Max Reed Geology Exam 2

What is an earthquake and how does it relate to faults?

• An earthquake is the sudden shaking of the Earth’s surface caused due to a quick release of stored potential energy into kinetic energy in the Earth's crust. 

• They relate to faults cause as stress builds up due to tectonic plate movement its is stored along faults (where the crust is locked by friction) and then when the stress exceeds the frictional resistance, the rock suddenly slips along the fault causing energy to be released in the form of seismic waves - what we feel as an earthquake when they reach the earth’s crust

What is displacement and what can geologists infer from it?

• Displacement (Offset): is the amount of movement across a fault. How much motion occurred from a single or cumulative events. 

• Geologist Can infer:

  • Direction of plate movement

  • Magnitude of earthquake

  • Past earthquake history

  • Potential for future earthquakes

Faults: What are they? What are the types: (Normal, Reverse, Strike slip), What is the difference between an active fault and an inactive fault?

• A fault is a fracture plane which sliding takes place

• Types:

  • Normal: caused when earth is being pulled apart, happens when hanging wall(rock above fault) moves down relative to footwall

  • Reverse: When crust is phased together, happens when haning wall moves up relative to footwall

  • Strike Slip: rocks slide horizontally past each other

• An active fault is one that is experiencing or recently experienced significant movement whereas a passive fault is a fault that hasn't moved in thousands of years and is no longer a threat for generating earthquakes. 

Why does elastic behavior of rock affect faults and earthquakes?

• Elastic behavior is the bending/stretching or rock

• Elastic behavior of rock allows them to deform and store energy as stress builds along a fault. When the stress exceeds the rock strength it fractures causing a fault slip releasing the stored energy as seismic waves. 

What is the difference between P and S waves? How do they propagate through rock and liquids?

• P waves (Primary Waves): are compressional body waves that go through the interior of earth and travel the fastest. Compress and expand the material they go through. Travel through all materials. 

• S waves (Secondary Waves): are shear body waves that go along earth’s surface and travel about 60 percent of speed of p waves. Move particles side to side or up and down. Can only travel through solids. 

What are L and R waves and how do they relate to the surface of the Earth?

• They are both types of Surface waves so move along surface

• L waves: waves that cause the ground to shimmy back and forth are the most damaging

• Cause the ground to go up and down as they move in a rolling motion (like ocean waves)

What are seismograms and how can they be used to triangulate the epicenter and source of an earthquake?

• A seismogram is the record of seismic waves generated by an earthquake. Shows arrival times of different waves allowing seismologists to analyze earthquake characteristics. 

• They can be used to determine location of the epicenter by taking the arrival times of different waves at each center and using these times to triangulate the epicenter.

How do foreshocks and aftershocks relate to the major earthquake (mainshock)?

• Fore shocks (small earthquakes b4 mainshock) are warnings of a larger earthquake to come

• Aftershocks (smaller quakes after mainshocks that occur as earth adjusts to new fault position) are the result of continued movement along the pre existing fault.

How are earthquake intensities classified?

• Earthquakes are classified using the Modified Mercalli Intensity Scale

• It assigns a roman numeral to different degrees of damages I to XII

• Maybe add chart number meanings if on quiz

How does liquefaction occur and what does it do to structures?

• Solidification is when buildings and structures sink as sand and liquids compress

• Occurs form when water in sediments rise to the top of sediments so the loose soil temporarily loses its strength and behaves like a liquid

• Causes buildings and roasts to tilt, sink, or collapse due to sudden loss of ground support and underground structures like pipes may float to the surface. 
  

What causes tsunamis and how are they different from normal wind-driven waves? Why are tsunamis so dangerous?

• Tsunamis are oceanic waves that are produced by the displacement of the sea floor that can crash onto shore with devastating effects. 

• Tsunamis

  • Influences entire depth of water

  • Wave velocity maximums is several 100’s of kmph

  • Water arrives a plateau that pours onto land with no loss of energy

• Wind waves:

  • Wind waves only affect the top 100 meters of water

  • Wave height and length is related to wind speed

  • Break in shallow water and expend all energy

Why is predicting earthquakes difficult? Why is the recurrence interval a flawed approach?

• Earthquakes are difficult to predict because of earth's complete system, a lack of clear warning signs, Fast release stress at different rates and in different ways, limited monitoring

• The recurrence Interval is flawed because, Earthquakes don’t follow a regular schedule, Variability: Some faults may go longer or shorter between quakes due to changes in stress, rock strength, or interactions with nearby faults, 

How are mountains formed by convergent boundaries? Divergent boundaries? 

• Convergent boundaries: Mountains form from collision and compression. Continental plates crumple (e.g. Himalayas) or oceanic plates subduct and create volcanic mountains (e.g. Andes).

• Divergent boundaries: Mountains form as magma rises and pushes the crust up at mid-ocean ridges or continental rift zones (e.g. East African Rift).

What is the main difference between brittle and ductile deformation? Why would rocks undergo one or the other?

• Brittle: Breaks (fractures/faults) - happens at low temps, low pressure, shallow depths (plate shatter when dropped)

• Ductile: squishing/spreading/bending/ expanding rock- higher temperature high pressure deeper crust.

•  Rocks undergo brittle deformation near the surface under low temps/pressures or fast stress.

•  Rocks undergo ductile deformation at depth under high temps/pressures or slow, sustained stress.

What is the difference between rotation and distortion? Why would rocks under go one or the other?

• Rotation: Rock bodies turn or pivot around a point or axis.
  
  

• Distortion: Rock bodies change shape (bend, stretch, or compress) without moving location. 

• ➡ Rocks undergo rotation when uneven or asymmetric forces act on them, causing them to pivot.

• ➡ Rocks undergo distortion when stress deforms their shape, stretching, folding, or compressing them.

What is the difference between a syncline and an anticline and how do they form?

• Syncline: A downward fold (like a trough) with youngest rocks in the middle.

• Anticline: An upward fold (like an arch) with oldest rocks in the middle.

• Formed by compression forces that cause layers to bend.

Understanding how layers of rock are layered upon each other is central to larger scale geology. What does the strike represent? What does the dip represent? (Draw example)

• Strike: The direction of a horizontal line on an inclined rock surface.

• Dip: The angle and direction a rock tilts down from the horizontal.

What forces can drive orogenesis? How does exhumation and delamination relate to the upward lift of rock? 

• Orogenesis is mountain building with mechanisms of deformation, uplift, and metamorphism

• Exhumation: Uplift + erosion brings deep rocks to the surface.

• Delamination: Dense lower lithosphere peels off and sinks, causing lighter crust to rise (uplift).

What is geomorphology? What is a landscape and a landform?

• Geomorphology: The study of Earth’s landforms, their processes, history, and structure.

• Landscape: A large-scale, visible area of Earth’s surface with a mix of landforms (e.g. mountain range with valleys).

• Landform: An individual natural feature of the Earth's surface (e.g. mountain, valley, plateau).

What are examples of positive landforms? What are examples of negative landforms? What are examples of neutral/flat landforms?

Examples of positive, negative, and neutral/flat landforms?

• Positive landforms (elevated): Mountains, hills, plateaus.

• Negative landforms (depressed): Valleys, basins, canyons

• Neutral/flat landforms: Plains, piedmonts.

Earth’s terrestrial landscapes in slide shows and descriptions. (alphabetical order)

• Badlands: deeply dissected erosional landscape formed in soft rock terrain (sedimentary rocks) often in semiarid regions

• Basins: large low lying expanse between mountains formed from extension as underlying content rises

• Mountain ranges: young or rising high elevation areas driven b y crustal uplift

• Piedmont: area of generally flat or gently sloped hills flanking mountains characterized by streams eroding uplands and areas filled with sediments

• Plains: flat to gentle sloped areas formed from erosion of positive landforms filling negative landforms with sediment or continental uplift 

• Valley: elongated low area between mountains or hill typically with river/stream running through. Created by diverging tectonic plates and erosion
  
  

How are fossils made? 

Fossils form when the remains, impressions, or traces of ancient organisms are preserved in sedimentary rock. This typically happens when an organism dies and is quickly buried by sediment (like mud, sand, or volcanic ash). Over time, the sediments harden into rock, and the organic remains can be preserved in various ways — as mineralized bones, imprints, molds, casts, or trace fossils.

What must occur during fossilization? 

Rapid burial — Protects remains from scavengers, decay, and weather.

Presence of sediment — Sediment must cover the remains to shield them.

Lack of oxygen (anoxic environment) — Slows decay and bacterial activity.

Mineral-rich water — Can percolate through remains, leading to permineralization or replacement with minerals.

Long periods of time — Needed for sediments to harden into rock and chemical changes to occur.

How can fossils from organisms lacking bones be made?

• Impressions or Carbon Films: Leaves, jellyfish, and soft-bodied creatures might leave a thin, carbon-rich film or impression in fine-grained sediment.

• Trace Fossils: Tracks, burrows, footprints, or feeding marks record their activity.

• Amber Preservation: Small soft-bodied insects and organisms can get trapped in tree resin (which hardens into amber).

• Permineralization: In rare cases, soft tissues may fossilize if quickly mineralized.

• Molds and Casts: An organism decays, leaving a cavity (mold) which later fills with minerals or sediment (cast). 

  
  

What is geologic time and why is it a different concept than our daily use of time? 

Geologic time covers billions of years, while our daily time relates to human lifespans. It uses vast, relative, and absolute divisions (eons, eras, periods) to describe Earth's history.

How are the principles of geology/stratigraphy used to understand how rock layers relate to one another?

They help scientists deduce the sequence of geological events and relative ages by examining how layers were deposited, altered, and disrupted over time.

Which is longer: Eons, Eras, or Periods? What are the four Eons? What happened generally in each of the four Eons?

Eons→ Eras→ Periods

• Hadean: (4600-4000 mya) Formation of earth, no fossils or life, early formation of earth atmosphere and ocean, very few rocks

• Archean Eon: (3960-2500 mya) 

  • First life (bacteria and archaea)

  • Continents begin to form

  • Oceans cover most of earth

  • Contents form (oldest rock sample)

  • Oxygen first happens 

• Proterozoic (2500-542)

  • Atmospheric oxygen

  • Oceans have life but not land

  • Eukaryotes and multicellular life 

• Phanerozoic: (542 mya - present)

  • Abundant fossil records

  • Complex life 

  • Mass extinctions 

  • The 3 eras

What are the three Eras of the Phanerozoic? What happened generally in each of the three Eras? 

• Paleozoic: Fish, land plants like mosses, amphibians, forests, 

• Mesozoic: Dinosaurs, reptiles, insects, trees

• Cenozoic: Mammals and humans evolve.

e ready to name up to four periods of the Phanerozoic and what generally happened. 

• Devonian: age of fishes fish and marine life dominate oceans and first amphibians

• Pennsylvanian and Mississippian: carboniferous periods where forests are formed in swamps removing massive amounts of CO2

• Triassic: Early dinosaurs and trees escape swamps to drier areas

• Jurassic: Dinosaurs dominate

• Cretaceous: dinosaurs killed by large asteroid affecting climate dramatically mammals rise

• Quaternary: Ice ages happen and humans appear

How do index fossils work? Can you provide an example of an index fossil? 

• They date rock layers by identifying fossils of species that lived during specific, brief time spans

• Ex: Trilobites

What are radioactive isotopes and how do they work? What is a half-life for a radioactive isotope? 

• Isotopes are versions of elements with the same number of protons but different number of neutrons in its nucleus

• Radioactive isotopes are unstable that will break down and decay over time to become more stable in the form of losing energy by emitting radiation 

• A half-life is the amount of time it takes for half of the atoms in a sample of a radioactive isotope to decay into a different, more stable form.

How do radioactive isotopes help with geochronology? 

• By measuring isotopic ratios and knowing the half-life, scientists determine the age of rocks and fossils.

What are stromatolites and what do they indicate? 

• Fossilized microbial mats, indicating early life and photosyn

Generally, how did life start? 

• Life evolved form self replicating chemical like amino acids and peptide chain proteins into cellular life due to posit feedbacks or replication during the Archean. 

Was oxygen always in the atmosphere? What happened during the great oxygenation event?

• Oxygen was not always in the atmosphere. Atmospheric oxygen from photosynthesizing  organisms in oceans made oxygen which made the ozone 2.4billion years ago during the great oxygenation event when oxygen reacted with ultraviolet light. 

What are banded iron formations and why do they matter? 

Sedimentary rocks marking when oxygen reacted with iron in oceans, recording atmospheric oxygen rise.

How did snowball earth form and end? 

Massive cooling from reduced greenhouse gases + expanding ice cover = Snowball Earth.
Volcanic CO₂ buildup eventually reheated the planet = end of Snowball Earth.

How did the Earth’s atmosphere and climate change during the Mesozoic? 

☀ Warm, high CO₂, no ice caps, high sea levels.
🌴 Lush forests, tropical seas, and diverse reptiles/dinosaurs.

Changes:
🌍 From hot and dry (Triassic) ➝ warm and humid (Jurassic) ➝ high seas and flowering plants (Cretaceous) ➝ sudden cooling and mass extinction at the end.

What are three important things happened during the Mesozoic and how did the Mesozoic end?

• Dominance of dinosaurs. 

• Appearance of birds and mammals.

• Breakup of Pangea. - Ended with an asteroid impact (~66 million years ago).

How did the Earth’s atmosphere and climate change during the Cenozoic?

• CO₂ levels fell, climate cooled, ice ages occurred, modern ecosystems emerged.

Where was proto North America during the beginning of the Phanerozoic?

• Proto-North America (Laurentia) was located near the equator, oriented sideways, and surrounded by shallow seas.

What is the Taconic orogeny? What happened during the taconic orogeny?

• The Taconic Orogeny (~450 Ma) was a mountain-building event caused by a volcanic island arc colliding with the eastern edge of proto-North America. It created the earliest Appalachian mountains.

What is the Acadian orogeny? What happened during the Acadian orogeny?

• The Acadian Orogeny (~375 Ma) occurred when the microcontinent Avalonia collided with proto-North America, causing further uplift and deformation of the Appalachians.

What is the Alleghanian orogeny? What happened during the Alleghanian orogeny?

• The Alleghanian Orogeny (~325–260 Ma) happened when Africa collided with North America, completing the formation of Pangea. This caused massive mountain building, creating some of the highest peaks in the Appalachians.

Why did Pangea rift and how did this affect North America?

• Pangea rifted due to rising mantle heat and tectonic forces breaking apart the supercontinent (~200 Ma). This formed the Atlantic Ocean and shifted North America westward, starting new mountain building on its western margin.

What happened on the west coast of North America to create the Rocky Mountains?

• The Rocky Mountains formed mainly due to subduction of the Farallon plate under North America during the Laramide Orogeny (Late Cretaceous to early Cenozoic), which caused crustal uplift far inland.

Why are there so many sedimentary rocks in the eastern (especially Pennsylvania, West Virginia,Kentucky, Tennessee, Ohio) United States?

• During the Taconic orogeny, as the mountains were formed they dumped lots of sediment into there bassins leading to the midwest which was a large shallow ocean so there was extensive limestone deposition. 

Why are there marine sedimentary rocks in the now desert-dry areas of Arizona, Nevada, Colorado, Idaho, and Montana?

• In the Paleozoic and Mesozoic, these areas were often covered by inland seas. Marine sediment was deposited and later uplifted as the land rose and seas receded, leaving behind marine rocks in desert regions.

What are the three collisions and one split that caused the geology of Virginia?

• Taconic Orogeny (volcanic arc collision)

• Acadian Orogeny (Avalonia collision)

• Alleghanian Orogeny (Africa collision)

• Pangea Rifting apart

What are the five geologic regions of Virginia

Left to right

• Appalachian Plateau

• Valley and ridge

• Blue Ridge 

• Piedmont

• Coastal plains

What is a river/stream?

Body of flowing water confined within a channel.

What is the difference between a permanent and ephemeral stream? 

• A permanent stream is a stream that flows continuously throughout the year supported by constant water source

• Ephemeral stream flows only temporarily typically after heavy rains or snow melts

Why does area and velocity matter for river discharge?

• Discharge is volume of water flowing though a river channel per unit of time 

• Q = area of cross section x velocity

• Area: wider and deeper rivers carry more water

How do suspended and bed loads differ in a stream? 

• Bed Loads: sediments along the bottom of stream like gravel or pebbles moved by rolling and jumping

• Suspended loads:Fine-grained materials like silt and clay carried within the water column, making the water appear muddy.

Examples of River morphology and Why are some streams braided or meandering? 

• Straight: channel migration limited by low energy and high bank strength

• Braided: Form where there’s a high sediment load, variable discharge, and easily erodible banks. The channel splits into multiple intertwining channels separated by sediment bars.

• Meandering: Occur where the gradient is gentle, sediment is finer, and banks are stable. Erosion occurs on the outside of bends (cut banks) and deposition happens on the inside (point bars), creating wide, looping bends over time. (Almost a river curve)

• Anastomosing: well established channels that merge and converge around stable islands

How does a stream erode a landscape and how does it change through time? 

• Erosion methods:

  • Hydraulic action: Water pressure breaks rock apart.

  • Abrasion: Sediments scrape and wear down the channel.

  • Solution: Minerals dissolve into water.

• Through time: Streams tend to deepen and widen their valleys, transport sediment, and shift course. They can form V-shaped valleys, canyons, floodplains, oxbow lakes(U shaped lake formed when meander is cut off), and eventually reach a base level where they deposit sediment (like in a delta).

How do people try to protect against flooding? What are the issues with these attempts?

• Methods: 

  • Dams: Control waterflow and store excess water

  • Levees: Raised embankments along rivers

• Issues

  • Levees may fail catastrophically if overtopped.

  • Dams can trap sediment, affecting downstream ecosystems

  • May increase flood severity downstream or shift flooding problems elsewhere.

What is the recurrence interval for a flood and how does it relate to annual probability?

• RI: average time between floods of a specific size in a given area

• AP: Chance of a flood of that size happening in any given year

What is ground water and how does it relate to surface deposits and bedrock types? 

• Groundwater is water that percolates underground in soil or rock (bedrock) layers through pores fractures and weathered rock 

• Surface deposits are high porosity 

• Bedrock types vary in porosity.

How does porosity and permeability differ across rock types and affect groundwater? 

• Porosity: percentage of rock blue made up of open space

• Permeability: How easily fluids can flow through those pores.

• Gravel & sand: High porosity & permeability.

• Clay: High porosity but very low permeability (tiny, poorly connected pores)

• Granite (unfractured): Low porosity and permeability.

What is a karst landscape and how does it relate to groundwater and as a geologic hazard?

A karst landscape forms in areas of soluble rock (like limestone) where groundwater dissolves the rock, creating caves, sinkholes, disappearing streams, and underground drainage systems.

Hazards:

• Sinkholes: Sudden ground collapse as cavities below grow too large.
  
  

• Contaminant movement: Water moves rapidly through underground channels, making pollution harder to control and clean.

What is a water table and how does it relate to recharge and discharge? 

Water Table: The boundary between the saturated zone (pores filled with water) and the unsaturated zone (pores contain air and water) underground

Recharge:
Water from precipitation or surface water that infiltrates the ground and replenishes the aquifer.

Discharge:
Where groundwater naturally flows out to the surface, like springs, wetlands, or into rivers.

What is the difference between a confined and unconfined aquifer? 

• Unconfined Aquifer:
  Water is directly recharged from the surface. The water table rises and falls with changes in recharge.
  Example: shallow wells.

• Confined Aquifer:
  Sandwiched between impermeable layers (aquitards). Water is under pressure and can rise in wells without pumping (artesian wells). Recharge occurs where the aquifer is exposed at the surface.

What are aquifers and aquitards?

Aquifer:
A rock or sediment layer that stores and transmits groundwater well due to high porosity and permeability.

Aquitard:
A rock or sediment layer with low permeability that slows or stops groundwater flow. Acts as a barrier between aquifers.

How does capillary action and hydraulic pressure move groundwater upwards against gravity? 

Capillary Action:
The ability of water to move upward through tiny pores due to surface tension and adhesion to pore walls — like water climbing up a thin straw.

Hydraulic Pressure (Hydraulic Head):
Pressure differences caused by elevation and gravity. Water moves from areas of higher pressure (or elevation) to areas of lower pressure, sometimes forcing it upward if confined.

How and why is groundwater used non-renewable/unsustainably? 

• Aquifers are over exploited and at risk of ground subsidence due to thousand of year recharge rate

What factors govern if a region can be classified as a desert? 

 desert is a region that contains no permanent liquid surface water and has no more than 25 cm of annual rainfall.

What are the main types of deserts on Earth? How do climatic patterns create deserts? 

• Subtropical: forms due to the descending dry air in the global atmospheric cirulaiton which prevents cloud formation and rain. 

• Rain Shadow Desert:

  • Forms on leeward side of mountains

  • Moist air rises cools and precipitates on windward side leaving dy air to descend on other

• Coastal: occurs along coasts where cold ocean currents cool air making it unable to hold much moisture. Air is dry. 

• Polar: very little precipitation in arctic regions cause cool air which holds less moisture

How does weathering and erosion occur in a desert?

• Physical Weathering is dominant due to limited moisture for chemical weathering.
  Key processes:

  • Thermal expansion and contraction from intense temperature swings

  • Frost wedging in cold deserts

• Water erosion: when it rains it rains hard causing flash floods and run off that move large amounts of sediment quick 

• Wind erosion 

  • Deflation: removal of loose, fine particles.

  • Abrasion: wind-driven particles scrape and shape rocks.

What is desert varnish and desert pavement? 

Desert Varnish:

• A dark, shiny coating on exposed rock surfaces

• Formed by microbial activity and chemical weathering concentrating iron and manganese oxides from windblown dust over time.

Desert Pavement:

• A surface layer of tightly packed pebbles and stones

Formed as wind and water remove finer sediments, leaving coarser material behind.

What creates desert dunes, alluvial fans, and playas?

Desert Dunes:

• Form when wind deposits sand in mounds or ridges
  
  

• Their shape depends on wind strength, direction, sand supply, and vegetation presence

Alluvial Fans:

• Develop where a canyon mouth opens onto a flat plain
  
  

• Flash floods deposit sediment in a fan shape as water loses energy

Playas:

• Dry lakebeds in closed desert basins
  
  

• Temporarily fill with water after rare rains, then evaporate, leaving behind clay, salt, and minerals

How does particle size affect wind erosion?

• Fine particles (silt, clay):

  • Easily lifted into the air and transported over long distances in suspension.

• Medium particles (sand):

  • Moved by saltation (bouncing and skipping along the ground)

• Coarse particles (gravel, pebbles):

  • Too heavy for wind to lift

  • May roll or slide short distances, but generally remain in place, contributing to desert pavement

The finer the particle, the farther and higher it can travel.

How does the depth and shape of the ocean floor vary moving away from continents? How does this vary in tectonically active areas versus passive margins. 

• Ocean floor shape varies from shallow continental shelves to deep abyssal plains; tectonically active areas have narrow shelves, steep slopes, trenches, and seamounts, while passive margins have broad shelves and gentle slopes.

What creates underwater topography for the ocean floor?

• Underwater topography is created by tectonic activity (mid-ocean ridges, trenches, seamounts), sediment deposition (continental rise, abyssal plains), and erosion.

Draw out the ocean floor topography picture and define topography features:

• Continental shelf: Submerged gently sloping extension of a continent before drop off into deeper ocean. 

• Continental slope: Steeper incline beyond shelf leading down to deep ocean floor

• Continental rise: base of slope where sediments accumulate before abyssal plain it is a more gradual slope

• Abyssal plain: Broad flat and deep part of ocean floor typically 3-6 thousand meters deep covered by fine sediment. 

• Seamounts: underwater volcanic mountains rising from ocean floor don't reach surface

What causes tides? How high and low does sea level fluctuate at the coast line typically?

• Tides are caused by gravitational interactions with the moon and sun; typical coastal sea level fluctuation is a few meters

What are atypical tides that cause flooding? 

• Spring tides: tides that are especially high or low tides when the son and moon and earth align

• Storm surges are abdominal rises in sea level due to storm winds that lead to flooding. 

What are the key parts of waves? What generates waves in the ocean? How about rogue waves? (DRAW IT OUT!)

• Wave parts

  • Crest: highest point of wave

  • Through lowest point of wave above water

  • Wavelength: horizontal distance to from crest to crest

  • Wave Height: Vertical distance from crest to trough

  • Wave base:The depth below the water’s surface where wave motion essentially stops, usually at a depth equal to half the wavelength.

• What generates waves: Waves in the open ocean are primarily generated by wind transferring energy to the water’s surface. The size and strength of a wave are influenced by:

  • Wind speed — stronger winds create bigger waves.

  • Duration — how long the wind blows over the water.

  • Fetch — the distance over which the wind blows without interruption.
    
    Rogue waves are exceptionally large, unexpected waves that can appear suddenly and are much taller than the surrounding waves. They can form through:

    • Constructive interference — when multiple smaller wave crests coincide, combining their energies into one larger wave.

    • Current-wave interactions — especially when strong ocean currents collide with waves moving in the opposite direction, amplifying wave height.

What drives the movement of sand to and along a coast? 

• Longshore current: waves approaching the shore at angle creating current of water moving parallel to shoreline

• Wave refraction: plays a role by bending waves as they approach shallow water, concentrating energy on headlands (eroding them) and dispersing it in bays (depositing sediment).

• Erosion etc

Why are some coasts rocky while others have vast stretches of sand? 

• Rocky

  • Tectonically active areas with high wave energy

  • Characterized by features like cliffs, headlands, sea arches, and wave-cut platforms.

  • Wave action is strong enough to erode loose material, leaving behind harder, resistant rock formations.

• Sandy

  • Tectonically passive margins

  • Occur in areas with a plentiful supply of sand and sediments, transported by rivers, waves, and currents

  • Lower wave energy or protective features (like barrier islands) allow sediments to settle and accumulate, forming beaches and sand dunes.

What are typical coastal landforms for an erosional and depositional/accretional coastline? 

• Erosional:

  • Sea cliffs — steep rock faces formed by wave erosion.

  • Headlands — rocky outcrops extending into the ocean, absorbing wave energy.

  • Sea arches — formed when waves erode through a headland.

  • Sea stacks — isolated columns of rock left after arches collapse

  • Wave-cut platforms — flat areas at the base of cliffs created by wave erosion.

  • Wave cut notches

  • Fjords

• Despostional:

  • Beaches — accumulations of sand, gravel, or pebbles along the shore.

  • Barrier islands — elongated, offshore islands of sand parallel to the coast.

  • Tidal flats — low-lying areas that are alternately covered and exposed by tides.

  • Deltas — landforms at river mouths where sediment is deposited faster than it can be removed by wave action

  • Salt marshes

  • Lagoons

What are glaciers? How do they form and behave on the landscape? What does their movement do? 

• Glacier: mass of ice formed by compaction and recrystallization of snow lying largely or wholly on land and showing evidence of past or present movement 

  • Mountain glaciers follow existing valleys, eroding and reshaping them as they move.

  • Continental glaciers (ice sheets) spread out over broad areas, flattening and reshaping the landscape below.

• As glaciers move, they act as powerful agents of erosion and deposition, carving valleys, sharpening mountain ridges, and transporting rock and sediment far from their source areas.

How does the zone of ablation and zone of accumulation relate to the equilibrium line? What do they tell us about glacier advance or retreat?

• Zone of accumulation — the upper area where snowfall adds more ice than melts.

• Zone of ablation — the lower area where more ice is lost than gained, through melting, sublimation, or calving.

• The equilibrium line separates these two zones. It’s the point on the glacier where annual ice gain equals ice loss.

• If the zone of accumulation grows larger than the zone of ablation, the glacier’s front advances.

• If the zone of ablation grows larger, the glacier retreats (Melting)

• The position of the equilibrium line moving up or down the glacier indicates changing climate conditions affecting the glacier’s health and behavior.
  

How do glacial features (U shaped valleys, cirques, aretes, horns, hanging valleys, fjords, drumlins, moraines, esters, and kettle holes) relate to the action of ice and glaciers on the landscape? Where will you find each of the types of features (below, next to, or top of a glacier

Or do they form after a glacier retreats)? (2 types of feature categories)

Erosional Features (from ice carving rock):

• U-shaped valleys — carved beneath glaciers as they widen and deepen pre-existing V-shaped river valleys.

• Cirques — bowl-shaped depressions at a mountain’s head where glaciers originate.

• Arêtes — sharp ridges between adjacent glacial valleys or cirques.

• Horns — pyramid-shaped peaks formed when multiple glaciers erode a mountain from several sides.

• Hanging valleys — smaller valleys left perched above the main glacial valley, often leading to waterfalls.

• Fjords — deep, flooded coastal valleys created by glaciers and later filled with seawater.

Depositional Features (from ice and meltwater dropping sediment):

• Drumlins — elongated hills of glacial till, shaped beneath glaciers, with the tapered end pointing in the direction of ice movement.

• Moraines (lateral, terminal) — ridges of debris deposited along the sides (lateral) or at the end (terminal) of a glacier.

• Eskers — long, sinuous ridges formed by sediment deposited by subglacial meltwater streams.

• Kettle holes — depressions left when chunks of buried ice melt, often forming small ponds or lakes.

 What happens when glaciers encounter the ocean?

• Tidewater glaciers break off (calve) icebergs into the ocean.

• Meltwater mixes with seawater, which can affect ocean salinity and currents.

• In coastal areas, when glaciers retreat, they leave behind deep, steep-sided valleys that can flood with seawater, forming fjords.

• Large-scale ice melting contributes to sea level rise and can disrupt marine and coastal ecosystems.

How does Earth’s orbit and spin affect the amount of solar radiation reaching it?  (What do terms mean and their time periods)

• Earth’s orbit and spin determine how much solar energy different parts of the planet receive over time. 

• Eccentricity: 

  • How elliptical earth’s which affects how much solar radiation earth gets at different times of year due to be closer/further from sun

  • Cycles every 100,00 years

• Obliquity(tilt):

  • Angle of earth axial tilt form 22.1 to 24.5 degrees 

  • Controls how much sunlight is at different latitudes 

  • Tilt influences strength of seasons more tilt more extreme seasons

  • 41,000 years

• Precession (wobble): 

  • Wobble of earth axis like a spring top that happens over 26,00 years

  • Changes earth timing of seasons relative to earth’s position in orbit

  • Alters which hemisphere points towards the sun at certain times of they year

How do the changes in Earth’s orbit affect the Earth’s climate? 

• These orbital changes (called Milankovitch cycles) alter the distribution and intensity of solar energy over tens to hundreds of thousands of years.

• When the cycles alling/amplify each other over a long timescale they can tip the climate towards an icehouse or greenhouse state. 

When do eccentricity, obliquity, and precession matter most for Earth’s climate?

They matter most when their effects align or amplify one another. For instance:

• Eccentricity becomes especially significant when it amplifies seasonal contrasts caused by tilt and precession.
  
  

• Obliquity is critical in determining the severity of seasons — strong tilt can lead to ice melting, while weaker tilt can help ice sheets persist.
  
  

Precession matters when combined with eccentricity, affecting whether a hemisphere’s summer occurs when Earth is closer or farther from the Sun.

How does the global carbon cycle relate to Earth’s climate system? 

The global carbon cycle regulates the amount of carbon dioxide (CO₂) and other greenhouse gases in the atmosphere. These gases trap heat, so when atmospheric CO₂ rises, temperatures generally increase, and when it falls, the climate cools. This cycle interacts with other systems like the oceans, biosphere, and geosphere, influencing long-term climate trends.

What is the global carbon cycle? How does the inorganic carbon cycle differ?  (Draw out the inorganic)

• The global carbon cycle describes how carbon moves between Earth’s atmosphere, oceans, living organisms, and rocks. It includes both natural processes (like respiration, photosynthesis, ocean absorption) and human impacts (like fossil fuel burning).

• Inorganic: focuses specifically on carbon in non living stems: CO₂ in the atmosphere, carbonates in rocks, dissolved CO₂ in oceans, and geological processes like weathering and volcanic eruptions. Marine or terrestrial deposition. 

What is the difference between weather and climate? 

• Weather is the day-to-day state of the atmosphere — temperature, humidity, wind, and precipitation at a specific time and place.
  
  

• Climate is the average pattern of weather conditions over a long period (typically 30 years or more) in a specific region or globally

What are negative and positive feedback cycles in the global carbon cycle? 

• Positive feedback amplifies changes in the climate system.
  Example: Warming melts ice, lowering Earth’s albedo (reflectivity), causing more heat absorption and further warming.
  
  

Negative feedback stabilizes the system by counteracting changes.
Example: Increased atmospheric CO₂ can boost plant growth, which in turn absorbs more CO₂, slightly offsetting the increase.

How does ice formation affect the global climate? (1 important term define it)

• Albedo: reflectivity of a surface: high(ice/snow) reflects sunlight, low(ocean/dark) absorbs sunlight

• Ice and snow have a high albedo, reflecting sunlight back into space. When more ice forms, Earth absorbs less heat, leading to further cooling. Conversely, when ice melts, darker surfaces like ocean water and land absorb more heat, warming the planet

How have humans altered the global carbon cycle? How does the human-emitted carbon dioxide affect Earth’s climate system?

Humans have significantly altered the carbon cycle by:

• Burning fossil fuels (coal, oil, natural gas)
  
  

• Deforestation
  
  

• Industrial agriculture
  
  

These activities increase atmospheric CO₂ and methane levels, enhancing the greenhouse effect and warming the planet. This warming influences sea levels, weather patterns, and ecosystems globally.

Is sustainability an achieveable goal? Which aspects are or are not?

• Achievable: Renewable energy, sustainable agriculture, and efficient waste management have made significant progress.
  
  

Challenging: Global overconsumption, finite natural resources, economic dependence on fossil fuels, and political/social barriers make achieving full sustainability difficult on a global scale.