Fossils found in Tibet by FSU geologist revise history of elevation, climateJune 12, 2008TALLAHASSEE, Fla. -- 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?" Florida State University | |||||||||||||||||||||
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Related Tibetan Plateau News Articles Chinese earthquake provides lessons for future The May 12 Sichuan earthquake in China was unexpectedly large. Analysis of the area, however, now shows that topographic characteristics of the highly mountainous area identified the mountain range as active and could have pointed to the earthquake hazard. Topographic analysis can help evaluate other, similar fault areas for seismic risk, according to geologists from Penn State and Arizona State University. Geologists study China earthquake for glimpse into future The May 12 earthquake that rocked Sichuan Province in China was the first there in recorded history and unexpected in its magnitude. Now a team of geoscientists is looking at the potential for future earthquakes due to earthquake-induced changes in stress. China quake rare and unexpected, says new MIT study A new analysis of the setting for last month's devastating earthquake in China by a team of geoscientists at MIT shows that the quake resulted from faults with little seismic activity, and that similar events in that area occur only once in every 2,000 to 10,000 years, on average. New findings from Tibetan Plateau suggest uplift occurred in stages The vast Tibetan Plateau--the world's highest and largest plateau, bordered by the world's highest mountains--has long challenged geologists trying to understand how and when the region rose to such spectacular heights. New Tibetan ice cores missing A-bomb blast Ice cores drilled last year from the summit of a Himalayan ice field lack the distinctive radioactive signals that mark virtually every other ice core retrieved worldwide. That missing radioactivity, originating as fallout from atmospheric nuclear tests during the 1950s and 1960s, routinely provides researchers with a benchmark against which they can gauge how much new ice has accumulated on a glacier or ice field. Heatwave on the top of the world The French Intergovernmental Panel on Climate Change (IPPC, or GIEC in French) has just announced the conclusions of its 4th report, which restates that global warming has increased the average temperature by 0.74°C over the last century. New data shakes accepted models of collisions of the Earth's crust New research findings may help refine the accepted models used by earth scientists over the past 30 years to describe the ways in which continents clash to form the Earth's landscape. Scientists use seismic waves to locate missing rock under Tibet Geologists at the University of Illinois at Urbana-Champaign have located a huge chunk of Earth's lithosphere that went missing 15 million years ago. By finding the massive block of errant rock beneath Tibet, the researchers are helping solve a long-standing mystery, and clarifying how continents behave when they collide. Himalayan megaquakes powered by elastic energy in Tibetan plateau, says U of Colorado study Computer simulations indicate that Himalayan mega-earthquakes must occur every 1,000 years or so to empty a reservoir of energy in southern Tibet not released by smaller earthquakes. Tibet Provides Passage for Chemicals to Reach the Stratosphere NASA and university researchers have found that thunderstorms over Tibet provide a main pathway for water vapor and chemicals to travel from the lower atmosphere, where human activity directly affects atmospheric composition, into the stratosphere, where the protective ozone layer resides. More Tibetan Plateau News Articles |
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