EAS Final Guide PDF

Final Exam EAS Topics Glaciers: Different parts of glaciers, Glacial movement, Glacial erosion Glaciers are permanent bodies of ice consisting largely of recrystallized snow that show evidence of downslope or outward movement due to their own weight1. Here are the key aspects to focus on for a final...

Final Exam EAS Topics Glaciers: Different parts of glaciers, Glacial movement, Glacial erosion Glaciers are permanent bodies of ice consisting largely of recrystallized snow that show evidence of downslope or outward movement due to their own weight1. Here are the key aspects to focus on for a final exam: Parts of a Glacier Accumulation zone: Area of net mass gain, covered by remnants of the previous winter's snowfall1. The accumulation zone is at the highest altitude of the glacier, usually covered in snow year-round Ablation zone: Region of net loss where bare ice and old snow are exposed1 Equilibrium line: Point where accumulation equals melting Glacial Movement Glaciers move to lower elevations under the force of gravity through two processes: 1. Internal flow: Occurs due to the glacier's own weight Results from deformation of ice crystal structure Upper portions may fracture, forming crevasses1 2. Basal sliding: Meltwater at the base reduces friction Allows the glacier to slide across its bed Glacial Erosion and Deposits Glacial drift: All sediment deposited by glacial erosion Till: Unsorted glacial drift deposited directly from ice Moraines: Deposits of till with different forms (e.g., ground, terminal, lateral, medial)1 Types of Glaciers Continental: Ice sheets: Largest types of glaciers on Earth, they cover large areas of the land surface, including mountain areas Modern ice sheets cover Greenland and Antarctica. Ice shelves: Sheets of ice floating on water and attached to land. Usually occupy coastal embankments. May extend hundreds of km from land Mountain: Alpine, cirque, valley, fjord, and piedmont glaciers Hydrologic Cycle: Water Distribution The ocean is the largest water reservoir, containing over 97.5% of Earth's water, mostly saline. Polar ice sheets hold 74% of Earth's fresh water in frozen form. Groundwater is the largest reservoir of unfrozen fresh water. Streams Different Types Ephemeral streams: occur only after rainfall/floods, with no base flow. Perennial streams: flow year-round, sustained by base flow. Stream Flow Consists of storm flow (from precipitation runoff) and base flow (from groundwater and absorbed precipitation). Load Types Bedload: largest material dragged along the bottom (5-50% of total load). Suspended load: finer materials carried within the water. Dissolved load: ions from rock and organic material. Particle Movement Particles are transported differently based on size and density. Stream velocity affects sediment distribution in meanders: Lowest velocity along inside meanders, forming point bars. Highest velocity along outside meanders, creating cut banks. Groundwater Aquifer Systems Unconfined aquifers: have a water table and direct connection to the surface. Confined aquifers: bounded above and below by impermeable rock (aquiclude). Artesian aquifers: confined aquifers with high hydrostatic pressure, resulting in free-flowing water. Porosity and Permeability Porosity: percentage of total rock volume consisting of open pore spaces. Permeability: measure of how easily fluids can pass through rock. Both properties together determine water storage and movement in rock. Types of Wells Wells in unconfined aquifers: water level in well equals the water table. Artesian wells: tap into confined aquifers with high pressure, causing water to rise above the top of the aquifer. Atmospheric Layers The atmosphere is divided into several layers, each with unique properties: Troposphere The troposphere is the lowest layer of the atmosphere and is often referred to as the "weather layer"1. It extends from the Earth's surface to about 9 km at the poles and 12 km at the equator1. Key characteristics include: Temperature decreases with increasing altitude Naturally convective layer Contains most of the atmosphere's water vapor and weather phenomena Stratosphere The stratosphere lies above the troposphere and extends to about 50 km altitude1. Its notable features are: Temperature increases with altitude Not naturally convective; mostly stable and stratified Contains most of the atmosphere's ozone Absorbs the bulk of solar radiation Mesosphere and Thermosphere Above the stratosphere lie the mesosphere and thermosphere:  Mesosphere: Does not absorb solar energy; many meteors burn up in this layer1 Thermosphere: Contains only 1% of atmospheric gases; absorbs short-wavelength solar energy (ultraviolet)1 Temperature Changes in the Atmosphere Temperature variations in the atmosphere are complex: In the troposphere, temperature decreases with altitude (lapse rate) The stratosphere experiences temperature inversion, with temperature increasing with altitude These changes create distinct layers separated by "pauses" where temperature trends reverse Ozone Layer The ozone layer is primarily located in the stratosphere: Absorbs most of the sun's harmful ultraviolet radiation Ozone concentration is higher at the poles due to seasonal weather patterns and atmospheric circulation1 Plays a crucial role in protecting life on Earth from harmful solar radiation Pressure and Wind Atmospheric pressure and wind are closely related: Air always moves from high-pressure to low-pressure areas Wind patterns are influenced by temperature differences, the Earth's rotation (Coriolis effect), and topography1 Global wind patterns form distinct circulation cells: Hadley, Ferrel, and Polar cells1 Albedo Albedo refers to the reflectivity of Earth's surface: Earth's average albedo is about 30% Higher at the poles due to ice cover Oceans have lower albedo when the sun is directly overhead (~2%) compared to the horizon (~40%)1  Affects the amount of solar radiation absorbed by Earth's surface Heat Transfer in the Atmosphere Heat is transferred in the atmosphere through three main processes: 1. Convection: Vertical movement of air due to temperature differences 2. Conduction: Direct transfer of heat between molecules 3. Radiation: Transfer of energy through electromagnetic waves Carbon Dioxide Cycle The carbon dioxide cycle is a crucial part of Earth's climate system: CO2 is a greenhouse gas that absorbs and re-emits infrared radiation Oceans play a significant role in absorbing atmospheric CO2 CO2 is incorporated into marine organisms and carbonate shells Oceans act as a repository or sink for CO2, helping to regulate atmospheric concentrations1 Understanding these atmospheric properties and processes is essential for comprehending weather patterns, climate change, and the delicate balance of Earth's ecosystems. Simplified Notes Glaciers Glaciers are permanent bodies of ice formed from recrystallized snow, moving downslope due to their weight.1 Parts of a glacier:12 ○ Accumulation zone: The highest part of the glacier where snow accumulates, leading to net mass gain. ○ Ablation zone: The lower part of the glacier where melting exceeds accumulation, resulting in net mass loss. ○ Equilibrium line: The boundary between the accumulation and ablation zones, where mass gain equals mass loss. Glacial movement: Glaciers move through two main processes:2 ○ Internal flow: Movement within the glacier due to ice deformation under its own weight. ○ Basal sliding: Movement of the entire glacier over its bed, facilitated by meltwater reducing friction. Glacial erosion and deposits:3 ○ Glacial drift: All sediment transported and deposited by glaciers. ○ Till: Unsorted glacial drift deposited directly from the melting ice. ○ Moraines: Landforms made of till, classified based on their position relative to the glacier (e.g., lateral, medial, terminal). Types of glaciers:34 ○ Continental glaciers: Vast ice sheets covering large land areas (e.g., Greenland, Antarctica) and ice shelves extending over water. ○ Mountain glaciers: Various types found in mountainous regions, including alpine, cirque, valley, fjord, and piedmont glaciers. Hydrologic Cycle Water distribution:4 ○ Oceans hold the vast majority of Earth's water (over 97.5%), but it is mostly saline. ○ Polar ice sheets contain 74% of Earth's freshwater, but it is frozen. ○ Groundwater is the largest reservoir of unfrozen freshwater. Streams:45 ○ Ephemeral streams: Flow intermittently after rainfall or floods, lacking base flow. ○ Perennial streams: Flow continuously throughout the year, sustained by base flow from groundwater. Stream flow:5 ○ Comprises storm flow (runoff from precipitation) and base flow (from groundwater and absorbed precipitation). Load types:5 ○ Bedload: Large particles dragged along the streambed. ○ Suspended load: Finer particles carried within the flowing water. ○ Dissolved load: Ions from dissolved rock and organic matter. Particle movement:5 ○ Influenced by particle size, density, and stream velocity. ○ Meanders: Bends in a stream channel where velocity variations lead to deposition on the inside (point bars) and erosion on the outside (cut banks). Groundwater Aquifer systems:6 ○ Unconfined aquifers: Directly connected to the surface, with a water table marking the upper boundary. ○ Confined aquifers: Bounded above and below by impermeable layers (aquicludes). ○ Artesian aquifers: Confined aquifers with high hydrostatic pressure, causing water to rise naturally in wells. Porosity and permeability:6 ○ Porosity: The percentage of void space in a rock or sediment. ○ Permeability: The ease with which fluids can flow through a material. ○ These properties together determine how much water a material can hold and how easily water can move through it. Types of wells:7 ○ Wells in unconfined aquifers: Water level in the well reflects the water table. ○ Artesian wells: Tap into confined aquifers, with water rising above the aquifer due to pressure. Atmospheric Layers Troposphere:78 ○ The lowest layer of the atmosphere, where weather occurs. ○ Temperature decreases with altitude. Stratosphere:8 ○ Layer above the troposphere, characterized by temperature inversion (temperature increases with altitude). ○ Contains the ozone layer, which absorbs harmful ultraviolet radiation. Mesosphere and Thermosphere:9 ○ Mesosphere: Temperature decreases with altitude; meteors burn up in this layer. ○ Thermosphere: Characterized by increasing temperature with altitude; absorbs high-energy solar radiation. Atmospheric Processes Temperature changes:910 ○ Temperature generally decreases with altitude in the troposphere and increases with altitude in the stratosphere, creating distinct layers separated by "pauses." Ozone layer:10 ○ Located in the stratosphere, absorbs most of the sun's harmful ultraviolet radiation, protecting life on Earth. Pressure and wind:1011 ○ Wind is driven by pressure differences, flowing from high to low pressure. ○ Global wind patterns are influenced by temperature differences, Earth's rotation (Coriolis effect), and topography. Albedo:11 ○ The reflectivity of Earth's surface, influencing how much solar radiation is absorbed. ○ Higher albedo at the poles due to ice cover. Heat transfer:12 ○ Convection: Vertical movement of air due to temperature differences. ○ Conduction: Direct heat transfer between molecules. ○ Radiation: Energy transfer through electromagnetic waves. Carbon dioxide cycle:1213 ○ CO2 is a greenhouse gas that traps heat in the atmosphere. ○ Oceans play a major role in absorbing atmospheric CO2, acting as a carbon sink. Glaciers Definitions: ○ Glacier: Permanent ice mass from recrystallized snow. ○ Ice Sheets: Largest glaciers (Greenland, Antarctica), capable of raising sea levels by 66m if melted. ○ Types of Glaciers: Alpine (mountains), Cirque, Valley, Fjord, Piedmont, Ice caps. ○ Zones: Accumulation (mass gain) vs. Ablation (mass loss). Glacial Movement: ○ Internal Flow (Creep): Ice deforms under stress, creating crevasses at surface layers. ○ Basal Sliding: Meltwater lubricates glacier base, promoting sliding (common in temperate glaciers). Erosion & Deposition: ○ Moraines: Deposits of till (lateral, terminal, medial). ○ Kettle Lakes: Depressions filled after glacier melts. ○ Erratics: Large rocks transported by glaciers, distinct from local geology. ○ Features like outwash plains and eskers form through meltwater deposition. Hydrologic Cycle Water Distribution: ○ 97% in oceans, 3% freshwater (ice, groundwater, surface water). Stream Dynamics: ○ Load Types: Dissolved (ions), Suspended (silt/clay), Bed (large particles like gravel). ○ Flow: Ephemeral (intermittent), Perennial (constant). ○ Meandering Streams: Sediment deposits on point bars, erosion at cut banks, can form oxbow lakes. Groundwater: ○ Aquifers: Confined (trapped by impermeable layers, artesian wells possible). Unconfined (connected to surface, water table visible). ○ Porosity: % of rock volume that is pore space. ○ Permeability: How easily water flows through rock.  ○ Wells: Dug (shallow, easily contaminated). Drilled (deep, secure from contamination). Atmosphere Layers: ○ Troposphere: Weather occurs; temperature decreases with altitude. ○ Stratosphere: Contains ozone layer; temperature increases with height due to UV absorption. Key Processes: ○ Albedo: Reflectivity (e.g., ice = high albedo, absorbs less heat). ○ Solar Radiation: Shortwave (sun) vs. Longwave (Earth re-radiation). ○ Heat Transfer: Conduction, convection (rising warm air), and radiation. Pressure & Wind: ○ Coriolis Effect: Deflects moving air right in the Northern Hemisphere and left in the Southern Hemisphere. ○ Jet Streams: High-speed air currents; Polar and Subtropical jets affect weather patterns. Carbon Dioxide Cycle: ○ Short-term: Photosynthesis (removes CO₂), Respiration/Decay (releases CO₂). ○ Long-term: Carbonate-silicate weathering (sequesters CO₂ in rocks). ○ Fossil Fuels: Rapid release of carbon stored for millennia. Oceans Key Features: ○ Continental Margins: Passive (no tectonic activity, broad shelf, e.g., East Coast USA) vs. Active (near tectonic boundaries, narrow shelf, e.g., Pacific Coast). ○ Abyssal Plains: Flat areas formed by sediment settling. ○ Trenches: Deep, narrow features from subduction (e.g., Mariana Trench). ○ Mid-Ocean Ridges: Divergent boundaries creating new crust. Sediments: ○ Lithogenous: Eroded from land, coarse near shore. ○ Biogenous: Organic material (shells, skeletons); calcareous (calcium-based) and siliceous (silicon-based). ○ Hydrogenous: Precipitated from seawater (e.g., manganese nodules). Circulation: ○ Surface Currents: Driven by winds, influenced by Coriolis effect. ○ Thermohaline Circulation: Density-driven (temperature/salinity differences); "global conveyor belt." ○ Upwelling: Nutrient-rich water rises, supporting marine life. ○ El Niño: Weak trade winds, warmer waters in Eastern Pacific, reduced upwelling, lower productivity. ○ La Niña: Stronger winds, cooler waters, higher upwelling and productivity.