0:00:59 > 0:01:02One of the best ways to investigate the landscape of Britain
0:01:02 > 0:01:04is through walking and climbing.
0:01:04 > 0:01:06In this programme, we're going to challenge three pairs
0:01:06 > 0:01:10of young people, each climbing different rock formations,
0:01:10 > 0:01:12to investigate the geological and geographical processes
0:01:12 > 0:01:13which have taken place.
0:01:13 > 0:01:16Today, we're in the Snowdonia National Park, Wales.
0:01:16 > 0:01:19We'll be climbing the Cwm Idwal Slabs.
0:01:19 > 0:01:22These magnificent rocks were folded by tectonic activity
0:01:22 > 0:01:24around 400 million years ago.
0:01:24 > 0:01:27The movement of the Earth's plates crumpled and squashed the rock
0:01:27 > 0:01:29into new shapes.
0:01:29 > 0:01:32Volcanic eruptions, followed by glacial activity in the last ice age
0:01:32 > 0:01:35also helped to carve and shape the landscape.
0:01:35 > 0:01:39'I'm Dr Tom Challands. I'm a geologist and I'm also a climber.'
0:01:39 > 0:01:42I'm here today to challenge two young climbers and geologists
0:01:42 > 0:01:45to investigate the type of geological processes
0:01:45 > 0:01:47that contributed to forming these big cliffs
0:01:47 > 0:01:49that we see here behind us.
0:01:49 > 0:01:54Over 450 million years ago, this was the site
0:01:54 > 0:01:56of a massive violent pyroclastic eruption,
0:01:56 > 0:02:00the same type of activity seen more recently in Krakatoa.
0:02:05 > 0:02:09The area is important historically, and not just for climbing.
0:02:10 > 0:02:14It's here, 170 years ago, Charles Darwin tested the early theories
0:02:14 > 0:02:17of glaciation and glacial erosion,
0:02:17 > 0:02:20applying what he'd learnt from his earlier travels in the Alps.
0:02:23 > 0:02:27Our first climber is Alex, he's 15 and from Essex.
0:02:28 > 0:02:32I study Geography and Geology at GCSE level
0:02:32 > 0:02:34and I enjoy the field work in both subjects.
0:02:34 > 0:02:37I really love climbing because I find it exhilarating
0:02:37 > 0:02:40and it challenges me, puts all my skills to the test.
0:02:41 > 0:02:43Maddie is also 15 and from Birmingham.
0:02:43 > 0:02:45I don't really have that many expectations,
0:02:45 > 0:02:48just have fun and try and learn as much as possible.
0:02:48 > 0:02:49'Indoors, it's set out for you.'
0:02:49 > 0:02:52'I'm going to have to think about what to do, where to put my feet.'
0:02:52 > 0:02:55It's raining, but that's not going to hinder me.
0:02:55 > 0:02:56I'm going to power through.
0:02:56 > 0:02:58The weather's not very good.
0:02:58 > 0:03:00It's looking slightly tricky and slippy underfoot.
0:03:00 > 0:03:03They're going to have quite a big challenge ahead.
0:03:06 > 0:03:09It's still raining, but I'm going to set you the challenge still
0:03:09 > 0:03:12because I know you're made of stern stuff and that you're keen
0:03:12 > 0:03:14and you're eager to get on with it.
0:03:14 > 0:03:16So here's today's challenge.
0:03:24 > 0:03:26We've given Maddie and Alex 20 minutes
0:03:26 > 0:03:28to plan their tactics before climbing.
0:03:28 > 0:03:30To help, they've been given this box of tricks.
0:03:30 > 0:03:33They can choose four from this range of geological equipment.
0:03:33 > 0:03:37Some will be really useful on this climb - others will be useless.
0:03:38 > 0:03:41They don't know this area or the route they'll climb.
0:03:41 > 0:03:44They'll have to use these items and their knowledge of geography
0:03:44 > 0:03:46and geology to find as many clues as possible
0:03:46 > 0:03:48to unlock this rock's history.
0:03:49 > 0:03:52It's good they're looking at the bigger picture
0:03:52 > 0:03:55and not just what they think they'll encounter immediately on the climb.
0:03:55 > 0:03:57This is how to choose the best equipment.
0:03:59 > 0:04:03That looks like an anticline because it's bedded diagonally, like that,
0:04:03 > 0:04:08pointing upwards. You can see the nice beds on top of each other.
0:04:08 > 0:04:12We've chosen two compasses with hand lens on the end,
0:04:12 > 0:04:15a grain size card which will help us measure the grain size,
0:04:15 > 0:04:17and a note book to write everything down.
0:04:17 > 0:04:20Obviously, you can see this is a U-shaped valley
0:04:20 > 0:04:22so there must have been a glacier at one point here,
0:04:22 > 0:04:25and there are truncated spurs.
0:04:25 > 0:04:27There's a tarn which also indicates there's a glacier there
0:04:27 > 0:04:29- because it's a melted glacial lake. - Yep.
0:04:29 > 0:04:33'They've jumped to a few conclusions about glacial activity
0:04:33 > 0:04:35'in the area without any real evidence, but...'
0:04:35 > 0:04:37I've got a lot of hope for them.
0:04:37 > 0:04:40They're both very intelligent kids, they're really on the ball and from
0:04:40 > 0:04:43what I've been hearing them discuss they're going on the right lines.
0:04:43 > 0:04:47We chose a compass because it helps us measure the dip and strike
0:04:47 > 0:04:50of the rocks, and also it's got a hand lens on it
0:04:50 > 0:04:52which is helpful for telling grain size.
0:04:52 > 0:04:54We've picked a grain size card,
0:04:54 > 0:04:58because as well as telling grain size, which helps us identify rocks,
0:04:58 > 0:05:02it also tells us how to measure sorting of grains,
0:05:02 > 0:05:06roundness of grains, and as well as that, percentage area of coverage
0:05:06 > 0:05:07of the rock that the grain has.
0:05:07 > 0:05:11Which is all helpful in helping us identify rocks.
0:05:11 > 0:05:14I wanted to ask Dr Tom how to measure dip and strike again,
0:05:14 > 0:05:17because I wasn't actually sure how to measure it.
0:05:17 > 0:05:21I have a rough idea, but I want to be sure before I go up the cliff.
0:05:21 > 0:05:23We're measuring the dip of the rock
0:05:23 > 0:05:26because it lets us know if it's been tilted or folded.
0:05:26 > 0:05:28It's a real clue to the tectonic history
0:05:28 > 0:05:30and it'll help with the challenge.
0:05:30 > 0:05:36First of all the dip of a bed of rock is the angle at which it tilts,
0:05:36 > 0:05:38the maximum angle that it tilts,
0:05:38 > 0:05:41and we can easily find the maximum angle of tilting
0:05:41 > 0:05:45simply by getting some water, and we're not short of that today.
0:05:45 > 0:05:48If we drip a little bit on the rock,
0:05:48 > 0:05:52the direction the water will travel in is the direction of maximum dip.
0:05:52 > 0:05:56This compass also has a small dial
0:05:56 > 0:06:01on the inside of the actual circular part, here.
0:06:01 > 0:06:05What we want to do is align the compass
0:06:05 > 0:06:10so East and West are lined up with the arrow at this end.
0:06:10 > 0:06:13The dial here which goes from zero degrees at the bottom to 90 degrees
0:06:13 > 0:06:17at the side is horizontal when we have the compass in this position.
0:06:18 > 0:06:20You're then going to place it
0:06:20 > 0:06:23on the piece of rock you want to measure the dip of,
0:06:23 > 0:06:27and what's very important is to make sure it's a solid piece of bedrock,
0:06:27 > 0:06:31not a loose boulder because a loose boulder will give a false reading.
0:06:31 > 0:06:34We're going to move the compass clinometer around
0:06:34 > 0:06:38until this arrow here stops moving back and forth.
0:06:38 > 0:06:44It seems to be pretty still there, and it's reading 21 degrees.
0:06:44 > 0:06:47Then what we do is use a pencil,
0:06:47 > 0:06:50draw along the rock along the edge of the compass.
0:06:50 > 0:06:53It's very important to use a pencil or a piece of chalk,
0:06:53 > 0:06:54something that will wash away.
0:06:54 > 0:06:56We don't want to scratch or damage the rock.
0:06:56 > 0:06:58We'll take our compass,
0:06:59 > 0:07:05and now, lining our compass up with that line we've just made,
0:07:05 > 0:07:09we then rotate the bezel here, the dial,
0:07:09 > 0:07:11until the red arrow in the middle
0:07:11 > 0:07:13lines up with the red floating arrow,
0:07:15 > 0:07:20and the number that reads at the top of the compass clinometer here,
0:07:20 > 0:07:25and in this case it's 268 degrees, is the direction of dip.
0:07:25 > 0:07:28Here we have a dip of 21 degrees,
0:07:28 > 0:07:33we have a dip direction of 268 degrees
0:07:33 > 0:07:39and the strike which goes two ways is 268 minus 90 or plus 90 degrees.
0:07:39 > 0:07:42So we have our strike, dip and dip direction.
0:07:42 > 0:07:44That's much clearer, definitely.
0:07:44 > 0:07:46Brilliant, so now you've chosen your piece of equipment,
0:07:46 > 0:07:49you know what measurements you're going to make, how to make them,
0:07:49 > 0:07:52I think we should go and do the climb and collect some data.
0:07:52 > 0:07:53How does that sound?
0:07:53 > 0:07:54Sounds good.
0:07:54 > 0:07:56Right. Let's go and do that, then.
0:08:02 > 0:08:04'This field study is also a climbing challenge,
0:08:04 > 0:08:07'so if you don't know what you're doing, it has its risks.'
0:08:07 > 0:08:09Got all the gear?
0:08:09 > 0:08:12'These climbs shouldn't be undertaken without expert help.'
0:08:13 > 0:08:16The geology is really helping the climb.
0:08:16 > 0:08:19This huge crack, which could be a joint or a fault, is really useful,
0:08:19 > 0:08:21and is revealing some early clues.
0:08:23 > 0:08:27Maddie, there's a little line of, like, quartz in the middle.
0:08:31 > 0:08:35The crack here is the defining feature of this rock face.
0:08:35 > 0:08:38How it was formed will help them with the challenge.
0:08:38 > 0:08:41They just need to look for evidence which will tell them if it's a joint or a fault.
0:08:42 > 0:08:45Looking into the depths of the crack, there don't appear to be
0:08:45 > 0:08:50any broken up bits of bits of rock like we might expect from a fault.
0:08:55 > 0:09:00Those broken up bits of rock are actually fault breccia.
0:09:00 > 0:09:02If we can't see that fault breccia in here,
0:09:02 > 0:09:06that might indicate that it's not a fault but rather a joint.
0:09:14 > 0:09:17In this crack, there's a massive lump of quartz.
0:09:17 > 0:09:19If that has significance, I'm not sure.
0:09:20 > 0:09:25It's great to see Alex and Maddie noticing the changes in the rock
0:09:25 > 0:09:29as they climb, and looking for solid areas to take their readings.
0:09:29 > 0:09:30Different strike readings.
0:09:30 > 0:09:34They've obviously taken on board the mini briefing on using the
0:09:34 > 0:09:38- compass clinometer and are making frequent measurements as they climb. - OK.
0:09:38 > 0:09:41It might be simple, but that notebook is vital,
0:09:41 > 0:09:43or they'll never remember their results.
0:09:44 > 0:09:48Two or more set of cracks can reveal how the order of events happened
0:09:48 > 0:09:51in the rock but what they can't reveal is how long it took.
0:09:51 > 0:09:53You need to gather other evidence for that.
0:09:55 > 0:09:57So I'm a little bit further up the climb now
0:09:57 > 0:09:59and I've found another set of cross cutting joints,
0:09:59 > 0:10:02cutting across the main fracture here,
0:10:02 > 0:10:06but what else we have is vegetation growing in this fracture.
0:10:06 > 0:10:09This is an example of biological in situ weathering.
0:10:17 > 0:10:19Look at that!
0:10:21 > 0:10:26This looks like this parent rock right here,
0:10:26 > 0:10:29this, obviously, is some quartz,
0:10:29 > 0:10:31which begs the question how it got there.
0:10:31 > 0:10:35Little parts of quartz, some bigger, some smaller,
0:10:35 > 0:10:40some really small ones, a yellower one and a more grey one,
0:10:40 > 0:10:44which indicates some type of weathering, possibly,
0:10:44 > 0:10:45or something else in the rock.
0:10:45 > 0:10:49These loose bits of quartz Alex has found washed in here
0:10:49 > 0:10:51are great examples of weathering and erosion.
0:10:51 > 0:10:57What we have here on the surface of the slab are some quartz crystals.
0:10:57 > 0:11:00A quartz bedding plain, almost.
0:11:00 > 0:11:02This is actually a quartz injection,
0:11:02 > 0:11:07that's a vein that's injected along the bedding plane itself.
0:11:09 > 0:11:11This is the final measurement of the climb.
0:11:11 > 0:11:13They've taken one at the base, one in the middle
0:11:13 > 0:11:17and now we're at the top of the climb, just taking one more.
0:11:20 > 0:11:23So from this vantage point in the climb
0:11:23 > 0:11:26we have a really good view of the head of Cwm Idwal,
0:11:26 > 0:11:29the large synform right at the heart of the Cwm.
0:11:29 > 0:11:32It's the curves you can make out in front of me on the rock face.
0:11:32 > 0:11:36We can also make out a large periglacial landslide below it.
0:11:36 > 0:11:39There's a clue to the glacial past of this area in the name
0:11:39 > 0:11:41"Cwm", as in Cwm Idwal.
0:11:41 > 0:11:42It's the welsh word for corrie,
0:11:42 > 0:11:45and a corrie is a glaciated mountain valley.
0:11:45 > 0:11:49Further down at the foot of the slabs we have roche moutonnees.
0:11:49 > 0:11:51A bit further down by Cwm Idwal
0:11:51 > 0:11:54there are also some very, very clear moraines.
0:11:54 > 0:11:56So we're starting to get a good picture
0:11:56 > 0:11:58of the geology and geomorphology.
0:11:59 > 0:12:01OK, guys, I think it's time we got down now.
0:12:06 > 0:12:08Hands off the rock. In back, now.
0:12:08 > 0:12:12That's it. That's it. Just like being low down on the climbing wall.
0:12:12 > 0:12:14Maddie and Alex abseil back to base.
0:12:14 > 0:12:17This'll give them one last chance to look at the structure
0:12:17 > 0:12:19and spot any last minute bits of evidence.
0:12:21 > 0:12:24I'm quite confident that they've got a good idea
0:12:24 > 0:12:26of what's happened here in Cwm Idwal.
0:12:26 > 0:12:28We're looking at the bigger picture.
0:12:28 > 0:12:31They looked at it before they went up the route,
0:12:31 > 0:12:33they looked at it when they got to the top of the route
0:12:33 > 0:12:36and they also made some small-scale observations and measurements as well.
0:12:36 > 0:12:39So, you've seen what I think. Now they've got 20 minutes
0:12:39 > 0:12:43to pull together their evidence and see if they can answer the question.
0:12:43 > 0:12:46So, we asked them to describe how the slabs have been affected by the
0:12:46 > 0:12:50tectonic history of this place and what caused the subsequent erosion?
0:12:54 > 0:12:56We found quite a lot of evidence actually,
0:12:56 > 0:12:58from erosion to different rock types and minerals.
0:12:58 > 0:13:02And I think all of it will definitely help us with our question.
0:13:02 > 0:13:06We just need to sit down together and confer and relay back
0:13:06 > 0:13:10our different information and then try and find out something concrete
0:13:10 > 0:13:12that we can put forward for the question.
0:13:12 > 0:13:16There's quite a lot of quartz up the joint that we found.
0:13:16 > 0:13:20That might be from a hydrothermal ore vein which is tectonics
0:13:20 > 0:13:23because of the magma that's come up in an igneous intrusion
0:13:23 > 0:13:25somewhere around here.
0:13:25 > 0:13:29That's heated rainwater that's percolated through the ground
0:13:29 > 0:13:32and as that rain water comes up, it collects minerals such as quartz.
0:13:32 > 0:13:35We found some trachopyrate as well,
0:13:35 > 0:13:37which is another mineral that we would find.
0:13:37 > 0:13:39Obviously it carried it up and as it went up it cooled,
0:13:39 > 0:13:41and solidified in these joints.
0:13:41 > 0:13:43Obviously the tectonic activity
0:13:43 > 0:13:46has created these quartz hydrothermal ore veins.
0:13:46 > 0:13:48The compass clinometer helped us measure
0:13:48 > 0:13:51three different dip and strike angles and the direction of dip.
0:13:51 > 0:13:55It increased in steepness as we went up.
0:13:55 > 0:13:59At the beginning it was 42, and then mid-point it was 52,
0:13:59 > 0:14:02and at the top the final reading was 60.
0:14:02 > 0:14:04It helps us see how the rock's been affected as it goes up,
0:14:04 > 0:14:08for example, if it's steeper at the top, less steep at the bottom.
0:14:08 > 0:14:11This is a great point to spot,
0:14:11 > 0:14:13because we were climbing on the limb of this fold we can see here.
0:14:13 > 0:14:16I think the main erosive features are definitely the truncated spurs
0:14:16 > 0:14:19- that you can see, and the moraine, you can see it everywhere.- OK.
0:14:19 > 0:14:23- And the main structural features? - The quartz veins.
0:14:23 > 0:14:26The way the joints are facing as well
0:14:26 > 0:14:29and all the other evidence for erosion with smooth rock.
0:14:29 > 0:14:33So the structure has contributed towards the erosion and weathering.
0:14:33 > 0:14:36That's a lot of good interpretations based on your observations,
0:14:36 > 0:14:38and that's exactly what geologists do.
0:14:40 > 0:14:42So, today's challenge was all about the effects
0:14:42 > 0:14:44of tectonic activity and glacial erosion.
0:14:44 > 0:14:47Let's look in detail at what actually happened here.
0:14:51 > 0:14:54We start with the deposition of volcanic rocks, tuffs and lavas
0:14:54 > 0:14:57during the subduction of the Laurentian plate
0:14:57 > 0:14:58beneath Avalonia and Baltica.
0:15:00 > 0:15:03Scotland, England and Wales are united for the first time.
0:15:04 > 0:15:07Leading to the Caledonian mountain building period event.
0:15:11 > 0:15:13Layers of rock are bent under extreme pressure,
0:15:13 > 0:15:17and hot, briny hydrothermal fluids formed during the collision
0:15:17 > 0:15:21deposit minerals such as quartz inside the newly-formed cracks.
0:15:26 > 0:15:27Until the ice age.
0:15:30 > 0:15:31But this landscape is for ever
0:15:31 > 0:15:33changing due to further erosion
0:15:33 > 0:15:35because of melt water and vegetation
0:15:35 > 0:15:37as well as wind and rain.
0:15:39 > 0:15:41The geology challenge was pretty hard, but I did learn from it.
0:15:41 > 0:15:45I was quite scared to do the climb, but actually when I did it,
0:15:45 > 0:15:46it was really fun.
0:15:46 > 0:15:49I'll probably take away learning not to be afraid to try new things
0:15:49 > 0:15:52and even if something's wrong, always just say it,
0:15:52 > 0:15:54because there's a chance that it might include something
0:15:54 > 0:15:55that could be developed on.
0:15:55 > 0:15:59Today's actually taught me definitely a lot more about geography.
0:15:59 > 0:16:02Some of the things we found, like the truncated spurs,
0:16:02 > 0:16:03I did not know about them.
0:16:03 > 0:16:06Without Maddie, I would have completely missed all that.
0:16:06 > 0:16:08I would definitely do it again if I could.
0:16:08 > 0:16:10So that's it's for today here on Idwal slabs.
0:16:10 > 0:16:13It's been an adventurous day for climbing, for geology,
0:16:13 > 0:16:15and most certainly adventurous weather.
0:16:18 > 0:16:21Still to come, we'll look at a rock face affected by human activity...
0:16:26 > 0:16:28..and climbing in an area which was formed
0:16:28 > 0:16:30as the result of a massive river delta.
0:16:54 > 0:16:58Castle Inn is a redundant limestone quarry in Conwy, North Wales.
0:16:59 > 0:17:03Although no longer providing limestone to the building industry,
0:17:03 > 0:17:05the past quarrying and the way the rock weathers
0:17:05 > 0:17:07means it's still used by us today.
0:17:09 > 0:17:12Castle Inn forms part of the local leisure industry
0:17:12 > 0:17:14as a climbing wall and nature reserve.
0:17:17 > 0:17:19I'm Dr Tom Challands and I'm here today
0:17:19 > 0:17:21to challenge two keen young climbers
0:17:21 > 0:17:24and geologists to answer a couple of questions
0:17:24 > 0:17:26about the rock face we have behind us.
0:17:26 > 0:17:29The rock face we're going to climb today is made of limestone,
0:17:29 > 0:17:30which is particularly interesting
0:17:30 > 0:17:33as it's got several different types of structures on it
0:17:33 > 0:17:37This quarry is now a nature reserve.
0:17:37 > 0:17:39I hope the young climbers we have with us
0:17:39 > 0:17:42are going to spot some things about the way this rock was formed,
0:17:42 > 0:17:46but also about the geography and the way this old limestone quarry
0:17:46 > 0:17:48has been affected by human use, but also by nature.
0:17:51 > 0:17:54I'm Tom and I'm 14 from Stockport.
0:17:54 > 0:17:56My hobby is rock climbing.
0:17:56 > 0:17:58I'm here because I want to learn a lot about the rocks.
0:18:00 > 0:18:02My name's Laurie. I'm 14 years old
0:18:02 > 0:18:04and I live in Derbyshire.
0:18:05 > 0:18:07I love being outdoors on field trips, yeah.
0:18:07 > 0:18:08Outdoors all the time.
0:18:08 > 0:18:11You're not stuck in the classroom looking at the computer.
0:18:13 > 0:18:16Well, I know that Tom and Laurie are both really good climbers
0:18:16 > 0:18:19and they seem very keen to get on with the job.
0:18:19 > 0:18:23I'm interested to see what they make of the challenges because we've got two things to ask them.
0:18:23 > 0:18:25We've got to ask them a lot about geography
0:18:25 > 0:18:28and also we are going to ask a little bit about the geology,
0:18:28 > 0:18:30because the two things really are mixed together.
0:18:30 > 0:18:34- So here we are in the quarry, and I'm going to set you the challenge. Are you ready?- Yep.
0:18:44 > 0:18:47So here it is written down for you to look over and think about,
0:18:47 > 0:18:50and what we have in this suitcase here
0:18:50 > 0:18:53is some equipment that will help you make observations,
0:18:53 > 0:18:57take measurements and collect the type of data that you need.
0:18:57 > 0:18:59So you've now got 20 minutes to go away,
0:18:59 > 0:19:02choose four pieces of equipment from here, put your heads together,
0:19:02 > 0:19:05make a plan, and then we'll get on with climbing the route,
0:19:05 > 0:19:07going and collecting your data.
0:19:07 > 0:19:11They can choose four from a range of items in this case.
0:19:11 > 0:19:15Some will be useful for this climb, others will be no use at all.
0:19:15 > 0:19:18They don't know this area or the route they're going to climb.
0:19:18 > 0:19:21They'll have to find as many clues as possible
0:19:21 > 0:19:23to unlock this rock's history.
0:19:23 > 0:19:25So part of the question we've asked Tom and Laurie today
0:19:25 > 0:19:28centres around the principal of uniformitarianism.
0:19:28 > 0:19:31Using the present as the key to the past.
0:19:32 > 0:19:36It's hard to believe, looking at today's weather, but this rock
0:19:36 > 0:19:40was created in a climate we'd now expect to find in the Bahamas.
0:19:40 > 0:19:41Is that hydrochloric acid?
0:19:41 > 0:19:44Oh, yeah, we used it in science.
0:19:44 > 0:19:46We were dripping it onto the limestone.
0:19:46 > 0:19:48So we can test if the rocks are actually limestone.
0:19:50 > 0:19:52Definitely hydrochloric.
0:19:52 > 0:19:55We've got the geological timescale which lets us know
0:19:55 > 0:19:57in the rocks there's many fossils,
0:19:57 > 0:20:02and we get to know how old the rock is, and my prediction is
0:20:02 > 0:20:06the higher up it'll get, the newer the fossils will be.
0:20:06 > 0:20:08Also, I've got a magnifying glass,
0:20:08 > 0:20:13to work out the fossils in the rock and we'll be able to work them out
0:20:13 > 0:20:15and compare them to this sheet.
0:20:15 > 0:20:20As well as that, our final item is the micro fossils sheet.
0:20:20 > 0:20:23We'll be able to find out what the fossils are called.
0:20:23 > 0:20:26I'm quite confident because I think we've chosen the right things,
0:20:26 > 0:20:27but we'll see.
0:20:27 > 0:20:30They might not be able to learn much about how this rock was formed
0:20:30 > 0:20:34just using a geological time scale and with the microfossil card,
0:20:34 > 0:20:35well, they're microfossils.
0:20:35 > 0:20:38They'd really need a microscope to see them.
0:20:38 > 0:20:42However, the hand lens will be very useful for looking at some larger fossils they might see
0:20:42 > 0:20:45and finally the hydrochloric acid will be really useful
0:20:45 > 0:20:47to find out whether or not this is limestone.
0:20:47 > 0:20:49Laurie, Tom, one of the things you wanted to do
0:20:49 > 0:20:51before you went climbing was test whether or not
0:20:51 > 0:20:54this rock is limestone.
0:20:54 > 0:20:56So, to do that, we have some hydrochloric acid here.
0:20:56 > 0:21:00It's very dilute, but we don't want to be taking hydrochloric acid with us,
0:21:00 > 0:21:04and we don't want to be knocking pieces of rock off, so let's just put this down on the floor.
0:21:05 > 0:21:07Get this over our eyes.
0:21:07 > 0:21:08What are you expecting to see?
0:21:08 > 0:21:10- I think it bubbles a bit.- Yeah.
0:21:10 > 0:21:12OK, let's see what we get.
0:21:14 > 0:21:17- There we go. It's bubbling pretty vigorously.- Yeah.
0:21:17 > 0:21:20Those bubbles are carbon dioxide that are being released,
0:21:20 > 0:21:24as the hydrochloric acid reacts with the calcium carbonate
0:21:24 > 0:21:26in the limestone,
0:21:26 > 0:21:29and given that there also seems to be some other objects in this rock,
0:21:29 > 0:21:33I'd say we have a positive limestone identification.
0:21:34 > 0:21:36We're going to go up the rock face now,
0:21:36 > 0:21:40and we're going to be able to look at how the rock is formed.
0:21:40 > 0:21:42We might be able to see some layers
0:21:42 > 0:21:45if it is sedimentary rock like we think,
0:21:45 > 0:21:48and maybe we can see whereabouts the rock is as we get higher up
0:21:48 > 0:21:51and we'll be out of the shade of the trees.
0:21:51 > 0:21:54I'm really looking forward to going up there and just checking,
0:21:54 > 0:21:57checking out the rock and hopefully finding out some good clues
0:21:57 > 0:21:59to help us with our investigation.
0:21:59 > 0:22:02Tom and Laurie's field study challenge has its risks,
0:22:02 > 0:22:03if you don't know what you're doing.
0:22:03 > 0:22:06It shouldn't be undertaken without expert help.
0:22:09 > 0:22:13It's the natural bedding planes, along with the fractures and joints
0:22:13 > 0:22:15in the rock that's helping them on the route.
0:22:16 > 0:22:19Some produce big climbing holds, but smaller edges formed where
0:22:19 > 0:22:23the rock has simply broken off, making for trickier climbing.
0:22:34 > 0:22:35Lots of this stuff.
0:22:35 > 0:22:39Corally, isn't it, here. It gets a bit darker over here.
0:22:39 > 0:22:43Here, on the face of the limestone surface, we have this white,
0:22:43 > 0:22:47crusty deposit, and this is a tufa deposit.
0:22:47 > 0:22:50It's formed by the reprecipitation of dissolved limestone.
0:22:50 > 0:22:53Smooth. Not much friction.
0:22:55 > 0:22:57This is because limestone is a soft rock,
0:22:57 > 0:23:00made from the relatively unresistant mineral calcite.
0:23:00 > 0:23:04It polishes easily to give the smooth surface Tom has spotted.
0:23:04 > 0:23:08It's like a layer of rock, like a thin strip going all around here.
0:23:10 > 0:23:14Tom's just seen a bedding plane picked out by a thin layer of mud.
0:23:14 > 0:23:17Another really good climbing hold on this limestone rock face.
0:23:19 > 0:23:22It's quite polished from where climbers have been on it.
0:23:22 > 0:23:25That could be how people use the rocks now.
0:23:25 > 0:23:29So here we see further interaction of humans with the rock face.
0:23:29 > 0:23:34It's a bolt used for sport climbing, and like we see at Cwm Idwal,
0:23:34 > 0:23:39it's good example of how humans start to erode away the rock
0:23:39 > 0:23:40as they climb up it.
0:23:40 > 0:23:43There's a good view all the way over there,
0:23:43 > 0:23:47and we're not quite in the bottom of the valley but nearly.
0:23:50 > 0:23:55Wow, these are weird, here. It's like it's run down or melted.
0:23:55 > 0:23:58They're kind of all dripping down, almost like stalactites.
0:24:02 > 0:24:07So here we have a beautiful example of tufa again, but this time,
0:24:07 > 0:24:10rather than the tufa flowing over the rock face, it's been
0:24:10 > 0:24:13dripping from a single point to produce these beautiful,
0:24:13 > 0:24:18beautiful stalactites that have a really nice ring to them as well.
0:24:23 > 0:24:26Fossils found here could reveal what's known as
0:24:26 > 0:24:29an environment of deposition, and if they're the right type
0:24:29 > 0:24:33it'll point to deposition in warm, shallow, tropical seas.
0:24:33 > 0:24:35Oh, yeah, look. I've found a fossil.
0:24:35 > 0:24:38Let's see. I've got this thing, I'll have a look.
0:24:43 > 0:24:47So here now near the top of the climb we can see some nice shells
0:24:47 > 0:24:50fossilised into the rock, and these are brachiopods,
0:24:50 > 0:24:54filter feeding organisms, but they're not very complete.
0:24:54 > 0:24:56They're all broken up and fragmented,
0:24:56 > 0:24:59and that tells us that they were not deposited here,
0:24:59 > 0:25:01they didn't live here, but they were broken up,
0:25:01 > 0:25:04they were transported from a calm, coral sea environment
0:25:04 > 0:25:05and moved into this position.
0:25:06 > 0:25:10And from here we get a really good view of the extent of this quarry.
0:25:16 > 0:25:18Let's look at it on this.
0:25:19 > 0:25:21You think it could be...?
0:25:21 > 0:25:24I can't really see it on there, it's like a polo mint.
0:25:24 > 0:25:27Yeah, it's got like a...
0:25:27 > 0:25:29There's these ones as well.
0:25:29 > 0:25:32Unfortunately this is a microfossils card, so it can't help them at all.
0:25:32 > 0:25:35You would need a much more powerful microscope than their hand lens
0:25:35 > 0:25:39to pick out any microfossils in this rock face.
0:25:39 > 0:25:40Could they be burrows?
0:25:42 > 0:25:43Maybe.
0:25:43 > 0:25:46Right here at the top of the limestone quarry cliff face
0:25:46 > 0:25:50we can see that the limestone that's been exposed to the surface
0:25:50 > 0:25:55the longest has started to form this nice, wobbly, blobby castified
0:25:55 > 0:26:00surface with these rivulets here, and this is formed from
0:26:00 > 0:26:03the dissolution of limestone by weak carbonic acid.
0:26:05 > 0:26:07Whereabouts do you want to stop?
0:26:07 > 0:26:09Er, about here.
0:26:09 > 0:26:11About there. OK, got you there.
0:26:13 > 0:26:17What makes you think it's coral that's in front of you?
0:26:17 > 0:26:20It's kind of similar to what you find at the seaside.
0:26:20 > 0:26:21Okie-doke.
0:26:21 > 0:26:24It's formed under water, isn't it, Limestone, I think.
0:26:24 > 0:26:27They're a bit like barnacles, really.
0:26:28 > 0:26:32So if we lower you down slowly, have a good look at the rock close up
0:26:32 > 0:26:35to see if you can see any really small fossils.
0:26:35 > 0:26:36OK.
0:26:36 > 0:26:38'Now, sometimes comparing what you see today
0:26:38 > 0:26:41'and applying it to the past can lead you astray.'
0:26:41 > 0:26:44'What they're calling barnacles is actually tufa.'
0:26:44 > 0:26:47So those little fossils that you're looking at in front of you,
0:26:47 > 0:26:51are they the round polo mints like the ones that we saw
0:26:51 > 0:26:56in the hydrochloric acid test, or are they long, sort of elongate?
0:26:56 > 0:26:58These ones are a bit longer.
0:26:58 > 0:26:59Yeah.
0:26:59 > 0:27:00They're joined together, then?
0:27:00 > 0:27:02This one's like the polo mint one.
0:27:02 > 0:27:04There, yeah.
0:27:04 > 0:27:06Like little discs stacked upon each other.
0:27:06 > 0:27:08It was really good, it was quite easy climbing,
0:27:08 > 0:27:12but it meant I could look at the rocks and look at the fossils in the rocks.
0:27:12 > 0:27:15It was quite hard to look for the kind of things like the fossils,
0:27:15 > 0:27:19but once you got used to it, Laurie was quite good at it as well,
0:27:19 > 0:27:22and we were looking through them and we found out the names
0:27:22 > 0:27:26of a couple, so we will be able to see how old the fossils were.
0:27:30 > 0:27:31So you've seen what I think.
0:27:31 > 0:27:35With the climb over, Tom and Laurie have 20 minutes to look at
0:27:35 > 0:27:37what they've discovered and to think about the question.
0:27:37 > 0:27:41What climate and conditions this rock was formed under,
0:27:41 > 0:27:44and since then, what processes have affected it?
0:27:44 > 0:27:47It's been used by humans, obviously, by bolting the routes.
0:27:47 > 0:27:49Yeah, there were lots of bolts.
0:27:49 > 0:27:52- So rock climbing. It's also been quarried, hasn't it?- Yeah.
0:27:52 > 0:27:54Not sure what for, but...
0:27:54 > 0:27:56Maybe to get the calcite out.
0:27:56 > 0:27:57Yeah.
0:27:57 > 0:27:59What else do you think?
0:27:59 > 0:28:01Well, there's lots of plants growing in it,
0:28:01 > 0:28:03- and it's a nature reserve, I think, now.- Yeah.
0:28:03 > 0:28:06So people are looking after it.
0:28:06 > 0:28:07We found fossils,
0:28:07 > 0:28:12and maybe they suggest that animals were living around here.
0:28:12 > 0:28:15We think it's formed in layers.
0:28:15 > 0:28:16Yeah.
0:28:16 > 0:28:19And different textures of the rock and colour.
0:28:19 > 0:28:21- Is that all our evidence?- Yeah.
0:28:23 > 0:28:27So, Tom, Laurie, can you just summarise the evidence
0:28:27 > 0:28:30that you came across, and what interpretations you've made?
0:28:30 > 0:28:34Well, obviously the rock's been bolted by humans to climb on,
0:28:34 > 0:28:39and as well as that, something's been quarried out of these rocks.
0:28:39 > 0:28:41What do you think has been quarried, then?
0:28:41 > 0:28:43I'm not sure. Maybe some kind of fossil or crystal?
0:28:43 > 0:28:47So limestone is used a lot in industry,
0:28:47 > 0:28:50and also a lot of the houses around here are made of limestone
0:28:50 > 0:28:54- themselves, so it could have been used as a natural resource in that way.- Yeah.
0:28:54 > 0:28:56So, Laurie, the geology part of it.
0:28:56 > 0:29:00So, first of all, using present day knowledge
0:29:00 > 0:29:03about where rocks are formed, what evidence did you go
0:29:03 > 0:29:06and then look for to interpret how this rock may have been formed?
0:29:06 > 0:29:09After we found out that the rock was limestone,
0:29:09 > 0:29:13we knew that it was a sedimentary rock,
0:29:13 > 0:29:17and so we know that they are built up by clay and bits of mud
0:29:17 > 0:29:21all going on top of each other, and eventually kind of fossilising.
0:29:21 > 0:29:24So did the tests that we did with the hydrochloric acid
0:29:24 > 0:29:27tell us that it was a specific type of sedimentary rock?
0:29:27 > 0:29:29We knew that it was limestone then.
0:29:29 > 0:29:32So that's what it told us, that it was limestone. Brilliant.
0:29:32 > 0:29:35As we were climbing up, we could see the layers of where these
0:29:35 > 0:29:39different types of mud and clay had all gone on top of each other.
0:29:39 > 0:29:44And amongst the mud, there was also some, did you say fossils?
0:29:44 > 0:29:46Yeah, we found lots of fossils.
0:29:46 > 0:29:49They were round and looked a bit like polo mints.
0:29:49 > 0:29:52OK, so the fossils didn't seem to be whole,
0:29:52 > 0:29:55they were all broken up and mixed up, OK.
0:29:55 > 0:29:57When you were climbing,
0:29:57 > 0:30:00you came across some quite strange structures.
0:30:00 > 0:30:04Yeah, it was a bit like going into a cave.
0:30:04 > 0:30:06- There were these, like, stalactites. - OK.
0:30:06 > 0:30:10We were wondering whether maybe they were formed from water
0:30:10 > 0:30:15dripping down the rocks, which is how stalactites are formed.
0:30:15 > 0:30:18We wondered whether it was maybe underwater at some point.
0:30:18 > 0:30:21Can you think of any modern-day environment
0:30:21 > 0:30:24where you might have, sort of, limey mud,
0:30:24 > 0:30:29where organisms might be living on the bottom of the sea.
0:30:29 > 0:30:32Anywhere around the world that sounds familiar to that?
0:30:32 > 0:30:36We did think of maybe the coral reef in Australia.
0:30:36 > 0:30:37Right, OK.
0:30:37 > 0:30:40Well done, guys. I think you've done really well.
0:30:40 > 0:30:43'Well, today's challenge was all about the conditions
0:30:43 > 0:30:44'under which this rock was formed
0:30:44 > 0:30:47'and the subsequent processes that have affected it.'
0:31:17 > 0:31:21Our shelly mud, now a limestone, is exposed near the earth's surface.
0:31:43 > 0:31:46Tom and Laurie both weren't really geologists,
0:31:46 > 0:31:47they've come from geography,
0:31:47 > 0:31:51and as a team, that meant that they really had to look at the evidence
0:31:51 > 0:31:54and find things together, so they were both in the same boat there.
0:31:54 > 0:31:57I think working as a team was quite useful, seeing as we could put
0:31:57 > 0:32:01both our thoughts together and combine them into something better.
0:32:01 > 0:32:03I think it did pay off, being confident.
0:32:03 > 0:32:07We were positive about things, and it went well for us.
0:32:07 > 0:32:10What they did was they really started to relate to each other,
0:32:10 > 0:32:13they started to share ideas and share their evidence.
0:32:13 > 0:32:15I think it's very important to gather lots of evidence
0:32:15 > 0:32:18before you come to the final conclusion.
0:32:18 > 0:32:21If I got the opportunity to do this again, I'd definitely do this.
0:32:21 > 0:32:24I had a really good time.
0:32:24 > 0:32:26That's it's from Castle Inn,
0:32:26 > 0:32:29but still to come, we'll be moving to Staffordshire
0:32:29 > 0:32:32and climbing in an area which owes it's formation to river action.
0:33:27 > 0:33:30Today the gritty sandstone Roaches in Staffordshire
0:33:30 > 0:33:33form part of the Peak District's National Park.
0:33:33 > 0:33:36Thanks to the eerie and stunning rock formations,
0:33:36 > 0:33:39it's popular with tourists who visit for walking and climbing.
0:33:42 > 0:33:45I'm Dr Tom Challands and I'm here today at the Roaches
0:33:45 > 0:33:48to challenge two young enthusiastic climbers and geologists,
0:33:48 > 0:33:50by posing a geological question to them
0:33:50 > 0:33:52that they are going to have to answer
0:33:52 > 0:33:55by climbing up the cliff face here and collecting evidence.
0:33:58 > 0:34:01I'm Anna. I am 16 years old
0:34:01 > 0:34:03and I study GCSE geology.
0:34:03 > 0:34:06I like, sort of, finding out how things have formed
0:34:06 > 0:34:08and how they evolve, almost, over the years.
0:34:12 > 0:34:15I'm Jonny. I'm 15 and I live in Cornwall.
0:34:15 > 0:34:17I enjoy geology because I enjoy working in the field
0:34:17 > 0:34:20and collecting data and evidence.
0:34:20 > 0:34:21Here at the Roaches,
0:34:21 > 0:34:25the sand that formed these rocks we have here around us today,
0:34:25 > 0:34:29was deposited in an ancient river delta about 300 million years ago.
0:34:29 > 0:34:32If you have trouble imagining what this may be like,
0:34:32 > 0:34:35look at these pictures of a modern-day braided river.
0:34:35 > 0:34:38And what's happened since is that these rocks were consolidated
0:34:38 > 0:34:41and compacted to form hard sediment.
0:34:41 > 0:34:43The hard rock that we are going to climb on today
0:34:43 > 0:34:46is that soft rock above and below have been weathered away
0:34:46 > 0:34:49to leave a nice, big gritstone escarpment.
0:34:49 > 0:34:52What's going to be very difficult for the children today
0:34:52 > 0:34:54is to make that relation between a modern environment
0:34:54 > 0:34:56and the ancient environment here.
0:34:56 > 0:34:58That's a key part of geology.
0:34:58 > 0:35:01It's about uniformitarianism, the present is the key to the past.
0:35:02 > 0:35:05So by reflecting on modern depositional environments
0:35:05 > 0:35:06like the Mississippi Delta,
0:35:06 > 0:35:09hopefully they will be able to recognise some of those structures
0:35:09 > 0:35:13and some of those meandering river forms here in the Roaches rock.
0:35:13 > 0:35:17Jonny, Anna. We're sitting here at the bottom of a rather misty,
0:35:17 > 0:35:20wet Roaches crag and it's about time we gave you a challenge to do,
0:35:20 > 0:35:22so we can get moving and get your brains ticking.
0:35:22 > 0:35:25Your challenge today is this.
0:35:37 > 0:35:40There's some paper there that you can make notes on,
0:35:40 > 0:35:43and also choose four pieces of equipment
0:35:43 > 0:35:46from our geological kit box here.
0:35:46 > 0:35:49Choose wisely and choose them
0:35:49 > 0:35:51according to the challenge we have just set.
0:35:51 > 0:35:55They can choose four from this range of geological equipment.
0:35:55 > 0:35:59Some will be really useful on this climb - others will be useless.
0:35:59 > 0:36:02They don't know this area or the route they're going to climb.
0:36:02 > 0:36:04They'll have to find as many clues as possible
0:36:04 > 0:36:06to unlock the rock's history.
0:36:09 > 0:36:12I think it's a good challenge and I'm looking forward
0:36:12 > 0:36:15to going climbing and collecting some evidence.
0:36:15 > 0:36:17This might be useful, for grain sizes.
0:36:17 > 0:36:18Oh, OK yeah.
0:36:20 > 0:36:24We chose the hand lens so that we can look at the different grain sizes
0:36:24 > 0:36:29in more detail so we can see sort of where they are placed,
0:36:29 > 0:36:30which should help us
0:36:30 > 0:36:34I also chose the Geological Time Scale because that means that
0:36:34 > 0:36:37we might be able to date round about when it was formed
0:36:37 > 0:36:40which might help us with our investigation.
0:36:40 > 0:36:44The other thing we chose was a compass clinometer to work out
0:36:44 > 0:36:45the angle of the rocks.
0:36:45 > 0:36:46We think it's going to go OK
0:36:46 > 0:36:50if we can find the right evidence to prove our investigation.
0:36:51 > 0:36:53Jonny and Anna are both doing their GCSE geology
0:36:53 > 0:36:56and know how important it is to look at the grain size
0:36:56 > 0:36:58and the grain shape of sedimentary rocks.
0:36:58 > 0:37:01So they've got a grain size card and a hand lens
0:37:01 > 0:37:03to look at the grains as well, and that's brilliant.
0:37:03 > 0:37:05What they haven't taken is the notebook.
0:37:05 > 0:37:07They may spot all of these things,
0:37:07 > 0:37:10but they won't be able to write down their observations.
0:37:10 > 0:37:12It's very important to record your data.
0:37:12 > 0:37:16They've also got the compass clinometer and that will allow them
0:37:16 > 0:37:20to measure the direction of current flow, in beds and foresets,
0:37:20 > 0:37:23cross-bedding that they might observe in the rocks.
0:37:23 > 0:37:27So the weather's clearing up now, the rock's still a bit greasy,
0:37:27 > 0:37:29hopefully if the sun does come out a bit
0:37:29 > 0:37:31and it will be just enough to dry off.
0:37:37 > 0:37:39We're about to start climbing up the rock face,
0:37:39 > 0:37:44to find some evidence to see whether the sediments were deposited
0:37:44 > 0:37:45and which way up the rocks are.
0:37:45 > 0:37:47If you don't know what you're doing,
0:37:47 > 0:37:50Anna and Jonny's field study challenge has its risks.
0:37:50 > 0:37:52It shouldn't be undertaken without expert help.
0:37:52 > 0:37:56I'm looking forward to it. I think it's going to be a good challenge.
0:37:56 > 0:38:00Here you can start taking measurements almost immediately,
0:38:00 > 0:38:01even before you start the climb.
0:38:01 > 0:38:04These large, rounded rocks Jonny is clambering over
0:38:04 > 0:38:06are ideal to take the first reading.
0:38:06 > 0:38:08I've not got a pen.
0:38:08 > 0:38:09Got the chalk?
0:38:13 > 0:38:17It's really important to use either chalk or a pencil
0:38:17 > 0:38:19when taking dip and strike measurements.
0:38:19 > 0:38:22It washes away, so there's no damage to the rock.
0:38:22 > 0:38:24I think the strike is measured at about 30.
0:38:24 > 0:38:27- Does that sound about right? - Yeah, that sounds right.
0:38:29 > 0:38:33Jonny's making good use of the way the rock is eroded
0:38:33 > 0:38:34to help him climb.
0:38:34 > 0:38:37These cracks, smooth ledges and the coarse, gritty rock all help.
0:38:37 > 0:38:40One thing that Anna and Jonny may have found difficult is to tell
0:38:40 > 0:38:45the difference between bedding and foresets of cross beds.
0:38:45 > 0:38:47Here we can see clearly the difference.
0:38:47 > 0:38:52The bedding plane is at a shallower angle to the foresets
0:38:52 > 0:38:56that dip down, away from the bedding plane.
0:38:58 > 0:39:00And the foresets will give us an idea
0:39:00 > 0:39:02of the direction of current flow,
0:39:02 > 0:39:03whereas by measuring the bedding plane
0:39:03 > 0:39:06it just tells us some structural geological information.
0:39:10 > 0:39:13Jonny's doing well, wedging his hands and fingers
0:39:13 > 0:39:16into the weathered rock surface to pull himself upwards.
0:39:18 > 0:39:22'This section is tough, and it being damp makes matters worse.'
0:39:22 > 0:39:25'Jonny needs to carefully balance and transfer his weight
0:39:25 > 0:39:27'from foot to foot.'
0:39:28 > 0:39:30Trust those feet, Jonny.
0:39:30 > 0:39:32Trust them!
0:39:32 > 0:39:34Push down with your palms to push you up higher.
0:39:34 > 0:39:36Yes, perfect.
0:39:38 > 0:39:40Excellent. Brilliant, well done.
0:39:47 > 0:39:50'Another chance to take some vital readings, he's making great use
0:39:50 > 0:39:54'of this well-defined bedding plane to act as a ledge to stand on.'
0:39:54 > 0:39:56It looks like it could be the front of crossbeds.
0:40:04 > 0:40:06OK, it's 21.
0:40:10 > 0:40:11About...
0:40:14 > 0:40:1620.
0:40:16 > 0:40:18It's definitely about 20, I think.
0:40:21 > 0:40:24What this climb is allowing us to do is get a really good profile
0:40:24 > 0:40:27through the rock section to see if the lithology,
0:40:27 > 0:40:29if the type of rocks are changing.
0:40:29 > 0:40:32And here we are about half way up the climb now, and just having
0:40:32 > 0:40:36a quick look at it, we still have the same type of sandstone.
0:40:38 > 0:40:42Being a Cornish granite climber, this should be second nature to you.
0:40:42 > 0:40:45'This is called a mantelshelf.
0:40:45 > 0:40:47'He needs to push with his hands and arms
0:40:47 > 0:40:48'to get his weight over the ledge.
0:40:48 > 0:40:51'Really tough.'
0:40:53 > 0:40:55Brilliant, well done.
0:40:58 > 0:40:59Brilliant, fantastic.
0:40:59 > 0:41:04'At last, after an agonising wait, Anna heads on up.'
0:41:08 > 0:41:10So, here on the climb, it's worthwhile just looking
0:41:10 > 0:41:13at the grain size of the rock we have in front of us.
0:41:13 > 0:41:16And using this grain size card, we can quickly measure
0:41:16 > 0:41:19how big the grains of sand are in this gritstone.
0:41:19 > 0:41:22Simply compare the size of the grains.
0:41:22 > 0:41:26They seem to be a coarse sand to a very coarse sand.
0:41:26 > 0:41:29With occasional larger pebbles of quartz,
0:41:29 > 0:41:32which are rounded sub-angular.
0:41:32 > 0:41:35Though the majority is this coarse sandstone.
0:41:35 > 0:41:39The roundness of the grains tells us how far they've been transported
0:41:39 > 0:41:41from where they were originally weathered.
0:41:41 > 0:41:43A well-travelled grain is smooth and round.
0:41:43 > 0:41:46The more angular, the more local.
0:41:46 > 0:41:49That's the most important bit on this first section.
0:41:49 > 0:41:51It's all about your feet.
0:41:51 > 0:41:52Oh!
0:41:52 > 0:41:53You're doing really well here.
0:41:55 > 0:41:58It gets greener and slimier right above where you are there.
0:41:58 > 0:41:59That's it.
0:41:59 > 0:42:00Yes.
0:42:00 > 0:42:01Oh!
0:42:02 > 0:42:04'Anna's doing really well.'
0:42:04 > 0:42:07'The lower part of this climb is hard because there are
0:42:07 > 0:42:10'so few defined bedding planes to provide good climbing holds.'
0:42:19 > 0:42:21I'm going to take another measurement here.
0:42:21 > 0:42:23'Anna's checking grain size as it can tell us
0:42:23 > 0:42:25'a lot about the energy of water flow.'
0:42:25 > 0:42:28'Large grains point to fast-flowing, high energy water,
0:42:28 > 0:42:32'whereas small grains indicate a lower energy.'
0:42:32 > 0:42:36Further down, there was a few, like, coarser ones within the finer ones.
0:42:36 > 0:42:40But here there doesn't seem to be as many, like, coarse ones.
0:42:40 > 0:42:42OK, then. That's a really good observation.
0:42:42 > 0:42:45'Anna is climbing up a vertical joint here,
0:42:45 > 0:42:46'very typical of grit stone.
0:42:46 > 0:42:50'These joints allow the climber to wedge in their feet and hands
0:42:50 > 0:42:51'and to get good purchase.'
0:42:51 > 0:42:54- Well done, Anna. You're doing well. - Great.
0:43:00 > 0:43:03Quite large, but slopey rounded holes there.
0:43:05 > 0:43:07'They missed a trick not picking the notebook
0:43:07 > 0:43:10'but full marks for taking the initiative
0:43:10 > 0:43:11'and writing on their hands.'
0:43:13 > 0:43:16You can see, just the rocks in front of us here
0:43:16 > 0:43:19is slightly, slightly polished.
0:43:19 > 0:43:23Very clear if you look down at the slab, see, it's mostly green,
0:43:23 > 0:43:26apart from the lighter-coloured areas
0:43:26 > 0:43:29where people have been using little bits for their feet.
0:43:29 > 0:43:34So even on this tough, millstone grit that was used
0:43:34 > 0:43:35to make grinding stones,
0:43:35 > 0:43:38it still does wear away and polish down a bit.
0:43:38 > 0:43:42So where the fine grain sand sediment is weathering away,
0:43:42 > 0:43:44it leaves these big ledges
0:43:44 > 0:43:48that weather and erode into these slopey surfaces.
0:43:48 > 0:43:50In climbing terms, we call them slopers.
0:43:59 > 0:44:02'The top of this climb is so different from the base.'
0:44:02 > 0:44:05'Large joints have created a chimney effect
0:44:05 > 0:44:07'which is tricky to squirm up and through.'
0:44:12 > 0:44:14Brilliant.
0:44:19 > 0:44:21Brilliant, well done.
0:44:21 > 0:44:24That's an almighty stretch.
0:44:24 > 0:44:26Fantastic.
0:44:26 > 0:44:29So, just to remind you, we asked Jonny and Anna to find out
0:44:29 > 0:44:33if the sediments that formed these rocks are from an ancient
0:44:33 > 0:44:35river delta or deep marine environments,
0:44:35 > 0:44:37and are they the right way up?
0:44:37 > 0:44:40We've got twenty minutes to look at your evidence and observations,
0:44:40 > 0:44:42and come up with an interpretation
0:44:42 > 0:44:44and conclusion to the question we asked you earlier on.
0:44:44 > 0:44:46- OK.- Well done, brilliant.
0:44:49 > 0:44:52You've had some time to sum up your evidence. How's it been?
0:44:52 > 0:44:54Has it been easy or difficult?
0:44:54 > 0:44:56Well, some bits have been easier than the others.
0:44:56 > 0:45:00It's easier to tell where it was deposited than which way up it is.
0:45:00 > 0:45:04We think it was a delta, because if it was a deep marine environment
0:45:04 > 0:45:08then there would be bigger grains at the bottom and smaller at the top.
0:45:08 > 0:45:10But it's been fairly consistent the whole way through,
0:45:10 > 0:45:13which indicates it might have been a delta, rather than deep marine.
0:45:13 > 0:45:18So rather than having sporadic influxes of sediment
0:45:18 > 0:45:21which then settle the coarse grains first,
0:45:21 > 0:45:23medium, then going into fine mud,
0:45:23 > 0:45:25we are just seeing sandstone, sandstone, sandstone.
0:45:25 > 0:45:29Yeah, it's just a very similar thickness the whole way through.
0:45:29 > 0:45:30Why is that like the river?
0:45:30 > 0:45:34There is cross-bedding that indicates that there was a flow of water
0:45:34 > 0:45:37going over the bed when it was deposited and you wouldn't get
0:45:37 > 0:45:40that in deep marine because there is not usually a current.
0:45:40 > 0:45:41But the way up structure, then,
0:45:41 > 0:45:43whether or not this is the right way up.
0:45:43 > 0:45:45Why did you struggle there?
0:45:45 > 0:45:47We just don't think that we got enough evidence
0:45:47 > 0:45:48to say which way up it was.
0:45:48 > 0:45:49It wasn't conclusive.
0:45:49 > 0:45:52There were different things that indicated it was upside down
0:45:52 > 0:45:55and things that indicated that it was the right way up.
0:45:55 > 0:45:59If it was the right way up, it would be like a...is it concave?
0:45:59 > 0:46:00Yeah, that's right.
0:46:00 > 0:46:05Yeah, and if it was the wrong way up, it would be more...
0:46:05 > 0:46:06Convex.
0:46:06 > 0:46:08Yeah, convex. That's the one.
0:46:08 > 0:46:11And you're saying that here, because they're so large,
0:46:11 > 0:46:13you can't really see the curve, it just seems to be straight.
0:46:13 > 0:46:14Yeah.
0:46:14 > 0:46:19I really like your interpretation of ruling out
0:46:19 > 0:46:22the deep marine environment in favour of the delta.
0:46:22 > 0:46:23So, well done, guys.
0:46:23 > 0:46:26I think that was brilliant that you accepted that you just haven't got
0:46:26 > 0:46:28enough data to answer the second part of the question
0:46:28 > 0:46:30and that's the way geology and science goes.
0:46:31 > 0:46:34Today's challenge was all about the present
0:46:34 > 0:46:37being the key to the past - uniformitarianism.
0:46:37 > 0:46:39Let's look in detail what happened here.
0:46:42 > 0:46:44During the Carboniferous period...
0:47:13 > 0:47:15Finer grained sediments form.
0:47:15 > 0:47:19Here's a calm, sometimes marshy area with muddy or fine sand.
0:47:19 > 0:47:22Here's a cross section through a delta sea transition.
0:47:32 > 0:47:35Repetition of the sea levels rise-fall-rise
0:47:35 > 0:47:37produces mud-sand-mud-cycles.
0:47:51 > 0:47:54What was really impressive was that they were not afraid to say
0:47:54 > 0:47:57that they didn't have enough information
0:47:57 > 0:47:58to answer part of the question.
0:48:00 > 0:48:04The day's been changeable, we've had some mist, we've had some rain.
0:48:04 > 0:48:07I had good fun on the climb, having had a little slip myself.
0:48:07 > 0:48:09'But that is all part of climbing.'
0:48:09 > 0:48:11Did I put my climbing shoes on?
0:48:11 > 0:48:13Really good way of combining climbing and geology together,
0:48:13 > 0:48:16which are two of my favourite things.
0:48:16 > 0:48:18The climb was really, really good.
0:48:18 > 0:48:21It was quite difficult at the bottom and then it was a bit simpler
0:48:21 > 0:48:23in the middle, because there were more handholds and footholds.
0:48:23 > 0:48:26And then the chimney bit was quite difficult and scary.
0:48:26 > 0:48:30And then we got pulled over the edge, and then you were done.
0:48:34 > 0:48:37So that's it's from our three climbs.
0:48:37 > 0:48:40I hope the three challenges have helped you think about how to
0:48:40 > 0:48:43gather and test evidence to uncover how a landscape is formed and shaped,
0:48:43 > 0:48:48and also show how field study can be an exhilarating part of this.
0:48:52 > 0:48:55I'd love a scone. Thank you very much, sir.
0:48:55 > 0:48:57Ha-ha!
0:49:05 > 0:49:06That's Bulgarian.
0:49:06 > 0:49:07Bulgarian?
0:49:07 > 0:49:10That's the most beautiful knot I've ever seen.
0:49:10 > 0:49:13Subtitles by Red Bee Media Ltd