Arctic Basin Analysis and Earth Systems Change

我们过去几年的工作表明，地球历史的标志是在有记录以来最大规模的大灭绝之前的7000万年(被称为二叠纪)期间，地球环境和生物圈发生了一系列不可逆转的挫折。物种灭绝发生在大约2.52亿年前的二叠纪-三叠纪(P-T)界线之前。最近的二叠纪灭绝(LPE)比白垩纪末期灭绝恐龙的毁灭性要大得多，后者发生在大约1.87亿年后。在最近的二叠纪灭绝之前，没有恐龙，但有一个丰富的环境，居住着高度进化的陆地和海洋动植物，与今天的环境非常相似。对生命的最后一次打击是西伯利亚大规模火山喷发的结果，火山喷发也点燃了煤炭储量，污染了空气和海洋，并使世界生态系统陷入混乱。西伯利亚火山喷发是一系列不幸事件中的最后一次，这些事件使世界陷入了另一种状态。我们的星球花了500万年才从灾难中恢复过来。LPE越来越被视为最糟糕的情况，可能是无人值守的人类燃烧化石燃料造成的。科学家和流行作家认为，如果我们继续向大气中排放二氧化碳，地球可能会发生什么，科学家和流行作家认为这是一个不祥的例子--失控的温室效应、迅速的气温上升、海洋酸化、气候带的迁移、大规模灭绝。LPE是地球生物圈的一次重大“状态转变”，许多人担心，如果我们继续迫使生物系统接近它们的临界点，人类可能会面临类似的转变。当然，人类在2.52亿年前并不存在，不能将灭绝归咎于人类；所以我们必须寻找其他解释。这项研究是为了找出这种毁灭性的环境剧变的原因可能是什么。在寻找答案的过程中，我们将研究加拿大北极的斯维尔德鲁普盆地(NWT和Nunavut)，该盆地包含一个厚厚的沉积序列，其中含有丰富的地质信息，涉及最近二叠纪灭绝之前和之后的事件。我们决心证明Sverdrup盆地记录了地层和环境的变化，这些变化只能通过起源于地球坚硬的地壳或地壳下更粘稠的地幔的构造过程来解释。研究生团队将在北极收集大量数据，主要是在努纳武特的埃尔斯米尔岛和阿克塞尔海贝格岛的山区。我们的科学方法被称为“盆地分析”，它将地层学和沉积学等经典学科与地球化学、地球物理和古气候学等其他学科结合起来，仅举几例。这项研究的一个积极成果将是在地层学家和地球物理学家之间进行富有成效的对话，他们都对沉积盆地的起源及其沉积物填充有着浓厚的兴趣，但他们过去并没有以任何有意义的方式相互接触。这项研究的另一项成果将是通过丰富的古老沉积序列的历史记录来阐明现代关于我们星球命运的辩论。斯维尔德鲁普盆地也是加拿大最有前途的前沿盆地，已知的油气田是近40年前发现的。我们的研究将有助于了解含有这些碳氢化合物的岩石的来源。最后，该项目将培训新一代科学家，掌握在具有挑战性的北极环境中进行研究的艺术，而此时，政府和大学中的一批年长的北极科学家即将退休。

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.