Conclusion Flashcards
(1) I have shown that…..
Tectonic activity produces a huge range of distinctive and contrasting landscapes associated with movements at different types of plate boundary.
(2) Intrusive landforms can what?
Vary enormously in scale but tend to have formed over long time scales to allow for insertion, cooling and denudation of the country rock to reveal the generous intrusion.
(3) This contrasts with…..
Extrusive landscapes which can be much larger in scale, e.g. the Columbia river lava plateaux covering 130,000km2, and tend to be more tectonically dynamic up to the present day despite forming over many thousands of years.
(4) this is exemplified by……
The 1980 Mt St Helens eruption which resulted in a range of permanent secondary landscape changes.
(5) these included: (Lahars)
Which rushed down the sides of the mountain before flowing into rivers at the base of the mountain and in some cases permanently diverting them.
(5) these included: (a gas blast)
From the exposed magma which devastated an area 30Km wide and extended 20km northwards, flattening trees within the surrounding zone.
(5) these included: (the volcano itself)
Was reduced in Height by 390 meters and a 3Km long crater was formed on the north-facing slope.
(6) seismic landscapes can…..
Vary hugely in scale and are characterised by very prominent but subtle features in the landscape.
(7) however…..
They also tend to be tectonically active and exhibit this with large episodic earthquakes, such as along the San Andreas fault in California.
(8) tectonic processes therefore…..
Play the most significant role in determining the morphology of landscapes affected by vulcanism.
(9) this remains true if……
The tectonic activity is current due to geographical location at a plate boundary or subduction zone (California Coast and the Cascade cordillera), or if the activity occurred millions of years ago and is no longer present (northern England and north west Scotland.)
