IMAGENES DE INVIERNO

Leaving fall
Last year's crop of oak leaves receive a dazzlingly white outline in a layer of morning hoar frost at the edge of a field along Benton County Road 80 near Sauk Rapids, Minn.

Frosty treat
Snow covers clusters of berries of a guelder rose tree after heavy snowfall in the Siberian town of Divnogorsk, Russia.

Lone squirrel
A squirrel sits on a snowy tree branch in a Moscow park on Nov. 17, 2009. Moscow is undergoing its first snows of the winter as temperatures fluctuate above and below the freezing point.

EARTH ATMOSPHERE CAME FROM OUTER SPACE

Earth's atmosphere came from outer space, find scientists.

The gases which formed the Earth's atmosphere - and probably its oceans - did not come from inside the Earth but from outer space, according to a study by University of Manchester and University of Houston scientists.

The report published this week in the prestigious international journal 'Science' means that textbook images of ancient Earth with huge volcanoes spewing gas into the atmosphere will have to be rethought.
According to the team, the age-old view that volcanoes were the source of the Earth's earliest atmosphere must be put to rest.
Using world-leading analytical techniques, the team of Dr Greg Holland, Dr Martin Cassidy and Professor Chris Ballentine tested volcanic gases to uncover the new evidence.
"We found a clear meteorite signature in volcanic gases," said Dr Greg Holland the project's lead scientist.
"From that we now know that the volcanic gases could not have contributed in any significant way to the Earth's atmosphere.
"Therefore the atmosphere and oceans must have come from somewhere else, possibly from a late bombardment of gas and water rich materials similar to comets.
"Until now, no one has had instruments capable of looking for these subtle signatures in samples from inside the Earth - but now we can do exactly that."
The techniques enabled the team to measure tiny quantities of the unreactive volcanic trace gases Krypton and Xenon, which revealed an isotopic 'fingerprint' matching that of meteorites which is different from that of 'solar' gases.
The study is also the first to establish the precise composition of the Krypton present in the Earth's mantle.
Project director Prof Chris Ballentine of The University of Manchester, said: "Many people have seen artist's impressions of the primordial Earth with huge volcanoes in the background spewing gas to form the atmosphere.
"We will now have to redraw this picture."

ANDES MOUNTAINS ARE OLDER THAN PREVIOUSLY BELIEVED

Photo Pascale Baron

Andes Mountains Are Older Than Previously Believed

“No one had ever dated mountain-building events in the eastern range of the Colombian Andes,” said Mauricio Parra, a former doctoral candidate at the University of Potsdam (now a postdoctoral fellow with the University of Texas) and lead author.

“This eastern sector of America’s backbone turned out to be far more ancient here than in the central Andes, where the eastern ranges probably began to form only about 10 million years ago.”
The team integrated new geologic maps that illustrate tectonic thrusting and faulting, information about the origins and movements of sediments and the location and age of plant pollen in the sediments, as well as zircon-fission track analysis to provide an unusually thorough description of basin and range formation.
As mountain ranges rise, rainfall and erosion wash minerals like zircon into adjacent basins, where they accumulate to form sedimentary rocks. Zircon contains traces of uranium. As the uranium decays, trails of radiation damage accumulate in the zircon crystals.

At high temperatures, fission tracks disappear like the mark of a knife disappears from a soft block of butter. By counting the microscopic fission tracks in zircon minerals, researchers can tell how long ago how long ago rocks began to be uplifted, or exhumed toward the earth surface.
Classification of nearly 17,000 pollen grains made it possible to clearly delimit the age of sedimentary layers.
The use of these complementary techniques led the team to postulate that the rapid advance of a sinking wedge of material as part of tectonic events 31 million years ago may have set the stage for the subsequent rise of the range.
“The date that mountain building began is critical to those of us who want to understand the movement of ancient animals and plants across the landscape and to engineers looking for oil and gas,” said Carlos Jaramillo, staff scientist from STRI. “We are still trying to put together a big tectonic jigsaw puzzle to figure out how this part of the world formed.”

FOREST AND SEA

USA NATIONAL PARKS

Shenandoah National Park, Virginia.

Saguaro National Park, Arizona.

Glacier Basin, Rocky Mountain National Park, Colorado.

Del Norte, Redwood National Park, California.

Cliff Palace, Mesa Verde National Park, Colorado.

Turquoise Lake, Lake Clark National Park, Alaska.

Grant Grove, Kings Canyon National Park, California.

Exit Glacier, Kenai Fjords National Park, Alaska.

Hawaii Volcanoes National Park, Hawaii.

Middle Prong of the Little River, Great Smoky Mountains National Park.

Great Sand Dunes National Park, Colorado.

Cape Royal, Grand Canyon National Park, Arizona.

Muir inlet, Glacier Bay National Park, Alaska.

McDonald Lake, Glacier National Park, Montana.

The Maidens, Gates of the Arctic National Park, Alaska.

Everglades National Park, Florida.

Dry Tortugas National Park, Florida.

Mesquite Sand Dunes, Death Valley National Park, California.

Wonder Lake, Denali National Park, Alaska.

Crater Lake National Park, Oregon.

Congaree National Park, South Carolina.

Delicate Arch, Arches National Park, Utah

Inspiration Point, Channel Islands National Park, California

Cathedral Valley, Capitol Reef National Park, Utah.

Carlsbad Caverns National Park, New Mexico.

Sequoia National Park and Kings Canyon National Park

Sequoia National Park and Kings Canyon National Park are home to several natural biggies, from immense mountains to deep canyons via giants of the leafy sort.

These two adjacent national parks were the country’s second and third so designated, and together with Giant Sequoia National Monument as well as vast tracts of federal wilderness take in a significant portion of the Sierra Nevada

Travelers on the Generals Highway will climb over 5000 feet from chaparral and oak-studded foothills to the awe-inspiring sequoia groves. From there, trails lead to high-alpine wilderness or down beneath the surface to quiet limestone caverns.

Though scenic drives and short nature trails offer the casual visitor opportunity to get a glimpse of what makes this place so special,

Not surprisingly, the parks are not only big physically, but big as in popular, particularly with outdoors enthusiasts. .

the best way really to squirrel out park secrets is on an extended hike into the more remote reaches of the parks.

Sequoia and Kings Canyon National Parks are located in east central California, about 200 miles north of Los Angeles

OPALO