Geologic Events in a Century By smitha65 1 CE Hadean Event: Proto-Earth and Planetoid Theia Collide 1 CE Origin of Earth 10 Oldest Rocks 17 Earliest Chemical Evidence of Life 17 Archean Event: Oceans Cool & Form 54 First Eukaryotic Cells Appear 60 Free Oxygen in the Atmosphere 69 Formation of Early Rodinia 84 Early Multicellular Organisms 84 Proterozoic Event: Snowball Earth Hypothesis 88 Cambrian Explosion 88 Early Shelled Organisms 89 Early Fish Appear 90 End-Ordovician Extinction 91 First Land Animals 91 Late Devonian Extinction 91 Acadian Orogeny 93 Final Assembly of Pangea 93 Earliest Trees Appear + Formation of Coal Deposits 94 End-Permian Extinction 95 Dinosaurs Become Dominant 95 End-Triassic Extinction 95 Mesozoic: Major Volcanic Eruptions 96 Earliest Angiosperms Appear 97 Coniferous Plants are most abundant 98 North America and Europe Separate 98 End-Cretaceous/ K-PG Extinction 99 Mammals + Flowering Plants Become Abundant 99 Great American Biotic Interchange 99 First primate, genus Homo appears 99 Beginning of Recorded Human History 99 My Birth Year (2001) 99 Modern Homo Sapiens Appear 99 Most Recent Ice Age Ends
