Argon argon radioactive dating method
Most sediment is either laid down horizontally in bodies of water like the oceans, or on land on the margins of streams and rivers.
Each time a new layer of sediment is deposited it is laid down horizontally on top of an older layer.
A fossil can be studied to determine what kind of organism it represents, how the organism lived, and how it was preserved.
However, by itself a fossil has little meaning unless it is placed within some context.
Second, it is possible to determine the numerical age for fossils or earth materials.
Thus, any deformations of strata (Figures 2 and 3) must have occurred after the rock was deposited.
" First, the relative age of a fossil can be determined.
Relative dating puts geologic events in chronological order without requiring that a specific numerical age be assigned to each event.
Sometimes sedimentary rocks are disturbed by events, such as fault movements, that cut across layers after the rocks were deposited.
This is the principle of cross-cutting relationships.
The principle of superposition states that in an undeformed sequence of sedimentary rocks, each layer of rock is older than the one above it and younger than the one below it (Figures 1 and 2).