An Isotopic and Elemental Study of Deccan Traps Dikes

德干圈闭岩脉的同位素和元素研究

• 批准号: 0229824
• 负责人: John Mahoney
• 金额: $ 12.16万
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-01 至 2007-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0229824&HistoricalAwards=false
• 关键词: Isotopic; Elemental; Study; Deccan; Traps

EAR-0229824MahoneyIn the plume-head model, major lithospheric extension is predicted to follow continental flood volcanism, whereas significant extension is a prerequisite for flood volcanism in other models. In the Deccan Traps of India, a large swarm of dikes with no preferred orientations has been interpreted to be the main feeder system, and the lack of preferred orientations has been taken as strong evidence that peak eruptive activity was not accompanied by significant extension; in turn, this has been argued to provide some of the best evidence available worldwide for the plume-head model. However, the key conclusion that this swarm is a feeder system is based only on a preliminary, unpublished study of a small number of dikes. Furthermore, two other major dike systems are present; the dikes in both have strong preferred orientations and were emplaced under persistent lithospheric extension. No systematic geochemical study of any of the three swarms has been done. Fortunately, many well-located samples from all three have been analyzed recently for major elements and several trace elements. We propose to carry out detailed trace element (~100 samples) and Nd-Pb-Sr isotopic (~65 samples) analysis of dikes from all three swarms. The combined Nd-Pb-Sr isotopic, trace element, and major element data will be used to evaluate the affinities of the dikes with the lava formations and determine the location of the major Deccan feeder system(s).Broader Impacts: Training of a doctoral student is an important part of the project, which also entails collaborative work involving US, Indian, and Italian scientists.

在羽状头模型中，主要的岩石圈伸展被预测为大陆溢流火山作用，而在其他模型中，显著的伸展是溢流火山作用的先决条件。 在印度的德干圈闭中，一个没有优选方向的大型岩脉群被解释为主要的补给系统，而缺乏优选方向被认为是火山喷发活动高峰期没有伴随显著延伸的有力证据;反过来，这被认为是全球范围内羽状头模型的最佳证据。 然而，这个群体是一个馈线系统的关键结论只是基于一个初步的，未发表的研究少数堤防。 此外，还有另外两个主要的岩脉系统，这两个岩脉都有很强的择优取向，并在持续的岩石圈伸展下侵位。 目前还没有对这三个群进行系统的地球化学研究。 幸运的是，最近对这三个地区的许多位置良好的样本进行了主要元素和几种微量元素的分析。 我们建议对所有三个岩群的岩脉进行详细的微量元素（~100个样品）和Nd-Pb-Sr同位素（~65个样品）分析。 结合Nd-Pb-Sr同位素，微量元素和主要元素的数据将被用来评估与熔岩地层的堤坝的亲和力，并确定主要德干馈线系统的位置（S）。更广泛的影响：博士生的培训是该项目的重要组成部分，这也需要涉及美国，印度和意大利科学家的合作工作。