roots growing into cracks in the rocks and widening them, and animals digging into rocks for shelter.
What is Exfoliation?
Exfoliation is physical weathering. Rocks that are formed deep underground are formed under pressure. Tectonic forces can push the rocks to the surface and when released from the pressure they begin to flake. This produces scree which is loose rocks. This can also happen with changes in the temperature causing rocks to expand and contract.
What is Dissolution?
Dissolution is chemical weathering. Water or acids in water will dissolve the minerals that make up the rock. An example is that acid rain will dissolve the calcite in limestones. Sinkholes
What is Oxydation?
Oxydation is chemical weathering. Oxygen will react with some elements in the rock causing them to oxidize. An example is: when Iron is oxidized it rusts and the rust is more brittle and easier to break down.
What is Biological (chemical)?
Chemical Biological Weathering can be physical or chemical. Organisms can chemically weather rocks by producing compounds that dissolve minerals in the rocks, that the organism can absorb. An example is that lichens will dissolve minerals in the rocks they attach to, leaving pits in the rock.
What is the difference between Weathering and Erosion?
Weathering is the breaking down of rock both physically and chemically, erosion is the removal of the rock. The eroded rock will be deposited in a different location, in a process called deposition.
Weathered rock is eroded through…
water, wind, ice and mass movement(gravity)
