Evolution of the Earth 13 7 Billion Years

Evolution of the Earth 13. 7 Billion Years in the Making PART 3: Cambrian Dr. Gregg Wilkerson Earth Science Bakersfield City College

Rodinia broke up into Lauritania and Gondwanaland: 600 to 800 Million Years Ago

Proterozoic to Cambrian Transition • Microscopic Life • To • Megascopic Life

Life and Calcium Carbonate: 540 million years ago • Biogentic Limestones

The Cambrian Explosion of Life: 540 Million Years Ago • 25% Oxygen • Great Diversity of Life

Trilobites

Cambrian Explosion • All modern taxa and many extinct ones

The Great Cambrian Transgression • Shoreline migrated inland in North America, east to west • Observed in the Grand Canyon strata

Paleozoic Life

Precambrian to Devonian Life

Caladonian Orogeny: 490– 390 million years ago • Caused by the closure of the Iapetus Ocean when the continents and terranes of Laurentia, Baltica and Avalonia collided

Phases of the Caladonian Orogeny • East Greenland Orogen, formed from Cryogenian Neoproterozoic to Devonian • Taconic phase – A mountain building period that affected most of New England in the NE U. S. and Canada during the Ordovician Period. • Acadian phase in the Eastern U. S. during Silurian and Devonian Periods.