Key Question: How do plateau landscapes form? Key Words: Plateau(x) Undercutting

What is a plateau? STARTER: In pairs look at the photo and make A definition for what a plateau is (post it on board) Think of some examples a plateau is an extensive area of flat ground raised above the surrounding area.

….they can refer to very large areas e.g. the Tibet plateau, or they can refer to smaller areas e.g. Table Mountain, Cape Town, S. Africa

How do plateau form? They can be formed by any strong, resistant rock type. From the list below decide which are most to least likely to form plateau? Well cemented sandstone Basalt LEAST LIKELY Limestone Chalk Extension explain why! Mudstone Granite MOST LIKELY

Basalt also forms plateau! Inner Hebrides flood basalt plateau e.g. Staffa and Mull. What process makes the cliffs so steep? UNDERMINIG !!!

1. Draw the diagram on p.44 of Basic Mapskills Limestone also forms plateau e.g. Ingleborough, Yorkshire Dales 1. Draw the diagram on p.44 of Basic Mapskills Millstone Grit (Sandstone) Carboniferous Limestone 2. Explain why Ingleborough has formed a limestone Plateau? Impermeable slates Think about the: EXTENSION: why do caves form within the limestone? Why has the footpath been laid? Dip of strata. What the rock is made of. Resistance of Strata. Permeability of Strata.

Now complete the activities on the worksheet. Ethiopian Plateau

Ethiopian Plateau Dartmoor Ethiopian plateau and Dartmoor. Plenary: Compare and contrast the geology and scenery of the Ethiopian plateau and Dartmoor. Ethiopian Plateau Dartmoor upland Horizontal strata Freeze-thaw weathering Dry so little chemical weathering Cliffs and steep sided gorges plutonic Erosion by rivers No strata! Onion skin weathering Wet so lots of chemical weathering Rounded slopes volcanic Wind erosion

Landscapes formed from large igneous intrusions Cairngorms, Scotland: A 400 million year old granite pluton

Plutonic rocks cool … (where?) Volcanic rocks cool… (where?) underground On the surface

Cornwall is famous for it’s granite moorlands of Dartmoor and Bodmin Moor So what’s happening underground? Granite shows as areas of lower gravity. What does the gravity data indicate to you? That there is a larger area of granite beneath

E Section W-E across the Copy out the diagram and label : pluton, dyke feeding pluton, batholith, erosion surface, exposed granite and country rock Section W-E across the Cornubian batholith E Haig Fras Island Dartmoor Bodmin Moor Land’s End Scilly Isles ©Slide by CMC 50km

Dartmoor Red herring alert! Describe the landscape choosing from the descriptors below: Steep slopes, moderately steep slopes, gentle slopes, flat land, low land, upland, thin acid soils, thick clay soils, limey soils, caves, tors, swallow holes, influenced by angle of dip, no bedded rocks so no strata, uniform scenery, varied scenery, moorland, fine grained rocks, coarse grained rocks. Red herring alert!

Chemical weathering What type of weathering is important on Dartmoor; a wet area with acidic soil and temperatures above freezing for most of the time? Chemical weathering

Recall…Chemical weathering of granite Clay + quartz grains+ dissolved minerals Granite + acids ------- + --------- + --------