Lesson 7: Weathering Flashcards
Which property of water is most directly responsible for frost wedging?
The expansion of water as it changes from liquid to solid
Sheet jointing/exfoliation of plutonic rocks is usually produced by________.
Pressure release
How does mechanical weathering aid chemical weathering?
Mechanical weathering increases surface area for chemical attack
Which of the following is NOT a form of physical weathering?
a. dissolution (solution)
b. impact/abrasion
c. frost wedging
d. salt crystal growth
a. Dissolution
When exposed rock bakes in the Texas sun, it _______.
Expands
Salt crystal growth (salt wedging) is common in _____ climates and in costal areas.
arid
T/F: When a rock is mechanically weathered, it changes composition (new minerals are formed)
False
Rocks can be “sand-blasted”; this type of mechanical weathering is termed _____.
Impacts/abrasions
Alternate wetting and drying of soft or poorly-cemented rock (shales) cause fairly rapid breakdown of the rock. Most disintegration occurs during the ______ cycle.
drying
What affects the rate of chemical weathering of a mineral? (5)
The composition of the mineral, type of weathering, grain size, climate, and other factors
___ and ___ climates promote the fastest chemical weathering.
Hot;wet
The mineral most RESISTANT to weathering is _____.
Quartz
Given your understanding of the weathering process, what is responsible for the red color of the rocks and soils around the Red River in North Texas?
Oxidation of iron-bearing minerals
____ is one of the most water-soluble minerals.
Halite
The mineral hematite forms from what chemical weathering process?
a. salt wedding
b. solution/dissolution
c. hydrolysis
d. oxidation
d. oxidation
The ______ a rock is exposed to agents of weathering, the greater the degree of alteration, dissolution, and physical breakup.
longer
What causes most rainwater to be slightly acidic?
Carbon dioxide in the air reacts with water from carbonic acid.
