Lecture 1.1 Flashcards
What are Earths 4 spheres? Provide examples of how each interacts with one another?
Land- Lithosphere
Life- Biosphere
Water- Hydrosphere
Air - Atmosphere
What is geology? Physical Geology?
Is the discipline that studies the planet earth.
Physical geology examines earth materials and seeks to understand the many processes that operate on our planet.
How old is the Earth?
4.6 billion years old
What is the Richter Scale?
[ground displation ]
How strong the magnitude is ( 10^2 , 10^4 etc)
How does geology influence where we live?
-Rivers
-Flat land
-Type of soil
-Avoid earthquakes, landslides, volcanic eruptions , flood events
What’s the difference between the craton vs stable platform vs shield?
The stable interior is a Craton, composed of continental shields, that has a stable platform ( sedimentary rock)
Understand continental shelf vs slope vs rise
land——shelf
slope
rise
What are elements? Atoms? What are the different components to an atom? be able to draw and label the structure of an atom.
Elements: Are the most fundamental substance into which matter can be separated chemically.
Atoms: Are the smallest unit of an element that has the property of the element, protons, neutrons, and electrons.
Calculate/ determine the Atomic Number. Determine the element given the Atomic Mass.
Atomic Number; Number of protons in the nucleus.
( CARBON HAS 6 PROTONS [ ATOMIC NUMBER IS 6])
Atomic Mass; Mass of Nucleus ( PROTONS + NEUTRONS)
What are isotopes? Be able to identify an isotope given the atomic number and atomic mass and/or atomic structure of an “unknown’ element.
The number of protons in the atoms of each element is constant, but the number of neutrons may vary. Atoms with different mass numbers are known as isotopes of the element.
Why are elements important? What are anions? Cations?
Outermost electrons determine the chemical behavior of an element. Anion: negative charge
Cation: Positive charge
Name and describe the different chemical bonds.
Ionic Bond: Transfer of ( gain or loss) of electrons, between metal and non-metal.
Covalent Bond: Sharing of electrons between two atoms, typically non-metals.
Metallic Bonds: Free-state electrons hold together positive metallic ions. MOST IMPORTANT
What is it about water that makes it such an important agent for weathering/erosion on earth?
-Asymmetrical charge makes it very effective in dissolving ionic bonds, effective at weathering rocks and minerals.
-High heat capacity, takes a lot of energy, heat reservoir
What are the most abundant elements on Earth? Atmosphere? Hydrosphere? Biosphere?
Earth: O and Si
Atmosphere: N, O, Ar
Hydrosphere: H and O
Biosphere: H,C,N and O
What is a mineral?
- Crystalline structure
-natural
-Inorganic
-Solid
-Chemical composition
-Unique crystal structure
Understand and describe the different diagnostic properties of minerals.
-Crystal form: outward appearance (a geometric shape )
-Cleavage: Minerals tend to break along the planes of weakness in a crystal lattice, smooth ( 3 planes)
-Hardness: resistance to scratching or abrasion ( MOHS hardness scale )
Color: a variety of coloring, depending on its chemical composition * UNRELIABLE*
Luster: ( reflection, source of mineral )
Fracture: Random breakage, forming irregular surfaces.
Streak: color in powdered form.
What are rocks? What are the 3 “families” of rocks?
- Aggregated mineral particles
-Igneous
-Sedimentary
-Metamorphic
How are igneous rocks formed? Where are you most likely to observe igneous rocks on Earth?
-formed by cooling and solidification of magma or lava
-Internal thermal activities
-Extrusive, or volcanic rocks ( small crystals )
-Intrusive, or plutonic rocks ( big crystals )
What are the difference between extrusive and intrusive igneous rocks?
Extrusive: rocks formed by lava ( volcanic rocks)
Intrusive: rocks formed from magma at death or plutonic rocks
What are the 3 plate boundaries? Where might you find them?
-Divergent ( rift)
-Convergent ( subduction zone)
-Transform ( strike slip )
Explain Earth’s geothermal gradient. Why does it exist? How are we exploiting this “resource”?
- Temperature within the Earth increases with increasing depth.
-remnant heat from formation
-radioactive decay
-varies by tectonic setting
-Temperature increases 25 C/km
What is the difference between magma and lava? What is the source region for magma?
Magma: molten rock material, existing below the surface of the earth.
Lava: The surface form of magma, flowing across the surface.
Source: Ultimate source is from the mantle, partially melting in the lower crust and the upper mantle at the depth of 10-700 km.
How is magma chemistry affected during emplacement and en route to the surface?
-Assimilation: Host rock is dislodged
Crystallization & Setting: minerals settle, changing the composition of the remaining melt.
Magma mixing: younger magma body intrudes and mixes with older one.
What are the fundamental types of magma? What is Felsic vs Mafic?
Felsic( granite) : Typical crystallized minerals, quartz, feldspar, continental crust.[lower temp, higher viscosity]
Mafic( Basaltic): Olivine, pyroxene, average oceanic crust. [ Higher temp, high fluidity]
Intermediate( Andesitic): plagioclase and amphiboles.
Ultramafic( periodic): High magnesium, iron, average mantle material.
How does magma/lava cool? Explain the relationship between magma/lava cooling rate and mineral size ( texture ) ? How does cooling rate relate to intrusive vs extrusive volcanic rocks?
*Lose heat to air, water, or underlying rocks
- Circulating water
-Conduction into wall rocks
-Loses gases
* A large blob cools slowly
* A shallow sheet cools faster than a deep sheet.
Understand / explain the difference between aphanitic vs phaneritic vs glassy texture? What is porphyritic texture? What does it signify?
Aphanitic: fined grained, very small
Phaneritic: Coarse-grained
Glassy Texture: piece of glass, flash freezing of magma
Porphylitic: Big crystals, little crystals, two different cooling rates.
Explain Bowen’s Reaction Series?
Crystallization and melting process
What are volcanic necks?
Erosion explosions make a volcanic rock
- Devil’s Tower , WY
-Hard to walk up, easy to walk down
-Lose rubble
-Hexagonal shaped
What determines the violence of an eruption
-Composition
-Trapped gas
-Temperature
*Viscosity
Be able to identify and describe the different intrusive and extrusive, deposits/feature given a picture
-Ground formation will start to make a dome ( sill)
-magma trapped, can more horizontal
-Dikes run perpendicular
What is a caldera? How do Calderas form? Are there Calderas in the US( YES) ? What is the significance of the Yellowstone Hot Spot?
Caldera: Formed from multiple episodes of explosions. ( Collapsed crater)
*Lots of gases mixed with suspended clouds of ash and dust
What are metamorphic rocks? How do they form?
Transformed and deformed pre-existing rocks.
What is a protolith?
Parent( pre-existing) rocks that gets formed. [basalt-greenstone]
Explain contact metamorphism . Where is the most common?
*Heat from magma, an increase in temperature with depth-geothermal gradient.
Explain the difference between confine and differential pressure/stress
Differential stress is stress that is greater in one direction
Confining Stress is stress equal from all directions
How does pressure/stress affect the rock/ protolith? Why? Where is this most common?
Pressure/stress can have a profound effect on the texture of the rocks
Deep depths/conditions
What is Strain? Stress? What are the 3 Strain types?
Strain: change in shape or volume due to stress
Stress: force applied per unit area
3 Types of Strain: -Elastic ( non permanent)
-Ductile( does NOT break, flow/bend)
-Brittle ( does not return to original shape & it breaks )
What are the different types of stress?
-Confining Stress
-Tensional Stress
-Compressional Stress
-Shear Stress
Explain hydrothermal alteration? Where is it most common?
-Magma located to the surface
-Mid ocean ridges
-Divergent boundaries
-Water heats up, cold water sinks into crust, hot water rises , reacts with rock.
What is foliation? What are the different types of foliation?
Foliation is a planar fabric that cuts through the rock- Parallel alignment of platy mineral particles or alternating bonds
1) Slaty cleavage - fined grained ( thin layers)
2) Schistosity- coarse grained ( visible)
3) Gneissic Banding- coarse-grained and alternate ( black and white)
Explain how you can determine metamorphic grade from foliation? Index minerals?
Foliation type tells us the metamorphic grade, and so does the size of the crystals
What is regional metamorphism?
-Occurs over broad areas of the crust.
* have undergone deformation
What are the common metamorphic rock protoliths?
Slate: shale
Gneiss: Schist or Granite
Schist: Phyllite
Quartzite: Sandstone
Anthracite: Bituminous coal
Marble:Limestone
What are sedimentary rocks? How do they form? Why are they import
Rocks form at the earth surface and are composed of weathered rock and mineral fragments, minerals from chemical solution or organic matter ** Important host rocks for economic deposits of natural resources, they record clues of past chances in the biosphere, atmosphere, and hydrosphere.
What is physical weathering? Chemical Weathering? Precipitation?
Physical weathering: rocks that are physically broken/deteriorate ( Ex: freeze-thaw cycles )
Chemical Weathering: The chemical decomposition rocks ( CaCo3+H2CO3–>Ca+2HCO3)
Chemical Precipitation: The formation of minerals from supersaturated mixtures of chemicals ( Rock Candy)
What are the three primary ways grains move around in wind/water?
- Swept up and suspended
- Roll along the surface
- Skip along the surface ( Saltation)
*EROSION
Provide examples of modes of transportation
-Sorting
-Rounding
-Texture
-Composition
What is the difference between clastic and non-clastic sedimentary rocks?
Clastic: weathered rock and mineral particles
Non-Clastic: chemical or bio chemical particles
How is sedimentary rocked formed?
Loosen by weathering, transported by basin, where sediment is trapped, becomes compacted and cemented.
What are the common types of classic sedimentary rocks? Non-Clastic?
Sandstone
Shale
Siltstone
Conglomerate/Breccia
Nonclastic:
Coquina
Skeletal
Oolitic limestone
Micrite
Travertine
Chalk
How does coal form? Oil/natural gas?
Dead plant matter submerged in swamp environment –> forces of heat/pressure
What is a transgression? Regression? How does sea level rise/fall affect sedimentation.
Transgression: ( Sea moving in) - rise of sea level
-sequence: sandstone, shale, limestone
-Fining upwards sequence ( FUS)
Regression: ( Sea moving out ) -drop of sea level
-Sequence: limestone, shale, sandstone
-Coarsening upwards sequence ( CUS)
What do sedimentary structures reveal about the environment
Sedimentary structures are indicators that reflect the conditions of sedimentary environment.
fossils, ripples, cross bedding, graded bedding, stratification, mud cracks
Why are fossils important
provide important evidence for evolution and the adaptation of plants and animals to their environments
What types of natural resources may be found in sedimentary rocks?
-groundwater
-petroleum
-coal
-cement from limestone
-salt
-uranium
The tendency of minerals to break along planes of weak atomic bonds to produce flat, shiny, receptive surfaces is called?
cleavage
Which group of minerals is the most abundant and called “the rock forming minerals ?”
Silicates
Which of the following is NOT a mineral ?
Petroleum
Which of the following common minerals is sofest?
Talc
The single property that can be used to identify any mineral is
multiple properties must be used to identify a mineral
The melting associated with the addition of carbon dioxide (CO2) or water (H2O) to rocks is referred to as
addition of volatiles
Which type of magma has the greatest silica content?
Felsic
As compared to aphanitic igneous rocks, phaneritic rocks are
coarse grained
In the Bowens reaction series, the first mineral to crystallize from a mafic melt
Olivine
Which of the following accurately lists the rock in order from low to high metamorphic grade?
slate-phyllite-schist-gneiss-migmatite
Which of the following is NOT an example of non-foliated metamorphic rock?
Schist
A protolith subjected to metamorphism
may belong to any of the three primary rock types
Which of the following processes CANNOT induce metamorphism
Cementation and compaction of grains during diagenesis
Where would you expect to find metamorphic rocks forming
Deep inside a mountain range
A fine-grained clastic sedimentary rock that splits into thin sheets is
shale
When graded beds are observed in a rock outcrop, this tells geologists that a
Turbidity current deposited these beds, depositing coarser material first
Which transport medium carries the largest particles?
Ice in glaciers
The sedimentary rocks breccia and conglomerate most commonly form in a _____________ environment
Mountain stream
