In 1980, a controversial paper proposed that a giant asteroid had struck Earth at the end of the Cretaceous period, killing the dinosaurs and every other large land vertebrate. Years later, impacts have been proposed as the cause of every other known mass extinction. What impact has Impact Theory had on understanding these events?

The people of Xuan Wei, China, suffer the world's highest incidence of lung cancer among non-smokers. Burning coal from the Permian-Triassic boundary may be to blame.

Energy, climate change mitigation and healthcare reform grabbed most of the U.S. policy headlines in 2009. But a few other policy gems  — for example, human spaceflight, renewable energy projects on public lands, mining reform and natural hazards — have started coalescing in Congress. EARTH contributor Corina Cerovski-Darriau outlines some of the less high-profile topics we can expect to see debated in 2010.

Sequestering carbon dioxide in underground aquifers may be one way to remove it from the atmosphere. But, once stored underground, will the greenhouse gas stay put? Evidence suggests that the gas mainly dissolves in the water, not the rock — but that should still keep it secure.

David Harwood’s geology field course for future teachers is not a network reality show — but it does have all the humor, drama, challenges and bleepable moments of “Survivor.” Geology 160 also offers authentic geological history that students see, taste and scrape from under their fingernails.

Reconstructing the history of supercontinents requires careful detective work. A longstanding challenge for geological sleuths is locating the ancient front, or leading, edge of a drifting continent — the part that is constantly reshaped by new collisions.

When it comes to mass extinction events, what seems like a simple tale — for example: dinosaurs die, mammals take over — is much more complicated. But extinctions aren't random, either: Written in the rocks are certain "rules" these events seem to follow.

A hundred years after it was discovered, the world’s most famous fossil site still holds surprises.
 

Some scientists say giant, wedge-shaped sandy deposits on the coast of southern Madagascar are evidence of a giant tsunami spawned by an asteroid strike 10,000 years ago. But new research suggests these deposits were formed by winds, not mega-tsunamis.

The Inca knew there was something sinister about the cinnabar mine in Huancavelica, Peru. Now scientists have unraveled a story of mercury pollution from the mine extending back 3,500 years.

Beyond Buenos Aires: From cactus-covered deserts to cloud forests to the sky-scraping Andes Mountains, northwestern Argentina promises contrasting landscapes, astounding geological formations and natural beauty — and a chance to eat llama.

As lunar exploration gears back up, scientists are still puzzling over a longstanding challenge: How to drill into the tough lunar soil to discover what lies beneath. The solution, however, may be quite close to home.

A geologic period just got a little older.

After months of increased rumbling, the volcano came violently awake late Sunday night.

Water-powered mills were key to early American industry; by 1840, tens of thousands of milldams were altering the waterways of the eastern United States. But those dams, it turns out, didn't change streamflow in quite the way geologists once thought they would — and that means restoring the waterways won't be as straightforward, either.