earth sciences Flashcards
What are earths three layers
the crust, the mantle, the core
Which layer is the hard outer layer of the earth
The crust
Which layer is the thinnest layer
The crust
Under the oceans what layer is only about 5 km deep
The crust
Under most of the land what layer is about 30 km deep
The crust
Under mountains what layer is about 100 km deep
The crust
What is under the crust
The mantle
Which layer is very thick and is about 2900 km thick
The mantle
Describe the outer part of the mantle
It is cooler and more solid than the inner part
What forms the lithosphere
The cooler outer part of the mantle and the crust together
Where is the Mohorovicic discontinuity
Where the upper part of the mantle ends and the liquid part begins
The mantle is also called
The mesosphere
What is the mantle made up of
Liquid rock
What is the layer just below the lithosphere And is made of liquid rock that is more like liquid plastic
The asthenosphere
What is the core also called
Centrosphere
What layer is the very inner part of the earth
The core
Core has two parts what are they
The outer core and the inner core
What is the outer core And how thick is it
It’s liquid and about 2200 km thick
Is the inner core and how thick is it
It is solid and is about 1250 km thick
What creates earths magnetic field
The liquid outer core spins against the inner core
What is sial
It is the lighter materials and is composed of mostly silicon and aluminum
What is sima
It is the dancer material that is composed largely of silicon and magnesium
What does sial form
The continents and landmasses
What does sima form
It forms the ocean bottoms
Is the most common rock in sial
Granite
Most common rock in sima
Basalt
What is Isostasy
The balance or equilibrium achieved when one thing is in balance with another
Is the theory of Isostasy
The earth is surrounded by a layer of sima In a continuous shell. On the slayer blocks of sial Float. New land is always being made and all the land is always being worn away this means that the weight of the sial Is always changing, so balance cannot be found
What is the continental drift theory
300 years ago all the continents were attached informed one large continent called Pangea
Who suggested the continental drift theory
Alfred Wegner
Is some evidence of continental drift
What’s the line fit, geological fit, paleoclimatology, Paleo glaciation, fossil correlation, palaeomagnetism
why didn’t other scientists believe Wagner
Is evidence was only circumstantial, he could not explain how the continents moved.
What is subduction
IThe process that occurs when two tectonic plates come together. One plate goes up, and the other goes down. The plate that goes down is said to be subducting, and the part of the cross that is going down goes to the mantle, where it melts and becomes magma
What are the three basic types of rock
Igneous/ fire rock, Sedimentary/layers of dust, Metamorphic/rock that changes physically or chemically
What are the main processes that change rock
Erosion heat and pressure
What happens to magma when it crystallizes
Becomes igneous rock
What happens if the igneous rock is subducted and is moved back into the mantle
Melts and becomes a magma again
What happens if igneous rock experiences heat and pressure
It may change its form completely and become metamorphic rock
What happens if igneous rock is eroded
The particles break away and become sediments
What happens when sediments from eroded igneous rock experience great pressure
They harden into sedimentary rock
What happens when new sedimentary rock erodes
It becomes sediments again
Happens when sedimentary rock experiences heat and pressure
It changes into a metamorphic rock
Happens when sedimentary rock gets subducted
Melts into the mantle as magma
What happens to metamorphic rock when heat and pressure happens
The rock changes chemically or physically into a new type of rock
What happens when metamorphic rock Erodes
It becomes sediments again
Happens when metamorphic rocks get subducted
It melts into the mantle as magma
What Happens when plates move apart
Initially, causes rifts, later, plate formation (fault mountains, volcanoes)
What happens when plates move together
Plate Destruction-subduction (fold mountains, fault mountains, volcanoes)
What Happens when plates experience lateral movement
Causes violent movement also known as earthquakes
What is plate subduction
Two plates come together, the heavier plate slides under the lighter one, and the higher one slides up and over the heavier one
What happens when two plates make contact
Fold mountain is created
What happens when plates move away from each other and space is left between them
Becomes a valley or fills with water and becomes a Sea
Does an earthquake happen
One Plate will try to slide past another plate, friction will hold the plates in place, but pressure will build up. When the pressure to move is too much, the plates one move suddenly and quickly against each other
How Is a volcano made
Are you a small opening is made in the crust, the molten lava and other material build up a cone
The funnel shaped opening called
Crater
What are the three basic types of volcanos
Cinder cones, dome cones, composite cones
What Kind of volcanos are very explosive and cause a lot of destruction
Cinder cones
What Volcano has steep sides and a narrow base and grows very quickly
Cinder cones
Why are cinder cones not taller
Their eruptions are often so violent that they blow the whole top part of the mountain apart
What volcano is not explosive but rather thick magma oozes out and generally moves slowly
Dome volcano
What does a dome volcano look like
Wide base but low, gently sloping sides
What kind of volcano Steep sides when it erupts violently and a wide base when it erupts gently
Composite cone
What Are destructive affects of volcanos
- explosions, lava flows
- Tsunamis
- nuees Ardents (large dark clouds of hot steam and poison gas)
- earthquakes
- mudslides (mixture of ash and water)
What are benefits of volcanos
- Soils from mineral rich volcanic rock are great for farming after erosion has occurred
- Builds new land
What is a dike
Magma cools in a vertical crack
What is a sill
Magma flows between strata of sedimentary rock forms a thin but extensive sheet
What is a laccolith
A sill that is large enough to raise a dome shape on the surface of the earth
What is a batholith
Mass of magma that has intruded into a wide area and has no depth
What happens when the plates are put under stress
A fracture often occurs in the rocks
What is the line of fracture called
A fault
Does this fault look like
And on one side of the fall will go up and the other side will go down
What is the Cliffs called that the fault mountains create
Escarpment
What Is compression
When the plate is being pushed together
What is tension
When the plate is being stretched
What is shearing
When two plates slide past each other
When two plates push together, the lighter plate will slide upward and the heavier plate will slide down, what is this movement called
Reverse or thrust fault
What causes landslides
The cliff (the hanging wall) is heavier on the top, it will collapse, causing landslides
When two plates pull away from each other, one side will slide downward, what is this called
A normal fault
If the movement along the fault line is horizontal, no changes in elevation usually occur, what type of fault is this called?
Strike-slip fault
When tectonic plates are compressed, instead of breaking what else could happen
They can bend and warp
Can folding and faulting occur at the same time?
Yes
What is the upward part of the fold called?
Anticline
What is the downward part of the fold called
Sincline
Sometimes the fold becomes so big that it flops over, what is this called
Overturned anticline
What is weathering
The process by which rock breaks down into smaller pieces
What are the two types of weathering
Mechanical and chemical
What is mechanical weathering
The breakup of rock into increasingly smaller pieces, with no change to the chemical structure of the rock
What is chemical weathering
The disintegration or dissolution of rock. The chemical structure of the rock is changed
What is erosion
The process by which rock disintegrates, dissolves, or are broken down and the particles are carried away
What are three methods of erosion
Wind, water, glaciers
What are the four main causes of mechanical weathering
Temperature changes
Frost action
Root action
Animal and insect activity
How does temperature change weathering work?
During the heat of the day the rocks expand, but at night they contract. This process happens over and over again causing a huge stain on the rock. The strain will crack and break the rock
What speeds up temperature change weathering
The greater the temperature variation
How does frost action weathering work
Water get into crack and freeze, the freezing water expands and pushes against the sides of the crack making the crack a little bit bigger every time this happens. The crack will become so large that the rock will split apart
How does root action weathering work
As a root grows in the cracks of a rock it forces the sides of the crack to widen. After a while the crack becomes so big that the rock spilts apart
How does animal and insect activity weathering work
Animals and insects burrow or dig in the ground and let’s water into the ground. The water weather the rocks either by drag action or by chemical erosion
_________________ can cause rocks to dissolve
Chemical interactions
What takes longer chemical weathering or mechanical weathering
Chemical
Chemical weather happens faster where
In hot climates
Most chemical weathering is caused by what 3 ways
Oxygen
Rain water
Carbon dioxide
how does oxygen weathering work?
air links up with some elements of other rocks, an oxide is formed, the oxide is brittle and causes the rock to crumble.
How does rain water weathering work? (1st way)
Rain water can dissolve some minerals. The minerals wash out of the rock with the water, making the rock weak and crumble
How does rain water weathering work? (2nd way)
Rain water links up wth minerals in the rock and forms new substances, the new substances break away from the rock and the rock crumbles
Rain water weathering will faster weather___ _______________
On rocks which it lands on
What is creep
The sand particles are too large to be picked up so it rolls on the ground
What percentage of soil is moved by creep
25%
What is saltation
The soil particles get picked up and bounce off the ground
What percentage of soil is moved by saltation
50%
What is suspension
When soil particles are kept in the air by the wind
What percentage of soil is moved by suspension
25%
What is a u-shaped valley
V-shaped called frowned by rivers will fill with glacial ice which erodes the sides leaving a U-shaped valley
What is a cirque
A scooped out basin at the head of an alpine glacier valley
What is a tarn
A small mountain lake, that forms in a cirque basin
What is a horn
A sharp, jagged peak that forms when several cirques surround a mountain
What is an arête
A sharp ridge that divides two cirque basins
What is a col
Is created on the second advance of the glacier
What is a striation
When glaciers move debris across the surface of the earth, scratches, called straitions, are left on the ground, indicating the direction of the retreat of the glacier
What is a spillway
As water from a melting Glasgow flows over the land, it cuts deep valleys into the earth.
What is a till plain
Is a flat area of land where a glacier has deposited the till
What is till
Rocks after materials left behind for the retreat of the glacier
What is a terminal moraine
Material deposited by a glacier at the farthest point the glacier reached
What is a lateral moraine
Debris transported by a glacier that collects along the sides of the glacier
What is a drumlin
- a glacial landform that is made of till and is shaped like a tear drop
- it forms in the direction of the ice movement
- scientists don’t know how these are formed
What is an erratic
A dropped of rock from the melting of the glacier that carried it, these rocks are dropped off anywhere and look very out of place
What is a lacustrine plain
Fertile bottom of an ancient glacial lake that is now used for agriculture
