Geological Timescale

By obisletc

  • Precambrian

    Precambrian
    1) There is very little plant life during this period 11) Nearly half of the valuable mineral deposits in the world occur in the rocks of this period

  • Cambrian

    Cambrian
    10) The presence of stromatolites indicates that shallow seas covered much of earth during intervals in this period 22)Trilobites appear

  • Ordovician

    Ordovician
    jawless fish were alive. formation of early terrestrial arthropods (example is a spider).

  • Silurian

    Silurian
    24) Eurypterids ,sea starts and coral become more common. 33) Vascular land plants and animals, such as scorpions begins to envolve on land.

  • Devonian

    Devonian
    31)first tetrapods on Earth (land living vertebrates). 37) first seed plant appeared.

  • Carboniferous Mississipian

    Carboniferous Mississipian
    2)Swamps and forests cover the land 34)Ichthyosaurs are living in the ocean , new invertebrates call ammonite develop

  • Carboniferous Pennsylvania

    Carboniferous Pennsylvania
    4) Giant cockroaches appear 15) Coal deposits form

  • Permian

    Permian
    38) Evironmental change causes mass extinction of sea invertibrates as the seas retreat 21) Early reptiles resembling large lizards appear

  • Triassic

    Triassic
    16) Enter the squirrel sized dinosaur and the first forest dwelling mammals apper 29) Small rodents evolve

  • Cretaceous

    Cretaceous
    15) Coal deposits form 35) Impact hypothesis- dinosaur mass extinction

  • Paleocene

    Paleocene
    6)Himalays develop due to uplifting caused bye the indian subcontinent and Eurasian continents colliding 12) First primates evolve

  • Eocene

    Eocene
    17) Flying squirrels, whales and bats appear 26) First modern horses appear

  • Oligocene

    Oligocene
    27) Many early mammal become extinct, clams and snails flourish 32) Antarctic icecaps begin to form

  • Miocone

    Miocone
    8)Appalachian Mountains are created because of the collision of tectonic plates and savannahs form 18) Various species migrated between continents acriss land bridges

  • Pliocone

    Pliocone
    20) Species that did mot envolve to survive extreme cold moved to waemer climates areas or become extinct 36) Mediterranean sea dries up and refills several times due to tectonic forcesa dn dropping sea levels

  • Holocene

    Holocene
    19) The last glacial period ended and sea levels rose, Great lakes formed 28) Modern human developed agriculture and use tools made of brozen and iron

  • Anthropocene

    Anthropocene
    7) Humans kind has caused mass extinctions of plat and animal polluted the oceans and altered the atmosphere 14) People think It began with the industrial age in the early 1800's other think it began with the atomic age in the 1950's