Dynamic Earth Flashcards
How are igneous rocks formed?
Igneous rocks are formed by molten rock from volcanoes cooling on the Earth’s surface.
How are metamorphic rocks formed?
Metamorphic rocks are formed from heat and pressure changing them over a long period of time. They could have been igneous or sedimentary or both.
How are sedimentary rocks formed?
Sedimentary rocks are formed from sedimentary material bound together through pressure over time. These can be either fine particles or coarse particles or both.
What is weathering?
Weathering is the breaking down into smaller particles of rocks and soil through natural processes such as wind and water.
Briefly explain the rock cycle
The rock cycle is the interactive process between igneous, metamorphic and sedimentary rocks.
What is the theory about plate tectonics
Plate tectonics is the theory that the earth’s outer layer, the lithosphere (crust and upper mantle) is divided into plates.
What is continental drift?
Continental drift is the motion by which the tectonic plates can move relative to each other.
Explain convection currents
Convection currents in the layer below the lithosphere (caused by the heat of radioactive decay rising) cause the tectonic plate movement.
List how many plate boundaries there are and what they are?
There are 3 types of plate boundaries – divergent, convergent and transform.
Explain what happens in divergent boundaries
Divergent boundaries involve plates moving apart from each other. Earthquakes and sea-floor spreading occurs as magma solidifies making more crust.
Explain what happens in convergent boundaries?
Convergent boundaries occur when plates move together. When the plates collide one plate will go over another (subduction). Mountains form (folding of tectonic plates) and earthquakes and volcanos are present (magma rises up and fills the gaps).
Explain what happens in transform boundaries?
Transform boundaries involve plates sliding past each other horizontally in opposite directions. Faults often occur (rocks fracture apart due to the pressure). No magma is formed and earthquakes occur.
Where are volcanoes and earthquakes more frequently found?
Most active volcanoes and earthquake zones are located along the boundaries of the plates.
Explain what hot-spots are?
Hot-spots are stationary areas of hotter magma below the lithosphere. The tectonic plates move over them volcanos can form in areas where there is no tectonic boundary. An example of land forming from a hot spot is Hawaii.
Australian Volcanoes are extinct and be able to name at least one example.
Australian Volcanoes are extinct and be able to name at least one example.
