Fossils found in Tibet revise history of elevation, climate

Jun 11, 2008
Kunlun Mountain Pass Basin, Tibetan Plateau
Kunlun Mountain Pass Basin, Tibetan Plateau. Credit: Courtesy of Associate Professor Yang Wang, Florida State University Department of Geological Sciences

About 15,000 feet up on Tibet's desolate Himalayan-Tibetan Plateau, an international research team led by Florida State University geologist Yang Wang was surprised to find thick layers of ancient lake sediment filled with plant, fish and animal fossils typical of far lower elevations and warmer, wetter climates.

Back at the FSU-based National High Magnetic Field Laboratory, analysis of carbon and oxygen isotopes in the fossils revealed the animals' diet (abundant plants) and the reason for their demise during the late Pliocene era in the region (a drastic climate change). Paleo-magnetic study determined the sample's age (a very young 2 or 3 million years old).

That fossil evidence from the rock desert and cold, treeless steppes that now comprise Earth's highest land mass suggests a literally groundbreaking possibility:

Major tectonic changes on the Tibetan Plateau may have caused it to attain its towering present-day elevations -- rendering it inhospitable to the plants and animals that once thrived there -- as recently as 2-3 million years ago, not millions of years earlier than that, as geologists have generally believed. The new evidence calls into question the validity of methods commonly used by scientists to reconstruct the past elevations of the region.

"Establishing an accurate history of tectonic and associated elevation changes in the region is important because uplift of the Tibetan Plateau has been suggested as a major driving mechanism of global climate change over the past 50-60 million years," said Yang, an associate professor in FSU's Department of Geological Sciences and a researcher at the National High Magnetic Field Laboratory. "What's more, the region also is thought to be important in driving the modern Asian monsoons, which control the environmental conditions over much of Asia, the most densely populated region on Earth."

The fossil findings and implications are described in the June 15, 2008 issue of the peer-reviewed journal Earth and Planetary Science Letters. The journal can be accessed online at www.elsevier.com/locate/epsl.

Yang co-authored the paper ("Stable isotopes in fossil mammals, fish and shells from Kunlun Pass Basin, Tibetan Plateau: Paleoclimatic and paleoelevation implications") with paleontologists from the Department of Vertebrate Paleontology at the Natural History Museum of Los Angeles County, and the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences (Beijing). The collaborative research project, which since 2004 has featured summer field study on the remote Tibetan Plateau, is funded by a grant from the Sedimentary Geology and Paleobiology Program of the U.S. National Science Foundation.

"The uplift chronology of the Tibetan Plateau and its climatic and biotic consequences have been a matter of much debate and speculation because most of Tibet's spectacular mountains, gorges and glaciers remain barely touched by man and geologically unexplored," Yang said.

"So far, my research colleagues and I have only worked in two basins in Tibet, representing a very small fraction of the Plateau, but it is very exciting that our work to-date has yielded surprising results that are inconsistent with the popular view of Tibetan uplift," she said.

This summer, Yang and her colleagues from Los Angeles and Beijing will conduct further fieldwork in areas near the Tibetan Plateau. "The next phase of our work will focus on examining the spatial and temporal patterns of long-term vegetative and environmental changes in and around the region," she said. "Such records are crucial for clarifying the linkages among climatic, biotic and tectonic changes."

There is much still to learn and understand about those changes.

"Many of the places we've visited in Tibet are now deserts, and yet we found those thick deposits of lake sediments with abundant fossil fish and shells," Yang said. "This begs the question: What came first and caused the disappearance of those lakes? Global climate change? Or, tectonic change?"

Source: Florida State University

Explore further: NASA's spaceborne carbon counter maps new details

add to favorites email to friend print save as pdf

Related Stories

Brazil: Google fined in Petrobras probe

1 hour ago

A Brazilian court says it has fined Google around $200,000 for refusing to intercept emails needed in a corruption investigation at state-run oil company Petrobras.

Atari's 'E.T.' game joins Smithsonian collection

1 hour ago

One of the "E.T." Atari game cartridges unearthed this year from a heap of garbage buried deep in the New Mexico desert has been added to the video game history collection at the Smithsonian.

Sony threatens to sue for publishing stolen emails

1 hour ago

A lawyer representing Sony Pictures Entertainment is warning news organizations not to publish details of company files leaked by hackers in one of the largest digital breaches ever against an American company.

Microsoft builds support over Ireland email case

2 hours ago

Microsoft said Monday it had secured broad support from a coalition of influential technology and media firms as it seeks to challenge a US ruling ordering it to hand over emails stored on a server in Ireland.

Recommended for you

Scientists make strides in tsunami warning since 2004

12 hours ago

The 2004 tsunami led to greater global cooperation and improved techniques for detecting waves that could reach faraway shores, even though scientists still cannot predict when an earthquake will strike.

Trade winds ventilate the tropical oceans

12 hours ago

Long-term observations indicate that the oxygen minimum zones in the tropical oceans have expanded in recent decades. The reason is still unknown. Now scientists at the GEOMAR Helmholtz Centre for Ocean Research ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

out7x
1 / 5 (2) Jul 17, 2008
What does the isotope dating, in fossils, say?

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.