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

阿根廷南部被动边缘的地壳结构及其对破碎过程中羽流影响的影响。

• 批准号: 78947913
• 负责人: Dr. Dieter Franke
• 金额: --
• 依托单位: Bundesanstalt für Geowissenschaften und Rohstoffe (BGR)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2008
• 资助国家: 德国
• 起止时间: 2007-12-31 至 2015-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/78947913?language=en
• 关键词: Crustal; structure; southern; Argentine; passive

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.

在拟议的研究范围内，我们将调查南纬50°至45°阿根廷边缘的深层结构，即阿根廷南部火山边缘与福克兰高原以北的剪切边缘之间的过渡地带。现有的广角反射/折射数据将揭示地壳的深层结构，特别是岩浆底侵的数量。由此产生的速度-深度模型将用于改进多道地震数据的处理，以确认剪切边缘和深部结构的向海倾斜反射层序列的弱迹象。这些结果将用于量化与羽流头距离有关的火山/岩浆物质的侵位量。这将有助于重新评估不同的裂谷模型和火山岩就位的机制。在该项目的第二阶段（Post-Doc），我们将把研究范围扩大到北部。我们建议研究前/同裂谷地堑的程度，拉伸因素，上地壳与下地壳伸展的变化，所有沿着阿根廷边缘。这项研究将解决地壳和火山/岩浆结构沿着边缘的变异性，并将对南大西洋裂谷的演变提供新的认识。