SOIL 10 Weathering & Erosion Assignment (2)
docx
keyboard_arrow_up
School
Merced College *
*We aren’t endorsed by this school
Course
10
Subject
Geology
Date
Apr 3, 2024
Type
docx
Pages
4
Uploaded by jessica074796
SOIL 10 - (WEATHERING & EROSION ASSIGNMENT) (Weathering): (Ch. 2 )- (Pg. 29
)
1) Define Weathering. (Pg. 32) (2 pts.)
The process of wearing or being worn by long exposure to the atmosphere.
2) Briefly describe the following types of physical weathering: (Pg. 33) (6 pts.)
-Temperature
Temperature changes can also contribute to mechanical weathering in a process called thermal stress. Changes in temperature cause rock to expand (with heat) and contract (with cold). As this happens over and over again, the structure of the rock weakens.
-Abrasion by water, ice, and wind
Abrasion weathering-forces such as wind and water cause rocks to breakdown into smaller pieces. Exfoliation weathering-rocks expand and break as pressure is released from unloading. Frost wedging-
rocks break as water freezes and expands.
-Plants and animals
Animals can cause physical weathering by digging burrows into the ground allowing rock to be exposed. Examples: ground squirrels, prairie dogs, ants and earth worms, pocket gophers. 3 agents of physical weathering that can cause abrasion.
3) Define exfoliation. (Fig. 2.5) (2 pts.)
Exfoliation is a process in which large flat or curved sheets of rock fracture and are detached from the outcrop due to pressure release: As erosion removes the overburden from a rock that formed at high pressure deep in the Earth´s crust, it allows the rock to expand, thus resulting in cracks and fractures along sheet
4) What is chemical weathering enhanced by? (Pg. 34) (1 pt.)
Spreading finely ground silicate powder, rich in easily released cations, over the terrestrial surface { Schuiling and Krijgsman, 2006; Manning, 2008]. This could enhance natural rates of chemical weathering because the large surface area of the powdered material would result in rapid dissolution of the mineral.
5) List and define the (5) primary soil forming factors and define each. (Factors Influencing Soil Formation) (Pg. 36) (5 pts.)
Climate: Temperature and moisture influence the speed of chemical reactions, which in turn help control how fast rocks weather and dead organisms decompose. Soils develop faster in warm, moist climates and slowest in cold or arid ones.
Organisms: Plants root, animals burrow, and bacteria eat – these and other organisms speed up the breakdown of large soil particles into smaller ones. For instance, roots produce carbon dioxide that mixes with water and forms an acid that wears away rock. Learn more on our Soil Biology page!
Relief (landscape): The shape of the land and the direction it faces make a difference in how much sunlight the soils gets and how much water it keeps. Deeper soils form at the bottom of a hill because gravity and water move soil particles down the slope.
Parent material: Every soil “inherits” traits from the parent material from which it formed. For example, soils that form from limestone are rich in calcium and soils that form from materials at the bottom of lakes are high in clay. Every soil formed from parent material deposited at the Earth's surface. The material could have been bedrock that weathered in place or smaller materials carried by flooding rivers, moving glaciers, or blowing winds. Parent material is changed through biological, chemical and environmental processes, such as weathering and erosion.
Time: All of these factors work together over time. Older soils differ from younger soils because they have had longer to develop. As soil ages, it starts to look different from its parent material. That is because soil is dynamic. Its components—minerals, water, air, organic matter, and organisms—
constantly change. Components are added and lost. Some move from place to place within the soil. And some components are totally changed, or transformed.
6) Describe the following terms: (View Fig. 2.13) (4 pts.)
-Alluvial Fans (Pg. 40)
A fan-shaped mass of alluvium deposited as the flow of a river decreases in velocity.
-Delta Deposits (Pg. 41)
Delta deposits are composed of fine channel sands separated by organic silts and clays interfingered with flood plain silts. The 3D relationships of these materials is shown in the idealized illustration of the Mississippi Delta.
-Peat (Fibric) (Pg. 47)
Peat material is either fibric, hemic, or sapric. Fibric peats are the least decomposed and consist of intact
fibre. Hemic peats are partially decomposed and sapric are the most decomposed. Phragmites peat are composed of reed grass, Phragmites australis, and other grasses.
-Muck (Sapric) – Pg. 47)
Sapric materials are the most decomposed and are defined as having less than 1/6 of the total organic content identifiable as plant fiber after rubbing with ones fingers. Fibric materials are defined as those having ¾ or more identifiable plant remains after rubbin.
7) List and describe the (4) basic processes of soil: (View Fig. 2.29) (4 pts.)
-Transformations -Chemical or physical change of materials
-Translocations -Movement, usually down, of clay or organic matter by water.
-Additions
-
Adding C or organic materials from leaf fall
-Losses
-Loss of soil due to erosion or deep leaching of nutrients.
*All of question #7 are located on (Pgs. 58-60)
(Erosion): (Ch. 14) – (Pg. 606)
1) Define geologic erosion. (Pg. 608) (2 pts.)
Erosion is the geological process in which earthen materials are worn away and transported by natural forces such as wind or water. A similar process, weathering, breaks down or dissolves rock, but does not involve movement.
2) What are the (3) steps involved in soil erosion by water? (Pg. 612-613) – (View Fig. 14.5) (3 pts
The erosion process includes three primary stages: detachment, transport, and deposition
3) Describe the following terms for the cover and management of soil (4 pts.)
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help
-Cover Crop (Pg. 618) Crop, harvest, produce, yield refer to the return in food obtained from land at the end of a season of growth. Crop, the term common in agricultural and commercial use, denotes the amount produced at one cutting or for one particular season: the potato crop.
-Bench Terrace (Pg. 621)
Bench terraces are platform like constructions along a slope, which is used to cultivate steep slopes. This
type of terraces is generally constructed on slopes < 10 % and are widely used throughout the world.
4) What are the (4) factors that influence wind erosion? (Pg. 641) (4 pts.)
climate, topography, vegetation, and tectonic activity.
5) What are (3) factors that can help to control wind erosion? (Pg. 642) (3 pts.)
Establish and maintain vegetation or vegetative residues.
Reduce field widths.
Produce, or bring to the soil surface, aggregates or clods.