Planet Earth - Topics 8-10 Flashcards
Original remains
A type of fossil in which all parts of the original organism have been preserved
Carbonaceous film
A type of fossil found in sedimentary rock. When organic material is compressed leaving a thin carbon film
Petrified
A rock like substance formed when water penetrated dead organic matter and dissolved the raw mineral matter
Trace fossils
A type of fossil in which evidence of an animals activities have been preserved. Example: footprints, worm holes, burrows
Cast
A type of fossil in which sediments or minerals have filled a mould and hardened into rock
Mould
A type of fossil in which the hard parts of the organism have dissolved, leaving a cavity in the rock
Strata
Layers of sedimentary rock
Principal of superposition
A geological theory according to this theory in undisturbed layers of rock the oldest layers will be on the bottom and the youngest layers will be on the top
Relative dating
Determining the order in which geological events occur and relative age of rocks by their positions in the rock layer
Index Fossil
A type of fossil that can be used to determine the age of the material in which it was found
Half life
The amount of time that a given amount of radioactive substance takes to be reduced by one half
Radiometric dating
The process of determining the age of a geological specimen by measuring the relative amount of radioactive particles that are present in the specimen
Radiocarbon dating
The method used to determine the age of organic remains by measuring the amount of radioactive carbon found in the remains
Era
A large division of geological time, shorter than an eon. Marked by the beginning of a new point in history or the new development of something
Period
On the geological time scale, a smaller division of eras determined by some recurring phenomena
