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