Flashcards in Chapter 9 Deck (32):
The first win of Precambrian time. The eon prece ding the protozoic. It extends between 4.5 and 2.5 billion years ago
A time span on the geologic time scale beginning about 6.5 million years ago, following the Mesozoic era
Rock layers that were deposited without interruption
The process of establishing the equivalence of rocks of similar age in different areas
A principle of relative dating. A rock or fault is younger than any rock (or fault) through which it cuts
A type of unconformity in which the beds above and below are parallel
The largest unit of time on the geologic scale, next in order of magnitude above area
A unit of the geologic time scale that is a subdivision of a period
A major division on the geologic time scale; are divided into shorter units called periods
The remains of traces of organisms preserved from the geologic past
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.
The time required for one half of the atoms of a radioactive substance to decay
A piece of one rock unit that is contained within another. Are used in relative dating.
A fossil that is associated with a particular span of geologic time.
A time span on the geologic time scale between the Paleozoic and Cenozoic eras from about 248 to 65.5 million years ago.
An unconformity in which older metamorphic or intrusive igneous rocks are overall by younger sedimentary strata
The number of years that have passed since an event occurred
Numerical (absolute) dating
Layers of sediment that are generally deposited in a horizontal or nearly horizontal position
Original horizontality, principle
The systematic study of fossils and the history of life on Earth
A time span on the geologic time scale between the Precambrian and Mesozoic eras - from about 542 million to 252 million years ago
A basic unit of the geologic time scale that is a subdivision of an era. May be divided into smaller units called epochs.
An unconformity in which the older strata dip at an angle different from that of the younger beds
All geologic time prior to the Phanerozoic eon. A term encompassing both the Archean and Protozoic eons.
The eon following the Archean and preceding the Phanerozoic. It extends between 2500 and 542 million years ago.
The spontaneous decay of certain unstable atomic nuclei
The procedure of calculating the absolute ages of rocks and minerals that contain certain radioactive slopes
A process of determining the chronological order of events by placing rocks and structures in the proper sequence or order
A surface that represents a break in the rock record, caused by erosion and non-deposition
Dating of events from the very recent geologic past (the past few tens of thousands of years) based on the facet that the radioactive isotope of carbon is produced continuously in the atmosphere