Exam 1 Flashcards
What is the estimated age of the universe?
13.8 billion years
How many Earth’s worth of resources would our current population require if we were to all live at the American standard of living?
4.1
What is the current population of the Earth?
7.5 billion
Most of the galaxies in the universe exhibit what kind of shift in the visible light spectrum, indicating that galaxies are moving away from us?
Red shift
What is the name of the effect that compresses or expands the wave length of light depending on the direction and speed of an object?
Doppler
Which gas makes up the majority of Earth’s atmosphere?
Nitrogen
When looking at the composition of the entire Earth, which element is most common?
Fe (iron)
What process is predominately responsible for driving plate tectonics?
Slab pull
Who first proposed the theory of plate tectonics?
Alfred Wegner
What type of mineral is most abundant on Earth?
Silicate minerals
What type of bond is the strongest?
Covalent
What is the apparent banding or layering within a metamorphic rock called?
Foliation
Doppler Effect
Shows the universe is expanding; works with sound but also light. Towards = blue, away = red. Bodies in space are red shifted
Nebulae
Composed of Helium and Hydrogen gas. Dust grains clump and collide to form planets
Differentiation
The process of density separation; allowed Earth to gain atmosphere. The early atmosphere was ammonia, hydrogen sulfide and methane, and the ammonia oxidized to water and nitrogen.
Geodynamo System
Inner core: Solid, nickel and iron, not rigidly connected to mantle
Outer core: Liquid, Fe and Ni, pressure causes inner core to be solid. Cooling of the outer core would kill the MOA of plate tectonics (magnetic field)
Declination
Difference between geographic and magnetic North
Lithosphere
Contains 12 major tectonic plates, predominantly basalt oceanic crust. Continental crust is granitic. Volcanoes and quakes at plate boundary. Oxygen and silicon make up most of the Earth crust and form rocks
Plate Tectonics
Evidence: Jigsaw fit of continents, glacial deposits, creatures on different continents.
Modern Evidence: Mid Ocean Ridge
Paleomagnetism
Polar reversals are reflected in the rock record
Types of Plate Boundaries
Divergent - Plates moving away (Mid Ocean Ridge)
Convergent - Plates move towards each other (Ocean subducts since it’s more dense)
Transform - Plates move sideways past each other
Continent-continent collision responsible for mountain building (Himalayas)
What causes plate movements?
Slab pull - Very heavy plate moves crust
Convection
Ridge Push - Pushing down of ridge leads to crust being pushed out and away
Minerals
Inorganic, solid, natural, regular crystalline structure. Specifically ordered; a solid with disordered atoms = glass.
Silicates
Have Si and O
Quartz, Muscovite, Feldspar
Carbonates
Calcite CaCO3
Dolomite
Native Elements
Au, Ag, Cu, C
Sulfides
Pyrite Fes2
Oxides
Hematite Fe2O3
Cystalline structure
Based on atomic patterns that are both predictable and repetitive
New Madriol Fault
3 magnitude 7s in 1811-1812
Induced Seismicity
Wasterwater injection wells causing man-made earthquakes
Magnitude
Amount of ground motion resulting from an earthquake
Mercalli Scale
Measures intensity - effect on people; used to describe old earthquakes when seismometer equipment was not present
Moment Magnitude
Amount of energy released by an earthquake. Measures displacement, rupture area, and strength of rocks
Earthquake Hazards
Shearing and rolling from Love and Rayleigh Waves
P waves are fast but aren’t usually damaging
S waves can damage due to shearing
Liquefaction
Land eventually liquefies after being shaken for a while
Aftershocks
Crust re-accommodating stress change from earthquake
Tsunamis
Caused by vertical displacement; usually occur at convergent (reverse) faults, but can also occur at normal faults. 2004 tsunami led to warning system of buoys in the Indian Ocean. Subsidence can cause flooding: Japan’s tsunami changed the length of the Earth’s day
Normal Faults
These have a crustal extension and rocks above steeply inclined fault surface slip DOWN and over rocks beneath fault surface.
Found at Transform boundaries
Reverse Faults
These have a crustal compression and Rocks above steeply-inclined fault surface slip UP and over rocks beneath fault surface.
Found at convergent boundaries
Thrust Faults
are same as reverse faults, but have more gently-inclined surface
Strike Slip Faults
a fault in which rock strata are displaced mainly in a horizontal direction, parallel to the line of the fault.
Japan Tsunami
P waves traveled 4 miles per second
Originated Pacific-Eurasian plate
4 miles deep, 60 miles long
Caused by plate tectonics springing upward
Crystals
External flat faces, form best in open cavities
Atom Bonding
Lattice atoms are held in place by atomic bonds.
Types: Covalent Ionic Metallic Van der Waals
Covalent Bonds
Hold molecules together through the sharing of electrons
Ionic Bonds
Electron given up to fill outer shell of another element
Metallic Bond
Nuclei and inner shells float in a sea of free electrons.
Electrons stream through metal if there is electric current.
Specific Gravity
Related to density; mineral weight over equal weight of water volume
Crystal Form
Euhedral – Good crystal faces; grown in open cavity.
Anhedral – No crystal faces; grown in tight space.
Subhedral – Between the two.
Face development indicates growth history.
Anhedral crystals common; euhedral less so.
Cleavage
Tendency to break along planes of weakness.
Cleavage produces flat, shiny surfaces.
Described by number of planes and their angles.
Sometimes mistaken for crystal habit.
Cleavage is through-going; often forms parallel “steps.”
Crystal habit is only on external surfaces.
1, 2, & 3 planes of cleavage possible.
Fracture
Some minerals lack planes of weakness.
Due to equal molecular bonds in all directions.
These minerals don’t have cleavage; they fracture.
Example: Quartz displays conchoidal fracture.
Shaped like the inside of a clam shell.
Breaks along smooth curved surfaces.
Produces extremely sharp edges.
Types of Rocks
Igneous - Form from cooling melts
Keys: Interlocking crystals
Sedimentary - Form from lithification of sediments.
Keys: Composed of clasts of other rocks
Metamorphic - Form from the deformation of pre-existing rocks due to heat and pressure
Keys: Foliation (apparent stacking or banding)
Stress
Force applied to an object. Can be Compressional, Tensile, or Shear
Strain
Deformation of an object in response to stress.
Elastic Deformation - Returns to original shape after stress is removed
Plastic Deformation - Permanent alteration
What causes volcanic eruptions?
Geodynamo system
Ring of Fire
Where the majority of earthquakes and volcanoes occur; massive subduction, many small plates interacting, high speed plate movement
Magma
Molten rock beneath surface
Lava
Magma on surface
Viscosity
Low = fluid
High = rigid
Think of as synonym for “chunky”
Higher heat = low viscosity
Silica
Low amount = lower viscosity
High amount = higher viscosity
Mafic Eruptions
Low SiO2, low viscosity, high temp, low gas
Felsic Eruptions
High SiO2, high viscosity, lower temperature, high gas, explosive
Basalt
Volcanic rock resulting from mafic eruptions
Pillow Basalts
Form in water
Hawaiian Eruptions
Very lava flowy
Strombolian Eruptions
Fountain
Vulcanian Eruptions
Essentially a geyser
Surtseyan Eruptions
Lava erupts into a body of water
Plinian Eruptions
Big, explosive, mushroom cloud
Cinder Cones
Small-volume, usually mafic and composed of pumice/scoria. Monogenetic
High amount of gas in eruptions
Step 1: Cinders. Step 2: Lava
Lava seeps out of the side
Shield Volcanoes
Large, broad, high volume. High fluxes of basaltic lava: polygenetic
Fissures
Less viscous lava erupts and spreads out from large crack. Example: Mid-Ocean Ridge basaltsCan lead to flood basalts
Composite/Strato-Volcanoes
Large, steep-sided volcanoes produced from many eruptions of pyroclastics and lava flows. Polygenetic
Domes
Low volume blisters of high-viscosity, intermediate to felsic magma that ooze to the surface
Craters
Created as rising magma encounters groundwater; the water flashes to steam and explodes. Monogenetic
Calderas
Biggest eruptions; multi-vented
Magma Sources
Divergent Plate Boundaries - Crust pulling apart allows shallow magma to ooze to the surface as a result of decompression melting.
Subduction - Introduces volatiles into the upper mantle (H2O, organic matter, gases) and lowers the melting temperature of magma
Hotspots
Related to mantle plumes
Debris Avalanche
High volume volcanic landslide triggered by earthquake, over-steepning or heavy rainfall. Released lateral blast at Mt St Helens
Lahar
Dense flows of water, ash, mud and rock. Caused by melting snow/glacier; historically most deadly result of volcanoes. Big dangers: long run out distance, moves very fast, low chance of survival
Toxic Gases
Volcanoes emit toxic gases such as SO2 - Sulfur Dioxide, H2S - Hydrogen Sulfide (Rotten egg smell)
Phreatic Explosion
Occur when ground water flashed to steam by magma in the subsurface; no fresh material
Pyroclastic Flow
Dense cloud of ash, lava, hot gases. Moves up to 450 km/hr. Form from a collapsing eruption column or from collapse of a lava dome
Secondary Hazards
Small earthquakes - Earth rumbles at low frequency (episodic trembling) during volcano quakes
Tsunamis
Starvation: Ash kills crops and livestock
Ground Deformation
Inflation of change in tilt indicates fresh magma moving in under the volcano. Measurements made with tiltmeters and GPA networks
Sulfur Dioxide Measurements
COPSIC measures concentration of volcanic gas; increased gas emission correlates with volcanic activity
