Geoscience Dr Koo Complete Final Study Guide

ENV-151 CBU

Physical Weathering

The mechanical breakdown of rocks into smaller pieces without changing their chemical composition

Chemical Weathering

The breakdown of rocks through chemical reactions, often involving water, oxygen, or acids.

Effect of Physical Weathering on Chemical Weathering

Physical weathering increases surface area, which accelerates chemical weathering by exposing more rock to chemical processes.

Hydrolysis

Chemical reaction between minerals and water, breaking down silicates.

Oxidation

Reaction with oxygen, forming rust in iron-rich rocks.

Dissolution

Minerals dissolve in water (e.g., limestone dissolves in acidic water).

Erosion

The removal and transport of soil or rock by wind, water, or gravity.

Conservation Practices

Contour, Plowing, Cover Crops, Windbreaks, Decreasing Slope Angle

Weathering and Biological Activity

The key processes in soil formation.

Leaching

The removal of dissolved minerals from soil by water percolation.

Soil Horizons

O A E B C

O Horizon

Organic-rich top layer (humus).

A Horizon

Topsoil, rich in organic matter.

E Horizon

Zone of leaching (eluviation).

B Horizon

Subsoil, where minerals accumulate.

C Horizon

Partially weathered rock

Great Plains

The region most affected by wind erosion.

Warm, wet climates

Increase chemical weathering.

Cold, dry climates

Favor physical weathering.

Debris Flow

A chaotic, fast-moving mix of water, rock, and soil.

Creep

A very slow movement of soil downhill, often unnoticeable until structures lean or crack.

Rockslide

Large sheets of rock moving downslope along a weak structural plane.

Slump

A curved slip surface movement where material moves as a coherent mass.

Mudflow

A very water-rich flow of fine-grained sediments.

Gravity

The main driving force of mass wasting.

Friction

The resisting force keeping material in place.

Saturation

Excessive water can reduce friction and lead to slope failure.

Slope Angle

Steeper slopes are at higher risk for landslides.

Weathering

Rapid weathering weakens slopes and increases mass wasting.

Hard Approaches to mass wasting

Retaining walls, slope reduction, and drainage improvements.

Soft Approaches to mass wasting

Zoning laws and land-use restrictions to prevent development in high-risk areas.

Classifying mass wasting - Rock

rockfall, rockslide

Classifying mass wasting - Soil/regolith

slump, creep

Classifying mass wasting - Mud/debris AND Flow

mudflow, debris flow

Classifying mass wasting - Fall, Material drops freely

rockfall

Classifying mass wasting - Slide, Material moves as a unit

rockslide

Deposition

Occurs on the inside of a bend where velocity is lower

Erosion

Occurs on the outside of a bend where velocity is higher.

Cross-sectional Velocity (stream processes)

Highest in the center where friction is lowest.

Lateral Migration

Streams migrate in the direction of erosion.

Evaporation

Water changes from liquid to vapor.

Infiltration

Water enters the ground.

Transpiration

Water is released by plants.

Runoff

Water moves across land into streams.

Precipitation

Rain, snow, or other forms of water falling from the sky.

Tributary floods

last only hours compared to main rivers, which last weeks.

Humid climates

Most water comes from precipitation.

Arid climates

Most water comes from runoff

Droughts

Reduce groundwater contributions to streams.

Stream Patterns

Radial, Trellis, Dendritic

Radial

Found on volcanoes.

Trellis

Forms due to alternating weak and resistant rock

Dendritic

Occurs when geology is uniform.

Cut bank

The outer, erosional part of a meander

Point bar

The inner, depositional part of a meander

Gradient

Highest in upstream areas (mountainous regions)

Hydraulic Radius(stream feature)

Highest in deeper, faster sections of streams

Discharge

Volume of water moving past a point in m³/s.

Largest Freshwater Source

Glacial ice

Lowest Stream Elevation

Base level

Flood Prevention Measures

Levees and dams

Flood insurance

mitigation for financial loss from floods

Government Response Agency

FEMA (Federal Emergency Management Agency)

Bed Load

Moves by rolling/sliding along the bottom (causes most erosion)

Suspended Load

Fine particles carried in water

Dissolved Load

Minerals dissolved in water, responsible for cave formation.

Drainage Basin

The area drained by a stream and its tributaries

Cone of Depression

A dip in the water table around a well caused by excessive groundwater withdrawal.

Surface Subsidence

The sinking of the ground due to excessive groundwater extraction, leading to land compaction.

Porosity

The percentage of a material’s volume that is made up of pore spaces, determining its ability to store water.

Permeability

The ability of a material to allow fluids to pass through it, dependent on pore space connectivity.

Water Table

The upper level of the saturated zone of groundwater.

Aquifer

A body of rock or sediment that stores and transmits groundwater.

Recharge Zone

The area where water infiltrates the ground and replenishes an aquifer.

Groundwater Flow

The movement of groundwater through porous rock and sediment.

Septic System

A system for waste disposal that can impact groundwater quality if not properly maintained.

Invasive Species

Non-native species that can disrupt wetland ecosystems and reduce biodiversity.

Hydrosphere

The component of Earth’s system that includes all water bodies, including groundwater.

Biosphere

The regions of Earth occupied by living organisms, including wetlands.

Sand and Gravel Aquifer

A highly permeable aquifer composed of sand and gravel that allows water to move quickly.

Groundwater Contamination

The introduction of pollutants such as chemicals or waste into groundwater sources.

High Plains Aquifer

A major aquifer in the central U.S. that is being depleted due to overuse.

Non-Point Source Pollution

Pollution that comes from multiple diffuse sources, such as agricultural runoff.

Hydrophytic Vegetation

Plants adapted to grow in water-saturated soil, characteristic of wetlands.

Wetlands

Areas where water covers the soil for part or all of the year, playing a role in flood control and water filtration.

Runoff

Water from precipitation that flows over land surfaces instead of infiltrating the ground.

Zone of Saturation

The subsurface area where all pore spaces are filled with water.

Specific Retention

The amount of water a rock or sediment can retain against gravity.

Freshwater Lens

A layer of freshwater that sits atop denser saltwater, commonly found in coastal areas.

Artesian Aquifer

A confined aquifer that contains groundwater under pressure, allowing it to rise without pumping.

Base Level

The lowest point to which a stream can erode, often sea level or a lake.

Evapotranspiration

The combined process of water loss from evaporation and plant transpiration.

Floodplain

A flat area adjacent to a river, prone to periodic flooding and sediment deposition.

Recharge Rate

The speed at which groundwater is replenished through infiltration.

Groundwater Depletion

A reduction in groundwater levels due to excessive withdrawal.

Water Table Fluctuation

Seasonal or annual changes in the water table level due to precipitation and usage.

Groundwater Management

Strategies for sustainable use and conservation of groundwater resources.

Earth Science

The investigation of interactions among the four components of the Earth system: atmosphere (air, weather), hydrosphere (water, ice), biosphere (plants, animals), and geosphere (land, rocks). It also includes the exosphere, which involves the sun and space

Renewable Resources

Natural resources that can be replenished over short periods of time through natural processes, such as sunlight, wind, and water.

Nonrenewable Resources

Resources that cannot be readily replenished by natural processes on a human timescale, such as fossil fuels and minerals.