time- a limited period or interval, as between two successive events. seconds minutes hours days...
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Time- a limited period or interval, as between two successive events.
Seconds
Minutes
Hours
Days
Years
1. 1. Relative Time- subdivisions of the Earth's geology in a specific order based upon relative age relationships. These subdivisions are given names, most of which can be recognized globally, usually on the basis of fossils.
Example: Thanksgiving is between Halloween and New Year’s Eve.
Fossil- remains, impressions, or other evidence of life preserved in rock.
1. 2. Absolute Time- numerical ages in "millions of years" or some other measurement. These are most commonly obtained via radiometric dating.
Example: The school year is 180 days long.
mya = millions of years agobya = billions of years ago
Example: The following are equal amounts of time3,800,000,000 years ago3,800 mya 3.8 bya
The Earth is thought to be 4.6 billion years old.
Can you grasp how big 1 billion is???
Hmmm…….Lets put it in perspective!
Geologic Time Scale
Subdivided into segments of time:
Eon
Era
Period
Epoch
Largest
Smallest
Geologic Time Scale
Subdivided into segments of time:
3-Eons PhanerozoicProterozoicArchean
Youngest
Oldest
Geologic Time Scale
Subdivided into segments of time:
Phanerozoic CenozoicDivided into 3 Eras Mesozoic
Paleozoic
Youngest
Oldest
Eon Era
Geologic Time ScaleSubdivided into segments of time:
Phanerozoic Cenozoic
Mesozoic
Paleozoic
Youngest
Oldest
Eon EraPeriod
Quaternary
Tertiary
Cretaceous
Jurassic
Triassic
Permian
Carboniferous
Devonian
Silurian
Ordovician
Cambrian
NeogenePaleogene
PennsylvanianMississippian
Geologic Time ScaleSubdivided into segments of time:
Phanerozoic Cenozoic
Mesozoic
Paleozoic
Youngest
Oldest
Eon EraPeriod
Quaternary
Tertiary
Cretaceous
Jurassic
Triassic
Permian
Carboniferous
Devonian
Silurian
Ordovician
Cambrian
Holocene
Pleistocene
Pliocene
Miocene
Oligocene
Eocene
Paleocene
Epoch
Geologic Time Scale- summary of major
events in Earth’s past that are preserved in the
rock record.
Based on relative and absolute time.
Found on pages 8-9 in your
ESRT
Hadean Eon
Accretion disc Meteorite
Hadean Eon4.5 to 3.8 billion years ago
•Pre-dates the Earth
•No rocks on Earth are this old, except for meteorites
•Solar system formation
•Earth turned from molten to solid about 3.8 bya
•Earth began forming “protocontinents” in the Achean Eon
430 Million Years Ago!
New York
Diatoms
Trilobites
540-250 million years ago
Eurypterids
Horseshoe Crabs
Eurypterids
Stomatolites
Cycads Today Cycad Fossils
Dinosaurs
Oldest Archean: Greek for “ancient”
Proterozoic: Greek for “earlier life”
Youngest Phanerozoic: Greek for “visible life.” We are currently in the Phanerozoic Eon.
1. Eon- the largest segment of geologic time.
Oldest Paleozoic: “old life”
Mesozoic: “middle life”
Youngest Cenozoic: “recent life.” We are currently in the Cenozoic Era.
2. Era- Eons are subdivided into Eras based on the fossil record.
3. Period- Eras are subdivided into periods. Names of time periods are based on the names of
rock formations around the world.
We are currently in the Quaternary Period.
Examples: Permian period comes from the province of Perm in Russia
Pennsylvanian period comes from the US state.
Cretaceous period is Latin for “chalk.”
We are currently in the Holocene Epoch.
4. Epoch- smallest unit of time on the geologic time scale.