What landforms are found at different plate boundaries

What landforms are found at different plate boundaries? Fold mountains and Ocean Trenches AQA Geography Year 10

Learning objectives • Why fold mountains and ocean trenches form at destructive plate margins. • The difference between composite volcanoes which are associated with destructive plate margins and shield volcanoes which are associated with constructive plate margins.

Fold mountains • Young fold mountains (formed over last 65 million years) are the highest areas in the world. • All peaks over 7000 m are in central Asia, including Mt Everest at 8, 850 m. • Young fold mountains include ranges such as the Himalayas, the Rockies, the Andes and the Alps. • Fold mountains are large mountain ranges where rock layers have been crumpled as they are forced together.

The Himalayas Mountain range, northern Nepal Height 8, 848 metres

• The Rockie Mountains USA and Canada highest peak is Mount Elbert in Colorado at 4, 401 m

• The Andes South America Mount Aconcagua in Argentina has a height of 6960 m

The Alps The highest point is Mont Blanc At 4, 807 m

Ocean trenches are deep sections of the ocean, usually where an oceanic plate is sinking below a continental plate. Compare the blue ocean trenches to the following map of tectonic plate margins. Q 1. At what type of plate margin do fold mountains and ocean trenches form? Add the ocean trenches and fold mountains onto your blank maps of the world

What landforms are found at different plate boundaries? • Both fold mountains and ocean trenches result from plates moving together. If both landforms occur in the same area, they are found in association with subduction. • If fold mountains occur by themselves, they are in areas where collision is taking place.

Formation of fold mountains • Animation

Composite and Shield Volcanoes Low rounded peak Eruptions are frequent and nonviolent Wide base and gentle slopes Layers of runny lava (low viscosity) with little ash. Multiple layers of thick lava and ash Steep slopes and narrow base Eruptions infrequent but often violent

VISCOSITY • Viscosity is the resistance a material has to change in form. • Low Viscosity = NOT STICKY = Fast flowing. CREAM! • High Viscosity = STICKY = Slow flowing. TREACLE!

Activities 1. Write five questions you would ask to find out about the contrasts between a composite and shield volcano. 2. Swap questions with a partner and answer their questions. 3. What were the good points about the questions you have just answered? How might they be improved?

Popocatepetl composite volcano in Mexico is on the Ring of Fire!

Mauna Loa, Hawaii, is an excellent example of a shield volcano

What is happening here? Which type of volcano would you associate with this activity and why?