Collaborative Research: US-EAGLE \(Ethiopia-Afar Grand Lithospheric Experiment\): Modification of Lithospheric Structure During Continental Breakup

合作研究：US-EAGLE（埃塞俄比亚-阿法尔大岩石圈实验）：大陆破裂期间岩石圈结构的改变

• 批准号: 0208592
• 负责人: Kevin Mickus
• 金额: --
• 依托单位: Missouri State University
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-01 至 2006-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0208592&HistoricalAwards=false
• 关键词: Collaborative; Research; US; EAGLE; Ethiopia

0208592MickusThe architecture of continental margins in terms of how they are created is not well understood because most of the previous work has been on successfully rifted margins after rifting is complete. Both continental (fault dominated) end-members and oceanic (magma dominated) rift end-members are well studied, but the transitional stage is not understood. This project will document this critical transition from continental to oceanic rifting. The PIs will carry out seismic experiments, integrated with geochemical, gravity and structural studies, to study lithospheric structure in one of the rare areas where the transition from continental rifting to incipient spreading is captured - the main Ethiopian Rift (MER). In the MER the along-axis transition to initial seafloor spreading provides a spatial proxy for temporal variability. Specific objectives are: 1) to determine detailed crust and mantle structure across and along a transitional rift segment and 2) to understand magmagenesis beneath and within the rift. The PIs will obtain crustal P-and S-velocity cross-sections that can be interpreted for lithology across the Ethiopian rift at 10 deg. N where active magmatic centers first appear, and along-strike to the north to study the transition into fully magmatic rifting. They will interpret existing and new gravity data in light of their new seismic data, and use geochemical data to constrain the physical state of the upper mantle and magmatic inputs to the crust.The project (US - EAGLE) is fully integrated with the already funded UK - EAGLE initiative. Scientists at Leicester, Leeds and London, have been awarded UK funds to carry out a single refraction profile across the Ethiopian rift in January 2003, coupled with local seismicity studies and teleseismic recording. The US - EAGLE PIs will shoot and record a complementary orthogonal along-axis wide-angle profile; and will shoot fan shots into these linear arrays and the local seismic network to provide a measure of 3D coverage. Together, these seismological experiments form a nested, multi-scale seismic image of the Ethiopian rift and plume. The seismic studies will be coupled with geochemical and petrological and gravity studies (US), and structural, thermochronological, magnetotelluric and additional gravity studies (UK).***

0208592毫无理解的是，大陆边缘的架构尚未很好地理解，因为以前的大多数工作都在裂开后成功地裂开了边缘。大陆（断层主导）的末端会员和海洋（岩浆主导）裂谷末端成员都进行了充分的研究，但尚不清楚过渡阶段。该项目将记录从大陆裂谷到海洋裂谷的关键过渡。 PI将进行地震实验，并与地球化学，重力和结构研究整合在一起，以研究从大陆裂口到初期扩散的罕见地区之一 - 埃塞俄比亚主要的裂谷（MER）。在MER中，轴向向初始海底蔓延过渡为时间变异提供了空间代理。特定目标是：1）确定跨和沿过渡裂谷段的详细地壳和地幔结构，以及2）在下方和裂谷内理解岩浆。 PI将获得地壳P和S速度横截面，这些横截面可以在10度以10度的整个埃塞俄比亚裂谷中解释为岩性。 n首先出现了主动岩浆中心，并沿着北部沿着北部的速度研究向完全岩浆裂谷的过渡。他们将根据其新的地震数据来解释现有的重力数据和新的重力数据，并使用地球化学数据将上地幔和岩浆输入的物理状态限制为地壳。莱斯特，利兹和伦敦的科学家被授予英国资金，在2003年1月在埃塞俄比亚裂谷中进行单个折射率，再加上当地的地震研究研究和远距离宣传记录。美国 - Eagle PIS将沿轴宽角轮廓射击并记录一个互补的正交；并将在这些线性阵列和局部地震网络中拍摄风扇镜头，以提供3D覆盖的量度。这些地震实验一起形成了埃塞俄比亚裂谷和羽流的嵌套，多尺度的地震形象。地震研究将与地球化学和岩石学和重力研究（US）以及结构，热量，磁铁性和其他重力研究（英国）结合。***