Boreal extinction and recovery patterns in the Permian of Spitsbergen

地质记录中的大规模喷发塑造了地球上的进化和生命历程，没有它们，人类就不会存在。因此，了解是什么导致了大规模的灭绝是科学研究中最吸引人的话题之一。我们离解开这些古老的谋杀之谜还有很长的路要走。通过研究深时间重大变化的原因和后果，我们可以获得对当今气候变化和影响地球生命的问题的独特视角。有史以来影响地球的两次最大的地震发生在1000万年内，分别发生在中二叠世和二叠纪-三叠纪（PT）的边界。后一次事件杀死了多达95%的海洋物种，是地质记录中最大的生命危机。这两个事件都是众所周知的二叠纪赤道地区，其可能的原因包括火山活动，海平面变化和海洋氧气耗尽。然而，人们对中高纬度地区的环境或动物变化记录知之甚少，也不清楚低纬度地区的损失是否在其他地方发生。该项目将通过检查北极斯匹次卑尔根岛的二叠纪序列来验证这一点，那里的海洋岩石暴露在悬崖中，其中包含动物群和环境变化的记录。在研究期间，斯匹次卑尔根位于北纬40 - 60度，远离赤道，在北方海。由于无法准确测定岩石的年代，该地区的研究受到了阻碍。因此，在北方领域的事件的相对年龄是不清楚的。已知这些岩石含有丰富的化石，但它们对两次灭绝事件的反应尚不清楚。火山活动被认为是导致中国南部中二叠世灭绝的原因，但尚不清楚其影响是否超出了该大陆。海洋变暖和缺氧是PT事件的因素，但北方海的凉爽沃茨应该不太容易受到影响（因为氧气在较低温度下更容易溶解）。人们对两次地震之间北方生态系统的恢复知之甚少：在PT边界被摧毁之前，生命是否完全恢复，或者这场危机如此严重，因为生态系统已经受到早期事件的压力？更好地了解该地区动物的损失和恢复将有助于我们评估相互竞争的灭绝机制。北方记录与世界其他地区的相关性是该项目成功的关键，将使用化学地层学来实现。因此，我们将制作一个碳同位素曲线-这是最近建立的其他地区，但尚未为斯匹次卑尔根。因此，该项目将：a）建立一个二叠纪年龄模型，使斯匹次卑尔根群岛各剖面在全球范围内相互关联;和B）检查该时间框架内环境和动物群变化的记录。为了实现第二个目标，我们将采用各种技术：对化石进行实地和显微镜检查，以确定灭绝和恢复的时间;层序地层学（反映海平面变化的岩石类型变化）;以及分析岩石中的黄铁矿（以评估海洋氧气水平的变化）。所有这些方法以前都被成功地使用过，但从未被应用于北方界的研究。最终，该项目旨在确定北方地区的两次大规模灭绝事件，并确定其时间和原因。这将检验二叠纪期间赤道移动的驱动力是否真的可以被认为是全球性的。研究结果将通过学术出版社向科学界公布，并通过项目网站、学校外展活动和大众媒体向更广泛的受众公布。

Mass extinctions in the geological record have shaped the course of evolution and life on Earth, and without them, humans would not exist. Understanding what causes mass extinctions is therefore one of the most fascinating topics for scientific research. We are still a long way from solving these ancient murder mysteries. By studying the cause and consequence of major changes in deep time, we can gain a unique perspective on current-day climate change and the issues affecting life on Earth. Two of the biggest extinctions ever to affect the Earth occurred within 10 million-years of each other, in the Middle Permian and at the Permian-Triassic (PT) boundary. The latter event killed up to 95% of marine species and is the greatest crisis of life in the geological record. Both extinctions are well-known from Permian equatorial regions, where their probable causes include volcanism, sea-level change, and oceanic oxygen depletion. However, little is known of the record of environmental or faunal change in mid-high latitudes, and it is not clear whether the causes of low-latitude losses were operating elsewhere. This project will test this by examining superb Permian sequences from the Arctic island of Spitsbergen, where marine rocks are exposed in cliffs that contain a record of faunal and environmental change. During the study interval, Spitsbergen was located at 40-60 degrees north, far removed from equatorial settings, in the Boreal seas. Study in the region has been hampered by an inability to accurately date the rocks. Thus, the relative age of events in the Boreal realm is unclear. The rocks are known to contain abundant fossils but their response to the two extinction events is unknown. Volcanism is thought to have caused the Middle Permian extinction in South China, but it is not clear if its effects reached beyond that continent. Warming and lack of oxygen in the oceans are factors in the PT event, but the cool waters of the Boreal seas ought to have been less susceptible (because oxygen is more readily dissolved at lower temperatures). Little is known of the recovery of the Boreal ecosystem between the two extinctions: did life recovery fully before being devastated at the PT boundary, or was that crisis so severe because the ecosystem was already stressed by the earlier event? An improved understanding of faunal loss and recovery in the region will help us to evaluate the competing extinction mechanisms. The correlation of the Boreal record with other parts of the world is integral to the success of the project, and will be achieved using chemostratigraphy. Thus, we will produce a carbon isotope curve - which has recently been established for other regions but not yet for Spitsbergen. The project will therefore: a) develop a Permian age model, allowing Spitsbergen sections to be correlated globally; and b) examine the record of environmental and faunal change within that time framework. To achieve the second objective, we will employ a variety of techniques: field- and microscope examination of fossils to pinpoint the timing of extinction and recovery; sequence stratigraphy (changes in rock type that reflect changing sea-levels); and analysis of pyrite in the rocks (to assess changes in oceanic oxygen levels). All of these methods have been used successfully before, but have never been applied to studies of the Boreal realm. Ultimately this project aims to identify two mass extinction events in the Boreal realm, and to ascertain their timing and causes. This will test whether the drivers of equatorial extinctions during the Permian can truly be considered global. The results will be publicised to a scientific audience through the academic press, and to a wider audience via the project website, school outreach activities, and the mass media.