Behaviour of the Earth’s magnetic field during superchrons: comparative study of the Cretaceous and Meso-Neoproterozoic Maya events recorded in the flows of the Okhotsk- Chukotka Volcanic Belt (NE Russia) and the sediments of the Yenisey Ridge (SW Siberia

超纪元期间地球磁场的行为：鄂霍次克-楚科奇火山带（俄罗斯东北部）和叶尼塞山脊（西伯利亚西南部）沉积物中记录的白垩纪和中新元古代玛雅事件的比较研究

• 批准号: 405632737
• 负责人: Privatdozent Dr. Florian Lhuillier
• 金额: --
• 依托单位: Sektion Geophysik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/405632737?language=en
• 关键词: Behaviour; Earth; magnetic; field; during

The Earth’s magnetic field, generated by a dynamo process in the outer core, is a dynamic object, the time variability of which, on centennial-to-millenial timescales, is called palaeosecular variation (PSV). On multimillion-year timescales, this field is known to stochastically reverse its polarity, but can surprisingly also produce prolonged periods (> 20 Myr) with stable polarity termed superchrons. These persistently occurring events over the Earth’s history, documented both during the Phanerozoic and Proterozoic, are usually characterised by a strong dipolar field and low directional dispersion. Nevertheless, the possibility of more complex temporal dynamics with periods of higher variability within a superchron, has been recently proposed, and needs to be investigated further. Having a clear view of the behaviour of the geomagnetic field during superchrons, indeed has direct implications on the understanding of the outer core’s dynamics.To this end, we would like to investigate comparatively the behaviour of the Earth’s magnetic field during the Cretaceous Normal Superchron (CNS, 121–83 Ma) and the Meso-Neoproterozoic Maya superchron (PMS, ~1,000 Ma) recorded in the flows of the Okhotsk-Chukotka Volcanic Belt (NE Russia) and the sediments of the Yenisey Ridge (SW Siberia). The project includes two field campaigns in each area to collect a large amount of palaeomagnetic samples. On one hand, the almost unexplored magnetic record of the Okhotsk-Chukotka Belt offers a unique possibility to sample, at the same latitude, piles of volcanic flows from several time intervals within and after the CNS. On the other hand, the carbonate Kartochka formation of the Yenisey Ridge, is a nonpareil location to scrutinise the temporal evolution of the field during and around the PMS, and conduct relative palaeointensity experiments.The primary aim of this project is to produce detailed magnetostratigraphy for the Kartochka formation, and determine directional PSV estimates over various time intervals for the Okhotsk-Chukotka Volcanic Belt. We will pay special attention to the time dependency of the magnetic field to discern possible intermittencies of the geodynamo during the two investigated superchrons. We will also conduct relative (or where possible — absolute) palaeointensity experiments to determine the relative variability in intensity, which is assumed to be a robust and latitude-independent PSV estimator. One secondary method-related aspect of the project will be to better assess the robustness of pseudo-Thellier experiments. Ultimately, our new results will be compared with the existing palaeomagnetic dataset and the predictions from numerical dynamo simulations.

地球的磁场是由动态物体产生的，在百年至千年时间内的时间变异称为古氏差异（PSV）。在数百万年的时间尺度上，已知该领域会随机扭转其极性，但出乎意料的是，还可以产生长时间的（> 20 MYR），其稳定的极性称为超级节质。这些在地球历史上持续发生的事件，既记录在phanerokoic和propereroxoic期间，通常都以强烈的偶极场和较低的定向分散体为特征。然而，最近提出了更复杂的临时动力学，具有更高的变异性周期，最近提出了，需要进一步研究。清楚地了解了超基质期间的地磁领域的行为，确实对对外部核心动态的理解有直接的影响。为此，我们想调查地球磁场在白垩纪正常超级载体期间（CNS，121-83 MA）和中等含量的neoproterozoic Maya Maya Maya Maya（pms s pm pmss，〜1，〜1，〜1，〜1，〜1，〜1，〜1，〜1，〜1，〜1000 no in Inty Insos， Okhotsk-Chukotka火山带（NE俄罗斯）和Yenisey Ridge的沉积物（SW西伯利亚）。该项目包括每个区域中的两个现场活动，以收集大量古磁样品。一方面，Okhotsk-Chukotka带的几乎出乎意料的磁记录为在CNS内外的几个时间间隔中的火山流量相同的火山流钢琴样品提供了独特的可能性。另一方面，Yenisey Ridge的碳酸盐Kartochka形成是一个非培训的位置，旨在审查PMS期间和PMS周围和周围域的临时演变，并进行相对的古生地强度实验。该项目的主要目的是为Kartochka形成的详细磁性绘制范围，并确定多个时间间隔，并确定Kartochka psv的详细磁法，并估算出正常的估计。 腰带。我们将特别注意磁场的时间依赖性，以辨别两个研究的超芯子期间Geodynamo可能的间歇性。我们还将进行相对（或在可能的情况下 - 绝对）古强度实验，以确定强度的相对变异性，这被认为是稳健和纬度独立的PSV估计量。该项目的一个次要方面将是更好地评估伪透 - 透明体实验的鲁棒性。最终，我们的新结果将与现有的古磁数据集和数值发电机模拟的预测进行比较。