Geology Exam 2 Study Guide: Age of Earth and Mass Wasting Concepts

Age of Earth and Geologic Processes

• The age of Earth is approximately 4.54 billion years
• Mass wasting: the downslope movement of rock, soil, or regolith under the influence of gravity
• Types of mass wasting: rockfall, landslide, slump, creep, and debris flow

Erosion, Land Subsidence, and Liquefaction

• Erosion: wearing away of the Earth's surface by natural forces such as wind, water, and ice
• Land subsidence: sinking of the Earth's surface due to the removal of subsurface material
• Liquefaction: process by which a solid becomes a liquid, often due to shaking or vibration

Slope and Gravity in Mass Wasting

• Slope: angle of the Earth's surface, which affects the likelihood of mass wasting
• Gravity: force that pulls objects towards the center of the Earth, contributing to mass wasting

Factors Affecting Mass Wasting

• Water: can contribute to mass wasting through erosion, weathering, and increased weight
• Joints and faults: can weaken rock and make it more susceptible to mass wasting
• Weathering: breakdown of rock into smaller particles, making it more susceptible to mass wasting
• Movement: can trigger mass wasting through vibrations or shaking

Stabilizing and Destabilizing Slopes

• Methods to stabilize slopes: terracing, re-vegetation, and drainage management
• Methods to destabilize slopes: deforestation, mining, and construction

Maps and Topography

• Topography: study of the shape and features of the Earth's surface
• Relief: variation in elevation of the Earth's surface
• Maps: tools used to represent the Earth's surface and its features

Landslides and Complex Landslides

• Landslides: movement of rock, soil, or regolith down a slope
• Complex landslides: landslides involving multiple types of movement or material

Limestone and Karst Topography

• Limestone forms through the accumulation of calcium carbonate from marine organisms
• Features of limestone caves/karst topography: stalactites, stalagmites, and underground streams

Hydrologic Cycle

• The continuous process by which water is circulated between the Earth and atmosphere
• Water reservoirs: oceans, lakes, rivers, and groundwater
• Volumes of freshwater: 2.5% of total water, 70% of freshwater is frozen in glaciers and ice caps

Freshwater and Saltwater

• Saltwater: 97.5% of total water, high salinity due to dissolved salts
• Freshwater: low salinity, essential for human consumption and agriculture

Rock, Soil, and Regolith

• Rock: naturally occurring solid mass of mineral material
• Soil: mixture of mineral and organic particles, air, water, and living organisms
• Regolith: layer of loose, unconsolidated rock and mineral material

Soil Destruction and Eutrophication

• Causes of soil destruction: erosion, salinization, and pollution
• Causes of eutrophication: excess nutrients, often from human activities, leading to aquatic plant growth

Freshwater Depletion and the Critical Zone

• Critical zone: region where rock, soil, water, and air interact, supporting life
• Freshwater depletion: over-extraction of freshwater resources, threatening human consumption and ecosystems

Drinking Water and Day Zero

• Humans get most of their drinking water from surface and groundwater sources
• Day Zero: the day when a city's water supply is depleted, requiring drastic measures

Porosity, Permeability, and Stealth Disasters

• Porosity: measure of the void space in a material
• Permeability: measure of the ability of a material to transmit fluids
• Stealth disasters: slow-onset disasters, such as droughts or soil salinization, that can have significant impacts

Earth's Atmosphere and Climate

• Atmospheric composition: 78% nitrogen, 21% oxygen, 1% other gases
• Greenhouse effect: process by which the atmosphere traps heat, maintaining a habitable temperature
• Weather vs climate: weather is short-term, local conditions, while climate is long-term, global patterns

Storms and Natural Disasters

• Thunderstorm: a storm characterized by lightning, thunder, and heavy rain
• Tornado: a rotating column of air that touches the ground, causing damage
• Hurricane: a rotating storm that forms over warm ocean waters, characterized by strong winds and heavy rain
• Storm surge: a rise in sea level due to storms, causing coastal flooding and damage

Latitudes, Layers of the Atmosphere, and Energy

• Latitudes: measure of distance from the equator, affecting climate and weather patterns
• Layers of the atmosphere: troposphere, stratosphere, mesosphere, thermosphere, and exosphere
• Highest energy storms: hurricanes, tornadoes, and supercell storms

Cold Weather Risks

• Hypothermia: a condition where the body's core temperature drops, causing damage
• Frost bite: damage to skin and tissue due to freezing temperatures
• Inland flooding: flooding that occurs away from the coast, often due to heavy rainfall or snowmelt