weathering Flashcards
(46 cards)
denudation
lowering of continental surfaces
3 elements of denudation
- weathering
- mass wasting/mass movement
- erosion
weathering AKA
how to lower
two types of weathering
- physical
- chemical
physical weathering
breaks down big rocks into smaller pieces BUT the chemical composition does NOT change
physical weathering AKA
disintegration
chemical weathering
big rocks are broken down to smaller rocks WITH their chemical composition changing (become new rocks)
chemical weathering AKA
decomposition
mass wasting is
the transfer of material downhill via GRAVITY
erosion is the
transfer of material by water, wind or ice
weathering is the
IN SITU breakdown of rock
what are 4 thing that control weathering
- rock properties
- climate
- soil and vegetation
- length of exposure
how are some rock properties affect weathering
- hardness
- composition
- solubility
- zones of weakness aka joints
how does climate affect weathering
depending on the temp and moisture, it can either accelerate or inhibit weathering
how do soil and vegetation affect weathering
exposes rock to variations in moisture and chemistry
physical weathering AKA
mechanical weathering
physical weathering converts rock into smaller pieces that can be act on more by
erosion
how do physical weathering and surface area relate
as the rock is broken down to smaller pieces, there is more surface area
an increase in surface area by physical weathering allows for _____
more reactions to take place
important physical weathering processes
- frost action
- salt weathering
- pressure-release jointing
- biological forcesq
what is frost action
the weathering processes caused by repeated cycles of freezing and thawing
describe the process of frost action
meltwater leaks into cracks and freezes causing fissures to expand under pressure and, with repeated cycles, shatter the surrounding rock.
where does frost action take place
in places that often go through rises and falls in temp through zero (like the Himalayas)
salt crystal growth process
- as water evaporates, it leaves salt in the rocks
- over times the crystallization breaks apart the rock