Geography Flashcards
Who’s ideas did they put together
Wegner and Hess
What are the slabs of rock under the earth called
Plates
Name all of the main plates
North American plate
South American plate
Nazca plate
Pacific plate
African plate
Eurasian plate
Indo- Australian plate
Antarctic plate
Name the layers of the Earth
Crust
Mantle
Outer core
Inner core
What do the plates float on
Liquid magma
What is it called when the liquid magma moves the plates around
Convection currents
What are the edges of the plates called
Boundaries
How hot is the mantle
2,000 - 4,000
Where is the crust at its largest
In the mountains
How does folding occur
Folding occurs at destructive plate boundaries. Great pressure leads to extreme heat. This softens the rock making it more bendable. Over millions of years in a very slow process the rocks are pushed upwards creating fold mountains. The upward folding of rock is called anticline and the downward folding of rock is called syncline. An example of fold mountains is the Himalayas where the Indian and Eurasian plates collide.
Explain how one type of igneous rock forms
Basalt : basalt is an igneous rock. It forms when lava emerges from a volcano or fissure. The lava then cools quickly, as it is exposed to the elements. It solidifies forming tiny crystals. Basalt is an extrusive igneous rock as it is formed on the Earths surface. Basalt is commonly used for a base in road construction. It is found in the Giants Causeway.
Explain how volcanoes occur
The most violent volcanoes happen at destructive plate boundaries and hotspots. Before an eruptions, magma and gasses build up in the magma chamber. When the pressure becomes too great, the volcanoes erupt through a pipe called a vent ejecting pyroclast. The top of a volcano can be blown off, the hole left is known as a crater e.g. Mount St. Helens 1980 eruption.
Describe how earthquakes occur
Most major earthquakes happen at destructive plate boundaries. These two plates collide and over decades of pressure build up at a point called a fault line. When the pressure becomes too great one plate slips releasing energy known as an earthquake. The point where the energy is released is called a focus. Energy radiates out in all directions, these waves are called shockwaves, most damage is done at the epicentre, which is the point directly over the focus on the Earths surface. When an earthquake happens in the ocean it can cause a huge wave called a tsunami e.g Japan 2011 earthquake and tsunami.
Explain how plate tectonics move
The core heats the magma in the mantle. The hot magma rises coming in contact with the crust. This creates friction which moves the plates. The magma is cooler now as it is farthest from the core. It sinks back to the core where the cycle is repeated. This cycle is called convection current which results in the plates moving e.g the Eurasian and North American plates are moving away from each other due to convection currents.
Write about mt St Helens
…
Write about Japan 2011 earthquake and tsunami
Where is marble found
Connemara green marble
Where is basalt found
Giants causeway co. Antrim
Where is limestone found
The Burran co. Clare
Explain how one type of sedimentary rock forms
Limestone is a sedimentary rock. When dead plants and animal build upon the ocean/lake floor it forms,s limestone. Over millions of years layers of sediments become compressed by the weight of other layers of dead plants and animals like cement. Limestone is an organic rock. Fossils can be found in Limes. Limestone can be found in the Burran Co.Clare. Limestone is commonly used for cement and in the construction industry.
Explain how one type of metamorphic rock forms
Marble is a metamorphic rock, it forms when limestone changes into marble due to the extreme heat and pressure. The change from the heat is called thermal metamorphism. Heat from the magma reaches up to 2000 degrees Celsius changing the make-up of rock it comes in contact with. Pure marble is white and different colours come from impurities. Green marble can be found in Connemara Co.Galway. Marble is most commonly used as a decorative stone e.g kitchen countertops.
Describe two ways humans interact with the rock cycle
Quarries supply materials for the construction industry such as gravel,sand,concrete blocks and decorative stone. Quarries also provide employment for truck drivers and engineers
