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分裂过程以及与热点有关的岩浆作用提供了独特的机会。我们提出联合陆上和海上地震实验，旨在描述沃尔维斯山脊位置的南部非洲被动边缘（图1），以评估假定的羽流与大陆岩石圈的相互作用，并确定从沿海褶皱带过渡到稳定克拉通的深层结构，沃尔维斯山脊撞击非洲大陆。该项目整合了三个实验，(A)陆上，海岸平行折射地震剖面，(B)两个陆上-海上广角地震样带，以及(C)海洋-大陆过渡处亚莫霍速度（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以及其他地球科学研究的结果（例如SPPSAMPLE内进行的研究）将有助于解决一些基本问题，如大陆地壳和羽头如何相互作用，岩浆底板的范围和体积是多少，以及哪些继承的（大陆）结构可能参与和利用了分裂过程。根据此提案，我们申请进行该两栖实验的陆上/海上部分的资金，部分海上实验的消耗品和差旅费，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.