Arctic Basin Analysis and Earth Systems Change

点击翻译按钮获取中文摘要

Our work in past years has shown that the Earth history was marked by a series of irreversible setbacks in the environments and in the biosphere during the 70 million year interval (a time known as the Permian) that preceded the largest mass extinction ever recorded. The extinction happened just before the Permian-Triassic (P-T) boundary some 252 million years ago. The latest Permian extinction (LPE) was far more devastating than the end-Cretaceous extinction that wiped out the dinosaurs, which occurred some 187 million years later. There were no dinosaurs prior to the latest Permian extinction, but there was a rich environment populated by highly evolved plants and animals on land and in the sea, very much like today’s environments. The final blow to life came as the result of a massive volcanic eruption in Siberia, which also ignited coal deposits, fouling the air and the ocean, and sending the world’s ecosystems into a tailspin. The Siberian volcanic eruption was the last in a series of unfortunate events that tipped the world into an alternate state. It took our planet five million years to recover from the devastation. The LPE is increasingly viewed as the worst case scenario that could result from the unattended anthropogenic burning of fossil fuel. Scientists and popular writers see the extinction as an ominous example of what could happen to our planet should we continue to pump CO2 in the atmosphere—runaway greenhouse, rapid temperature rise, ocean acidification, migration of climate belts, mass extinction. The LPE was a major “state shift” in the Earth’s biosphere, and many fear that humanity may be facing a similar shift if we continue to force biological systems towards their tipping point. Of course man was not around 252 million years ago and cannot be blamed for the extinction; so we have to look for other explanations. This research is about finding out what the causes of such a devastating environmental upheaval might have been. In our search for answers, we will be studying the Sverdrup Basin of Arctic Canada (NWT and Nunavut), which contains a thick sedimentary succession rich in geological information about the events that preceded and postdated the latest Permian extinction. We are determined to demonstrate that the Sverdrup Basin has recorded stratigraphic and environmental changes that can only be explained by tectonic processes originating in the rigid crust of the earth or in the more viscous mantle beneath the crust. Teams of graduate students will collect vast amount of data in the Arctic, mostly in the mountainous regions of Ellesmere and Axel Heiberg islands in Nunavut. Our scientific approach is called "basin analysis" and it integrates classic disciplines such as stratigraphy and sedimentology with other disciplines such as geochemistry, geophysics and paleoclimatology, to name a few. One positive outcome of this research will be to generate a productive dialogue between stratigraphers and geophysicists, who both have strong interests in the origin of sedimentary basins and their sediment fills, but who have not engaged one another in any meaningful way in the past. Another outcome of this research will be to shed light on the modern debate about the fate of our planet as viewed through the rich historical record of an old sedimentary succession. Also the Sverdrup Basin is Canada’s most promising frontier basin, with known oil and gas fields discovered nearly 40 years ago. Our research will contribute to understanding the origin of the rocks that contain these hydrocarbons. Finally, this project will train a new generation of scientists in the art of conducting research in a challenging Arctic setting, at a time when an older cohort of Arctic scientists in governments and universities is retiring.