Prehistory
Acasta Gneiss: Canada's 4-Billion-Year-Old Rock Formation
The Acasta Gneiss became the oldest securely dated intact rock on Earth, showing that evolved crust existed by about 4 billion years ago.
Region
Americas
Prehistory
Isua Greenstone Belt: Greenland's Ancient Rocks and Early Life
One of the oldest well-preserved sequences of volcanic and sedimentary rock on Earth, central to debates over the earliest traces of life.
Prehistory
Nuvvuagittuq Belt: The Debated Oldest Fossils in Quebec
A Canadian rock belt whose age and possible microfossils remain among the most debated claims for Earth's earliest life.
Prehistory
Huronian Glaciation: The Long Ice Age 2.4 Billion Years Ago
Repeated glaciations left tillites on several continents and coincided with the first lasting rise of atmospheric oxygen.
Prehistory
Gunflint Chert: Microfossils That Proved Precambrian Life
The first widely accepted Precambrian microfossils were described, opening the modern study of early life.
Prehistory
Sudbury Basin: Ancient Impact Crater and Nickel Mining Region
A giant impact created one of Earth's largest known impact structures and, indirectly, one of the world's richest nickel and copper ore districts.
Prehistory
Bangiomorpha: The Oldest Known Sexually Reproducing Organism
The fossil red alga provided the oldest widely accepted evidence of sexual reproduction, complex multicellularity and a eukaryote belonging to a living group.
Prehistory
Mistaken Point: Newfoundland's Ediacaran Fossil Coast
Rock surfaces at Mistaken Point preserve some of the oldest known communities of large, complex organisms, recognised as a UNESCO World Heritage Site in 2016.
Prehistory
Pikaia: The Cambrian Chordate and Early Relative of Vertebrates
Pikaia is now regarded as an early stem-group chordate, a distant relative of vertebrates rather than their direct ancestor.
Prehistory
Burgess Shale: Charles Walcott's Cambrian Fossil Discovery
Found in 1909, the Burgess Shale became the most famous record of Cambrian soft-bodied animals and transformed scientific understanding of early animal evolution.
Prehistory
Caledonian Orogeny: The Closing of the Iapetus Ocean
The Iapetus Ocean closed and Laurentia, Baltica and Avalonia fused into the continent of Laurussia, raising a long mountain belt.
Prehistory
Dunkleosteus: The Armoured Giant Fish of the Devonian Seas
Dunkleosteus became one of the best-known early vertebrate predators; it and all other placoderms died out by the end of the Devonian.