geological timescale

  • cambrian period-570-500 MYA

    cambrian period-570-500 MYA
    earliest marine lofe recorded. abundant amount..
  • ordovidan- 500-435 MYA

    ordovidan- 500-435 MYA
    The Early Ordovician climate was thought to be quite warm, at least in the tropics. As with North America and Europe, Gondwana was largely covered with shallow seas during the Ordovician. Shallow clear waters over continental shelves encouraged the growth of organisms that deposit calcium carbonates in their shells and hard parts.
  • Silurian

    During this period, the Earth entered a long warm greenhouse phase, and warm shallow seas covered much of the equatorial land masses. Early in the Silurian, glaciers retreated back into the South Pole until they almost disappeared in the middle of Silurian. The period witnessed a relative stabilization of the Earth's general climate, ending the previous pattern of erratic climatic fluctuations.
  • Devonian

    The Devonian was a relatively warm period, and probably lacked any glaciers.[9] Reconstruction of tropical sea surface temperature from conodont apatite implies an average value of 30 °C in the Early Devonian.
  • Carboniferous

    The early part of the Carboniferous was mostly warm; in the later part of the Carboniferous, the climate cooled. Glaciations in Gondwana, triggered by Gondwana's southward movement, continued into the Permian and because of the lack of clear markers and breaks, the deposits of this glacial period are often referred to as Permo-Carboniferous in age.
  • Permian

    The climate in the Permian was quite varied. At the start of the Permian, the Earth was still at the grip of an Ice Age from the Carboniferous. Oxygen levels decreased, wiping out plant life and the some of the giant insects from the Carboniferous.
  • Triassic

    The Triassic climate was generally hot and dry, forming typical red bed sandstones and evaporites. There is no evidence of glaciation at or near either pole; in fact, the polar regions were apparently moist and temperate, a climate suitable for reptile-like creatures.
  • Jurassic

    During the Jurassic, the primary vertebrates living in the seas were fish and marine reptiles. The latter include ichthyosaurs who were at the peak of their diversity, plesiosaurs, pliosaurs, marine crocodiles, of the families Teleosauridae and Metriorhynchidae.
  • Cretaceous

    The Berriasian epoch showed a cooling trend that had been seen in the last epoch of the Jurassic. There is evidence that snowfalls were common in the higher latitudes and the tropics became wetter than during the Triassic and Jurassic
  • Tertiary

    Climates during the Tertiary slowly cooled, starting off in the Paleocene with tropical-to-moderate worldwide temperatures and ending before the first extensive glaciation at the start of the Quaternary.
  • Quaternary

    The 2.6 million years of the Quaternary represents the time during which recognizable humans existed. Over this short a time period, the total amount of continental drift was less than 100 km, which is largely irrelevant to palaeontology