Antarctic Deep Water Circulation and Continental Weathering from the Eocene Greenhouse to the Oligocene Icehouse (IODP Expedition 318, Wilkes Land).

南极深水环流和从始新世温室到渐新世冰室的大陆风化（IODP 318 号探险队，威尔克斯地）。

基本信息

批准号：
NE/I006257/1
负责人：
Tina Van De Flierdt
金额：
$ 6.49万
依托单位：
Imperial College London
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2010
资助国家：
英国
起止时间：
2010 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FI006257%2F1
关键词：
Antarctic Deep Water Circulation Continental

项目摘要

We are currently living in a world of climate change. Global atmospheric concentrations of carbon dioxide are rising at a rate unprecedented in the history of the Earth, and there is no doubt that a large part of this rise is due to human acitivity. Our ability to predict the effects of increased CO2 concentrations in the atmosphere and associated warming, heavily depends on understanding the relationship between physical, chemical, and biological processes in the Earth system, which are intrinsically coupled to temperature and atmospheric CO2 through so called 'feedback mechanisms'. But how can we study such mechanisms? One important aspect is to study how the modern climate system operates, by direct observations. However, such observations can only cover time spans, which are relatively short. To see the full swings of the climate system, we need to go beyond human observations and look at climate archives of the past, such as sediment cores recovered from the bottom of the ocean. More than 30 years of internationally coordinated ocean drilling has retrieved drillcores containing climate records from hundreds of locations all across the ocean basins, reaching back in time more than 100 million years. Reconstruction of various parameters of the climate system from such cores, such as ocean temperatures, intensity of continental weathering, or past ocean circulation patterns, has provided valuable insights into the climate system, existing feedback mechanisms and how they operated in the past. The most significant (natural) climate swing of the past 65 million years was the transition from the Greenhouse world, characterised by subtropical conditions even at high latitudes (Arctic and Antarctic; ~50 million years ago) to the icehouse world we are currently living in (i.e., warm temperature at low latitudes, cold temperatures at high latitudes; started ~33 million years ago). To understand this climate transition, we have to study what actually happened at high latitudes. Expedition 318 of the Integrated Ocean Drilling Program (IODP) took on this challenge and aimed to drill for the first time in 10 years sediment cores close to the Antarctic continent. Drilling in the vicinity of Antarctica is a technically challenging task due to weather and ice conditions, but also due to the nature of the often coarse-grained sediments at the seafloor. Expedition 318 took place in January to March 2010, and what we came back with is a spectacular record of sediments that tells us a story about peak greenhouse conditions, the earliest moments of the icehouse world, and the history of the Antarctic ice sheet all the way from ~30 million years ago to today. While this material will enable us to address many longstanding questions in climate change, it is especially noteworthy that this is the first time peak greenhouse sediments have been recovered from an area proximal to the East Antarctic coast. These sediments, together with the ones characteristic of the first moments of the icehouse world, build the center of our proposed study. We developed a research plan to study continental weathering and ocean circulation, two of the key climate variables, in the new cores. Our results will build a critical step in developing a more comprehensive understanding of drivers, amplifiers, and feedbacks in the climate system.

我们目前生活在一个气候变化的世界。全球大气中二氧化碳浓度正在以地球历史上前所未有的速度上升，毫无疑问，这种上升的很大一部分是由于人类活动造成的。我们预测大气中二氧化碳浓度增加和相关变暖的影响的能力在很大程度上取决于对地球系统中物理、化学和生物过程之间关系的理解，这些过程通过所谓的“反馈”与温度和大气二氧化碳本质上耦合在一起。机制”。但我们如何研究这样的机制呢？一个重要的方面是通过直接观测来研究现代气候系统如何运作。然而，这种观察只能涵盖相对较短的时间跨度。为了了解气候系统的全面变化，我们需要超越人类的观察，着眼于过去的气候档案，例如从海底回收的沉积岩芯。 30多年来，国际协调的海洋钻探已经从整个海洋盆地的数百个地点取回了包含气候记录的钻芯，其时间可以追溯到一亿多年前。从这些核心重建气候系统的各种参数，例如海洋温度、大陆风化强度或过去的海洋环流模式，为了解气候系统、现有反馈机制及其过去的运作方式提供了宝贵的见解。过去 6500 万年最显着的（自然）气候波动是从温室世界（即使在高纬度地区（北极和南极洲；约 5000 万年前）也具有亚热带条件）到我们目前生活的冰屋世界的转变。（即低纬度地区气温较高，高纬度地区气温较低；大约开始于 3300 万年前）。为了了解这种气候转变，我们必须研究高纬度地区实际发生的情况。综合海洋钻探计划（IODP）318号探险队接受了这一挑战，旨在十年来首次在靠近南极大陆的地方钻探沉积岩芯。由于天气和冰况的原因，而且由于海底沉积物通常是粗粒的，在南极洲附近进行钻探是一项技术上具有挑战性的任务。第 318 次探险于 2010 年 1 月至 3 月进行，我们带回来的是一份壮观的沉积物记录，它向我们讲述了关于温室峰值条件、冰室世界的最早时刻以及南极冰盖自始至终的历史的故事。从大约 3000 万年前到现在。虽然这些材料将使我们能够解决气候变化中许多长期存在的问题，但特别值得注意的是，这是第一次从靠近南极东部海岸的地区恢复峰值温室沉积物。这些沉积物，连同冰库世界最初时刻的特征，构成了我们拟议研究的中心。我们制定了一项研究计划来研究新核心中的两个关键气候变量大陆风化和海洋环流。我们的研究结果将为更全面地了解气候系统中的驱动因素、放大器和反馈迈出关键的一步。