Hadean Time
4.5-3.8 bya
Earth Created
first oceans
Precambrian Time (4,500 to 544 mya)
first continents
 
Archaean Eon
first life
3.8-2.5 bya
Proterozoic Eon
soft-bodied organisms
2.5 bya - 544 mya
Phanero- zoic Eon
Multicellular life
Eras Paleopro-
terozoic

(2500 to 1600 mya)
blue-green algae
reclassified as Cyanobacteria
Mesopro-
terozoic

(1600 to 1000 mya)
First land fungi. Giant Continent Rodinia created.
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Neoproterozoic Era(1000 to 544 mya)
Macroscopic fossils of soft-bodied organisms.
multicellular animals. Continent of Rodinia breaks up.
   
Paleozoic Era (544-245 mya)
Invertibrates; Supercontinent of Pangaea created.
Mesozoic (245-65mya)
Reptiles; Breakup of Pangaea.
Cenozoic (65 mya-now)
Mammals
 

Geological Time

Many of the boundaries are placed at the time of Mass Extinctions.

EON
ERA
Periods
EPOCH
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Cenozoic Era

(65 mya to today)
(Recent Life)
Age of Mammals
Quaternary (1.8 mya to today) Modern man radiates, "science" appears. Holocene
(11,000 years to today)
Neandertals appear and disappear; Homo erectus and Homo sapiens appear. Saber-toothed cats, mammoths, and mastodons become extict. Pleistocene
(1.8 mya to 11,000 yrs)
Tertiary (65 to 1.8 mya)









K-T Boundary
(Hominids), the australopithecines. Pliocene
(5 to 1.8 mya)
Grazing horses, antelopes appear. Sierra Nevada mountains built with uplifting. Miocene
(23 to 5 mya)
Most modern bird forms and mammals have appeared. Oligocene
(38 to 23 mya)
First grasses appear, a resource for herbovores; trees thrive. Some modern mammals appear: advanced primates; camels, cats, dogs, horses & rodents. Himalayan Mountains formed from the collision of India with the Eurasian plate. (OEB)

Eocene
(54 to 37 mya)
Small mammals radiate. Paleocene
(65 to 54 mya)
Mesozoic Era
(245 to 65 mya)
(Middle Life)
The age of Reptiles.







P-T Boundary
Cretaceous (146 to 65 mya) - flowering plants (angiosperms); lizards; placental animals (early mammals); snakes; social insects; marsupial and primitive placental animals. Primitave primates. Modern insect forms radiate. N. America separates from Europe. Major extinction includes dinosaurs and ammonites. (K-T).

Divided
as:

Upper;

Middle;

Lower

Jurassic (208 to 146 mya) - Birds; crabs; frogs and salamanders Dinosaurs radiate to dominate the land. Pangaea is broken into two large continents Laurasia and Gondwanaland. Mountains in western north America started to be built with plate techtonics and volcanic eruptions.
Triassic (245 to 208 mya) - Breakup of Pangaea begins - Dinosaurs; crocodiles; marine reptiles; turtles; Pterosauria and mammals Major groups of seed plants appear. Modern ferns.
  Paleozoic Era
(544 to 245 mya)
(Ancient Life) Age of Invertebrates. Complex plants and animals burst into life as part of The Cambrian Explosion.
Permian (286 to 245 mya)
- Seedplants producing large trees. Major extinction of invertebrates (P-T) Supercontinent of Pangaea is complete.
Carboniferous
(360 to 286 mya)
Pennsylvanian (325 to 286 mya)
- Conifers & many winged insects appear. Use of eggs by some life forms. Supercontinent of Gondwanaland collides with the combination of Laurentia and Baltica - now known as Laurussia (Appalachian orogeny 310-250 mya) and creates the Great Smoky Mountains, the Appalachians, and the Cevennes of France. Around the same time another small continent, here called Angaria, collided with Baltica's eastern margin, uplifting the Ural Mountains.
Mississippian (360 to 325 mya)
- amphibians move from sea to land. Reptiles appear
Devonian (410 to 360 mya) - Land colonized by plants and animals Appearances include: insects; sharks; amphibians (tetrapods); lung fishes and earliest seed plants. Fish begin to dominate the seas. Continents continue to collide initially in what is now the Maritime Provinces of Canada (Acadian orogeny 410-350 mya) and creates a range of mountains extended from the Adirondacks north through Nova Scotia, the British Isles, Norway and the eastern margin of Greenland.
Silurian (440 to 410 mya) - Jawed fish, cartilaginous fish and vascular plants appear. Primitive terrestrial predators.
Ordovician (500 to 440 mya) - First land plants. Continents of Laurentia and Baltica collided (Taconic orogeny 480-440 mya) creating Taconic mountains in NY.
Cambrian (544 to 500 mya) - vertebrates; jawless fish; small shelly animals; conodonts; trilobites
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Neoproterozoic Era (1000 to 544 mya) - Macroscopic fossils of soft-bodied organisms. Continent of Rodinia breaks up.
Ediacaran (Vendian) (600 to 544 mya) - Oldest metazoans (multicellular animals)
Cryogenian (850-600)
Earth covered with ice that was a mile thick.
Tonian (1000-850)
Mesoproterozoic Era (1.6 to 1 bya) - Sexual reproduction appears - First land fungi. Giant Continent Rodinia created. Continental collisions (Grenville Orogeny) created initial mountains in the New York Bight. Outcroppings of granite from this period still protrude out of the forest in Harriman State Park.
Paleoproterozoic Era (2.5 to 1.6 bya) - More complex single-celled life - cyanobacteria (blue-green algae) oxygenating the atmosphere.
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Archaean(3.8 to 2.5 bya) First Life, Oldest Fossils, Stromatolite
- First life was bacterial. Early microbes thrive in an oxygen-free environment, feeding on organic molecules like glucose and producing energy in a process called fermentation. As populations grow and food supplies become scarce, bacteria that can generate their own food and energy evolve. Many of them use a process known as photosynthesis, converting energy radiated from the sun into chemical energy the organism can store and use.
Cyanobacteria (blue-green algae) evolve 3.3 bya and use photosynthesis, which uses carbon dioxide and releases oxygen molecules changing the Earth's atmosphere to an oxygen rich one from 2.7-2.2 bya.
As several chunks of smaller land blocks collide, the earliest continents form. About 2,500 mya, the continents join together to form the first supercontinent. Scientific evidence suggests the planet's major continents have come together only four or five times.
Hadean Time (4.5 to 3.8 bya) - Sometime during the first 800 million or so years of its history, the surface of the Earth changed from liquid (molten rock) to solid. Erosion and plate tectonics has probably destroyed most of the solid rocks that were older than 3.8 billion years.
4,055 mya - Oldest rocks, Granite. Found in what is now Canada's Northwest Territories. Granite is lighter than other rocks and would float up to the surface.
Gases released from magma inside Earth collect to form an atmosphere probably composed of nitrogen (N2), Carbon Dioxide (CO2), carbon monoxide (CO), water vapor (H2O); They may have combined to form some ammonia (NH3) and methane (CH4) also, although this theory is disputed now. THere was little or no free oxygen. (Newer schemes exclude ammonia and methane.)
4,200 mya - Water condenses in the cooling atmosphere, and heavy rains pour down on the planet. After several hundred million years of falling rain, great oceans form.

4,055 mya - First rocks.
mya: Million Years Ago
bya: Billion Years Ago
Source: Geologic Time Scale at The American Heritage® Dictionary and Paleobiology at fossilmuseum.net
Note: Epoch's are broken down into ages which are not shown above (e.g. Pleistocene epoch: Calabrian age; Pliocene epoch: Gelasian, Piacenzian and Zanclian ages. (See Detailed Geological Time-Scale)

You will also see the Precambrian periods labeled differently.
e.g. A Cryptozoic or Precambrian Eon (4500 to 544 mya) with Proterozoic and Archaean Eras. See Deep Time at pbs.org
The Hadean time may also be referred to as an Era or Eon, but since no evidece from that time exists today the purists say it is not either. (See USGS Paleontology)
But the above classification is the most common.

Early Atmosphere Issues

See Also: Taxonomy of Living Organisms and Evolution
Geological Time at fossilmall.com
The Geologic Time Scale at the USGS (U.S. Gelogical Survery)
Geologic Time at Union County College
Web Time Machine at Univ. of California Museum of Paleontology (UCMP)
Geologic Time Line at the San Diego Natural History Museum
Detailed Geological Time-Scale at palaeos.com

From http://www.danbyrnes.com.au/lostworlds/timeline/lwstory20.htm danbyrnes.com
Geological and Evolutionary Timeline at earthsci.org
GEOLOGIC TIME SCALE at Thee The Geological Society of America

Plate Tectonics
Geology And Geography Of The New York Bight at CUNY
Breakup and Assembly of Pangaea (PowerPoint)
The Formation of Pangaea:
This Dynamic Earth
Plate Tectonics: A Paradigm Under Threat
Geologic Time - EnchantedLearning.com
Dance of the Giant Continents at Burke Museum of Natural History and Culture at the U. of Washington
Current Keel Research at N. Ill. U.

Mass Extinctions
Extinctions
Geological Time
The History of Life at UC Berkeley
Earth's Climate History, by Antón Uriarte

Books:
"Big History", Cynthia Brown
"Maps of Time", by David Christian


last updated 21 Apr 2010