Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Glaciers in Tibet – never really large

04.06.2010
The Tibetan Plateau is the largest and highest mountain region on Earth with glaciers whose meltwater provides the water supply for more than 1.3 billion people through several of the largest rivers in Asia.

In a thesis in Physical Geography from Stockholm University, Jakob Heyman shows that the glaciers in Tibet have remained relatively small and have not been much larger than today for tens of thousands to hundreds of thousands of years back in time.

The study deals with the growth and decay of glaciers in Tibet far back in time, with the aim of attaining better knowledge of glaciations and their link to climate variations. The results show that the glaciers in Tibet have varied in size but that they have been fairly small far back in time.

In several places the glaciers seems to have been similar in size to today’s glaciers or just slightly larger during the entire last Ice Age. Considering that Tibet, often called the roof of the world or the third pole, is where the largest number of glaciers outside the polar regions are located, this is remarkable.

“At the same time as huge ice sheets covered northern Europe and North America during the last Ice Age twenty thousand years ago, the glaciers in Tibet were not much larger than today,” says Jakob Heyman.

The field data can be used, together with a mathematical model for the growth of a glacier, to find out how large the climatic variations have been during the last Ice Age. Preliminary results show that the climate was probably somewhat colder than today but was nevertheless relatively stable.

“If today’s temperature in Tibet were to decrease by five degrees or more, which is not much for an Ice Age cycle, a large ice sheet would probably start growing. No ice sheet seems to have existed in Tibet, and the cooling can therefore not have been that strong,” says Jakob Heyman.

To determine how large the glaciers have been, satellite images have been used to find landforms created by former glaciers, and field studies have been performed to find sediments and erratic boulders deposited during past glaciations. To find out when the ice disappeared, samples have been collected from boulders left by the ice and the number of particular isotopes formed in quartz when hit by cosmic rays has been measured. Because the cosmic ray intensity is known, the number of isotopes can be used to calculate the age for when the boulders were melted out of the ice.

Title of dissertation: Palaeoglaciology of the northeastern Tibetan Plateau

For more information
Jakob Heyman, Department of Physical Geography and Quaternary Geology, Stockholm University, tel +46 730-521979, +46 8-164787, e-mail jakob.heyman@natgeo.su.se

Pressofficer Maria Skuldt, maria.skuldt@kommunikation.su.se; +46-722 333 385

Maria Skuldt | idw
Further information:
http://su.diva-portal.org/smash/record.jsf?pid=diva2:312664
http://www.su.se/pub/jsp/polopoly.jsp?d=12201&a=80574

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Gold shines through properties of nano biosensors

17.08.2017 | Physics and Astronomy

Greenland ice flow likely to speed up: New data assert glaciers move over sediment, which gets more slippery as it gets wetter

17.08.2017 | Earth Sciences

Mars 2020 mission to use smart methods to seek signs of past life

17.08.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>