Champlain Sea Formation

Glacial activity between 8500 and 7000 BC created the saltwater Champlain Sea, causing lamprey, Atlantic salmon, and rainbow smelt to become landlocked.

When this happened

Champlain Sea Formation occurred in Between 8500 and 7000 BC, during the pre-columbian period of American history. The event spanned from -8500 to -7000.

Where this happened

Champlain Sea Formation took place in Vermont. Explore the full history of Vermont and primary source records from this era.

Indigenous peoples had inhabited North America for at least 15,000 years before European contact, developing complex societies across every region of the continent. The Mississippian culture, centered on the city of Cahokia near present-day St. Louis, reached its peak around 1100 AD with a population estimated at 10,000 to 20,000 — larger than contemporary London. The Ancestral Puebloans built multi-story stone complexes at Chaco Canyon and Mesa Verde between the 9th and 13th centuries. The Iroquois Confederacy, formed between roughly 1450 and 1600, united five nations under a constitution that influenced later American democratic thinking. Across the eastern woodlands, the Great Plains, the Pacific Coast, and the Southwest, hundreds of distinct nations maintained sophisticated trade networks, agricultural systems, and governance structures. European contact beginning in the late 15th century introduced epidemic disease — smallpox, measles, influenza — which devastated Indigenous populations by an estimated 50 to 90 percent within a century.

Content adapted from Wikipedia under the Creative Commons Attribution-ShareAlike 4.0 International License. Source: Wikipedia: Geological and marine history.