Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Geological demolition derby

17.11.2004


The spectacular rift valleys of the Tibetan plateau don’t all run north-south as previously thought, according to new research.


A satellite’s-eye-view of India and Tibet. Image from NASA’s Terra satellite. Photo credit: NASA



The rift valleys actually curve away -- some to the east, some to the west -- from the point where India is punching into the gut of Tibet. "Everyone looked at the rifts and said they went north-south," said Paul Kapp, assistant professor of geosciences at the University of Arizona in Tucson. "I looked and said -- they’re not." His work contradicts a leading theory that suggests the rifts are a consequence of Tibet flowing slowly out over India’s northern edge.

The new research indicates the Tibetan plateau is being compressed between the Indian subcontinent to the south and the solid wall of the North China block. As a result, Tibet is splitting much like an orange squeezed by a vise. Kapp’s research challenges the idea that the 16,000-foot-high Tibetan plateau, the highest-elevation region on Earth, is losing elevation. Previous research reported the Tibetan plateau reached its highest elevation eight million years ago and is now slowly deflating as it spreads out over India. "My hypothesis predicts that the plateau is getting higher. The other theory suggests the plateau is collapsing," he said. "We’re in a place where continents are slamming against each other. Instead of Tibet crumpling like an accordion, we see these rift valleys. The rifts are from the east-west stretching of the plateau."


The article, "India Punch Rifts Tibet," by Kapp and Jerome H. Guynn, a doctoral candidate in UA’s department of geosciences, is in the November issue of the journal Geology. Although the standard description says Tibet’s rift valleys run north-south, that didn’t square with what Kapp saw when he looked at topographic maps of the area. The problem nagged at him for years.

In fall of 2003, he was teaching structural geology. As he worked on the lecture about stress in the crust from continents colliding, he realized that collisional stress caused the pattern of Tibet’s rift valleys. He remembers thinking, "Yeah, that’s it!" "It took me eight years to recognize the pattern," he said. "It took me two days to come up with an explanation."

Geologists often use digital elevation models, or DEMs, that are developed from satellite imagery. Such maps, which look like a shaded relief map, show the Earth’s current surface in incredible detail. Kapp said that the detailed nature of such maps obscures the underlying pattern of the rifts.

So Kapp and Guynn used a computer to strip away the DEM’s superficial layers to expose the underlying structure of the plateau. Once they created a bare-bones map of the region, the curving patterns of the rifts were clear. "I took away all the secondary faults and then the pattern jumped out," Kapp said. Because India is crashing into Tibet, geologists call India "the indentor." Kapp says that because India is hitting Tibet head-on, the Tibetan plateau is developing splits, or rifts, that curve away from the axis of impact.

Once Kapp figured out what caused the rifts, he and Guynn created mathematical models to test the idea. According to the models, a head-on punch split the plateau just the way Kapp predicted. In addition to punching Tibet directly, a lower portion of the Indian subcontinent is sliding under Tibet and lifting the plateau, Kapp said. Measuring how much Tibet is moving up or down is extremely difficult, although the technology is getting better all the time. "I think there will be some serious arguing for probably the next five years."

The Himalayas and Tibet are an area of active research by many groups of geologists. Kapp said, "If you want to understand mountain-building, you go there." Kapp and Guynn are among them. This summer they’ll be there scanning the region’s rocks for more evidence to support their new theory.

Mari N. Jensen | EurekAlert!
Further information:
http://www.arizona.edu

More articles from Earth Sciences:

nachricht Water - as the underlying driver of the Earth’s carbon cycle
17.01.2017 | Max-Planck-Institut für Biogeochemie

nachricht Modeling magma to find copper
13.01.2017 | Université de Genève

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Water - as the underlying driver of the Earth’s carbon cycle

17.01.2017 | Earth Sciences

Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

17.01.2017 | Materials Sciences

Smart homes will “LISTEN” to your voice

17.01.2017 | Architecture and Construction

VideoLinks
B2B-VideoLinks
More VideoLinks >>>