Geology Test 2

Define a rock

A rock is a coherent naturally occuring solid that consists of an aggregate of minerals or glass

Explain what coherent means as it pertains to rocks

must be able to be bronken into naturally smaller peices

What are the two types of rocks pertaining to how they are held together

Clastic Rocks and Crystalline Rocks

What type of rock has grains that are naturally bonded by minerals that are precipitated out of water? Typically sedimentary rock.

Clastic

What type of rock contains gains that are interlocked together like jig saw peices? Typicslly igneous and metamorphic rock

Crystalline rocks

Rocks are classified based on what? What are the three types

Rocks are classified based on origin. The three types are Igneous, sedimentary, and metamorphic

What type of rock is a solidification of molten rock (liquid state)

Igneous

What type of rock is cementation of grains or the precipitation of mineral crystals out of water

Sedimentary

What type of rock is pre-existing rocks that undergo change due to temp, pressure, or environent

metamorphic rock

What are the four variation sin physical characteristics one might se in rocks

-Grain size and shape

-composition

-texture

-layering

(Giorno complained too long)

Explain the physical characteristic of grain size

microscopic to large and simiarly shaped to elongated

(quant vs inequant)

Explain composition as it pertains to rocks physical characteristics

proportion of chemical make up (minerals )

Explain texture as it pertains to physical characteristics of rocks

texture

Explain layering as it pertains to the physical characteristics of rocks

alignment of grains. do they form layers.

What is true of the rock cycle?

it is a cycle of different types of rocks becoming other types of rocks based on environment, For example, withering down of igneous rock becomes sedimentary rock, burial and heating up of sedimentary rock can lead to metamorphic rock. melting of metamorphic rock leads to igneous rock

What is true of igneous rocks

Igneous rocks MUST have molten liquid that cools.

What are the two type of igneous rock? What is the differnece

The two types are Intrusive Igneous Rock and Extrusive igneous rock

Intrusive igneous rock forms from molten magma UNDERGROUND

Extrusive igneous rock forms from molten lava at the SURFACE

What is true of the relationship between magma and lava

lavais magma that is at the at the surface.

What are the three ways in which magma forms

1)Decompression

2)Addition of Volitiles

3) Heat Transfer

Dio ate hotdog

What way is this that magma forms:

-pressure prohibits melting

ex: hot spot. _____ occurs and allows the mantle material to come up in an isolated spot due to it being an area of decreased pressure

Decompression

What way is this that magma forms?

-substances such as water (H2O) and carbon dioxide (CO2) react with hot rock and reduce the melting point

Ex: water from subducting material at a convergent boundary helps to create melting

Addition of Volitiles

What way is this that magma forms?

-heat from rising magma transfers high temperatures into adjacent materials

ex: magma body atbase of the crust transfers heat into the rock

Heat transfer

What are the two primary types of igneous melting? explain each

Feisic and Mafic.

Faisic relates to rock in crust. HIGH silica content.

Mafic has lower silica content and Fe and Mg as well. Oceanic crust.

What leads to differences in magma

composition based on where it comes from.

Source magma tends to become _____ felsic

more

What are the three controlling factors of magma movement

1) magma is denser than rock so it is buoyant (wants to move to the top)

2) pressure will squeeze the molten rock

3) silica content controls resistance to flow (viscosity)

If you have increased silica it will be ______ and is associated with _____

thick and viscous, felsic

If you have decreased silica, it willo be _____ associated iwth ______

thin and runny, mafic

What type of rock does this describe:

-located at or near surface, cools too fast to form crystals

-Mafic melt is typical lava flow

-felsic melt is typical volitiles and more explosive (more massive volcanos)

Extrusive Igneous rock

Which rock does this describe:

-located at depth and cool relatively slow which allows crystals to have time to grow

-typically intrudced as tabular sheets or blob shaped

-ex: dikes and sills

Intrustive Igneous Rocks

'‘blob shaped’ rocks are called ______ and later ____ if 100s of kilometers long

plutons or batholiths

what rock are you likely to get with rapid cooling

obsidian

What are the three factors of volcanic eruptions

1- lava flows

2-gas

3-pyroclastic debris

What type of volcanic eruption is described below:

-can be thin and runny or whick and viscus

lava flow

What type of lava flow is thin, runny, and basalt?

mafic (low silica content)

what type of lava flow is thick, viscous, rhyolite/andesite

felsic (high silica content)

Basaltic mafic lava flows create a shell as it cools known as a ______

lava tube

What are the types of basaltic lava flows? (general lava flows) (formations)

Pahoehoe

‘A‘ā

Pillow Basalts

Columnar Jointing

Flood Basalts

What type of basaltic lava flow is described:

-rope like ridges form

Pahoehoe

What type of basaltic lava flow is described?

angular rubbly flow. too viscous to create ropes

‘A‘ā

What type of basaltic magma flow forms underwater? Looks like pillars and is commmonly seen at midocean ridge

Pillow basalts

What type of basaltic lava flow is solid lava that shrinks as it cools to form polugonal columns that are hexagonal?

Columnar jointing

What type of basaltic lava flow is large volcanic eruptions that cver vast stretches of land with flow of mafic rocks? What is an example in the usa

Flood basalts.

Columbia plateau

Explain what forms when lava flows in areas with felsic rocks (andesite and rhyolite)

Higher viscocity due to more silica

Forms lava dome over vent

Mount St. Helens

All lava/magma contains dissolved gases also known as _____. What aspect of this plays a role in eruption?

volatiles.

amount significantly imapcts eruption.

Explain why volcanic gas from volcanos is dangerous

9% of magma is made of gas. Bubbles rise quicker in low viscosity (mafic) which reach surface before magma. Volatiles make volcanic eruptions bad. gasses are released when pressure decreases

Bubbles trapped in a solidified rock are called _____

vesicles

What is the term for solifidied fragments from an eruption?

Pyroclastics

What type of debris occurs when lava fountains can form due to expanding bubbles which produces cinders (lapelli or scoria) or largerblobs such as blobs and blocks

Basaltic Debris (mafic)

Whaat type of debris occurs when more viscous and higher content of gas (volatile) makes volcanos more explosive?

Andesitic/Rhyolitic Debris (intermediate to Felsic)

What are avalanche rocks called from Pyroclastic flow (ash of glass shards from intermediate to felsic)

Tuff

If snow/ice is present in high amounts, what is the mix of this and the debris called?

lahar

more felsic= more ______

volatiles

What are volcano types typeically defined by?

shape, size, and eruptive style

what are the 3 primary types of volcanos? What is the fourth secret type?

1)sheild volcanos

2)stratovolcanos

3) cinder cones

4)super volcanos

What type of volcanos are big, broad, and shaped like a sheild? Compose the biggest volcanos on the planet.

Very mafic and runny type of volcano

have very long lives

found at hotspots or along midatlantic ridges

Sheild volcano

What type of volcano is very steep and is what we typically think of when we think of a volcano?

-intermediate to felsic. toothpaste like

-highly explosive

-form near subduction zones.

-young lives, they don’t tend to last as long as sheild volcanos

Stratovolcano

What type of volcano is streep but very tiny? typically found alongside the other two volcanos. felsic.

-’young lives’

-FULLY MAFIC

-never found without the presence of other volcanos

cindercones

What type of volcano

-extremely eruptive

-generally exclusively felsic

-active plate techntonic boundaries very common for super volcanos

-include mount st.helens, krakatau, vesuvius

Super volcanos

What is the term for a circular depression at the top of the volcano formed from euption or collapse

craters

What is formed form collapse of magma chamber after a major eruption? not always circular and very large

calderas

name 5 volcanic hazards

1) lava flows

2) volcanic ash

3) pyroclastic flows and lahars

4) gases

5)tsunamis

Why is lava flow a hazard of volcanos?

-mafic basaltic lava can flow quickly and over great distances, which can bury houses, cars, and roads

-intense heat can create fires

What is the volcanic hazard of volcanic ash?

-abrasive, mildly corosive and harmful to eyes and lungs

-may disrupt transportation systems and damage jet engines

-is basically just shards of glass

explain the danger of pyroclastic flows and lahars

-concrete consistancy of lahar from rapid melting of snow and ice. can wipe out anything in path . really only felsic

-pyroclastic flow is an avalanche of hot volcanic ash.

explain the danger of volcanic gases

-lethal if exposed to certain types

-vog or volcanic smog

explain how and why tsunamis occur

tsumanis are generated by either underwater eruption, collapse of an underwater caldera, or a landslide form the flank of a volcano

What are the three classifications of volcano based on activity?

Active, Dormant, and Extinct.

Active volcanos are currently, recently, or likely to erupt, Have an active magma chamber.

Dormant volcanos may not have erupted for thousands of years, but may again someday

Extinct volcanos will never erupt again. Magma gets cut off

How can one monitor an active or dormant volcano?

Monitoring seismic activity. Earthquakes serve as a sign that a volcano may erupt soon. Seismogram is the spectific tool used

Where is the biggest volcano in our solar system located?

mars (it is no longer active)

Explain the geological differences of the moon as it pertains to volcanos. Why does it look how it presently looks?

the lighter part of the moon is more felsic. Darker is more mafic. Dark parts of the moon are from volcanism caused by magma that seeped out of the core when impacts occured.

Define Sediment

Sediment is loose unconsolidated materials made out of

!) fragments of rocks or minerals broken off bedrock

2) mineral crystals that precipitated out of h20

3) shells or fragements of shells

What does it mean for an uplift to occur

upward movement of Earth’s surface

What does it mean for a subsidence to occur?

sinking downward movmenet of Earth’s surface

What does it mean for Erosion to occur?

Grinding away and removal of material

What does it mean for Deposition to occur?

accumulation of transported sediment

Thought the process of weathering, existing rock can be broken down one of what 2 ways?

1)physical/mechanical weathering

2)chemical weathering

What are the 7 types of physical weathering?

1)Abrasion

2) Jointing

3) Frost Wedging

4) Salt Wedging

5) Root Wedging

6) Thermal Expansion

7) Animals

Name the type of physical weathering that is caused by the movement of sediment that are grinding against each other, which can then break down that material (primarily by h20, but also wind, ice, gravity)

abrasion

Name the type of way that rock breaks down:

separation of rock along a natural crack into blocks or sheets, which eventually tuble downslope

Jointing

Name the type of way that rock breaks down:

whenwater in a joint freezes and then expands, which can eventually break rocks apart

frost wedging

Name the type of way that rock breaks down:

precipitation of salt into the pores or joints of a rock, which eventually expands and weakens the rock (not super common)

Salt Wedging

Name the type of way that rock breaks down:

joints in rock are pushed apart by tree roots

root wedging

name the way that rock breaks down:

intense heat (fire or sun) can expand the outer layer of rock, whcih can eventually break it apart

thermal expansion

name the way that rock breaks down:

burrowing, worms, diggins mammans, and human excavation

animals

What is defined as the altering, or distributing minerals through chemical reasctions when they encounter either water solution or air.

Chemical weathering

What are the four types of chemical weathering?

1)dissolution

2)hydrolysis

3) oxidation

4)hydration

What is defineed as the mienrasl in a rock are slowly dissolved, primarily salts and carbonate minerals (ex: acid breaking down limestone)

dissolution

What is defined as water reacting with minerals to break them down into other minerals (ex: feldspar to clay)

oxidation

What is defined as the absorption of water into crystal structures which causes some minerals to swell and weather to rock

hydration

Define Differential weathering

Rocks with the same exposure/outcrop weather at different rates due to varying physical/chemical properties. Shale vs limestone on interstate.