Come here because of the Education Guardian Best of the Web article from 13th December 2005 ? Welcome - why not explore THE SITE more....
In the 'AS' exam, a requirement is to know an example of either LIMESTONE or GRANITE landscape. This page will help you learn more about these distinctive landscapes.
LIMESTONE: Yorkshire Dales - classic Malham round, Burren in Republic of Ireland, White Peak area of Peak District - we now have some great MEMORY MAP software to help us teach this area and go through the physical features. The LIMESTONE section of this website has a range of other links. We also use an excellent PHOTO JAM created by V. Vannet - a search on FLICKR or similar photo-sharing sites would provide plenty of suitable fodder.
A dry valley in the White Peak. Picture taken by Mister P. Notice classic valley shape, but absence of stream (that's a dry stone wall running down the middle)
GRANITE: Dartmoor (some excellent stuff from the National Park site), Isle of Arran: go HERE for a useful summary of the Igneous geology of the island, with some dramatic photographs. Also plenty of granite in the SW Peninsula, which is essentially one large granite feature known as a batholith.
There are some classic features on the island: glacial ones too. A useful place for fieldwork too.
Arran has a whole host of important Geological / Geographical case studies that can be used. Try a search for some useful sites.
OS 1: 25000 Map of Malham area including the classic Malham round, this is well featured in many textbooks, including David Waugh's 'Key Geography for GCSE', and also a GeoActive document on the walk. Also featured in 'Essential Mapskills' spiral bound book mentioned elsewhere on the site. (Once had an interview for a job at Malham Tarn Field Centre, but that's another story..) We have this on the ANQUET MAPS and MEMORY MAP platforms to allow us to see a 3D landscape.
Terrain forming on limestone is known as KARST TOPOGRAPHY. There are various types of limestone, but it is the Carboniferous limestone that we shall be considering.
Rock is permeable, but also soluble in rainwater due to formation of weak carbonic acid as rainwater falls through polluted air. Pure water can dissolve 1 part per 30,000, but as carbonic acid, dissolves 1 part per 7000.
Development of karstic topography depends largely on 4 factors:
a) Solubility: depends on amount of Calcium carbonate. Dolomitic limestone is less soluble than carboniferous or oolitic.
b) Type of permeability:
2 types: rock may be porous throughout, permitting mass permeation through its body, leading to formation of underground channels
or, rock may be dense but has well defined joints and bedding planes through which the transport of water is concentrated (the case with carboniferous limestone) - solution and corrasion form cave systems underground
c) Relief. If the limestone is close to base level, there may only be slight features formed by phreatic water (below the water table)
Where the limestone is higher up, rainwater is able to disappear underground and leave some of the typical features of the Dales, with very little surface drainage. Forms shallow cave systems (vadose) i.e. usually above the water table (below is phreatic - remember VIP...)
d) Rainfall: this is the erosive agent, so more rainfall means more erosion.
Carbonation enlarging cracks in limestone above Malham Cove, Yorkshire Dales. Picture taken by Mister P.
Another place where the limestone is re-deposited is at Mother Shipton's Cave in Knaresborough (site of my very first job interview... Knaresborough that is, not the cave...) This has a website HERE. Lots of 'tufa tea' jokes to be had.
To get the BEST WEBSITE ON LIMESTONE though, you need to head 'up North' to BBC Scotland's Education pages which, for some reason, have loads of stuff on limestone in the YORKSHIRE DALES. It has details on: Land Use, Surface Features, Underground Features, Mapwork (identifying features on the map), Field Drawing (skills practice), Revision and Webguide. Need to have FLASH to get the full features of the site. Recommended.
Watlowes Dry Valley, above Malham Tarn. Picture by Mister P.
A good article in the September 2002 issue of 'Geography Review', written by David Atkinson covers a lot of the issues relating to limestone weathering and scenery, and would be well worth reading for those with an interest.
QUEENSBURY SCHOOL in Bradford has added a VIRTUAL TOUR OF MALHAM COVE - apparently because of the poor weather the last time the school visited the area, so at least this guarantees that you stay dry as you visit the locations on the classic Malham round... Thanks to LK for adding this link.
Recently got sent a very nice CD-ROM postcard. Has good information and a VIRTUAL TOUR of the main Malham round. This is well worth buying if you ever go to the area. Wonder if it's available online ?
For more on Granite landscapes, I recommend Issue 436 of Geofile Online (published January 2003) - this has some excellent information and case study material and a read of this should set up most 'AS' students nicely for the exam.
Again, visit the Dartmoor National park site for downloads of PDF files on Granite and Tors. Tor Formation sheet has some excellent images and information well set out. I issue this to my groups as well before the exam. Well it saves me teaching it to them...
The underlying geology controls the surface features. Talks about the origins of the word granite, which comes from a word meaning 'grain' - not surprising given the nature of the rock. Also lots on tor formation and clitter slopes. Work of Linton is referred to: one of 2 theories as to the formation of these features. The key is in the bedding..
We have also used a programme from 27 years ago! Called 'The Land' it looks at different areas. Presented by Bill Grundy, the programme on Dartmoor features some good flared trousers and Vauxhall Victors. It has details on the basic features of the landscape:
- 'Moor and Tor' landscape
- Thin acidic soils
- Poor drainage leading to peat formation, blanket bog and standing water
- Usage of the area as military training ground, also a desolate location for prison.
- High rainfall and frequent mist in the area
- Absence of trees in many areas, although there are a few areas of ancient woodland e.g Wistman's Wood, which I remember visiting on an undergraduate fieldtrip.
- Granular disintegration and kaolinisation (hydrolysis) of granite is explored. Chemical weathering. Expansion of joints.
- Mining of china clay around the area: aureole - area surrounding the granite intrusion where rocks are metamorphic.
From the top of Hay Tor looking across to more Tors.
Recently visited the Dartmoor Visitor Centre at Princetown, which is the location of Dartmoor Prison, which you can buy postcards of (cue 'Wish you were here' jokes....) There is a 40 mph speed limit throughout the moor which is a good idea with so many livestock free to wander. Bought a couple of useful resources here. Ranger Ralph is the vehicle used to help teach younger people about the moor. I bought his guide to the moor. Spoke to one of the people in a Tourist Information centre who said that the Moor Care Less Wear had been introduced because of some money that had been made available to fund the project.
One of the best sites on Dartmoor is that produced by Richard Knight, which is linked to from HERE. He has a website featuring walks around Dartmoor, which also has lots of useful information on the moor, as well as the TORS. There are a series of panoramas as well. He has kindly given permission for them to be used for educational purposes. Please contact him via the site if you want to use the image.
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