Testing the core-mantle boundary & large igneous province hypothesis: a full-vector palaemagnetic study of the North Atlantic Igneous Province

测试核幔边界

• 批准号: 2743899
• 金额: --
• 依托单位: Imperial College London
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2743899
• 关键词: Testing; core; mantle; boundary; large

Background: Large Igneous Provinces (LIPs) are large areas of volcanism that erupt over millions of years causing rapid environmental change and mass extinctions, e.g., the PermianTriassic mass extinction. It has been suggested that LIPs are delayed expressions of energy release from the Earth's Core; hot plumes from the Core-Mantle Boundary (CMB) rise over a period of ~50 Myr to form hotspots. When a hotspot first breaks through the Earth's crust aLIP forms. Before the energy release at the CMB, it is very likely that the Earth's Core was hotter than usual. It is predicted that increases in temperature, will increase fluid-flow rates in the outer Core, increasing the efficiency of the geodynamo, leading to higher geomagnetic field intensities than usual (Biggin, et al., 2012). However, these ideas have not been rigorously tested. The Columbia River Basalts, north west USA, is a 'small' LIP that occurred~17-14 Ma and is associated with the Yellowstone hotspot, and the North Atlantic Igneous Province (NAIP) is a LIP that erupted ~64 to 54 Ma centred on the Icelandic hotspot. The NAIP was broken up during the formation of the Atlantic Ocean and now extends from eastern Greenland, the Faroe Islands, Northern Ireland and Scotland. If the hypothesis of Biggin et al. (2012) is correct, then there should be a low in the intensity recorded by the NAIP LIP basaltsdue to the initial formation of the plume that forms the Yellowstone hotspot. However, modern ancient absolute geomagnetic field intensity estimates recovered from NAIP rocks are very limited. There are older estimates, especially from Scotland, however, these no longer meet modern quality criteria.Project: There are two main aims of the project: 1) Test the CMB & LIP hypothesis of Bigginet al. (2012), by collecting samples from both the Faroe Isles and the western coast of theBritish Isles; 2) Determine extrusion rates of the NAIP, and to help understand its potential linkto the Paleocene-Eocene Thermal Maximum and climate change (Jones et al., 2019).

背景资料：大火成岩省（LIP）是数百万年来爆发的大面积火山活动，导致快速的环境变化和大规模的火山喷发，例如，二叠纪-三叠纪大灭绝有人认为，LIPs是来自地球核心的能量释放的延迟表现;来自核幔边界（CMB）的热羽在约5000万年的时间内上升形成热点。当一个热点第一次突破地壳时，就形成了一个LIP。在宇宙微波背景辐射释放能量之前，地核很可能比平时更热。据预测，温度的增加将增加外核中的流体流速，增加地球发电机的效率，导致比平常更高的地磁场强度（Biggin等人，2012年）。然而，这些想法并没有经过严格的测试。美国西北部的哥伦比亚河玄武岩是一个“小”LIP，发生于~17-14 Ma，与黄石热点有关，北大西洋火成岩省（NAIP）是一个LIP，爆发于~64 - 54 Ma，以冰岛热点为中心。NAIP在大西洋形成期间被打破，现在从格陵兰岛东部，法罗群岛，北方爱尔兰和苏格兰延伸。如果Biggin等人（2012年）的假设是正确的，那么NAIP LIP玄武岩记录的强度应该很低，这是由于形成黄石热点的羽流的最初形成。然而，从NAIP岩石中恢复的现代古代绝对地磁场强度估计非常有限。项目：本项目的主要目的有两个：1）通过从法罗群岛和不列颠群岛西海岸收集样本，检验Bigginet al.（2012）的CMB & LIP假设; 2）确定NAIP的挤出速率，并帮助了解其与古新世-始新世热最大值和气候变化的潜在联系（Jones等人，2019年）。