Impact of global disturbances on the evolution of life in the polar regions during the early Cenozoic (PALEOPOLAR)

新生代早期全球扰动对极地生命进化的影响（古极地）

• 批准号: NE/I005501/2
• 负责人: Stuart Robinson
• 金额: $ 10.01万
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2013
• 资助国家: 英国
• 起止时间: 2013 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FI005501%2F2
• 关键词: Impact; global; disturbances; evolution; life

The greenhouse world of the Late Cretaceous to mid-Paleogene (~100 - 40 million years ago) is of particular interest to earth scientists because there is good geological evidence to show that at this time tropical/subtropical conditions extended into Antarctica in the south and into the Arctic in the north. At this time the south polar ice cap was either much smaller or absent. Many modern groups of plants and animals have their evolutionary roots in this greenhouse world and it is possible that their expansion related directly to this prolonged period of global warmth. This greenhouse world was punctuated by a mass extinction event at 65Ma at the Cretaceous - Paleogene boundary (K-Pg). In addition, this warm world was interrupted by a series of abrupt extreme warming events, or hyperthermals, probably caused by the sudden release of massive amounts of CO2 into the atmosphere and oceans. The K-Pg mass extinction event probably had a much longer-lasting effect on global ecosystems than the more transient hyperthermals but we will test this idea by investigating the geological record from the polar regions, the regions on Earth most sensitive to environmental and climate change. Much of the geological record for this time interval for the polar regions comes from deep sea drill sites but the best onshore exposure is found on Seymour Island, Antarctica. We have recently investigated this locality in detail and now have a high resolution geological record from the end of the Cretaceous period, across the K-Pg boundary and into the mid-Paleogene period. Analysis of large collections of sediments and plant and invertebrate fossils will provide us with new information about climates on land and temperatures in shallow seas around Antarctica at that time. The fossils also allow us to reconstruct the composition of faunas and floras that lived in the polar regions and to determine how their diversity changed over time. We will produce a new palaeotemperature curve for the latest Cretaceous - mid-Paleogene interval in Antarctica, and will assess whether the hyperthermal events occurred so far south. By matching fossil diversity with the climate record we will assess the time taken for plants and animals to recover from the K-Pg mass extinction and investigate whether times of high biodiversity were linked to episodes of warming. For example, do sub-tropical plant fossils and an unusual marine fossil assemblage represent poleward incursions of warmth-loving biotas during a global warming event 55 million years ago, only to go extinct when cooler conditions returned? Some studies indicate that the K-Pg mass extinction reset the global evolutionary clock forever, with new species subsequently appearing at a much higher rate in the tropics than at the poles. We will test this important theory by adding our new Antarctic fossil data to a global database for the latest Cretaceous to the mid-Paleogene. Was the radiation of species through this interval really slower at the poles, and if so, why did the change in rates occur immediately after the K-Pg boundary? How does our record of palaeoclimate and biodiversity from Antarctica compare to that from the Arctic and from low latitude sites - were high latitude communities particularly sensitive to climate change and environmental disturbance, even in a greenhouse world? How did forests at the poles affect the climate system? Does our fossil record match the evolutionary history derived from modern marine faunas by molecular studies? By using a range of palaeoenvironmental indicators and analytical techniques (isotope geochemistry, sedimentary facies analysis, palaeobotany, palaeobiology, climate modelling) we will reconstruct the greenhouse world of the past and assess the impact of dramatic global events on the evolution of life, particularly in the polar regions.

地球科学家特别感兴趣的白垩纪到中期的温室世界（〜100亿年前）特别感兴趣，因为有充分的地质证据表明，目前热带/亚热带条件延伸到南方南极洲的南极洲和北部的北极地区。目前，南极冰盖要么小得多要么不存在。许多现代的动植物群体在这个温室世界中具有进化的根源，它们的扩张可能直接与这个长期的全球温暖时期有关。这个温室世界在白垩纪 - 古近纪边界（K -PG）的65mA的大规模灭绝事件打断了。此外，这个温暖的世界被一系列突然的极端变暖事件（或超热事件）打断，这可能是由于突然释放出大量二氧化碳和海洋而引起的。 K-PG质量灭绝事件可能对全球生态系统具有更长的持久影响，而不是更短暂的高温，但是我们将通过研究极地地区的地质记录，地球上对环境和气候变化最敏感的地质记录来测试这一想法。极地区域的此时间间隔的大部分地质记录都来自深海钻机，但在南极洲西摩岛（Seymour Island）发现了最佳的陆上曝光。我们最近详细研究了这个地方，现在从白垩纪末期，跨K-PG边界到中期时期具有很高的分辨率地质记录。分析大量沉积物，植物和无脊椎动物化石将为我们提供有关当时南极洲浅海的气候和温度上的气候的新信息。化石还使我们能够重建生活在极地地区的动物群和植物群的组成，并确定它们的多样性如何随着时间而变化。我们将为南极洲的最新白垩纪 - 中期间隔生成新的古植物曲线，并将评估过度热事件是否发生在南部。通过将化石多样性与气候记录相匹配，我们将评估动植物从K-PG质量灭绝中恢复的时间，并研究高生物多样性的时间是否与变暖发作有关。例如，亚热带植物化石和不寻常的海洋化石组合是否代表了5500万年前的全球变暖事件中热爱温暖的生物群岛的极力入侵，但在冷却较低的情况恢复时才灭绝？一些研究表明，K-PG质量灭绝将永远重置全球进化时钟，随后，新物种在热带地区的出现速度要高于波兰人。我们将通过将我们的新南极化石数据添加到全球数据库中，以便为中期中期的白垩纪添加我们的新南极化石数据来测试这一重要理论。通过此间隔的物种的辐射真的很慢，如果是的话，为什么速率变化在K-PG边界之后立即发生？我们从南极洲的古气候和生物多样性的记录与北极和低纬度地点相比如何 - 高纬度社区对气候变化和环境干扰特别敏感，即使在温室世界中？两极的森林如何影响气候系统？我们的化石记录是否与分子研究源自现代海洋动物群的进化史相匹配？通过使用一系列的古环境指标和分析技术（同位素地球化学，沉积相分析，古植物，古植物学，古生物学，气候建模），我们将重建过去的温室世界，并评估戏剧性全球事件对生命进化的影响，尤其是在极地地区。

项目成果

A cool temperate climate on the Antarctic Peninsula through the latest Cretaceous to early Paleogene

• DOI: 10.1130/g35512.1
• 发表时间: 2014-07
• 期刊: Geology
• 影响因子: 5.8
• 作者: D. Kemp;S. Robinson;J. Crame;J. Francis;J. Ineson;R. Whittle;V. Bowman;C. O’Brien

Climate Sensitivity on Geological Timescales Controlled by Nonlinear Feedbacks and Ocean Circulation

• DOI: 10.1029/2019gl083574
• 发表时间: 2019-08-28
• 期刊: GEOPHYSICAL RESEARCH LETTERS
• 影响因子: 5.2
• 作者: Farnsworth, A.;Lunt, D. J.;Robinson, S. A.
• 通讯作者: Robinson, S. A.