Chapter 9 Flashcards
The first win of Precambrian time. The eon prece ding the protozoic. It extends between 4.5 and 2.5 billion years ago
Archean Eon
A time span on the geologic time scale beginning about 6.5 million years ago, following the Mesozoic era
Cenozoic Era
Rock layers that were deposited without interruption
Conformable
The process of establishing the equivalence of rocks of similar age in different areas
Correlation
A principle of relative dating. A rock or fault is younger than any rock (or fault) through which it cuts
Cross-Cutting Relationship
A type of unconformity in which the beds above and below are parallel
Disconformity
The largest unit of time on the geologic scale, next in order of magnitude above area
Eon
A unit of the geologic time scale that is a subdivision of a period
Epoch
A major division on the geologic time scale; are divided into shorter units called periods
Era
The remains of traces of organisms preserved from the geologic past
Fossil
The definite and determinable order in which fossil organisms occur. enables us to identify many time periods by their fossil content
Fossil succession, principle of
The division of Earth History into blocks of tie-eons, eras, periods, and epochs. The time scale was created using relative dating principles.
Geologic Time scale
The earliest time interval (eon) of Earth history. The time before the planet’s first rocks.
Hadean Eon
The time required for one half of the atoms of a radioactive substance to decay
Half-life
A piece of one rock unit that is contained within another. Are used in relative dating.
Inclusions