PHYSICAL - Rocks Flashcards

Question

Name 2 examples of physical weathering

Answer 1

**Freeze thaw**/frost shattering and **Exfoliation**

Answer 2

Carbonation, hyrolysis and solution

Answer 3

1. Water from rainfall or smow melt and ice becomes **trapped** in a crack or joint in the rock 2. If the air temperature drops below freezing, the water will freeze and **expand by 9-10 per cent** putting pressure on the rock 3. The ice will ment when the temperature rises above freezing 4. The process repeats and the rock will weaken and eventually shatter into **angular fragments** called scree

Answer 4

* In warm places (eg the desert) exfoliation occurs * In the day **only the outer laye**r of rock is heated as rock is a poor conductor * When its warm, it expands and when its cool (aka at night) it contracts. * This repeats and eventually the outer layer peels off (the presence of water helps weaken rocks and makes it more suseptable to flaking)

Answer 5

* Rainwater picks up Co2 from the air * The rainwater becomes a **weak carbonic acid** * Acidic rainwater reacts with calcium to form **calcium bicarbonate**, which then dissolves **limestone** and **chalk**

Answer 6

Water reacts with the rock to produce a different substance This occurs in **granite** and can produce clay, known and kaolin/china clay

Answer 7

Some **minerals** dissolve in rainwater, this is called solution.

Answer 8

* Granite is an intrusive igneous rock that forms underground form molten rocks which has cooled and solidified * The magma often forces its way along bedding planes in sedimentary rocks to form horizontal layers of granite called **sills** and up joints to form **dykes**

Answer 9

**A huge dome shaped mass of granite that can be hundreds of 100km across** After millions of years, the overlyaing rocks may be worn away to expose the batholith

Answer 10

* Contains crystals of **quartz, mica** and **feldspar** * Very **dense** and therefore not **porous** * It's **pervious** (as it cooled it contracted and cracks formed) * Relitivley **impermeable**

Answer 11

* Freeze thaw -- widens joints * Exfoliation in some places * Hydrolysis (water reacts with feldspar crystal and turns them into kaolin or china clay)

Answer 12

* Tors * Bleak and treeless * Relitively flat topped moorland plateaus * Thin acidic soil * Frequent rock outcrops eg bowermans nose * Costal scenergy where granite and atlantic bleakers meet * Moorland vegetation of bracken and heather * V-Shaped valleys from Dart and Teigh

Answer 13

* The rock has **horizontal cracks** caused by **pressure released,** and **vertical joints** caused by **cooling,** these are formed at irregular intervals * The granite breaks up more quickly where there is a **concentration** of joins and they are close togetherm because **water can enter the rocks and rapid weathering can take place** * Each time the water freezes and expands in the joint, pressure is put on the rock until the rock splits apart * This debris is removed by rainwater and gravity in the process of **solifluction** * Where there are fewer joints, it takes longer for the granite to break ip and so it **remains upstanding** on the landscape (the tor)

Answer 14

* **Building stone** eg kerbstone * **Headstones, kitchen work surfaces** - resistant, impermeable, looks nice when polished * After being attacked by hydrolysis, it forms **china clay** which is used in **pottery, paper** and **toothpaste**

Answer 15

* Over **90%** of land within the National park is farmed. * **Soils** are poor and acidic and the environment is harsh therefore crops don't grow well * Used for grazing livestock (cattle, sheep) * 34,878 acres are common land which sheep, cattle and horses graze on * Employs about **2000** people

Answer 16

* Dartmoor is ideal for reservoirs * Several mandmade reservoirs are there * Avon Dam and Burratir * Supplies water to Plymouth, Exteter and Torquay (which brings in money)

Answer 17

* Millions drawn by **scenery** and **attractions** * Popular areas: Hay tor, Yes Tor, Moorland, Lydford Gorge and Valley of the River Dart * Variety of wildlife * Dartmoor ponies * Old mine workings and historical museums

Answer 18

* Many come to cycle, walk, hike, picnic * Hosts activities that rely on its remoteness: Prison built (so if convicts escape, no were to hide and granite hard to dig through) * Use for Gold d of e * (Army uses it for practises)

Answer 19

* Origional cracks from cooling * Rocks appear stacked upon eachother * Smooth surface due to weathering * Slower processes of weathering and faster processes of weathering * Cracks from weathering

Answer 20

* Soil is too thin for cultivation and too dry so it's not suitible for arable culvitation * Turf like grass cover surface so idea for **sheep grazing**

Answer 21

* Sparsely populated because of minimal water supply * Many dispersed farms, some villages boosted by tourism eg Malham and Grassington

Answer 22

* Tourists visit for walking, campling, climbing, pot-holing, caving, educational visits and for scenery * Over 8 million visitors provide employment (which helps boosts the economy)

Answer 23

* Formed 355-290 million years ago * Formed in warm, tropical shallow seas and is made up from the **remains of sea creatures** and **calcium carbonate** * As the sediments were layed down in layers it formed **horizontal bedding planes** and it also has **vertical joints** in each layer

Answer 24

Has lines of weaknesses which make it vulnerable to different types of weathering * Freeze-thaw: widens joints, shatters rock and creates scree * Carbonation (dominant): Removal rate about **4cm every 1000 years** * Limestone reacts with water (not necessarily acidic) and dissolves

Answer 25

* Limestone pavement * Sinkholes/swallow holes * Resurgent stream/spring

Answer 26

Flat areas of limestone with blocks separated by weathered-down joints

Answer 27

Joints have been widened and enlarged by **carbonation** to form _deep gashes_ (**grykes**) and flat _surfaced blocks_ called **clints**

Answer 28

* Limestone solution attacks joints and slowly widens them * Pitted surface caused by small pools of water which collect on top of clints and weather the surface away * The deep grykes are an idea, sheltered habitat for plants and animals (eg Harts tongue fern)

Answer 29

Where surface streams dissapear down joints at small holes (sink) or down large tunnel shaped hollows (swallow hole)

Answer 30

1. Water travels over impermeable rock 2. As water reaches permeable limestone it disspears down a vertical joint 3. The stream now travels underground along joints and bedding planes

Answer 31

This is where the stream **reappears on the surface,** after it has been flowing through the limestone. It usually occurs at the junction of limestone and an impermeable rock eg clay

Answer 32

The stream travels along joints and bedding planes until it is block by impermeable rock and can go no deeper Undergound river travels along surface of impermeable rock

Answer 33

Carbonation

Answer 34

As the water travels along joints and bedding plaes, it **enlarges them by carbonation.** Where there is a high concentration of these lines of weaknesses, the limestone will **dissolve completely** to form a cave (A cavern is a large cave)

Answer 35

Depositional features

Answer 36

* In the process of carbonation, the limestone is dissolved and carried with the water, this water drips constantly from the roof of the caves * As the water drips, some of it will slowly evaporate and calcium carbonate is deposited * In time a **stalatite** will form. A stalagtite is a icicle-shapes feature which hangs **downwards** from the roof * As the water drips to the floor, further deposition of limestone forms **stalagmites** (features that grow up from the cave floor) * If the meet, **pillars** are created

Answer 37

These are steep sided valleys without a river flowing in it

Answer 38

Formed during the last ice age * When the ground was frozen, making it act like an **impermeable layer**. Water from melting ice then flowed over this rock because it could not infiltrate - **carving a valley** * When the climate warmed, the rock thawed out and became permeable again. The stream then dissapeared below the surface, leaving a dry valley.

Answer 39

A steep sided valley left behihnd when a waterfall eroded the rock

Answer 40

Sedimentary

Answer 41

Type of **limestone** Consists of **calcium carbonate** Made from the **shells of dead sea creatures**, falling to the sea bed and being compacted

Answer 42

**Fine particles from the weathering of other rocks**, laid down in the sea

Answer 43

Because its less resistant

Answer 44

Permeable, porous, hard rock that is resistant to erosion

Answer 45

**Chemical weathering** as it is made of calcium carbonate **Freeze thaw** can shatter rock

Answer 46

**Impermeable** (even though is **porous**, as the spaces are too small for water to go through) **soft and easily eroded** (especially by rivers)

Answer 47

Chalk stick ups forming escarpments and because the clay has been eroded faster it forms vales (wide areas of flat land)

Answer 48

Harder chalk occurs next to softer clay. These layers are tilted at an angle to the surface as a result of earth movements. Both start at a similar height and weathering and erosion affect both – including carbonation on the chalk. The chalk is more resistant to erosion than the clay as it is harder and therefore it erodes more slowly and lies above the surrounding clay in the lower lying vale. There are two parts to the chalk cuesta/escarpment. There is a steeper slope that cuts across the diagonal organisation of the rock layers and the gentler dip slope that goes parallel with it. Thus, the rock structure is important in forming the landforms with its characteristic scarp slope at right angles to the tilt and the dip slope that follows it parallel to the tilt.

Answer 49

* Escarpment with steep scarp slope and gentle dip slope * Thin, dry soil * Little surface drainage * Dry valleys on dip slope * Short, tough grass

Answer 50

* Low lying land * Thick, stickly soil * High drainage density * Many streams on the surface * Thick, lush green grass

Answer 51

* Formed at the **junction** of permeable chalk and impermeable clay * Usually at the foot of a steep scarp slope * Can occur at the bottom of the dip slope, where the water table reaches the surface, often in the winter * Settlements will tend to cluster around these, often in a line = spring line settlements

Answer 52

* On the dip slope of the chalk * Relies of a time when rainfall was much higher so the chalk pores were full and the rock saturated, causing it to behave like an impermeable rock * Rovers flowed on the surface, carving a valley we see today * Or, due to frozen ground during the Ice Age

Answer 53

_Chalk_: Porous and permeable therefore a lack of surface drainage as water soaks into rock easily, dry landscape _Clay_: Made from fine grained particles therefore virtually impermeable as pore spaces too small to allow water to pass through, drainage density is high

Answer 54

_Chalk_: Thin soils, lack of moisture (may grow some cereals on) produces only short grassland uitable for (sheep) grazing _Clay_: Thick, sticky, retains too much water, produces ideal pasture land

Answer 55

Building material Cement, plaster and putty Source of lime for industry and farming, to neutralise acidic soils

Answer 56

Making bricks and pottery

Answer 57

Clay: Dairy and pasture as the soil is too wet for arable Chalk: Rough grazing on top of scarp due to poor soils Some arable like wheat and barle at the foot of the dip slope as these crops don't require much moisture and light Soils are easy to plough, also southerm climate

Answer 58

An **underground reservoir** of water stored in the pores and joints of a rock

Answer 59

Around 70% of water supplies in the SE of england (especially london) come from aquifiers

Answer 60

* Chalk is _permeable,_ so water can **pass through** it and can be **stored in the pores** in the rock * Clay is _impermeable_, so water in the chalk is **trapped** and cannot drain away

Answer 61

* Provides **clean, non-polluted water** (as water is naturally filtered as it percolates through the chalk into the aquifier) * Water is **accesible by boreholes** * Can be used to **supply emergency water** in times of drought

Answer 62

Water use has to be kept to the amount that nature can replace

Answer 63

* Finite supply * Takes a **long time for water to be replaced** * Has a **naturally limited storage capacity** which cannot be increased * There is **increased presure on this limited supply** due to rising population

Answer 64

* **Employ a lot of people** - this brings money to the local economy * When a quarry's built, **good transport links are built for the tricks** that carry the stone and an improved infrastructure will **attract other businesses** and **boost local economy**

Answer 65

* Tourists could be **put off** from visiting the area - thus **reduces the amount of money made from tourism** * When a quarry is closed down it **costs money to make them safe** (eg by filling in holes and putting up warning signs)

Answer 66

* Some quarries are used by schools and colleges for **educational visits** * Quarries that have been closed fown can be **used for recreational activities** eg climbing, water sports

Answer 67

* People are **annoyed by heavy traffic** caused by slow vehicles leaving quarries * Quarries are a **very dangerous environment,** people could be **harmed** or **killed** in them

Answer 68

* The landscape is often restored after the quarries are closed fown, this can create **new habitats** and **attract new species** of wildlife to an area

Answer 69

Whilst they're operating, they have a massive **impact on the environment** as **habitats are destroyed** and the **resources** in the landscape are **depleated**

Answer 70

!!!!!!!!!!!!!!!!!!!!!!!!

Answer 71

**Restoring/improving** the **environmental quality** of a quarry, either during its operation or afterwards

Answer 72

* Museum * Reservoir (water supply) * Farmland (sheep grazing) * Waste clump * Mountain biking/motor course * Dry ski slopes * Lakes (wildlife reserve, fishing, watersports)