Subscribe free to our newsletters via your
. 24/7 Space News .




TECTONICS
Tibetan Plateau may be older than previously thought
by Staff Writers
Philadelphia PA (SPX) Aug 21, 2012


File image.

The growth of high topography on the Tibetan Plateau in Sichuan, China, began much earlier than previously thought, according to an international team of geologists who looked at mountain ranges along the eastern edge of the plateau.

The Indian tectonic plate began its collision with Asia between 55 and 50 million years ago, but "significant topographic relief existed adjacent to the Sichuan Basin prior to the Indo-Asian collision," the researchers report online in Nature Geoscience.

"Most researchers have thought that high topography in eastern Tibet developed during the past 10 to 15 million years, as deep crust beneath the central Tibetan Plateau flowed to the plateau margin, thickening the Earth's crust in this area and causing surface uplift," said Eric Kirby, associate professor of geoscience, Penn State.

"Our study suggests that high topography began to develop as early as 30 million years ago, and perhaps was present even earlier."

Kirby, working with Erchie Wang, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, and Kevin Furlong, professor of geosciences, Penn State, and colleagues from Waikato University, New Zealand and Arizona State University, looked at samples taken from the hanging wall of the Yingxiu-Beichuan fault, the primary fault responsible for the 2008, Wenchuan earthquake.

The researchers used a variety of methods including the decay rate of uranium and thorium to helium in the minerals apatite and zircon and fission track dating, an analysis of tracks or trails left by decaying uranium in minerals again in apatite and zircon.

"These methods allow us to investigate the thermal regime from about 250 degrees Celsius (482 degrees Fahrenheit) to about 60 degrees (140 degrees Fahrenheit)," said Kirby. "The results show that the rocks cooled relatively slowly during the early and mid-Cenozoic - from 30 to 50 million years ago - an indication that topography in the region was undergoing erosion."

The results also suggest that gradual cooling during this time was followed by two episodes of rapid erosion, one beginning 30 to 25 million years ago and one beginning 15 to 10 million years ago that continues today.

"These results challenge the idea that the topographic relief along the margin of the plateau developed entirely in the Late Miocene, 5 to 10 million years ago," said Kirby. "The period of rapid erosion between 25 to 30 million years ago could only be sustained if the mountains were not only present, but actively growing, at this time."

The researchers also note that this implies that fault systems responsible for the 2008 earthquake were also probably active early in the history of the growth of the Tibetan Plateau.

"We are still a long way from completely understanding when and how high topography in Asia developed in response to India-Asia collision," notes Kirby. "However, these results lend support to the idea that much of what we see today in the mountains of China may have developed earlier than we previously thought."

.


Related Links
Penn State
Tectonic Science and News






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








TECTONICS
Scientists probe link between magnetic polarity reversal and mantle processes
Liverpool UK (SPX) Aug 03, 2012
Scientists at the University of Liverpool have discovered that variations in the long-term reversal rate of the Earth's magnetic field may be caused by changes in heat flow from the Earth's core into the base of the overlying mantle. The Earth is made up of a solid inner core, surrounded by a liquid outer core, in turn covered by a thicker or more viscous mantle, and ultimately by the soli ... read more


TECTONICS
LRO Spectrometer Detects Helium in Moon's Atmosphere

NASA's 'Mighty Eagle' Robotic Prototype Lander Flies Again at Marshall

Roscosmos Announces Tender for Moon Rocket Design

US flags still on the moon, except one: NASA

TECTONICS
Curiosity rover set for first test drive

Rover's Laser Instrument Zaps First Martian Rock

Fantastic Phobos

New NASA Mission to Take First Look Deep Inside Mars

TECTONICS
For US students, plane tickets, TVs are relics

Voyager at 35: Break on Through to the Other Side

XCOR Becomes Corporate Sponsor of Uwingu, a Space Apps Company

Florida Spaceport Stakes Claim to Commercial Missions

TECTONICS
Is China Going to Blast Past America in Space?

Hong Kong people share joy of China's manned space program

China's Long March-5 carrier rocket engine undergoes testing

China to land first moon probe next year

TECTONICS
ISS Orbit Adjustment to Continue on August 22

Cosmonauts Begin First Expedition 32 Spacewalk

ATV-3 Vehicle Fails to Adjust Space Station Orbit

ISS crew to embark on two spacewalks in August

TECTONICS
Russian Booster Rocket Lifts US Satellite in Seaborne Launch

India's GSAT-10 satellite continues its checkout for the upcoming Arianespace Ariane 5 mission

Flight Readiness Review Complete; No Constraints to Aug. 23 Launch

Pre launch verifications are underway for next Soyuz mission

TECTONICS
First Evidence Discovered of Planet's Destruction by Its Star

Exoplanet hosting stars give further insights on planet formation

Five Potential Habitable Exoplanets Now

RIT Leads Development of Next-generation Infrared Detectors

TECTONICS
Yap.TV tunes Internet Age viewing for the world

Good vibrations

Britain and Ireland tuning into Netflix

Apple is most valuable company ever at $623 bn




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