The Review 2007

26 27 When India Collided with Tibet A new hypothesis on the timing of the collision of India and Eurasia suggests it happened 20 million years later than previously believed, a finding that has implications for our understanding of global climate change and the formation of mountains. Two academics in the Department of Earth Sciences reported their findings in the Journal of Geophysical Research in 2007 based on newer, more precise dating methods. The collision originally was dated at 55 million years ago, although it was accepted that related events, such as the lifting of the Tibetan plateau and the appearance of ice sheets in Antarctica, occurred 20 million years later. The head of Earth Sciences, Professor Jonathan Aitchison, and Assistant Professor, Dr Jason Ali, thought there was a more direct cause-and-effect relationship be- tween these events. They have come up with a model that accounts for a later collision and explains why it was wrongly dated. “India travelled 6,000-7,000 kilometres northwest be- fore it collided with Asia. We believe that along the way it bumped into a series of volcanic island chains, an intra-oce- anic arc similar to Guam, and the remnants of this remained on its north shore,” Professor Aitchison said. These remnants were swept up in the collision with Eurasia 34 millions years ago, which also immediately up- lifted the Tibetan plateau. The new mountain range affected the flows of air and ocean currents, which led to global cli- mate change. Professor Aitchison and Dr Ali believe the findings suggest a re-think is needed on our understanding of moun- tain building, the rate of climate change from this event, and how geologists predict the location of mineral resources. Looking for Life on Mars The search for life on other planets is being informed by re- search conducted here on Earth through the University. Astrobiologist Dr Stephen Pointing of the School of Biological Sciences, is digging through rock and ice in the world’s driest and coldest places to see what microorgan- isms can survive in conditions similar to Mars. He is working with the American space agency, NASA, which will send a probe to Mars in 2009. Thus far, colonies of bacteria have been found inside and under rocks in hyper-arid deserts, living on nothing but sunshine and tiny amounts of rainfall. They have also with- stood desiccation and radiation levels equivalent to Mars in experiments. Dr Pointing recently expanded his investigations to include the Arctic and Antarctica so data from frozen en- vironments can also be incorporated to provide a more complete picture of possible life forms on Mars. “Part of my work with NASA is to explore the limits of life on Earth and predict what exists or may have existed on Mars,” he said. “When we put all the data together, we hope to have a useful model of what to expect on Mars and where to look for it.” The findings from deserts also have application on Earth. The relative abundance of bacterial colonies similar to those found in Dr Pointing’s research, is believed to indicate imminent catastrophic and irrecoverable shifts in an ecosys- tem state from arid to hyper-arid conditions, and will be im- portant in assessing the health of China’s vast deserts. Dr Stephen Pointing, working with NASA Dr Jason Ali (left) and Professor Jonathan Aitchison