Origins of the Earth and the pre-Cambrian Flashcards
What are the four most common elements in the structure of the Earth?
Iron, Magnesium, Silicon, and Oxygen
How did land form on the earth?
As the Earth cooled, lower density materials rise to the top of a ‘magma ocean’ and form a thin crust. While heavier materials sink and form the core. Earliest land begins with submarine volcano eruptions.
What is the approx age of the universe?
14 billion years
What is the approx age of the earth and the solar system?
4.5 billion years
Approx how old are the oldest rocks on the earth? What type is it?
4.3 billion years
Gneiss
Approx how old is life on Earth?
3.8 billion years
Where can Precambrian rocks be found in Britain?
Almost entirely in Scotland stopping at the line where the two continents joined to form Britain. With some also seen in Shropshire and the Malverns
What is the approx time frame of the Precambrian?
4500Ma to 542Ma
What are the main rock types of Pre-Cambrian rocks?
Archean rocks (the early half or so) are almost all metamorphic.
Proterozoic are still mostly metamorphic with some sedimentary and some fossils.
- Notable amounts of gneiss
What are the two continents that Scotland and the rest of Britain were a part of before colliding?
Laurentia (Scotland) and Avalonia
What are Pre-Cambrian fossils like? What do they tell us about the earth at the time?
Simple creatures that survived on chemosynthesis - showing an anaerobic atmosphere at the time.
Where is the region in England in which a famous Pre-Cambrian fossil was found?
Charnwood forest
