Cambrian

The Cambrian ( /ˈkæmbri.ən, ˈkeɪm-/ KAM-bree-ən, KAYM-) is the first <a href="/facts/Geological_period/6LBR11yQ">geological period</a> of the <a href="/facts/Paleozoic/5qe2wz7U">Paleozoic</a> Era, and the <a href="/facts/Phanerozoic_Eon/EKKuYnwl">Phanerozoic Eon</a>. The Cambrian lasted 51.95 million years from the end of the preceding <a href="/facts/Ediacaran/z8jSUITT">Ediacaran</a> period 538.8 Ma (million years ago) to the beginning of the <a href="/facts/Ordovician/BjMrLIEA">Ordovician</a> Period 486.85 Ma.
Most of the continents lay in the southern hemisphere surrounded by the vast <a href="/facts/Panthalassa/QKkoYuM3">Panthalassa Ocean</a>. The assembly of <a href="/facts/Gondwana/zqbAvsnY">Gondwana</a> during the Ediacaran and early Cambrian led to the development of new <a href="/facts/Convergent_boundary/rhgWhQx3">convergent plate boundaries</a> and <a href="/facts/Volcanic_arc/W2WawWYd">continental-margin arc magmatism</a> along its margins that helped drive up global temperatures. <a href="/facts/Laurentia/G54C2qc3">Laurentia</a> lay across the equator, separated from Gondwana by the opening <a href="/facts/Iapetus_Ocean/2rjw83DF">Iapetus Ocean</a>.
The Cambrian marked a profound change in <a href="/facts/Life/DNw7NUId">life on Earth</a>; prior to the Period, the majority of living organisms were small, <a href="/facts/Unicellular_organism/9PQsRuHU">unicellular</a> and poorly preserved. Complex, <a href="/facts/Multicellular_organism/rk8QBF7o">multicellular organisms</a> gradually became more common during the Ediacaran, but it was not until the Cambrian that fossil diversity seems to rapidly increase, known as the <a href="/facts/Cambrian_explosion/Wg29M7PN">Cambrian explosion</a>, produced the first representatives of most modern animal <a href="/facts/Phylum/ELT3Jyax">phyla</a>. The Period is also unique in its unusually high proportion of <a href="/facts/Lagerst%C3%A4tte/ByI7PT8h">lagerstätte</a> deposits, sites of exceptional preservation where "soft" parts of organisms are preserved as well as their more resistant shells.

Cambrian open-in-new

Cambrian