Electromagnetic, gravimetric and seismic measurements to investigate the Tristan da Cunha hot spot and its role in the opening of the South Atlantic

通过电磁、重力和地震测量来研究特里斯坦·达库尼亚热点及其在南大西洋开放中的作用

• 批准号: 173329718
• 负责人: Dr. Wolfram Geissler
• 金额: --
• 依托单位: GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2010
• 资助国家: 德国
• 起止时间: 2009-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/173329718?language=en
• 关键词: Electromagnetic; gravimetric; seismic; measurements; investigate

According to classical plume theory, the Tristan da Cunha hotspot is thought to have played a major role in the rifting of the South Atlantic margins and the creation of the aseismic Walvis Ridge by impinging at the base of the continental lithosphere shortly before or during the breakup of the South Atlantic margins. But Tristan da Cunha is enigmatic, as it cannot be clearly identified as a hot-spot but classifies also highly as a more shallow type of anomaly that may actually has been caused by the opening of the South Atlantic. The equivocal character of Tristan is largely due to lack of geophysical data in this region. To understand the tectonic processes of the opening of the South Atlantic, the formation of the Walvis ridge and to understand, whether Tristan da Cunha is the cause or the consequence of the rifting, it is of central importance to characterize the region around Tristan da Cunha with geophysical data in a more coherent way. We, therefore, propose a multi-disciplinary geophysical study of the region by acquiring marine electromagnetic, active and passive seismics as well as gravity data with the goal to identify the crustal structure and temperature and partial melt anomalies in the upper mantle.

根据经典的地幔柱理论，特里斯坦-达库尼亚热点被认为在南大西洋边缘断裂和海盆沃尔维斯海岭的形成中发挥了重要作用，因为它在南大西洋边缘断裂之前不久或期间撞击了大陆岩石圈底部。但特里斯坦-库尼亚是一个谜，因为它不能被明确地确定为一个热点，但也被高度归类为一个较浅的异常类型，实际上可能是南大西洋的开放造成的。特里斯坦的不确定性在很大程度上是由于缺乏该地区的地球物理数据。为了了解南大西洋打开、沃尔维斯海脊形成的构造过程，并了解特里斯坦-库尼亚是裂谷作用的原因还是后果，必须以更加连贯的方式利用地球物理数据来描述特里斯坦-库尼亚周围区域的特征。因此，我们建议通过获取海洋电磁、主动和被动地震以及重力数据，对该地区进行多学科地球物理研究，目的是查明上地幔的地壳结构、温度和部分熔融异常。