What is the primary process responsible for rock weathering?
A Chemical reactions
B Erosion
C Heating
D Cooling
Chemical weathering involves the breakdown of rocks through chemical reactions, often involving water, oxygen, or acids, which alter the rock’s mineral composition. This contrasts with physical weathering, which physically breaks rocks into smaller pieces.
Which soil type is most commonly found in floodplains?
A Clay
B Loam
C Sand
D Peat
Loam is a mixture of clay, silt, and sand, making it ideal for agriculture. It is commonly found in floodplains due to its fertility and ability to retain moisture while draining well. Clay and sand are extremes in water retention.
What is the term used for the downward movement of soil and rock due to gravity?
A Landslide
B Erosion
C Deposition
D Flood
A landslide occurs when soil and rock move downward due to the influence of gravity. It can happen quickly and is often triggered by heavy rainfall, earthquakes, or volcanic activity. Erosion and deposition are related but involve different processes.
What is the main cause of coastal erosion?
A Wind
B Tidal waves
C Wave action
D Ocean currents
Wave action is the primary cause of coastal erosion, as the constant impact of waves breaks down coastal rocks and sediments, gradually moving them away. Ocean currents and tidal waves also play a role, but wave action is the most direct cause.
What is the purpose of core sampling during a geotechnical investigation?
A To collect groundwater samples
B To measure air quality
C To examine rock minerals
D To assess soil strength
Core sampling is used to obtain cylindrical samples of soil or rock to assess their strength, density, and other properties. These samples are crucial in understanding the suitability of soil for foundation and construction projects.
What effect does vegetation have on slope stability?
A Decreases stability
B No effect
C Increases stability
D Causes erosion
Vegetation increases slope stability by anchoring the soil with roots, reducing the risk of landslides. Plants also absorb water, reducing the saturation of soil. The absence of vegetation can lead to increased erosion and destabilization.
What is the term for the deposition of material by wind?
A Aeolian deposition
B Sedimentation
C Glaciation
D Erosion
Aeolian deposition refers to the transport and deposition of materials by wind, typically in desert or coastal environments. This process can form dunes and other landforms. Sedimentation refers to the deposition by water, while glaciation involves ice transport.
What is the term for the process of rocks breaking into smaller pieces without changing their chemical composition?
A Chemical weathering
B Physical weathering
C Biological weathering
D Lithification
Physical weathering involves the mechanical breakdown of rocks into smaller fragments without altering their chemical composition. Common causes include temperature changes, freeze-thaw cycles, and physical abrasion. Chemical weathering involves changes in mineral composition, while biological weathering involves living organisms.
Which factor most significantly affects soil erosion in hilly areas?
A Soil type
B Wind speed
C Slope angle
D Vegetation
The slope angle significantly affects soil erosion in hilly areas. Steeper slopes are more prone to erosion because gravity accelerates the movement of soil. While soil type, wind speed, and vegetation play roles, the angle of the slope is a primary factor.
What is the main effect of soil compaction in construction?
A Decreases drainage
B Increases load-bearing capacity
C Increases soil volume
D Increases permeability
Soil compaction increases the density of the soil, which in turn increases its load-bearing capacity. It helps prevent settling and ensures that the soil can support heavy structures. However, it reduces permeability and drainage.
What is the term used for a type of sedimentary rock that forms from the remains of plants and animals?
A Organic
B Clastic
C Chemical
D Metamorphic
Organic sedimentary rocks form from the remains of plants and animals. Coal, for example, forms from plant material, while limestone can form from the shells of marine organisms. Clastic rocks are made of fragments, and chemical rocks form from mineral precipitation.
What is the main cause of mechanical weathering?
A Water
B Wind
C Plant roots
D Temperature changes
Temperature changes cause mechanical weathering through the expansion and contraction of rocks. This can cause rocks to fracture over time, especially in hot and cold climates. Water and wind contribute to physical weathering but not as directly as temperature fluctuations.
What is the primary method of determining the permeability of soil?
A Sieve analysis
B Permeameter test
C Proctor test
D X-ray diffraction
The permeameter test is used to determine the permeability of soil, or how easily water can pass through it. It is essential for understanding how soil will drain and whether it can support structures. Sieve analysis is used for particle size, and X-ray diffraction is for mineral composition.
What does the term “stratigraphy” refer to in geology?
A Study of faults
B Study of seismic waves
C Study of rock layers
D Study of minerals
Stratigraphy is the study of rock layers (strata) and their arrangement in the Earth’s crust. It helps to understand geological history, dating of rocks, and the processes that led to their formation. It is important in fields like paleontology and petroleum exploration.
Which of the following is a factor affecting slope stability?
A Soil moisture content
B Soil texture
C Soil depth
D All of the above
Slope stability is influenced by soil texture, depth, and moisture content. Fine-grained soils like clay are more prone to sliding when saturated. Shallow soils may not provide enough support, and moisture can reduce friction, leading to instability.