It is still the world's highest

Tibet is not losing its altitude, as stated by previous research

 
Published: Friday 31 December 2004

new research has now challenged the theory that the Tibetan plateau -- the highest region of the Earth -- is losing its elevation. As per the research, a lower portion of the Indian subcontinent is sliding under Tibet and lifting it further.

The work, from the department of geosciences, University of Arizona, usa, contradicts previous studies, which stated that the plateau reached its highest elevation eight million years ago and was now slowly deflating. The new work also shows that not all the rift-valleys of the plateau run north to south, as previously advocated. They bend over -- some to the east, a few to the west -- from the point where India juts forth into the middle fraction of Tibet.

The research is based on computer simulations of the topographic maps of the area. In 2003, as Paul Kapp, the lead researcher, prepared for a lecture on stress in the crust from continents' colliding, he realised that stress of the collision caused the pattern of Tibet's valleys.

Geologists often use digital elevation models (dems) developed from satellite images to study the geography of an area. Such maps show the Earth's current surface in detail, but not the underlying pattern of the rifts. So Kapp and his colleagues used a computer to strip away the superficial layers of dems to expose the underlying structure of the plateau. Once they created a bare-bones map, the curving patterns of the rifts were clear. "Because India is hitting Tibet head-on, the plateau is developing splits or rifts that curve away from the axis of impact," avers Kapp.

Once the researchers figured out what caused the rifts, they created mathematical models to test the theory. The models also showed that a head-on punch split the plateau much like an orange squeezed by a vice. The researchers now plan to scan the region's rocks for more evidence.

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