UA News

A UA-led team has received a National Science Foundation grant for work toward creating a timeline and geological map of the Tibetan Plateau – an intriguing and expansive terrain located in Central Asia.

The Tibetan Plateau has peculiar features and, if located in the United States, it would be more than twice the height of the Catalina Mountains and would span an area from the west coast to Denver.

The region has long had scientists perplexed and, for that reason and others, the Central Asian landmass and the High Himalayas are the center of a research project led by a team of University of Arizona researchers.

The team is setting out to try and answer some of the most evasive questions about the Tibetan Plateau: why is it located there? How did it form over time? Why is it so expansive? And has it remained the same since it was created?

Answering such questions will help people better understand climate systems and ocean chemistry in Tibet and around the world.

Peter DeCelles, a UA geosciences professor, said India has been "plowing into Asia for about 50 to 55 million years," resulting in the creation of the plateau and the Himalayas.

DeCelles specializes in studying plate tectonics and also works with rock and sediment samples to understand how mountain ranges and basins are formed. He has spent 15 years studying mountain ranges around the world, including regions in Tibet and Nepal, and said similar collisions are happening in other parts of the world.

Other areas are near Iran and Iraq, in the Mediterranean region, in other parts of Tibet and between Papua New Guinea and Australia.

However, the key feature in the Himalayan-Tibetan region is that it is so mature and well developed, he said. "But the most spectacular part of that belt is in the High Himalayas, so it is a particularly advantageous place to study."

DeCelles and his research team recently received a National Science Foundation grant to fund their work in Central Asia. The team is working with the Institute of Tibetan Plateau Research and Chinese Academy of Sciences in Beijing.

The Tibetan Plateau is intriguing because of its great elevation and vast regional extent, said DeCelles, the co-principal investigator on the newly awarded grant. But it appears to have been part of a lake basin at some point.

"Abundant organic material, including woody plant fragments, remains of algae, turtles and fish, and pollen grains, suggest that these lakes were situated at relatively low elevations under warm climate conditions," he said.

"We thought, ‘Well, that's kind of weird.' Why would you have a big lake basin forming among rapid erosion and large mountains? It doesn't make sense to have a basin there," DeCelles said.

The team has strong evidence to show the Himalayan range is comprised mostly of sedimentary rock and that when it formed, a huge slab of Indian continental rock was shoved about 500 miles northward beneath Asia.

For now, the UA team needs more exact information, particularly about the age of the rocks and sediments as well as a geological timeline of events.

"There is a lot of difficult analysis that has to take place," said DeCelles, a sedimentary geologist.

"It's like getting to a train wreck and you're supposed to figure out how it happened. You have to look at the wreckage and reconstruct the process pretty much from the start to the end," he said. "We can't run this kind of experiment in a lab. We have to find one that nature is running for us."

Over the course of their work in Asia, DeCelles and his colleagues have published geological maps, measured about 17 miles of rock layering, identified vertebrate fossils, fossil pollen and palynology and dated nearly 100 igneous rocks, among other things.

The new grant, funded at $50,000, for the project, "Investigation of Syncollisional Extension and Basin Development in the High Himalayas" is in addition to nearly $540,000 DeCelles and his team have received from NSF in recent years.

With the new grant, more analytical work can begin.

Paul Kapp, a UA associate professor in the geosciences department, has conducted research with DeCelles for about six years and will continue working with him in Central Asia.

Kapp, co-principal investigator on the new grant, said his expertise in bedrock geology and DeCelles' grounding in formations of mountain ranges and basins makes for a more solid research project.

"You need to map faults, structures and folds – that's my primary contribution," said Kapp, who also holds an appointment with the Chinese Academy of Sciences.

"But in order to understand how the rocks deform, you need to know how old they are," he said, adding that the collaborators are linking research on tectonics with sedimentation.

"I can't do my work without Pete's work and he can't interpret his work without the deformation history," Kapp said. "Most researchers shoot for that complementary multidisciplinary group approach and it's the ideal situation. Our work has demonstrated just how powerful it is."