Collaborative Research: Plate Tectonic and Geochemical Evolution of the Young Walvis Ridge and Implications for African Plate Motion Modeling

合作研究：年轻沃尔维斯海岭的板块构造和地球化学演化及其对非洲板块运动模型的影响

• 批准号: 0961396
• 负责人: Anthony Koppers
• 金额: $ 38万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2017-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0961396&HistoricalAwards=false
• 关键词: Collaborative; Research; Plate; Tectonic; Geochemical

The cause of the bifurcating tracks of seamounts and seafloor swells in the Walvis Ridge area in the South Atlantic just off South Africa has been a longstanding enigma in Marine Geology and in our understanding of hotspots and the plate tectonic evolution of Africa. This project will go to sea to dredge and analyze rocks from the part of the seafloor to the west of the Walvis Ridge and examine changes from hotspot to diffuse volcanism. The present location of the Walvis hotspot and the reason for its waning volcanic activity over the last 60 Myr will also be determined. Argon trapped in minerals in the collected seafloor volcanic rocks will be used to determine the age progression of the volcano tracks. Rock, major and trace element geochemistry and isotopes will be used to see if the younger rocks in the bifurcated tracks can be linked to the older Walvis Ridge. Multibeam bathymetric mapping and a map of seafloor magnetics will also be generated to examine structural trends and plate tectonic motions of this part of the ocean floor. Broader impacts of the work include international collaboration with a complementary German effort that is studying the older part of the Walvis Ridge, K-12 teacher and graduate and undergraduate student training, and support of a PI whose gender is under-represented in the sciences.

在南非附近的南大西洋瓦尔维斯海脊地区，海山和海底膨胀的分叉轨迹的原因一直是海洋地质学中的一个谜，也是我们对非洲热点和板块构造演化的理解中的一个长期谜。该项目将出海挖掘和分析从沃尔维斯岭以西的海底部分的岩石，并检查从热点到扩散火山活动的变化。沃尔维斯热点目前的位置以及它在过去60年里火山活动减弱的原因也将得到确定。收集的海底火山岩中的矿物中捕获的Ar将被用来确定火山轨迹的年龄进程。岩石、主要元素和微量元素的地球化学性质和同位素将被用来观察分叉轨迹中的年轻岩石是否可以与更古老的沃尔维斯山脊联系在一起。还将绘制多波束测深图和海底磁性图，以审查这一部分海底的构造趋势和板块构造运动。这项工作的更广泛影响包括与正在研究沃尔维斯岭较老部分的德国补充努力的国际合作，K-12教师、研究生和本科生培训，以及对在科学界性别代表性不足的PI的支持。