Ice Age

See ancient Earth from space

Publication: msnbc.com   Date: April 21, 2011   View Article

Over the past 750 million years, our blue marble has gone through remarkable changes— continents have shifted, ice ages have come and gone, sea levels have risen and fallen, and one-time deserts have turned green, allowing creatures to crawl out of the oceans and live off the land.

These changes are now being made visible by the Planetary Habitability Laboratory at the University of Puerto Rico at Arecibo. The first set of the Visible Paleo Earth visualizations are being released today, on Earth DAy, and more will be available in coming weeks.

Fungi, Feces Show Comet Didn’t Kill Ice Age Mammals?

Publication: National Geographic News   Date: June 22, 2010   View Article

Tiny balls of fungus and feces may disprove the theory that a huge space rock exploded over North America about 12,900 years ago, triggering a thousand-year cold snap, according to a new study.

The ancient temperature drop, called the Younger Dryas, has been well documented in the geologic record, including soil and ice core samples.

The cool-down also coincides with the extinction of mammoths and other Ice Age mammals in North America, and it’s thought to have spurred our hunter-gatherer ancestors in the Middle East to adopt an agricultural lifestyle.

Comet “Shower” Killed Ice Age Mammals?

Publication: National Geographic News   Date: April 7, 2010   View Article

The comet that created the annual Taurid meteor shower was also responsible for snuffing out large mammals in North America 13,000 years ago, a controversial new study says.

The geologic record shows that global temperatures plummeted by as much as 14 degrees Fahrenheit (8 degrees Celsius) just as Earth was thawing out from the last ice age.

This cold snap probably led to the extinction in North America of large animals such as saber-toothed cats and wooly mammoths. But scientists have been unsure what triggered the abrupt change.

Comet Impacts Triggered Ice Age Extinctions?

Publication: National Geographic News   Date: July 21, 2009   View Article

Rare diamonds found buried on an island near southern California strengthen the controversial idea that comet impacts wiped out huge beasts and an early human culture in North America about 12,900 years ago.

Similar “nanodiamonds” found in sediments across North America were presented earlier this year as proof that space rocks colliding with Earth led to the ancient mass extinction.

Sudden Ice Age Warming Linked to El Nino

Publication: National Geographic News   Date: March 17, 2004   View Article

During the last ice age, temperatures in the North Atlantic region rose sharply and quickly about every 1,500 years. The result: massive discharges of melted ice into the ocean which disrupted weather patterns around the world.

The trigger behind these abrupt climate cycles—called Dansgaard-Oeschger events—is the subject of a long-running debate that bears on the ability of scientists to predict climate.

© 2008-2010 Collected Writings By John Roach