Rock dating + earth's age Flashcards
What’s the first recorded date for Earth’s formation?
21st September 4004BC by James Usher in the 1600s, he counted generations from the bible
Who is credited with suggesting the Earth is millions of years old? Who is responsible for popularising this idea?
James Hutton’s ideas, popularised by Charles Lyle
How old does William kelvin suggest the earth to be? When and how does he do this?
20-40 million years old - mid 1800s, through ideas of an earth size object cooling to have a solid crust.
What is the principle of superposition?
The idea that the oldest rocks come first in vertical layers. But this is unreliable where continental collisions have occurred.
What is the principle of Faunal succession?
Using knowledge of evolution of species found in fossils to relatively date rocks.
What makes a good index fossil?
Independent of depositional environment, widespread, fast evolving, abundant, readily preserved (usually shelled), and easy to recognise!
What are GSSP’s?
Global boundary Stratotype Sections and Points - points in the lithostratigraphy that make boundaries between geological time periods.
Up to what sort of age can carbon-14 be used to date rocks?
About 40,000 years
How is optically stimulated luminescence used to date rocks?
By determining when rocks or fossils were last exposed to sunlight (and thus ionised radiation)
How are Cosmogenic Nuclides used to date rocks?
Measure how long something has been buried for
