February 26, 2014 Lesson on: Canyons, Wadiis and salt pans Key question: 1.How are the above landforms created? Dwight Sutherland 2014

TASK: Read the poem about the Grand Canyon. What geographic features of the Grand Canyon can you identify from this source? Glen Canyon Dam by Wilfred A. Elders (composed during the 2013 trip) Time and a river flowing, The river flowing free, From snowy mountain summits, To a balmy tropic sea. The Colorado River, A river running free, It carved a stupendous canyon, For all the word to see. Six million winter snow falls, The snowflakes falling free, Six million years of spring melts, Have rushed to meet the sea. The Kaibab Plateau rising, The river keeping pace? The tidal delta growing, An isostatic race? As upward went the Plateau, So downward cut the stream, Its riffles and its rapids, Down cut a mighty seam. Each surge of the raging river, Laid bare a rocky page, Layer after layer eroding, Each of an older age. Time and a river flowing, The river running free, The book of time was opened, To reveal earth's history. Time and a river flowing, Now concrete spillway drops, Restrain the annual flooding, And irrigate the crops. Vulcan tried to dam the canyon, Such conflict of water and fire! Though the lavas dammed the canyon, They fell to the river's ire. Two billion years of Earth's time, Or three score years and ten? How mighty is the canyon, How frail the works of men! Time and a river flowing, The river flowing free, Past the ruins of former dam-sites, After man has ceased to be! Dwight Sutherland 2014

Canyon – An example of hot arid landforms A canyon has 3 main characteristics Narrow valley Steep sides Created by river erosion Dwight Sutherland 2014

TASK: Describe how canyons like the Grand Canyon are formed. canyon-formed/14092.html canyon-formed/14092.html Key ideas you may want to include: Flash floods Baked surface River aims to get to baseline flow Little vegetation Layers of soft material between harder material Abrasion Infiltrate water Exogenous river Dwight Sutherland 2014

Canyon Landscape TASK: Study the diagram of a canyon (see below). As you watch the video (next slide) try to identify some of these. Dwight Sutherland 2014 Butte Mesa Steeped sides Exogenous river

Canyon Landscape TASK 1: Watch the video and try to identify some of these. Dwight Sutherland UT3hQlY4oek z748s4U Optional TASK 2: Study the image of the Grand Canyon Label a mesa, butte and steep sides.

TASK: Explain how wadis are formed. Use text, page Dwight Sutherland 2014 Wadi Degla in Egypt Key ideas you may want to include: Ephermeral river Braiding Steep sides Deposition Dry valley Transportation Hot arid and semi arid regions

Progress check discussion TASK: What’s the main difference between canyons and wadis? Dwight Sutherland 2014 CanyonWadi

TASK: Explain how salt pans are formed. Use text, page 148. Dwight Sutherland 2014 Etosha Salt Pan in Namibia. It can even be seen from space. See google earth link below. pan&ie=UTF- 8&ei=YgMSU5P0FdSrhAfOm4CAAw&sqi=2& ved=0CAgQ_AUoAg Key ideas you may want to include: Repeated process Ephermeral lakes Rate of evaporation Gentle sloping a relief (height of land) Loose grains can be transported Salt crystals Deposition

Lesson summary TASK: Classify these hot arid features as either water or wind features. Pediments Canyons Yardangs Sand dunes Wadis Pavements Salt pans Dwight Sutherland 2014