Midterm 2 study guide 1.2 Flashcards
Types of crust
Oceanic Crust
thinner, dense rock
Types of Crust
Continental Crust
thicker, less dense
Chapter 13, slide 18
When does rock become a rock?
Three Basic rock types
Igneous
formed by cooling and solidification of molten rock below the surface
Three basic rock types
Sedimentary
Rock is disintegrated into sediments
three basic rock types
Metamorphic
It’s when the original form of the rock is changed by heat and pressure
Intrusive rocks
surrounding rocks insulate, slowing cooling
Extrusive rocks
rapid cooling of lava
How does silica content affect mafic versus felsic rocks?
Felsic
Higher silica content such as granite makes them more viscous and lighter in color
How does silica content affect mafic versus felsic rocks?
Mafic
Lower silica means darker in color
How and where do sedimentary rocks form?
Rock is disintegrated into sediment and then build thickness and the pressure causes particles to interlock and cement. Primarily happens in riverbeds/ocean floors
Considering the rock cycle, how can one rock type turn into another?
Weathering, erosion, deposition, compaction, melting, and metamorphism
What evidence supports the theory of Continental Drift?
-Same land animals/species on two different continents
-two continents with the same geologic features such as africa and South America
-sea floor spreading
how do we know
Seafloor spreading
-When volcanic eruptions create new basaltic ocean floor and spreads away
-Paleomagnetism - past magnetic orientation of earth’s magnetic field reveals that the ocean floor was spreading away.
Plate boundaries
Divergent
Two plates diverge from one another
Plate boundaries
Convergent
location of two colliding lithospheric plates, one plate going down
Oceanic - continental
Oceanic - Oceanic
Continental - Continental
plate boundaries
Transform
two plates move laterally/vertically, boundaries neither create nor destroy crust
Hot spots
not associated with plate boundaries
caused by mantle plutes
produces flood basalts creating islands
why do volcanoes have different shapes
due to differences in magma and eruption style
Pyroclastics, why are they not magma or lava
tiny pieces of solid volcanic rock ejected in an eruption
What is folding, types of folding
Folding
Anticlines
Synclines
Crust becomes compressed
Anticlines - upfold, produces mountains or hills
Synclines - downfold, produces valleys
What is faulting, types of faulting?
Faulting
Normal Fault
Strike-slip Fault
structure is broken and one side is displaced (vertical or horizontal)
Normal fault - results from tension stress, very steep incline fault zone
Strike-slip fault - adjacent blocks moving horizontally, laterally to each other
Epicenter
Earthquakes
seismic waves in earth from sudden displacement along a fault line
epicenter - location on the ground directly above the origin of earthquake
