Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
9 Cards in this Set
- Front
- Back
|
How old the the earth estimated to be? |
4.6 billion years. |
|
|
Where were the oldest rocks on Earth found and how old? |
2.5-3.8 billion at Canadian shield on the coastline of Hudson bay. |
|
|
How old is Iceland? |
16-37 million. |
|
|
Describe the structure of the Earth, using depths and temperatures. |
*Crust- 0-100km, it's approx 0°C made of basalt and granite.
*Mantle - 100- 2,900km, it's liquid approx 500-200°C, made of Iron and rock. Makes up 85% of Earth's mass.
*Outer core- 2,900- 5,100km, it's liquid approx 5,000°C, made of Iron.
*Inner core- 5,100- 6,378 km, it's solid approx 7,000°C, Iron. |
|
|
What is the evidence for the structure of the Earth? |
The way different seismic waves travel through the earth ; Body waves; P waves are the fastest waves that can travel through liquids and solids, they are longitudinal waves up to 14 km/s. The wave direction is parallel to particle movement. S waves are the second fastest they can't travel through liquids so do not pass through through the inner core. They are about half the speed of P waves. They are transverse waves, the wave direction is perpendicular to the particle movement. Surface waves; Love waves are very destructive, they are much slower than P and S waves these move in a side to side motion, scientists believe that they travel at around 1-5km/s, particles move 90° to the wave direction. Rayleigh waves contain both transverse and longitudinal waves they are also known as a ground roll, they travel at around 2-5 km/s. |
|
|
Who was the first person to notice the jigsaw fit. |
Francis Bacon |
|
|
Who put forward the idea that the earth was once a supercontinent? |
Alfred Wegener proposed the theory of Pangea. |
|
|
What is the evidence supporting continental drift? |
1. Mid Atlantic Ridges- there is a mountain range running long the middle of the Atlantic ocean. Magnetic stripes were noticed along the edge of the ridge running parallel. This supports the theory of paleomagnetism and sea floor spreading. They correspond with when the Earth's magnetic field reversed from North to South, Iron particles erupting in magma align themselves with the polarity of Earth. 2. Rock age- supports the sea floor is spreading, younger rocks are found closer to the edge of the ridge (10mill) while older rock is found further away from it (156mill). 3. Fossil evidence - the Glossopteris is a fossilised fern that can be found in Africa, Antantica, Australia and South America. Other evidence is the Mesosaurus an extinct coastal reptile found in both Africa and South America it couldn't possibly cross the Atlantic ocean. Isle of Arran contain fossilised footprints from a reptile also found Eastern Canada. 4. Glacial evidence- widespread distribution of Permo- Carbioniferous glacial sediments are found in South America, Africa, Madagascar, Arabia, India Antantica and Australia. The continuity of glaciers and the orientation of glacial striations and deposit suggest the super continent Gondwana. 5. Mountain chains- the appalachain mountains which goes from the northeastern US to the Caledonians in Ireland, Britain, Greenland and Scandinavia.
|
|
|
What is the transition between the layers of the Earth known as? |
Gutenburg discontinuity. |
