A Hidden Story Transcript

A short video by Hugh Trevor

 0:15 A hidden story.

0:18 My name is David McAdam. I’m standing

0:21 here by the harbour in North Berwick.

0:24 North Berwick is a small coastal town

0:27 about 20 miles east of Edinburgh.

0:30 It is famous in Scotland as a holiday

0:32 destination.

0:34 It has sandy beaches, where in summer

0:37 people sit and children play.

0:40 There are two golf courses, one on the

0:43 west, on the other on the east.

0:47 The small hill behind the town is called

0:50 The Law

0:51 It is not too difficult to climb to

0:53 enjoy the view

0:55 on top. There are whale bones, sadly not

0:58 real ones anymore, a reminder of when

1:01 Scottish ports were bases for the

1:03 whaling industry.

1:06 Off North Berwick are four Islands.

1:09 To the north east, the Bass Rock is famous

1:12 as a gannet colony. You can take a boat

1:15 trip out to see the gannets close up.

1:18 It is a favourite with photographers and

1:21 naturalists.

1:25 To the north west is the island of Fidra.

1:29 When Robert Louis Stevenson was a boy, he

1:32 came to North Berwick for summer

1:33 holidays and it is thought that Fidra

1:37 was the inspiration for his famous book

1:39 ‘Treasure Island’.

1:42 Opposite North Berwick lies Craigleith

1:45 Island, home to orange billed puffins and

1:48 peregrine falcons.

1:51 The smallest island is called the Lamb

1:54 and is owned by Yuri Geller, the famous

1:57 spoon bender.

1:59 Now I'm a geologist and behind all these

2:02 features we see around North Berwick

2:04 there's a hidden story,

2:07 a geological story. Let me tell you about

2:10 it.

2:11 Some 350 million years ago there were

2:15 volcanoes in the east of Scotland.

2:18 The castle crag in Edinburgh is well

2:21 known as being the remains of an old

2:23 volcano,

2:24 but North Berwick Law and the Bass Rock

2:27 are also the sites of old volcanoes.

2:31 Let me show you this chart of the Bass

2:34 Rock as it was. Here it was a volcano

2:39 erupting from the surface, but erosion

2:42 wiped away the top part of the volcano

2:45 and we’re left with the Bass Rock as we

2:48 know it today.

2:50 Let me show you how a volcano works in

2:53 this diagram.

2:54 Deep down there is a magma chamber. The

2:58 magma comes up a pipe. When it gets to

3:01 the surface it forms a volcano which

3:04 erupts lava and ashes.

3:06 But many times the magma doesn't get to

3:09 the surface. Sometimes it comes up

3:12 vertically then goes horizontally and

3:15 forms what geologists call a sill.

3:18 Other times it goes sideways and stops

3:22 and forms a mushroom shape which

3:26 geologists calls a laccolith.

3:28 The colours in this diagram, the red shows

3:32 the molten magma and the green shows the

3:35 shape switch it forms when it cools and

3:38 solidifies.

3:40 Now imagine in the 350 million years in

3:44 which these rocks were formed there has been

3:47 lots of erosion by wind water and ice

3:51 and the top layers of this has all been

3:54 worn off

3:55 and we can demonstrate this here.

3:59 This pipe becomes a shape

4:02 like the Bass Rock.

4:05 But here the laccolith becomes a shape

4:08 like Craigleith.

4:11 If we erode down further we can uncover

4:15 the shape of Berwick Law

4:18 or we can uncover the sill that forms

4:21 the flat shapes of Fidra and the Lamb.

4:25 Now here by the harbour we can see the

4:27 lavas and the tuffs that emerge from

4:31 the volcano.

4:33 First there were green ashes, green

4:36 tuffs laid down, followed by layers of

4:39 red ashes red tuffs and then three lava

4:43 flows shown here in purple, orange and

4:46 purple.

4:47 A little later

4:49 cracks in the Earth’s surface were

4:52 filled by magma and formed this vertical

4:55 slab called a dyke.

4:58 Plate tectonics

5:00 effectively tilted the rocks here 25

5:04 degrees to the West. Erosion

5:07 wore away all the rocks in this part

5:10 and this line across here is the present

5:14 day surface, so this is the way we see

5:18 the rocks today.

5:20 To the East are the green tuffs and

5:24 then in the middle of the bay are the

5:27 black rocks or the remains of the dyke.

5:30 Round the boating pond are the red tuffs

5:34 and the three ridges around the harbour

5:37 are the remains of the three lava flows.

5:40 Here standing in the outer part of the

5:43 harbour, we can see the three lava flows.

5:46 The Seabird Centre is sitting on the

5:49 lowest lava flow, the middle lava flow

5:52 here forms two reefs stretching out to

5:55 sea and the top lava flow forms the

5:59 cliff in the distance with the starter’s hut

6:02 the hut that’s used for starting

6:05 the yacht races from North Berwick.

6:08 That’s Craigleith Island just peeping

6:10 out from the end of the lava flows.

6:14 During the last two million years

6:16 Scotland was covered by many ice sheets.

6:20 This diagram shows the way the ice built

6:23 up both in the Highlands and in the

6:27 south of Scotland

6:28 and it flowed into the low ground in the

6:31 middle of Scotland. Some of the ice

6:33 flowed West towards Glasgow and the rest

6:37 of the ice flowed East towards Edinburgh.

6:41 In Edinburgh, the flow of the ice from

6:44 the West

6:45 was blocked by the Crag of Edinburgh

6:47 Castle Rock

6:49 and when the ice hit the Crag and was

6:52 diverted,

6:53 some went to the North and gouged out

6:56 Princes Street Gardens, some went to the

6:59 South and gouged out the Grassmarket

7:03 while some went over the top. But the area

7:06 to the Lee of the Crag was sheltered by

7:08 the Crag and this gives the gently

7:11 sloping Ridge which is now the Royal

7:13 Mile.

7:15 This feature is known to geologists as a

7:18 crag and tail.

7:20 North Berwick has its own crag and tail.

7:23 The Law is the crag and you can see the

7:26 tail stretching eastwards for about a

7:29 kilometre or so.

7:31 Now there’s another feature about North

7:33 Berwick – the golf courses and indeed

7:36 the town itself, lie in a flat sandy area

7:40 behind the present beaches. It is sandy

7:43 because five thousand years ago when the

7:47 ice cap had melted, the sea level was

7:50 higher than it is now and the golf

7:52 course area was part of the seabed

7:56 but then with the weight of the ice gone

7:59 the land rebounded,

8:01 the level of the coastal area rose and

8:05 what had been seabed became dry land and

8:09 is used today for golf.

8:12 Also the cliffs that hemmed in the sea

8:15 those five thousand years ago are still

8:18 here in North Berwick today.

8:20 They are the little hills and steep

8:22 roads that exist in the town.

8:25 You notice them especially when you go

8:28 South out of the Town Centre like that

8:31 white van is doing now.

8:37 So come to North Berwick,

8:39 play on the beaches, play golf, go sailing

8:43 among the islands

8:44 but when you come, remember the hidden

8:47 story, the geological history which is

8:51 the backdrop to all you see today.