Geologic Time Scale
Relative Dating
Absolute Dating
Decay
Rocks
100
This is the largest time division.
What is an Eon?
100
In undisturbed strata, older layers are beneath younger layers
What is Law of Superposition?
100
Gives numerical ages
What is absolute dating?
100
Spontaneous transformation of an unstable nucleus (parent) to a daughter isotope.
What is radioactive decay?
100
Formed by cooling of magma/lava
What is an igneous rock.
200
This is greater than a period, but smaller then an Eon.
What is an Era?
200
The feature that cuts another is younger (e.g., an igneous intrusion cutting layered sediment is younger than the layers).
What is Law of Crosscutting?
200
This is the original and unstable atom.
What is the parent atom?
200
Every _________________, 50% of parent atoms become daughter atoms.
What is half-life?
200
Formed form bits and dpieces of other rockas and materoals.
What is sedimentary rocks?
300
This term encompasses the Hadean, Archean, and Proterozoic Eons. It also means simpel life.
What is Precambrian?
300
Rocks included in an layer are older than the layer they are in.
What is Law of Inclusion?
300
This is the stable atom the parent becomes.
What is the daughter atom?
300
Every isotopic pair has its own unique _______________.
What is half-life?
300
Formed form rocks that are exposed to heat and pressure.
What is metamophoc rock?
400
This period begins the development and appearance of complex life.
What is the Cambrian?
400
Order of layers oldest to youngest
What is P, K, M, S, X, R, B, J, F?
400
This specific parent isotope can only be used to date prior living things, like fossils.
What is Carbon-14?
400
25 % parent, 75% daughter
What is 2 half-lives?
400
Can be calssified as intrusive or extrusive.
What is igneous rock?
500
The samllest possible time dividsion that could be seen on a geologic time scale.
What is an Age?
500
The remains of ancient organisms used to determine the relative age of rock layers. It must have been abundant, widespread, and lived for a short, specific period of geologic time.
What is an index fossiil?
500
This is the most common form of absolute dating.
What is radiometric ir radioistopic dating?
500
The age of a fossil given 12.5% parent (carbon-14) with a half-life of 5730 years.
What is 5730 years?
500
Process(es) involved in becoming an igneous rock.
What is meltiong and solidification?