Metamorphic
How does metamorphism happen?
decrease in pressure or addition of water WITHOUT MELTING
What kinds of deforming forces are there? Describe them.
Tensional: pulls rock apart
Compressional: pushes rock together
Shearing: pushes in opposite directions
Relative: The occurrence of one event in relation to another
Absolute: The number of years that have passed from that event to now.
What is uplift and what is subsidence?
Part of the crust that goes up and part of the crust that goes down.
What are the three main kinds of volcanoes?
+300 if you can draw and describe them.
Shield, Cinder Cone, and Strato/Composite
Shield = flat, lava flow
Cinder Cone = tall, pyroclastic material
Strato = mix of both
What are the two main types of metamorphism?
Contact and Regional
How does a normal and reverse fault move older and younger rock?
Normal: Younger below older
Reverse: Older above younger
What is a half-life?
The amount of time required for there to be a 50% chance that an atom decays.
How can continents grow?
+100 points for a definition for both.
Magmatic Addition: magma transferred to continents at subduction zones
Continental Accretion: plate motions attach different continents/landmasses together.
What are the three kinds of lava?
+200 if you can tell viscosity and composition.
Andesitic: Intermediate, both
Rhyolitic: Felsic, high viscosity.
What is confining pressure and what is directed pressure?
+300 if you can give examples for each
Confining: Pressure from all directions
Directed: Pressure from a specific direction
What kind of deformation happens at low pressure and low temperature?
Brittle
Can we date sedimentary rocks?
No, unless we date the cement.
Which is the "more exciting" part of geology- Orogeny or Epeirogeny?
Orogeny - magmatism, mountain building, faulting, metamorphism
What are diatremes?
Volcanic vent filled with rapidly cooled igneous rock that was exposed by the surrounding volcano eroding away.
How is foliation classified?
What kind of folding are domes and basins?
Domes: Anticline
Basins: Syncline
What is the difference between an angular unconformity, nonconformity, and disconformity?
Angular: Angular beds below flat beds of sediment
Non: Igneous/metamorphic below flat beds of sediment
Dis: Flat beds below flat beds of sediment
What is isostasy? What does it determine?
gravitational balance of the crust on the mantle that determines elevation
What is a hotspot? What is the difference between an oceanic hotspot and a continental hotspot?
A single plume of unusually hot magma from the mantle that stays stationary as the plates move above it.
Oceanic: Mafic magma
Continental: Felsic magma, because of accretion.
What are facies?
Groups of rocks of different mineral compositions based on pressure and temperature conditions that correspond to particular tectonic settings.
Show how we do strike and dip and give a definition.
Strike: Direction of the intersection of a rock layer
Dip: Angle at which the beds dip from the horizontal.
DOUBLE POINTS
What are the six principles and what do they mean?
Superposition: The oldest layers are at the bottom, and the youngest are at the top.
Original Horizontality: Sediments are deposited in nearly horizontal beds.
Cross-Cutting Relationships: Geologic features that cut across rock must be younger than the rock they cut through.
Inclusions: Objects enclosed in rock must be older than the time of that rock formation.
Lateral Continuity: Layers are continuous until encountering an obstruction.
Faunal Sequence: Layers of sedimentary rock contain fossils in a definite sequence.
How does the Wilson Cycle work? Draw it out.
Continental rifting -> mid ocean ridge formation -> subduction of an oceanic plate -> subduction pulls another plate closer -> converging plates -> new continent formation.
What kind of lava forms at divergent? What kind of lava forms at convergent?
Divergent: Basaltic
Convergent: All!