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."
The Chinese National Key Projects Program, the National Natural Science Foundation of China and the National Science Foundation funded this research.
A'ndrea Elyse Messer | EurekAlert!
PR of MCC: Carbon removal from atmosphere unavoidable for 1.5 degree target
22.05.2018 | Mercator Research Institute on Global Commons and Climate Change (MCC) gGmbH
Monitoring lava lake levels in Congo volcano
16.05.2018 | Seismological Society of America
At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...
There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...
A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.
The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...
02.05.2018 | Event News
13.04.2018 | Event News
12.04.2018 | Event News
23.05.2018 | Life Sciences
23.05.2018 | Life Sciences
23.05.2018 | Physics and Astronomy