Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Geo > Rocks And Weathering > Flashcards

Rocks And Weathering Flashcards

1
Q

Oceanic Crust

A

6 - 10km
3g/cm3 (density)
Basaltic
200 million years old (younger)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Continental crust

A

35 - 70km
2.7 g/cm3
Silica, oxygen, aluminium
1500 million years old (old)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Tectonic plates

A

Sections of the lithosphere that move as a single unit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Sea floor spreading

A

The formation of fresh areas of oceanic crust which occurs through the upwelling of magma at mid ocean ridges

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Benioff zone

A

A zone of earthquake foci caused by a subduction oceanic crust

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Accretionary wedge

A

Where sediment on the ocean floor and some of the oceanic crust are scraped off and forced onto the other plate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Metamorphosis

A

When rocks compress and form new rocks under high heat or pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Epicentre

A

The point of the surface directly above the focus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Transform fault

A

When 2 plates slide past each other causing friction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Convection current

A

The rising, spreading and sinking of the mantle driven by heat by the core

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Weathering

A

The disintegration of material in situ

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Mechanical (physical) weathering

A

Rocks broken down without a change in the composition of the rock

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Chemical weathering

A

Rocks are broken down by chemical reactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Regolith

A

The name given to weathered material

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Scree

A

The collection of weathered material on a slope

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Talus

A

Broken down material that remains next to the original rock

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Joint

A

Fracture in rocks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Fissure

A

A large scale weakness in a rock

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Batholith

A

A rock formed underground by cooled magma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Exfoliation

A

Outer ,Ayers of rock that are weathered and peeled away

21
Q

Block disintegration

A

Sedimentary rock weathers in large sections (homogenous rock eg limestone )

22
Q

Granular disintegration

A

When rocks break away in small fragments ( heterogenous rock eg granite)

23
Q

Diurnal temperature range

A

Different in lowest and highest temp during the day

24
Q

Thermal expansion + contraction (type and describe)

A

Mechanical type of weathering
- absence of clouds
- suns heat causes outer layers of rock to expand
- radiation cooling at night causes rock to contract
- repeated daily causes outer layers of rock to be weathered

25
Oxidation
Chemical - when rock contains iron, water is present, oxygen is present in soil or atmosphere - iron (Fe) oxidises to produce hematite (Fe2O3) or magnetite (Fe3O4) rusting
26
Vegetation root action
Mechanical - roots have ability to grow in cracks and joints in rock - force cracks and joints to widen overtime - causes rock to break apart
27
Organic weathering
Chemical - humus is dark organic matter formed from plant and animal decays - during decay, humid acid is released - humid acid contains organic chelating agents like peptides and sugars - these extract metal ions from minerals and rocks
28
Carbonation
Chemical - CO2 is dissolved in water forming **carbonic acid** - carbonic acid reacts with calcite (calcium carbonate) forming calcium bicarbonate (calcium hydrogen carbonate) - calcium bicarbonate is soluble (forms limestone pavement) Occurs with chalk and limestone
29
Frost shattering / freeze thaw
Mechanical - when water in joints freezes at 0 degrees - fluctuations around freezing point - water expands by 9% when frozen - pressure causes rocks to break
30
Pressure release
Mechanical - huge pressure releases occur when layers of rock or ice that lie on top of another rock are removed - lower rock expands as pressure decreases and fractures occur along lines of weaknesses (bedding planes) - can eventually break off, called exfoliation joints
31
Hydrolysis
Chemical - feldspars make up 40% of the earths continental crust - reacts with acidic water, forming kaolinite which can be dissolved
32
Salt crystallisation
Mechanical - water evaporating leaving salt crystals - temp rises, salt crystals expand and exerts pressure on rock - in areas 26 - 28 degrees, sodium sulfate and sodium carbonate expands by 300%, forcing joints to crack opem
33
Wetting and drying
Mechanical (common at coasts) - clay rich rocks are pront to expand when they’re wet and contract when dry - creates cracks which are vulnerable to freeze thaw and salt crystallisation
34
Hydration
Chemical - additional of water to rocks, clays or soils - some minerals increase in volume - anhydride expands by 0.5% to become gypsum
35
Slope
An inclined surface
36
Slope evolution
The development of slopes overtime
37
Slope form
The shape of the slope in cross section
38
Slope processes
Activities acting on the slope
39
Unconsolidated sediment
Loose and not bound together material eg gravel
40
Rock juxtaposition
Ore resistant rock over less resistant rock
41
Heave / creep
Slow process where small particles eg soil zigzags down a slope due to expansion and contraction
42
Flows
When’s there’s a high water content and materials flow down a slope
43
Slumps
When there’s a high water content which lubricates a slope and a whole section moves down as one mass
44
Slides
Mass moves as a single block down a slope
45
Rock falls
Rapid fall of material down a steep slope
46
Surface wash (channelled flow)
When the soils infiltration capacity is exceeded and overland flow carries sediment creating cracks / channels on the surface
47
Sheetwash (unchannelled flow)
Areas of high velocity where material is dislodged by rain splash and water flows overland instead of in channels. Rills can form
48
Rills
A relatively shallow channel, generally less than tens of centimetres deep and carrying water and sediments for only a short period of time
49
Rain splash
The weight of raindrops dislodges material

Geo (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions