Free Newsletters - Space News - Defense Alert - Environment Report - Energy Monitor
. 24/7 Space News .




WATER WORLD
New clues about ancient water cycles shed light on US deserts
by Staff Writers
College Station TX (SPX) Oct 03, 2012


File image.

The deserts of Utah and Nevada have not always been dry. Between 14,000 and 20,000 years ago, when large ice caps covered Canada during the last glacial cooling, valleys throughout the desert southwest filled with water to become large lakes, scientists have long surmised. At their maximum size, the desert lakes covered about a quarter of both Nevada and Utah.

Now a team led by a Texas A and M University researcher has found a new water cycle connection between the U.S. southwest and the tropics, and understanding the processes that have brought precipitation to the western U.S. will help scientists better understand how the water cycle might be perturbed in the future.

Mitch Lyle, professor of oceanography, led the study with colleagues from Columbia University, University of California-Santa Cruz, Stanford University, Hokkaido University of Japan, Brown University and the U.S. Geological Survey. Their work, funded by the National Science Foundation, is published in the current issue of Science magazine.

The dry shorelines of these glacial lakes were first discovered by 19th century geologists when the west was first explored, Lyle explains, adding that the source of the additional water has been a mystery.

By assembling data from ocean sediments and from dry western valleys collected over the last 30 years, Lyle and the team found a new water cycle connection between the southwest U.S. and the tropics.

"Large ice caps profoundly altered where storms went during glacial periods. Before this study, it was assumed that Pacific winter storms that now track into Washington and Canada were pushed south into central and southern California," Lyle notes.

"However, by comparing timing between wet intervals on the coast, where these storms would first strike, with growth of the inland lakes, we found that they didn't match."

The team was able to time wet periods along the California coast from pollen buried in marine sediments from cores archived by scientists at the Integrated Ocean Drilling Program at Texas A and M. They evaluated lake level studies from southeast Oregon, Nevada, Utah, eastern California, New Mexico, and west Texas to find when lakes filled in different parts of the west.

"Many teams of scientists have been working on this problem since the 1950s, when radiocarbon dating first allowed ages to be put on old shorelines," Lyle adds. "The data we synthesized covers a wide latitude so that we could determine how the glacial wet intervals operated."

Only southern California coastal wet intervals matched with the progression of high lakes inland, pointing to the development of a tropical connection, where storms cycled into the region from the tropical Pacific, west of southern Mexico.

"We think that the extra precipitation may have come in summer, enhancing the now weak summer monsoon in the desert southwest. But we need more information about what season the storms arrived to strengthen this speculation," Lyle says.

Not only is the development of the glacial lakes important from a paleoclimate perspective, but it is likely that the lakes were important to the migration of people into North America, Lyle believes.

Many of the archaeological sites where early Indians settled when they first came into the U.S. are rock shelters at the edges of these ancient lakes. The lakes were a major source of fish, and a gathering place for deer and wildfowl at that time.

"What we need to do now is look at all of this on a finer scale," Lyle points out. "We need to understand better the processes that directed the storms thousands of years ago, and to predict better what changes might occur in the future."

.


Related Links
Texas A and M University
Water News - Science, Technology and Politics






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





WATER WORLD
Jordanian thirst for water grows
Amman (AFP) Oct 1, 2012
"I wish I could live at the Zaatari Syrian refugee camp because there is water there," a Jordanian man says, frustrated that he has not had any tap water of his own in months. "I cannot remember the last time I got municipal water. Maybe if I go live with the Syrian refugees I might get some of the water the government provides them," said the 50-year-old man from the northern city of Irbid. ... read more


WATER WORLD
China has no timetable for manned moon landing

Senior scientist discusses China's lunar orbiter challenges

NASA sees 'gateway' for space missions

Protection for Moon, Mars astronauts eyed

WATER WORLD
Near Possible Target for Use of Arm Instruments

Rock Grinding Action

Learning to live on Mars

Mars Rover Opportunity Working at 'Matijevic Hill'

WATER WORLD
SciTechTalk: NASA's planetary playbook

Bryan Campen joins XCOR as Director of Media and Public Relations

B612 Wins Funding Support From Prominent Business Leadersy

Cavenauts return to Earth

WATER WORLD
China Spacesat gets 18-million-USD gov't support

Tiangong Orbit Change Signals Likely Date for Shenzhou 10

China Focus: Timeline for China's space research revealed

China eyes next lunar landing as US scales back

WATER WORLD
Space freighter burns up in suicide dive

Space freighter undocking set for Friday

Russia to send all-novice crew to ISS

ATV undocking postponed

WATER WORLD
H-IIB Launch Service Privatization

Ariane rocket launches two telecom satellites

Ariane 5 maintains Arianespace's track record of success with the launch of ASTRA 2F and GSAT-10

California Governor Signs the Spaceflight Liability and Immunity Act

WATER WORLD
The Magnetic Wakes of Pulsar Planets

Stagnant Interiors Suppress Chances of Life on Super-Earths

Meteors Might Add Methane to Exoplanet Atmospheres

Two 'hot Jupiters' found in star cluster: NASA

WATER WORLD
HP stock sinks with slow turnaround

Malaysia hearing on Australia rare earths plant postponed

Ancient stinging nettles reveal Bronze Age trade connections

Probing the mysteries of cracks and stresses




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement