Antarctic weathering and hydrologic cycling through the Paleogene greenhouse to icehouse transition (IODP Expedition 318, Wilkes Land)

从古近纪温室到冰库过渡的南极风化和水文循环（IODP Expedition 318，Wilkes Land）

• 批准号: NE/J019801/1
• 负责人: Heiko Pälike
• 金额: $ 4.11万
• 依托单位: University of Southampton
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2012
• 资助国家: 英国
• 起止时间: 2012 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FJ019801%2F1
• 关键词: Antarctic; weathering; hydrologic; cycling; through

Over the past 65 million years of geologic time, Earth's climate has changed dramatically--transitioning from a world with warm oceans and limited polar glaciation to a world with cold polar regions and large continental ice sheets. This long-term change in global climate is known as the 'Greenhouse' to 'Icehouse' transition and primarily occurred during the Eocene and Oligocene geological epochs (between 55 and 23 million years ago). Study of this remarkable episode of ancient climate change can provide valuable information for understanding the mechanisms that precipitated this shift, as well as insight into the operation of different Earth system processes in the past. Further knowledge of these processes, involving the global carbon cycle and different climate feedback mechanisms, can be used to inform future predictions of climate change resulting from anthropogenic greenhouse gas emissions to the atmosphere.In an effort to gain further information on high-latitude climate conditions during the 'Greenhouse' to 'Icehouse' transition, the Integrated Ocean Drilling Program (IODP) recently cored marine sediments on the Antarctic margin off the Wilkes Land coast (directly south of Australia). The drillcores were recovered using a ship-based drilling platform and provide a window into Eocene and Oligocene climate history of the Antarctic coast and marginal seas. The proposed study is focused on clay mineral assemblages preserved in cores obtained from the Wilkes Land coast. Since clay minerals are a primary sedimentary weathering product shed from the terrestrial environment, variation in the types of clay mineral present throughout cores will provide important information on changes in the prevailing weathering regime. Specifically, clay minerals can be used to determine the timing of the switch from a chemical weathering regime (under warm, humid conditions) to physical weathering regime (influenced by glacial activity) during the Eocene-Oligocene time interval. Through collaborative work, the clay mineral records will be integrated with other climate proxy records currently being developed using a variety of approaches. The new Antarctic climate reconstructions that result from this research will provide critical high-latitude climate information that can be used to: (1) determine the nature of Antarctic climate conditions during peak Eocene warmth and during the onset of Oligocene glaciation, and (2) assess links between global climate change and atmospheric pCO2 variability through the 'Greenhouse' to 'Icehouse' transition.

在过去的6500万年的地质时代，地球的气候发生了巨大变化 - 从一个温暖的海洋和有限的极地冰川化的世界转变为具有冷极区域和大型大陆冰盖的世界。全球气候的这种长期变化被称为“冰舍”过渡的“温室”，主要发生在始新世和渐新世地质时代（55至2300万年前）。对古代气候变化的这一非凡事件的研究可以提供有价值的信息，以理解促成这种转变的机制，以及对过去不同地球系统过程的运行的洞察力。可以使用这些过程的进一步了解，涉及全球碳循环和不同的气候反馈机制，可用于告知未来对气候变化的预测，这是由于人为的温室气体对大气的排放而导致的气候变化。在努力获得有关“ Greenhouse”期间“ Greenhouse”期间高纬度气候条件的进一步信息，以“ Greenhouse”到“ Greenhouse”到“ Icehouse”到“ Icehouse”的过渡（Icehouse），曾经是ICEENT（ICEHOUSE）的陆上式（ICLECENT）。海岸（澳大利亚直接南部）。使用基于船舶的钻井平台回收了钻头，并为南极海岸和边际海洋的始新世和渐新世气候历史提供了一个窗口。拟议的研究集中在从威尔克斯土地海岸获得的岩心中保存的粘土矿物组合。由于粘土矿物是从地面环境中脱离的主要沉积风化产物，因此整个核心当前存在的粘土矿物类型的变化将提供有关现行风化状态变化的重要信息。具体而言，可以使用粘土矿物来确定从化学风化状态（在温暖，潮湿的条件下）到在始新世寡新世时间间隔期间从化学风化状态（在温暖，潮湿的条件下）到物理风化状态（受冰川活动的影响）的时间。通过协作工作，粘土矿物记录将与目前使用各种方法开发的其他气候代理记录集成。这项研究产生的新南极气候重建将提供可用于：（1）确定始新世温暖期间南极气候条件的性质，以及（2）在全球气候变化和大气PCO 2通过'''''''''''''''''''''和渐新地冰川变化之间的联系。