Ice Age Earth

Ice Age Earth• Between 2 million and 12,000 years ago, much of the

northern hemisphere was covered in ice.

Ice Ages arrive in cycles every 100,000 years or so, with brief 20,000 year “Interglacial” periods of relative warmth.

The last Ice Age ended about 10,000 ya

Ice Age North America 15,000 years ago

• The continent saw two large ice sheets dipping from the arctic to the northern part of the U.S.

Seattle during Ice Age

Ice Age Sea Levels Were 300 feet Lower!• Because so much water was locked up in continental

ice sheets, the ocean level was much lower.

Ice Age Coastline of North America

• The coastline of Washington was 30 miles further west

The Mississippi Valley and Delta is primarily built from ice age sediments

Deepwater delta deposits

Bering Land Bridge Connected North America and Asia

The Bering Land Bridge allowed movement of species between continents

Beringia Was an Ice Free Grassland During the Ice Age

Migration of Animals (both ways)

Great Biotic ExchangeFrom Asia to North America

• Moose, Elk, Deer, Caribou, Musk Ox, Bison, and Bighorn sheep

• Gray wolves

• Grizzly bears and polar bears

• Jaguars, bobcats, lynx

• Skunk, otters, tapirs, weasels, and wolverines

• Beavers, marmots, and snowshoe hares

America provided Lions, Cheetahs, Horses, and Camels to Asia

Extinct Ice Age Species• Woolly Mammoth

• Columbia Mammoth

• Mastodons

• Woolley Rhinoceros

• Ground sloths

Extinct Ice Age Species

• Short-faced Bear

• American lion

• American cheetah

• Sable-toothed cat

• Dire wolf

• American hyena

Extinct Ice Age Species

• American horses

• American camels

• Giant beavers

A Mammoth Tusk and Sloth Bones in

Seattle