The Geologic Time Scale. Sections of time ERA Two or more geological periods comprise an era, which...
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Transcript of The Geologic Time Scale. Sections of time ERA Two or more geological periods comprise an era, which...
The Geologic Time ScaleThe Geologic Time Scale
Sections of timeSections of time
• ERATwo or more geological periods comprise an era, which is hundreds of millions of years in duration.
• PERIODThe period is the basic unit of geological time in which a single type of rock system is formed, lasting tens of millions of years.EPOCHAn epoch is a division of a geologic period; it is the smallest division of geologic time, lasting several million years.
• Eon- Era- Period- Epoch- Age.
• Humans as we know ourselves appeared in the Pleistocene Epoch of the Quaternary Period in the Cenozoic era of the Phanerozoic Eon…..
Pre Cambrian timePre Cambrian time
• 4.6 Billion years ago- 542 MA
• Earth Forms• Stromatolites are
dominant life form
Paleozoic EraPaleozoic Era
• 542 to 251 mya • Multicellular life!!
Paleozoic, Cambrian, Paleozoic, Cambrian,
• 488-542 MA• Trilobites dominate• many phyla develop.• “Cambrian Explosion”
Paleozoic, Ordovician, Paleozoic, Ordovician,
• 488 to 444 mya • North America is
under shallow sea.• Modern Oxygen rich
atmosphere develops• Vertebrates Develop
Paleozoic, SilurianPaleozoic, Silurian
• 444 MA 416 MA• First Land Plants and
Animals
Paleozoic, Devonian, Paleozoic, Devonian,
• 416 MA -359 MA• First amphibians• Age of fishes
Paleozoic, Carboniferius, Paleozoic, Carboniferius, MissippianMissippian
• 359 MA – 318 MA• Amphibians Flourish• Forests and swamps
cover land
Paleozoic, Carboniferius, Paleozoic, Carboniferius, PennsylvanianPennsylvanian
• 318 MA – 299 MA• Giant flying insects• First Reptiles, ROAR!!
Paleozoic, PermianPaleozoic, Permian
• 299 MA – 251 MA• Pangea comes
together
Mesozoic EraMesozoic Era
• "The Age of Reptiles"
251 MA to 65.5 MA
Mesozoic, TriassicMesozoic, Triassic
• 251 MA – 200 MA• Dinosaurs appear• Mammals appear
• Cycads and conifers dominate
Mesozoic, JurassicMesozoic, Jurassic
• 200 MA- 146 MA• Dinosaurs are the
dominant animal.• Primitive vertebrate
flight, first birds
Mesozoic, Cretaceous, Mesozoic, Cretaceous,
• 146-65.5MA• Flowering plants
appear (angiosperms)• Modern Birds• All good until……
K-T ExtinctionK-T Extinction
• 65MA• Kills off Dinosaurs• Asteroid or volcano• Iridium rich dust….
Cenozoic EraCenozoic Era
"The Age of Mammals"
65.5 mya through today
Continents at present locations
Cenozoic, Tertiary, PaleoceneCenozoic, Tertiary, Paleocene
Tertiary-
65-55.8 mya
Paleocene- age on mammals begins
First Primates
Cenozoic, Tertiary, EoceneCenozoic, Tertiary, Eocene
• 55.8-33.9 mya • Rodents appear.
Primitive whales appear.
Cenozoic, Tertiary,OligoceneCenozoic, Tertiary,Oligocene
• 33.9-23 mya • Dogs and cats
appear!• But they did not look
like that -
Cenozoic, Tertiary, MioceneCenozoic, Tertiary, Miocene
• 23-5.3 MA• Due to high
abundance of grasses, herds of large mammals abound.
Cenozoic, Tertiary, PlioceneCenozoic, Tertiary, Pliocene
• 5.3-1.8• First hominids
(australopithecines). Modern forms of whales. Megalodon swam the seas
• Hominid- where humans and apes split
• Lions Tigers and Bears….
• Appear in the Pliocene
Cenozoic, Quauernary, PleistoceneCenozoic, Quauernary, Pleistocene
• Quaternary Period"The Age of Man"1.8 mya to today
• Pleistocene- The Last Ice Age1.8-.012 ma
• Humans (Homo sapien) appear. You better remember this!
• Mammoths, saber-toothed cats,
Quaternary, HoloceneQuaternary, Holocene
• 11,500 ya to today • Marked by complex
human civilization• Ice melted, and sea
level rose 140 m!