Weathering/Soil Flashcards
(39 cards)
What is the difference between mechanical and chemical weathering?
Chemical weathering changes the chemical composition of a rock and mechanical rock alters the size/shape of a rock.
Name the mechanical weathering types
Organic activity, ice/frost wedging, joints(sheeting and exfoliation), and abrasion.
What is organic activity?
It is when animals burrow into the rock or roots pry trees apart.
What is ice wedging?
Water seeks into rock cracks, and when the water freezes the rock is forced apart.
What are joints, sheeting, and exfoliation?
Joints happen when pressure is removed from a rock and the rock expands and cracks. When the cracks are parallel to the surface, it is called sheeting. When the sheets fall off, it is called exfoliation
What is abrasion?
Water or wind pick up grains of sand that pelt and polish rock.
Name the types of chemical weathering
Hydrolysis, carbonation, oxidation, organic acids, acid precipitation, and spheroidal weathering.
What is hydrolysis?
Water reacts with minerals to change the minerals composition.
What is carbonation?
CO2 dissolves in water to produce carbonic acid. This reacts with calcite.
What is oxidation?
Oxygen dissolved in water reacts with a mineral, and it results with colour change.
What are organic acids?
Lichen and moss produce acids that eat away at the rock from the surface.
What is acid precipitation?
Nitrous oxides and sulfur dioxide dissolve in rainwater and produce acids that dissolve rocks.
What is spheroidal weathering?
Water, CO2, and organic acids seep through cracks in rocks and cause chemical weathering.
How does climate affect the rate of weathering?
Precipitation increases weathering. Hot temperatures speed up chemical weathering, and cold temperatures have lots of mechanical weathering.
How does topography affect the rate of weathering?
Rocks on a slope erode more due to more exposure. Higher altitudes experience more ice wedging.
How does rock composition affect the rate of weathering?
Minerals that form at higher temperatures weather first. Sedimentary rocks weather fastest.
How does surface area affect weathering?
More surface area means more chemical weathering.
What are the four types of soil?
Pedalfer, pedocal, laterite, and regolith.
What are the properties of pedalfer?
It is found in temperate, forest areas. It had thick horizons and is acidic. It has aluminum and iron.
What are the properties of pedocals?
It is found in semi-arid and steppes. It is calcium rich and it is caliche. It is basic and fertile.
What are the properties of laterite?
It is found in high precipitation and warm temperatures areas. It is leached of nutrients and has a lot of chemical weathering. It doesn’t really have an A horizon and is high in iron. It is reddish in colour.
What are the properties of regolith?
It is found in polar and desert regions. Mostly mechanical weathering occurs and it is mainly the C horizon.
What is the difference between residual and transported soil?
Residual soil is made of the same material as the bedrock below and transported soil is not.
What is the difference between a fall, flow, and slide?
In a fall, the material has no contact with the ground. In a flow, individual particles move on one path. And in a slide, a whole “block” of material moves as one cohesive unit.
