Lithospheric structure of the Namibian continental passive margin at the intersection with the Walvis Ridge from amphibious seismic investigations (LISP-WAL)

被动大陆边缘为研究大陆伸展和裂解过程以及与热点有关的岩浆作用提供了独特的机会。我们提出了联合的陆上和近海地震实验，旨在描述瓦尔维斯海脊(图1)所在位置的南部非洲被动边缘，以评估推定的烟柱与大陆岩石圈的相互作用，并确定从沿海褶皱带到瓦尔维斯海脊撞击非洲大陆的稳定克拉通过渡的深部结构。该项目包括三个实验，(A)陆上、海岸-平行折射地震剖面，(B)两个陆上-近海广角地震断面，以及(C)海洋-大陆转换时次莫霍面速度(PN层析成像)的陆上和海上联合地震成像。对边缘岩石圈结构的了解，连同其他地球科学研究的结果(例如，在南极海生委内进行的研究)将有助于解决一些基本问题，如大陆地壳和烟柱头部如何相互作用，岩浆底侵的范围和数量是什么，以及继承的(大陆)构造可能如何参与和利用解体过程。根据这一建议，我们申请资金进行这一两栖实验的陆上/离岸部分，部分离岸实验的消耗品和旅行费用，以及分析两栖动物数据集的人员。

Passive continental margins offer the unique opportunity to study the processes involved in continental extension and break up and the role of hot-spot related magmatism. We propose combined on- and offshore seismic experiments designed to characterize the Southern African passive margin at the location of the Walvis Ridge (Fig. 1), to assess the interaction of the presumed plume with continental lithosphere and to determine the deep structure of the transition from the coastal fold belt to the stable craton, where the Walvis Ridge hits the African continent. The project integrates three experiments, (A) an onshore, coast-parallel refraction seismic profile, (B) two onshore-offshore wide-angle seismic transects, and (C) a combined on- and offshore seismic imaging of the sub-Moho velocity (Pn tomography) at the ocean-continent transition. The knowledge of the lithospheric structure of the margin together with results from other geoscientific studies (e.g., conducted within the SPPSAMPLE) will help to address fundamental questions such as, how continental crust and plume head interact, what the extent and volumes of magmatic underplating is, and how and which inherited (continental) structures might have been involved and utilized in the break up process. With this proposal we apply for funds to conduct the onshore/offshore part of this amphibious experiment, consumables and travel costs for part of the offshore experiment, and the personnel to analyse the amphibian data sets.