Geology

Brittle

- cold break=faults

Rock cycle

- the progressive transformation of Earth materials from one rock to another

What are the two important processes involved in lithification of sedimentary rocks?

Cementation and compaction

In a collision between two continental plates, can a continental plate subduct? Why or why not?

Continental plates are too buoyant to subduct.

What do you think will happen to the location of Los Angeles with continued activity along the San Andreas Fault over a long time span?

Los Angeles will slide to the northwest.

What is the difference between magic and felsic?

Mafic lava is less viscous(runnier) than felsic lava due to a lower silica content. This causes non-violent eruptions such as in the Hawaiian Islands. Mafic lava tends to be associated more with interplate volcanism and mid-ocean ridges and produces the rock type known as basalt.

Why are volcanic chains associated with convergent boundaries?

Partial melting occurs due to subduction.

The western edge of the Juan de Fuca Plate is a divergent boundary with a ragged, zigzag edge. (See the figure.) Which of the following describes the motion of the Juan de Fuca plate on its southern boundary at the Mendocino Fault?

The Juan de Fuca Plate has right-lateral motion with the Pacific Plate along the transform Mendocino Fault.

At a subduction zone where oceanic lithosphere meets continental lithosphere, which would subduct and why?

The oceanic lithosphere would subduct because it has a higher density at 3.0 grams per cubic centimeter.

Why are volcanoes NOT found at transform boundaries?

Transform boundaries do not cause changes to the pressure, temperature, or composition of the mantle.

Divergent boundaries are not one, smooth ridge of separation. Instead, they are broken into a series of segments, with different segments of fault offset from others. What features allow for the offset of divergent boundaries?

Transform faults

Beneath Earth's lithosphere, the hotter, weaker zone known as the _____ allows for motion of Earth's rigid outer shell.

asthenosphere

austrailia is composed of relatively old

continental crust

Intrusive igneous rocks are _____ and _____.

course grained and formed at depth

Which boundary is characterized as a long, linear rise in the seafloor, with shallow earthquakes and volcanic activity found along its length?

divergent boundary

Earth's surface is subjected to unusually high rates of weathering. The Moon and some of the inner planets of our solar system are also subject to surface weathering, but at much slower rates. Which of the following statements most reasonably explains Earth's uniquely rapid weathering rates?

earth has running water at the surface

the earthquakes that occur in southern california generally occur above a

fault

______________such as gneiss, phyllite, schist and slate which have a layered or banded appearance that is produced by exposure to heat and directed pressure

foliated

igneous

freezing of a melt (lava/magma)

Igneous rocks of felsic composition have __________ and __________ relative to mafic igneous rocks

greater silica; lower melting temperature

What are the two most important driving forces of metamorphism?

high heat and pressure

Old faithful at yellowstone acquires it energy from a

hot spot

metamorphic rockincreasing heat/pressure differential stress (solid state changes)

increasing heat/pressure differential stress (solid state changes)

What is the theory of plate tectonics?

independent plates moving with respect to one another

At a subduction zone, melting is triggered by _____.

introduction of water

_____ igneous rocks are those that cool below the surface.

intrusive

Plate A has oceanic lithosphere on its leading edge that is 10 million years old. Plate B has oceanic lithosphere on its leading edge that is 200 million years old. Which plate will be subducted if they collide with each other, and why?

Plate B will subduct because it is older—and therefore colder—and more dense.

Which fault in Southern California was created by the sliding of the Pacific Plate past the North American Plate?

San Andreas Fault

Divergent

mor, oceanic or continental

_________________such as marble and quartzite which do not have a layered or banded appearance.

nonfoliated

Crustal rifting is currently occurring in East Africa. Which of the following features would you expect to find there?

normal faults; long wide valley; lava flows

convergent

oceanic or continental, subduction, continental volcanic arces, mountain belts

In general, where do volcanoes form in subduction zones?

on the overriding plate, away form the convergent boundary

An igneous rock with a ______ texture solidified deep within Earth.

phaneretic

Ductile-stress

rocks bend flows/fold

layered_________________ exposed by erosion can be seen when looking a the grand canyon

sedimentary rock

Magma is made up of ________.

solids liquids and gases

What forces drive plate tectonic motion?

subduction of cold dense lithosphere connective flow at the mantle

The two most important criteria used for classifying igneous rocks are ______.

texture and mineral composition

Deep-ocean trenches are formed by _______.

the subduction of lithosphere into the asthenosphere

Rocks are produced and destroyed in many different environments T or F

true

T or F...Any rock can be transformced into any other rokc

true

sedimentary rock

weathering transport deposition lithification (detrital/clastic/chemical/biochemical) digenesis

What does aphanetic mean?

a fine-grained igneous rock having such compact texture that the constituent minerals cannot be detected with the naked eye

The East African rift is a divergent plate boundary that is splitting the continent of Africa into two pieces. What will eventually form around this divergent boundary?

an ocean