what are the effects of different plate margins on volcanic eruption?
- 0 votes
Answers for AQA spec only please
- 1 vote
Are you referring to how different plate boundaries produce different volcanic eruptions? If so it is all down to silica! Well more precisely magamatic differentiation e.g most evolved magma is found on oceanic vs continental covergence as plate thickness of continental plate is greatest so the magma gets really evolved as it travels through it (= silica enrichment as silica is last mineral to form) and then also more silica enrichment from melting subducting oceanic lithosphere as silica is first to melt. This produces silica rich, high viscosity lava (=acidic/ rhyolitic. >66% silica) composite and caldera volcanoes with explosive plinean and pelean eruption styles. If this is the kind of thing you are looking for here is a link to a powerpoint linking all this stuff together that may be of some help - http://getrevising.co.uk/resources/how_are_lava_type_volcano_shape_and_eruption_style_linked
- 1 vote
If you are talking about different plate margins and how they produce volcanoes then there are 2 types of plate boundries that form volcanoes, destructive and constructive.
destructive boundries form volcanoes by melting the oceanic crust when it is pushed down under the continental crust. This creates a magma chamber and the magma then rises up through cracks in the crust to form a composite volcano. These volcanoes are cone shaped and are made of layers of lava and ash. They are made of acidic lava which it thicker. this means that eruptions are less frequent but more explosive as the lava can block the main vent causing pressure to build up, and when this pressure is released the eruptions are more violent sometimes cause the volcano to blow it's self apart.
constructive plate boundires form volcanoes when the two plates pull apart creating a gap for the magma to rise to the surface. The volcanoes made are shield volcanoes.Tthese volcanoes are flatter with less steep sides and are less explosive than volcanoes formed on destructive plates. They are made from basic lava which is runny. this means that eruptions are less explosive as they don't cause blockages but therefore they are more frequent.
- -2 votes
convergent boundaries = volcano made, imagine two biscuits being pushed together, your get a little bulge where they crumble together