Geology Flashcards

1
Q

What happens at a Convergent Oceanic/Oceanic Plate Margin?

A

Deep Ocean Trench at Subduction Zone
Andesitic Volcanic Arc Caused by rising magma as crust melts below it
Benioff Zone Causing Shallow and Deep Earthquakes
Faster moving one subducts below slower one
Destructive as moving towards one another
Regional/Contact Metamorphism
Granite Batholith and Thrust Faults

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2
Q

What happens at an Divergent Oceanic/Oceanic Plate Margin?

A
Mountain Ridge-Mid-Atlantic Ridge
Basalt/Mafic Materials
Basaltic Shield Volcanoes
Transform Faults and Shallow Earthquakes
Magnetic Stripes
Constructive as moving away from one another
Rift Valleys
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3
Q

What happens at an Convergent Continental/Oceanic Plate Margin?

A

Oceanic Plate subducted below Continental Plate as Oceanic is more dense

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4
Q

What happens at an Convergent Continental/ Continental Plate Margin?

A
No Volcanoes
Big Mountains
Partial Melting of Deep Continental Crust
Batholiths
Silicic
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5
Q

Why do plates/rocks melt?

A

Temperature has increased
Pressure decreased
Saturated in water

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6
Q

What is the difference between acidic, mafic, medium and ultrabasic igneous rocks?

A

Acidic-More than 66% quartz content
Medium-66%-52% quartz content
Basic-52-44% quartz content
Ultrabasic-Less than 44% quartz content

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7
Q

The more quartz in a magma…

A

The more explosive the volcanic eruptions because the magma is sticky and viscous

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8
Q

What is the lithosphere?

A

The crust and the upper most solid mantle

Plates are made up of the lithosphere cracked into smaller pieces

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9
Q

What is the asthenosphere?

A

The magma below the lithosphere which allows for movement of the plates over lower part of the mantle

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10
Q

What happens at Conservative Plate Margins?

A

Plates are sliding past one another
Large Scale Fault Lines
Shallow Earthquakes

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11
Q

How might you support the land on either side of a road cutting?

A
Retaining Wall
Bolts
Anchor
Gabions
Drains
Fabric at Top
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12
Q

Tell me about V-Shaped Valleys

A

Formed in upland rivers, where they vertically erode the landscape to get to base/sea-level
Wider at top because material which falls of side of valley is taken away and eroded via abrasion and attrition
In places where the rocks are different hardness’s waterfalls will be formed, which may move backwards through the valley

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13
Q

Tell me about rivers in Lowland Areas

A

Form flood-plains, wide areas of land where the river meanders back and forth at a slow rate due to angle not so steep as nearer sea level

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14
Q

Tell me about U-Shaped Valleys

A

Formed by glacial erosion, where the ice cuts straight through the valley, not worrying about the path of the river, following a direct route down the hill
The ice plucks boulders and unconsolidated material from the valley floor, which gets dragged along with the glacier further eroding the base

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15
Q

Tell me about Super-Imposed Drainage

A

Rivers don’t follow underlying geology

Rivers form on overlying layer of rock which is then eroded away

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16
Q

Tell me about Plateaus

A

Flat layers of either igneous or sedimentary rocks which have a shallow dip and have a top layer which is harder than the surrounding rock form hills or mountains with very flat tops

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17
Q

Tell me about Scarps and Vales

A

Tilted beds of differing hardness in rocks lead to scarps or peaks being formed with vales in between
The sharply dipping side of these hills is the scarp slope and the shallower one is the dip slope

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18
Q

Tell me about Ridges

A

Long and narrow hills formed by rocks of different hardness’s (often dykes) being eroded slower than the surrounding rocks

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19
Q

Tell me about a Fault Scarp

A

Faults happen at rocks of different hardness and the fault marks the place the different rocks meet
The soft rock is the low ground, and the hard rock is the high ground

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20
Q

What is the difference between a concordant and discordant coast?

A

Concordant-Same rock facing the sea

Discordant-Different rocks facing the sea, so bays and headlands/high cliffs are formed due to softer and harder rocks

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21
Q

Tell me about Graptolites

A

Made up of stipes (body parts) and thecas (spikes)
As time went on and they evolved there became less stipes, their theca point outwards instead of inwards and theca become more complex, from straight lines to hooks
Shape of Stipe: Pendant (hanging down), to Horizontal, to Reclined (V-Shaped with theca on inside) to Scandent (standing up in straight line)

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22
Q

Tell me about ammonoids

A

Made up of the Body Chamber (the large part on the outside), then lots of small Chambers with Septa between them, circling inwards
Where the septa meets the shell there are suture lines
These line have become more complicated over time
The top bends are saddles and the bottom parts are lobes (like peaks and troughs in waves)

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23
Q

How are fossils formed?

A

Buried (often at bottom of sea) and then compacted
Oxygen, Hydrogen and Nitrogen leave body and soft body parts disintegrate
Hard parts are left, leaving a mould in rock when they dissolve
Then minerals come in mould to make perfect shape of old animal
You can also get dinosaur footprints fossilised

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24
Q

Which type of rock does Radiometric Dating not work and why?

A

Sedimentary rock, for it is fragments of other rocks so any kind of dating could be wrong
Having a certain element that has decayed in sedimentary rock may have done the decaying in another rock, so we can never be sure

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25
Q

What is a bed?

A

A single unbroken episode of sedimentary accumulation

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26
Q

What are bedding planes?

A

Where there has been a changed in sediment

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27
Q

What are laminations?

A

Thin layers less than 1cm thick

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28
Q

How is graded bedding formed?

A

Where rock has been dumped from a height

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29
Q

Tell me about cross-bedding

A

Formed in 2 ways, and is when there is lines across the beds, where the direction of the lines (going from top to bottom) is the direction of movement
Desert Dunes-Where sand carries small particles up the shallow side of the dune and then falls down the other (steeper) side and is collected there
River Beds-Current carries small particles which make lines

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30
Q

Difference between Catastrophism and Gradualism

A

Catastrophism is a natural disaster where things happen quickly and dramatically
Gradualism is a very slow and gradual change in Geology

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31
Q

From centre to outmost layer, list the structures of the Earth or layers of the Earth and tell me about them

A

Inner Core-Dense, hot and pressurized
Outer Core-Less dense
Both Cores-Causes Earths Magnetism and Spin due to Nickel and Iron content
Mantle-Causes Tectonic Plate Movement, largest layer
Crust-Thin and Solid

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32
Q

How is Granite Chemically Weathered?

A

Orthoclase Feldspar in Granite is broken down by hot
water leaving Mica and Quartz. Orthoclase Feldspar becomes China Clay or Kaolin which is used to make china and shiny magazines

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33
Q

How is Limestone made?

A

Sea Shells release their Calcium Carbonate which lithifies to form Limestone
Made in warm, brackish, shallow and still bodies of water, like lagoons

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34
Q

What is Corrosion?

A

Where rock fragments erode bedrock

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35
Q

What is Attrition?

A

Where rock fragments hit against each other

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36
Q

What is Abrasion?

A

Both Corrosion and Attrition

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37
Q

What is Hydraulic Action?

A

Where air is trapped in holes in rocks and squeezed by water

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38
Q

What is plucking?

A

Where ice freezes to bedrock and plucks away unconsolidated material like boulders

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39
Q

What is a load when it is in solution?

A

The load is dissolved in water

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40
Q

What is a load when it is in suspension?

A

Load is carried in main body of water and air

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41
Q

What is happening to a load when it is experiencing saltation?

A

Load is bounced along, sending next one into motion

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42
Q

What is happening to a load when it is experiencing traction?

A

Load is rolled or dragged along an eroded surface

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43
Q

What are the 5 Agents of Erosion?

A
Wind
Rivers
Gravity
Sea
Ice
James Bond
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44
Q

What is the difference between breccia and conglomerate and how are they formed?

A

Conglomerate has rounded rocks in it, while in breccia they are more jagged
Formed when rocks are deposited then squeezed together by pressure

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45
Q

Name the 4 types of Petroleum Traps

A

Anticline Trap
Fault Trap
Salt Dome Trap
Unconformity Trap

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46
Q

What is infiltration in hydrogeology?

A

When water enters and is absorbed by the soil

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47
Q

What is percolation in hydrogeology?

A

When water is absorbed by the rock

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48
Q

What is groundwater flow in hydrogeology?

A

When water in rocks moves towards and enters a sea or river

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49
Q

What is through flow in hydrogeology?

A

When water in soil moves towards and enters a sea or river

50
Q

What are porous rocks?

A

Rocks which allow water in due to gaps in between grains and cracks. They hold the water in the rocks, they have porosity

51
Q

What are permeable rocks and the opposite of that?

A

Rocks which allow water through them

Opposite is impermeable rocks, like igneous and metamorphic rocks and some sedimentary

52
Q

What are cuestas?

A

Hill or ridge with a gentle side and a steeper side (escarpment)

53
Q

What is an aquifer or artesian basin?

A

An underground water store in an underground basin

54
Q

What metal/substance makes up:
Halite
Galena
Chalcopyrite’s

A

Salt
Lead and Sulphur
Sulphides and Copper

55
Q

What metal/substance makes up:
Pyrite
Calcite
Haematite

A

Sulphides and Iron
CaCO3`
Very Pure Iron Ore

56
Q

Do acidic or basic igneous rocks have more quartz?

A

Acidic rocks have more quartz

57
Q

What minerals do acidic igneous rocks have in them?

A

Quartz, both types of feldspar, biotite mica

58
Q

What minerals do intermediate igneous rocks have in them?

A

Both types of feldspar, a bit of biotite mica, ferromagnesian minerals

59
Q

What minerals do basic rocks have in them?

A

Plagioclase feldspar, ferromagnesian minerals, olivine

60
Q

What is a volcanic pipe?

A

Tube linking magma chamber and outside world

61
Q

What is a volcanic neck?

A

Tube which lava comes out of, top bit

62
Q

What is a sill?

A

Underground rivers of magma, not horizontal intrusion of magma, but in fact always parallel to the sediments, unlike a dyke which cuts directly through the rock

63
Q

What is a lava flow?

A

An extrusive event where the lava flows on land

64
Q

How do you tell the difference between lava flows and sills?

A

Lava Flows-Bubbles (vesicles) at top of rock, grains are small, baked layer and xenoliths only at bottom
Sills-Xenoliths and baked layer at top and bottom, included fragments, medium sized grains, veins and intrusions at top and bottom of sill

65
Q

What is a xenolith?

A

Bit of country rock that has broken off or fallen into the batholith

66
Q

Why might you want to live near an andesitic volcano?

A

After ash breaks down on the soil it is rich with minerals and makes the soil fertile for growing of grapes, coffee and rice. Also you can find hydrothermal veins near the volcanoes which contain precious ores

67
Q

What gases are in volcanoes and what do they cause?

A

Water vapour, carbon dioxide, sulphurous gases which causes the volcano to propel ash into the air. Also, if gases run through cooling lava then pumice is created, rocks full of vesicles

68
Q

What is are stopes and adits?

A

Stopes-Tunnels dug along the line of a hydrothermal vein, directly digging at the vein often at steep angles
Adits-Tunnel driven in at a hillside at a low angle to get to the vein

69
Q

Name some acidic rocks and the acidic type of magma

A

Granite, rhyolite, obsidian and granitic magma

70
Q

Name some intermediate rocks and the intermediate type of magma

A

Andesite (finely grained), obsidian and andesitic magma

71
Q

Name some basic rocks and the basic type of magma

A

Gabbro, dolerite, basalt, obsidian and basaltic magma

72
Q

What is a phenocryst?

A

Large crystal in a rock which is porphyritic in texture and is formed due to a slow cooling of an igneous rock when intrusive, and then cooling quickly on the surface if it reaches it without fully crystallising

73
Q

What is a baked margin?

A

Occurring at a sill, dyke or lava flow, it is where the country rock close to the heat of the magma have been altered. On the outer edge of the s d or lf

74
Q

What is a chilled margin?

A

Igneous rocks at the edge of an igneous intrusion which have cooled quicker and has smaller crystals than the centre of the intrusion

75
Q

Name some metamorphic rocks

A

Marble, schist, slate, chiastolite slate (slate with white lines of chiastolite), gneiss, metaquartzite

76
Q

What are the controlling features of metamorphism?

A

Heat, pressure, time and the parent rock

77
Q

Tell me about contact/thermal metamorphism

A

Always caused by an igneous intrusion such as a sill, dyke, laccolith or batholith. The rocks have crystals varying in size. The area around the intrusion which gets changed is called a metamorphic aureole. Mainly heat changes it as pressure doesn’t change much

78
Q

Tell me about regional metamorphism

A

Always caused by pressure and heat. Caused by plate movement, where 2 plates, usually continental are moving together creating an orogeny. It causes large amounts of rocks to change under the pressures of the plates and mountains above it as well as the heat from being close to the asthenosphere

79
Q

What is interesting about rocks which have been regionally metamorphosed?

A

They have lines or folds such as foliation or schistosity
OR
Cleavage on rocks such as slaty cleavage

80
Q

What metamorphic rock does sandstone, limestone, mudstone and shale, and igneous rocks make?

A

Sandstone-Metaquartzite
Limestone-Marble
Mudstones and Shales-Contact makes Spotted Rock and Hornfels while Regional makes Slate, Schist and Gneiss
Igneous-Little Change

81
Q

Tell me about shale when it gets metamorphosed

A

Little Heat-Spotted Rock
More Heat-Spotted Rock
Lots of Heat, Near Intrusion-Hornfels

82
Q

Name the 4 types of stress

A

Confining-Equal squeezing on every side
Tensional-Pulling apart of rock
Shear-Top being pushed one way, bottom being pushed in the other (rhombus)
Compressional-Squeezing on 2 sides, pushing together

83
Q

What happens in a normal fault?

A

Rocks being pulled apart, hanging wall is fatter at bottom and goes down and foot wall is fatter at top and goes up

84
Q

What happens in a reverse fault?

A

Rocks being pushed together, hanging wall is fatter at the top and goes down and foot wall is fatter at bottom and goes up

85
Q

Tell me about thrust faults

A

Reverse faults at a very shallow angle, less than 45 degrees so top rock slides over other in the end

86
Q

Name the 4 types of dam

A

Embankment Dam-Arch Dam-Gravity Dam-Buttress Dam

87
Q

What is the direction of dip?

A

The direction the lower side of the fault is on

88
Q

If the fault angle is almost flat, is the dip angle more or less than 45 degrees?

A

Less than 45 degrees, the dip angle is 0 at horizontal

89
Q

Which side of a fault is the downthrow side on?

A

The direction opposite to the direction of the arrow pointing downwards

90
Q

If a fault is a horizontal, is is thrust or normal/reverse?

A

Thrust

91
Q

What type of tectonic stress creates a thrust fault?

A

Compression

92
Q

What level of hardness and above can not be scratch by a fingernail, copper coin and steel?

A

Fingernail-Mohs level 2.5
Copper coin-Mohs level 3.5
Steel-Mohs level 5.5

93
Q

When talking about sea level change, what words must you use?

A

Eustatic and Isostatic

94
Q

What does eustatic sea level change mean?

A

Global sea level change?

95
Q

What does Isostatic sea level change mean?

A

Local sea level change

96
Q

How are earthquakes measured?

A

Mercator scale-use of building damage
Richter scale-use number
Seismometers

97
Q

Is there a high or low heat flow at divergent plate margins?

A

High heat flow

98
Q

What type of rock is associated with rock erupted along a mountain chain near a convergent ocean-continental plate margin?

A

Andesite

99
Q

What type of rock do you associate with rock erupted at a divergent plate margin?

A

Basalt

100
Q

What type of rock is associated with rock intruded beneath a mountain chain as a result of melting of continental crust?

A

Granite

101
Q

What type of rock is associated with rock formed by recrystallisation of shale due to heat and pressure in a mountain chain?

A

Slate

102
Q

Where is an earthquake’s focus and epicentre?

A

Focus-Deep below surface, in crust, where the movement takes place
Epicentre-Location on surface which is directly over the focus

103
Q

What are seismic waves and seismometers?

A

Waves of energy emitted by the focus
Seismometer-Measures movement of ground, placed on country rock with a pen on a piece of paper so any shakes come up on the paper. This line is never straight as there are constant shakes

104
Q

Which waves come first in an earthquake?

A

Primary Waves, then Secondary Waves, then Surface Waves

105
Q

Describe Primary Waves

A

Push movement in rocks creating different distances between beds-it moves through solids and liquid

106
Q

Describe Secondary Waves

A

Moves land up and down, there is a fluctuation in levels of solid rock only (not liquids)

107
Q

Describe Surface Waves

A

Mix of Raleigh Waves and Love Waves with up and down movements and side to side movements as well. This type of wave is very damaging, going through crust

108
Q

What are some of the impacts of earthquakes?

A

Death, destruction, liquefaction, sewage pipes breaking, buildings falling over, fires, ruptured gas pipes, ind

109
Q

Why are fossils important?

A

They prove evolution and tell us about the history of our planet. It tells us about extinctions and what the environment and food and animals were like in the past

110
Q

Tell me about the Burgess Shales

A

Prove the Cambrian explosion of life by the way it preserved some soft body parts of animals. It contained many trilobites, as well as Hallucigenia and a 1m long animal called Anomalocaris. Found in the Canadian Rockies

111
Q

When were the 2 biggest mass extinctions?

A

250 million years ago and the K/T Mass Extinction

112
Q

Tell me about the greatest mass extinction

A

250 million years ago Pangea developed causing coastline to disappear. Also there was a great amount of eruptions in Siberia causing the atmosphere to change. This caused 80%-90% of life to disappear

113
Q

Tell me about the K/T mass extinction

A

65 million years ago a meteorite struck the Earth blocking out the sun with dust for months or years. Also the meteorite put a lot of sulphuric acid into the air and Indian volcanoes started furiously erupting. 60%-70% of life died

114
Q

How do you tell archosaurs from thecodontion from dinosaurs?

A

Legs become more under body as time goes on

115
Q

Tell me about the K/T extinction of dinosaurs?

A

Comet on collision course to Earth (Chicxublub) which polluted atmosphere with carbon monoxide and sulphur gas

116
Q

Why is the Hominoid Lucy useful and where was she found?

A

She had a knee joint which were stronger and a pelvis, which showed she walked upright. She is 3 million years old and was found in Ethiopia

117
Q

Tell me about raised beaches

A

Isostatic movement, where ice presses down land (and a beach is formed) and then the ice melts and the land rises up again, causing the original beach to be higher

118
Q

Tell me about a submerged forest

A

Eustatic, forest is seeded and then sea level rises so forest is submerged

119
Q

Tell me about drowned river valleys?

A

Also called rias or fjords (u shaped valleys flooded), where eustatically sea level rises after a valley is formed

120
Q

What does an ice core tell us?

A

Science people can drill through ice to where it has frozen thousands of years ago and see the CO2 bubbles in it, to compare the content in the air then and now

121
Q

3 ways to have less CO2 in the atmosphere

A

Find alternatives to fossil fuels. Individuals doing their bit (recycling). CCS (carbon capture and storage)

122
Q

Tell me about CCS

A

CO2 is captured in filers in factories outflow pipes of the gas. Cooled and condensed for transport. Transported to underground impermeable oil or gas deposits via oil rigs