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geology

Geology 101: Reading the story in the rocks

David Harwood’s field geology course gives future teachers an introduction to several of geology’s most fundamental principles, including the stratigraphic basics described by Nicholas Steno in 1669. Go to the head of the class with this quick primer.

20 Oct 2009

Surviving field school: Better than reality TV

David Harwood’s geology field course for future teachers is not a network reality show — but it should be. The three-week course has all the humor, drama, exacting challenges and bleepable moments of “Survivor.” But in contrast to the staged setups of TV “reality” shows, Geology 160 offers billions of years’ worth of authentic geological history that students see, taste and scrape from under their fingernails.

20 Oct 2009

Chemical clues reveal ancient geography

Reconstructing the history of supercontinents requires careful detective work. A variety of geological processes wipes the evidence clean, like a burglar who smears away his fingerprints. Yet even the most cautious criminals leave clues behind — and so do supercontinents.

07 Oct 2009

Benchmarks: September 16, 1987: Montreal Protocol Signed

Each year in late September to early October, atmospheric scientists watch with anticipation as ozone concentrations over Antarctica drop, opening a window in Earth’s defenses against harmful ultraviolet radiation. This ozone “hole” grew steadily in the 1990s and set a record for its size in 2006: At its peak, the hole covered an average area of 27 million square kilometers, approximately the size of North America. But scientists think that the overall ozone layer is on the slow road to recovery, thanks to the Montreal Protocol — one of the most successful international environmental agreements in history.
 
16 Sep 2009

Deciphering mass extinctions

What the planet’s past mass extinctions tell us about the future of life on Earth

The crash-landing of a 10-kilometer-wide asteroid 65 million years ago made for a very bad day for dinosaurs — or one very lucky day for mammals.

02 Sep 2009

Re-examining the Burgess Shale

About 505 million years ago, the continent that would become North America straddled the equator. With no terrestrial plants or animals, the land was a barren landscape. The warm, shallow sea bordering the continent, however, hosted a carbonated reef teeming with a diverse array of organisms, most of which were relatively small bottom-dwellers. Periodically, the animals would get washed over the reef and deposited at its base, where their bodies accumulated in the muddy sediments. Today, these creatures are beautifully preserved in the Burgess Shale.

24 Aug 2009

Giant dunes, not mega-tsunami deposits?

About four years ago, a group of scientists proposed that a series of giant, wedge-shaped sandy deposits found along the shores of southern Madagascar might be evidence of a giant tsunami — a “mega-tsunami” — generated by an asteroid that may have blasted into the Indian Ocean sometime in the last 10,000 years. Furthermore, the scientists said, such impacts and the resulting tsunamis may have occurred fairly frequently during this period. To search for evidence of these impacts, the researchers formed the Holocene Impact Working Group.

05 Aug 2009

The long legacy of Peru's "Mine of Death"

The Inca knew there was something sinister about the cinnabar they hauled out of the ground at Huancavelica in Peru hundreds of years ago. They called the mine the Mine of Death. Now, a new study has exposed a 3,500-year history of mercury pollution from the cinnabar mines, a much longer legacy than researchers had previously realized.

05 Aug 2009

Travels in Geology: Exploring mountains and eating llama in Northern Argentina

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. So with no disrespect to the more geologically famous ice fields and mountains of the Argentine Patagonia to the south, I suggest heading north from Buenos Aires if you get a chance to explore the country.

27 Jul 2009

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