Unit Six(fossils) Flashcards
Definition: Petrified
A rock like substance formed when water penetrated dead organic matter
What is silica?
A very hard rock
Original remains are…
An animal being preserved in ice, tar, resin, etc.
What is a trace fossil?
Footprints, wormholes, etc. that have been fossilized
What is a mould?
Hard parts of organism dissolve and leave a cavity in the rock
What is a cast?
A fossil in which sediments or minerals fill a mould and harden into rock
What is the principle of superposition?
The older layers of sedimentary rock are on the bottom and the newer layers on the top
Definition: Strata
Layers of sedimentary rock
What is relative dating?
A strategy used to figure out the age according to their position in the strata
What is a index fossil?
A type of fossil that can be used to determine the age of material it is found in.
What is half life?
The amount of a radioactive substance reduced by one half
What is radiometric dating?
Figuring out the age of a rock by measuring the amounts of radioactive particles in a rock
How many years ago was the Precambrian period?
4500milliom
How long ago was the paleozoic period?
590million
How long ago was the Mesozoic period?
248million
How long ago was the cenzoic period?
65
The northern portion of Pangea was called …?
Laurasia
The southern portion of Pangea was called…?
Gondwanaland
Definition:Petroleum
A type of oil found in rock formations on the earths crust
Definition: Bitumen
Solid form of petroleum
