Features of Plate Boundaries

Features of Plate Boundaries The key idea of the lesson is… Unique landforms occur at plate margins: location and formation of fold mountains, ocean trenches, composite volcanoes and shield volcanoes. By the end of the lesson you will… have a complete map showing where ocean trenches and young fold mountains are found. four, A4 case studies. Each case study will have a diagram, named example and explanation. detailed notes on the features of a named volcano (Stromboli, Italy or Mt. Teide, Tenerife).

Fold Mountains @ Collision Margins Geosyncline (depression) fills with layers of sediment from rivers. The two continental plates move towards each other, compressing the sediment. Sediments folded inwards and upwards to form major mountain ranges.

Fold Mountains @ Destructive Margins Pressure of subduction pushes the edge of the continental plate upwards and inwards, crumpling it up into mountains.

‘Young’ Fold Mountains ‘Young’ less than 65 million years old. Includes today’s major mountain ranges: Andes, Himalayas, Rockies and the Alps. Not ‘old’ fold mountains such as the Lakes.

Distribution

Ocean Trenches Form at destructive subduction zones. Very deep. Parallel to fold mountains. e.g. Peru-Chile, Japan

Location of Trenches

Features of Plate Boundaries Using the information around the room: Draw a labelled diagram for each feature Explain how the feature is formed Say what type of plate boundary they occur at Give named examples e.g. Himalayas Add the trenches and fold mountains to your tectonic map using page 12.

What do you know about volcanoes?

Magma Chamber Lava Flow Ash Cloud Main Vent Crater Crust Side Vent Parts of a Volcano Magma Chamber Lava Flow Ash Cloud Main Vent Crater Crust Side Vent

The heat melts the rock from the oceanic plate forming magma. The eruption creates layers of ash and lava which form the sides of the volcano. As more oceanic plate melts, more magma is formed creating a magma chamber under the ground. Each subsequent eruption builds the volcano. When continental and oceanic plates meet, the oceanic plate is forced under the continental plate because it is denser. As more magma is added the pressure in the magma chamber builds and the magma is forced up towards the surface, creating a dome. The volcano stops erupting and is dormant for a while. When the pressure gets too high, the magma erupts onto the surface creating a volcano. The place where the plates meet is called the subduction zone. The friction and the pressure mean that it is very hot. The volcano erupts again, creating more layers of lava and ash, making the volcano bigger.

Features of Plate Boundaries Using the information around the room: Draw labelled diagrams of shield and composite volcanoes. For each one: explain it’s formation, key features and give an example. Complete your Venn diagram to compare the two types of volcanoes.

Common Exam Questions Describe, with the aid of a diagram, how fold mountains are formed. Draw a labelled diagram(s) to explain why earthquakes occur at conservative plate boundaries. Give two differences between continental crust and oceanic crust. Explain how volcanoes form at constructive plate margins.

Features of Plate Boundaries The key idea of the lesson is… Unique landforms occur at plate margins: location and formation of fold mountains, ocean trenches, composite volcanoes and shield volcanoes. By the end of the lesson you will… have a complete map showing where ocean trenches and young fold mountains are found. four, A4 case studies. Each case study will have a diagram, named example and explanation. detailed notes on the features of a named volcano (Stromboli, Italy or Mt. Teide, Tenerife).

Homework Complete the grid. Due next lesson.