A Thumbnail Sketch of Earth History

The URL of this page is https://croninprojects.org/Vince/Course/PhysGeol/EarthHist.html

Originally after Emiliani, 1988
You are also encouraged to cruise the following web sites for some good information:

• http://map.gsfc.nasa.gov/m_mm/mr_age.html for the best current age of the universe
• http://www.pbs.org/wgbh/evolution/change/deeptime/low_bandwidth.html for the WGBH Boston PBS site devoted to Deep Time
• http://www.pbs.org/wgbh/evolution/humans/humankind/index.html for an account of Human evolutionary history
• The Geological Society of America's Geologic Time Scale: https://www.geosociety.org/GSA/Education_Careers/Geologic_Time_Scale/GSA/timescale/home.aspx
• The International Commission on Stratigraphy's "International Chronostratigraphic Chart": https://stratigraphy.org/chart

In the list that follows,
Ga is a unit symbol for "billion years" ,
Ma is the unit symbol for "million years", and
ka is the unit symbol for "thousand years"

Hadean, Gamowian & Planckian 13.8 to 4.5 Ga

• ∼13.8 Ga Beginning of present universe (time zero). Refer to the relevant part of the Baylor Geosciences Department's answers to frequently-asked questions
• time zero + 5.390x10-44 seconds: appearance of space, time, energy, and gravity
• bang -- rapid expansion
• time zero + 10-35 seconds: appearance of the strong force
• time zero + 10-10 seconds: appearance of the electromagnetic and weak forces
• time zero + 10-8 seconds: stabilization of the quarks
• time zero + 10-5 seconds: quark-antiquark annihilation
• time zero + 10-3 seconds: stabilization of protons and neutrons
• time zero + 10 seconds: stabilization of electrons
• time zero + 3.8 minutes: stabilization of 2H, 3He, and 4He nuclei
• time zero + 379,000 years: electrons captured by nuclei, and formation of H and He atoms and hydrogen molecules
• ∼13.4 Ga: Beginning of formation of quasars, galaxies and stars
• 4.6 Ga: Formation of the solar system; age of the meteorites

Precambrian 4500 to 570 Ma
http://www.pbs.org/wgbh/evolution/change/deeptime/precam.html

• 4.5-4.6 Ga Condensation of Earth. Refer to the relevant part of the Baylor Geosciences Department's answers to frequently-asked questions
• 4.51 Ga Formation of the Moon, probably due to impact of an asteroid about the size of Mars with the primordial Earth
• 4.4-4.3 Ga Formation of Earth's iron core; oldest detrital zircons
• 4.2 Ga Formation of Earth's primitive lithosphere, atmosphere, oceans & biosphere
• Development of simplest life forms: Archaeobacteria (asexually reproducing procaryote)
• 4 Ga Oldest rocks that survive in Earth's modern crust are formed
• 3.8 Ga Oldest (not fully substantiated) evidence of life on Earth, contained in rock record. Refer to the relevant part of the Baylor Geosciences Department's answers to frequently-asked questions
• 3.5 Ga Evolution of photosynthetic Cyanobacteria from more primitive Eubacteria (asexually reproducing prokaryotes)
• ∼3.2 Ga Oxygen starts becoming abundant in Earth's atmosphere; the sky starts to turn from red to blue.
• 3.1 Ga First algal stromatolites
• 2.5 Ga Banded iron formations
• 2.0 Ga Enough oxygen is present in the atmosphere to cause iron to rust at Earth's surface; formation of Gunflint Chert containing fossils of simple life forms in Canada
• 1.8 Ga Oldest eukaryote fossils (sexually reproducing green algae); eukaryotes probably developed much earlier
• 1.24 Ga Grenville orogeny begins along the east coast of North America
• 1.2 Ga True algae develop; divergence of algae, fungi, plants and animals
• 1.1 Ga Midcontinent rift begins to form in Minnesota, Iowa, Wisconsin, and Michigan; Rodinia supercontinent forms
• 900 Ma First multicellular organisms develop -- soft-bodied metazoans
• 800 Ma Major glaciation
• 700 Ma Rodinia supercontinent breaks up
• 600 Ma Ozone layer is now thick enough to protect organisms from the Sun's UV radiation

Paleozoic 543 to 245 Ma

• Cambrian 543-490 Ma
  http://www.pbs.org/wgbh/evolution/change/deeptime/paleoz.html for more information about the Cambrian
  • 543 Ma First organisms with hard parts (skeletons, shells) develop
  • ∼540 Ma First arthropods, including crustaceans, insects, trilobites
  • ∼535 Ma First chordates
  • ∼530 Ma First marine reefs
  • ∼530 to 520 Ma "Cambrian explosion"
  • Most continents were at equatorial latitudes; carbonate platforms developed in North America, Siberia, North and South China
  • Iapetus Ocean existed between Laurentia and North Europe-Avalonia-Gondwanaland.
  • Samfrau Arc from Eastern Australia around Antarctica, Africa, and South America
• Ordovician 490-443 Ma
  http://www.pbs.org/wgbh/evolution/change/deeptime/ordovician.html for more information about the Ordovician
  • Gondwana extended into southern polar latitudes, and was glaciated.
  • Iapetus Ocean began to close.
  • Taconic orogeny (M. Ordovician) in Appalachians as Avalonia.
  • Cadomia (England & Wales), and North Europe collided with Laurentia; Blue Ridge and Piedmont were thrust westward over the North American craton
• Silurian 443-417 Ma
  http://www.pbs.org/wgbh/evolution/change/deeptime/silurian.html for more information about the Silurian
  • First land plants develop; first spiders
  • Shallow continental seaways
  • Mongolia and Siberia collide, and several microcontinents accrete south of South China
  • Caledonian-Acadian orogenies (U. Silurian-L. Devonian) as Africa/Europe collided with northeastern North America. Caledonian orogeny involved collision of Norway and Greenland.
• Devonian 417-354 Ma
  http://www.pbs.org/wgbh/evolution/change/deeptime/devonian.html for more information about the Devonian
  • First land-dwelling invertebrate animals (e.g., bugs)
  • Ancestral Rocky Mountains begin to form
  • Acadian orogeny (M. Devonian) in Appalachians, reflecting closure between the Piedmont and Charlotte-Caroline-Kiokee belts; Africa collides with SE North America
• Carboniferous 354-290 Ma
  http://www.pbs.org/wgbh/evolution/change/deeptime/carbon.html for more information about the Carboniferous
  • First amphibians
  • First reptiles (land-dwelling)
  • Hercynian orogeny occurs as both margins of South Europe experience collision. Much of present-day Europe has accreted, and subsequent deformation telescopes the accreted terranes. Continuous with the Ouachita belt.
  • Ouachita-Alleghenian orogeny (Late Carboniferous-Permian) in the Appalachians records the final closure of Iapetus with the collision of South America-Africa with the SE coast of North America
  • Roberts Mountain allochthon is emplaced.
• Permian 290-248 Ma
  http://www.pbs.org/wgbh/evolution/change/deeptime/permian.html for more information about the Permian
  • First marine reptiles
  • Uralian orogeny as Kazakhstan collides with North Europe to produce the Ural Mountains.
  • Pangaea phase, including Tethys Ocean and the Samfrau arc surrounding Pangaea on its western and southern margins. Pangaea extends from pole to pole.
  • Sonoma orogeny (Permo-Triassic) involved accretion of arc systems to western North America
  • Massive plateau volcanism in Siberia
  • The greatest mass extinction in Earth history at 248 Ma

Mesozoic 248 to 65 Ma

• Triassic 248-206 Ma Beginning of "The Age of Dinosaurs"
  http://www.pbs.org/wgbh/evolution/change/deeptime/mesozo.html for more information about the Triassic
  • First mammals
  • Much of China has been accreted.
  • Golconda allochthon is emplaced atop the Roberts Mountain allochthon.
  • Opening of the Gulf of Mexico in late Triassic
  • Repeated collisions of microplates/arcs in western North America and southern/eastern Asia
• Jurassic 206-144 Ma
  http://www.pbs.org/wgbh/evolution/change/deeptime/jurassic.html for more information about the Jurassic
  • First flowers
  • Initial opening of the Atlantic Ocean, between Africa and N. America (∼180 Ma)
  • Initial opening of the Antarctic and Western Indian Oceans
  • First birds
  • Nevadan orogeny (140-150 Ma) involved accretion of more arc systems to western North America.
  • Motion along the Mojave-Sonora Megashear as North America separates from South America-Africa
• Cretaceous 144-66.4 Ma
  http://www.pbs.org/wgbh/evolution/change/deeptime/cretaceous.html for more information about the Cretaceous
  • Opening of the South Atlantic (∼125 Ma)
  • Bay of Biscay opens, and Pyrenees develop
  • Opening of the Labrador Sea between North America and Greenland (∼80 Ma)
  • Alpine orogeny begins as microplates rifted from Africa collide with Europe
  • Rifting of Madagascar
  • Opening of the Persian Gulf
  • Sevier orogeny (80-130 Ma) in Utah and Nevada, involving eastward-directed thrusts
  • Cordilleran orogenies in North and South America
  • Laramide orogeny (50-80 Ma) involved westward-directed thrusts in a belt around the Colorado Plateau; minimal volcanic activity
  • India rifted from Gondwanaland (∼100 Ma)
  • Massive plateau volcanism leads to the formation of the Deccan Traps in India
  • Meteorite impact(s) in Yucatan and elsewhere
  • One of the great mass extinctions in Earth history; extinction of Cycadeoidales, globotruncanids, ammonoids, belemnoids, ichthyosaurs, plesiosaurs, dinosaurs; end of "The Age of Dinosaurs"

Cenozoic 65 Ma to Present

• Paleocene 65-54 Ma
  http://www.pbs.org/wgbh/evolution/change/deeptime/cenozo.html for more information about the Paleocene
  • First prosimians - primates
  • First marine mammals (e.g., whales, dolphins)
• Eocene 54-33 Ma
  http://www.pbs.org/wgbh/evolution/change/deeptime/eocene.html for more information about the Eocene
  • India collides with Eurasia, beginning the Himalaya orogeny
  • Pacific plate changes direction, as reflected in the orientations of the Emperor-Hawaiian seamount chains (~43 Ma)
  • Separation of Australia from Antarctica
  • Appearance of apes
• Oligocene 33-24 Ma
  http://www.pbs.org/wgbh/evolution/change/deeptime/oligocene.html for more information about the Oligocene
  • First monkeys
  • Red Sea begins to open
  • East Pacific Ridge contacts the subduction zone in California; beginning of the proto-San Andreas Fault System
• Miocene 24-5.3 Ma
  http://www.pbs.org/wgbh/evolution/change/deeptime/miocene.html for more information about the Miocene
  • Subsidence of the Baja Trough and rise of metamorphic core complexes in Arizona (~20 Ma)
  • ∼16 Ma Ramapithecus
  • Development of Rhine Graben and Anatolian transform
  • Eruption of the Columbia River Basalts (~10-20 Ma)
  • Extension of the Rio Grande Rift and Basin and Range (~5-10 Ma)
  • Initiation of the Hellenic Arc south of Greece (~6 Ma)
  • Opening of the Gulf of California (5-6 Ma)
• Pliocene 5.3-1.8 Ma
  http://www.pbs.org/wgbh/evolution/change/deeptime/pliocene.html for more information about the Pliocene
  • Arabia collided with Iran to produce the Zagros Suture Zone.
  • 3.6 Ma Australopithecus afarensis
  • Closing of Isthmus of Panama, triggering widespread glaciation (from ∼3.2 Ma)
  • 3.0 Ma Australopithecus africanus
  • ∼2.5 Ma First members of genus Homo

• Pleistocene1.8 Ma to 11,000 years before present
  http://www.pbs.org/wgbh/evolution/change/deeptime/pleistocene.html for more information about the Pleistocene
  The emergence of humans (see the Understanding Evolution site from U.C. Berkeley at https://evolution.berkeley.edu/evolibrary/article/evograms_07
  • ∼1.8 Ma First Homo erectus
  • ∼300 ka First Homo neanderthalensis
  • ∼250 ka First (antique) Homo sapiens (Cro-Magnon)
  • ∼185 ka First Homo sapiens sapiens (modern humans)
  • 18 ka Maximum of the last ice age
• Holocene11,000 years before present to Right Now
  http://www.pbs.org/wgbh/evolution/change/deeptime/holocene.html for more information about the Holocene

This Web document and the original material contained in it are copyright (© 2002-2021) by Vince Cronin, and may be used with attribution for non-profit educational and research purposes.