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

根据经典的羽流理论，特里斯坦-达库尼亚热区被认为在南大西洋边缘裂谷和无地震瓦尔维斯山脊的形成中发挥了重要作用，在南大西洋边缘解体前不久或期间撞击了大陆岩石圈的底部。但特里斯坦-达库尼亚是一个谜，因为它不能被明确地确定为热点，但也被高度归类为更浅类型的异常，实际上可能是由南大西洋的开放造成的。特里斯坦的模棱两可的特征在很大程度上是由于该地区缺乏地球物理数据。为了了解南大西洋开放的构造过程和沃尔维斯海脊的形成，并了解特里斯坦-达库尼亚是裂谷的原因还是结果，以更连贯的方式利用地球物理数据描述特里斯坦-达库尼亚周围地区的特征至关重要。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，对该区域进行多学科的地球物理研究，目的是查明地壳结构和温度以及上地幔的部分熔融异常。

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.