Intrusive Activity

Question 1

(1) intro - when did the paleogene period last from?

Answer 1

65 million years ago until 23 million years ago

Question 2

(1) intro - before the paleogene period…..

Answer 2

Britain, Greenland and North America were all joined together as a large continent and a major intra-plate hotspot developed between Britain and Greenland

Question 3

(1) intro - what is a hotspot?

Answer 3

A column of super heated magma inside the mantle that rises towards the surface

Question 4

(1) intro - what did this hotspot cause?

Answer 4

Thermal uplift and eventually continental rifting and a new ocean ridge was formed along with the North Atlantic Ocean.

Question 5

(1) intro - these huge factors from the hot spot also caused what?

Answer 5

A large amount of associated volcanism in North west Scotland, Northern England and Northern Ireland.

Question 6

(2) case study: The Whin Sill, Northern England - when did the Whin Sill form and what is it made of?

Answer 6

Formed around 295 million years ago and is made from dolerite

Question 7

(2) case study: The Whin Sill, Northern England - what did crustal extension allow?

Answer 7

The intrusion of magma between the layers of country rock, forming a concordant intrusion.

Question 8

(2) case study: The Whin Sill, Northern England - the Whin will reaches a max thickness of……

Answer 8

70m and is found from Holy Island, Bamburgh on the East Coast right across Northumberland.

Question 9

(2) case study: The Whin Sill, Northern England - the sill is highly resistant to erosion which means what?

Answer 9

As the overlying country rocks have eroded away a number of striking landscape features have been produced.

Question 10

(2) case study: The Whin Sill, Northern England - what do the landscape features of the whin sill include?

Answer 10

Sea cliffs such as the Farne Islands and Bamburgh castle, waterfalls such as high force on the river tees, and bold escarpments throughout Northumberland.

Question 11

(3) Case study: Isle of Arran - where does it lie?

Answer 11

Off the west coast of Scotland

Question 12

(3) Case study: Isle of Arran - what does the northern half of the island include?

Answer 12

The highest peak, Goat Fell, at 874m

Question 13

(3) Case study: Isle of Arran - this part of the island is made mainly of what?

Answer 13

North Arran granite. It forms a circular body of igneous rock with very coarse-grained crystals, which get smaller towards the edges.

Question 14

(3) Case study: Isle of Arran - the North Arran granite is…..

Answer 14

A pluton or batholith, approx. 11km across. It was forced into the crust at great depth during the paleogene.

Question 15

(3) Case study: Isle of Arran - what did the North Arran granite intrusion do?

Answer 15

Deformed overlying country rocks (doming) so the sedimentary layers seen today are tilted away from the batholith.

Question 16

(3) Case study: Isle of Arran - some of the country rocks closest to the intrusion have what?

Answer 16

Been metamorphosed by heat from it, changing them to metamorphic rocks. The batholith itself has been revealed by extensive erosion of the softer overlying country rocks producing a mountainous landscape in the North of the island.

Question 17

(3) Case study: Isle of Arran - what is the kildonan shore In the south of Arran?

Answer 17

A sandy beach crossed with many parallel ‘walls’ of igneous rock, acting like groynes. These rocks are a dyke swarm.

Question 18

(3) Case study: Isle of Arran - these dykes vary in size from….

Answer 18

30cm to 30m wide, and are made from low-silica composition igneous rocks such as dolerite.

Question 19

(3) Case study: Isle of Arran - over 50 dykes form what?

Answer 19

A striking series of ‘rock’ walls along the shore

Question 20

(4) EVALUATION - I have shown that what?

Answer 20

Millions of years of denudation of the overlying country rock in this ancient landscape resulted in the formation of a variety of different igneous landscapes in northern Britain.

Question 21

(4) EVALUATION - the majority of factors that control this include what?

Answer 21

The age of the intrusion, its size and shape, the nature of the weakness it intruded into, and the relationship between the intrusion and the country rock.

Question 22

(4) EVALUATION - these factors combine to recreate what?

Answer 22

A landscape which is distinctive to the local area and the specific conditions found there

Question 23

(4) EVALUATION - subsequent climatic changes …..

Answer 23

Will then combine with the local geological conditions over millions of years to shape the landscape.
This process will continue into the future to reveal an evermore distinctive landscape.

Question 24

(4) EVALUATION - the lack of short term dynamism in the changes what?

Answer 24

Contrast markedly with certain extrusive volcanic features and seismic landscapes which undergo significant modelling with much greater frequency.