Crustal structure of the southern Argentine passive margin and implication for plume influence during breakup.

在拟议的研究中，我们将调查50°S至45°S之间的阿根廷边缘的深部结构，即阿根廷南部火山边缘与北部与福克兰高原交界的剪切边缘之间的过渡处。现有的广角反射/折射数据将揭示地壳的深部结构，特别是岩浆底侵的数量。得到的速度-深度模型将用于改进多道地震(MCS)数据的处理，以确认剪切边缘和深部构造的向海倾斜反射层序(SDR)的微弱指示。结果将被用来量化侵位的火山/岩浆物质的数量，作为与烟柱头部距离的函数。这将使重新评估不同的裂谷模型和火山岩侵位的机制成为可能。在项目的第二阶段(Post-Doc)，我们将把研究扩展到北部。我们建议研究整个阿根廷边缘的前/同裂谷地块的范围、伸展因素、上地壳和下地壳伸展的变化。这项研究将解决沿边缘的地壳和火山/岩浆结构的变异性，并将为南大西洋裂谷的演化提供新的线索。

Within the proposed study we will investigate the deep structure of the Argentine margin at 50°S to 45°S, i.e. at the transition between the volcanic margin of southern Argentina and the sheared margin which bounds the Falkland Plateau to the North. Existing wide-angle reflection/refraction data will reveal the deep structure of the crust and especially the amount of magmatic underplating. The resulting velocity-depth model will be used to improve processing of the multichannel seismic (MCS) data to confirm the weak indications for seaward dipping reflector sequences (SDRs) at the sheared margin and also the deep structures. The results will be used to quantify the amount of emplaced volcanic/magmatic material as a function of the distance from the plume head. This will enable a re-evaluation of different rift models and of the mechanisms for the emplacement of the volcanics. In a second phase of the project (Post-Doc) we will extent the studies to the north. We propose to study the extent of pre/syn-rift grabens, stretching factors, variations in upper versus lower crustal extension all along the Argentine margin. The study will resolve the variability of crustal and volcanic/magmatic structures along the margin and will shed new light on the evolution of the South Atlantic Rift.