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 ago bya = billions of years ago Example: The following are equal amounts of time 3,800,000,000 years ago 3,800 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 Phanerozoic Proterozoic Archean Youngest Oldest

Geologic Time Scale Subdivided into segments of time: Phanerozoic Cenozoic Divided into 3 Eras Mesozoic Paleozoic Youngest Oldest Eon Era

Geologic Time Scale Subdivided into segments of time: Phanerozoic Cenozoic Mesozoic Paleozoic Youngest Oldest EonEra Period Quaternary Tertiary Cretaceous Jurassic Triassic Permian Carboniferous Devonian Silurian Ordovician Cambrian Neogene Paleogene Pennsylvanian Mississippian

Geologic Time Scale Subdivided into segments of time: Phanerozoic Cenozoic Mesozoic Paleozoic Youngest Oldest Eon Era Period 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 Eon 4.5 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 million years ago

Eurypterids

Horseshoe Crabs Eurypterids

Stomatolites

Cycads Today Cycad Fossils

Dinosaurs

OldestArchean: Greek for “ancient” Proterozoic: Greek for “earlier life” YoungestPhanerozoic: 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.