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 However, the key conclusion that this swarm is a feeder system is based only on a preliminary, unpublished study of a small number of dikes.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.

EAR-0229824Mahoney 在羽头模型中，预计主要岩石圈扩张将跟随大陆洪水火山活动，而在其他模型中，显着扩张是洪水火山活动的先决条件。 在印度的德干地盾中，一大群没有优先方向的堤坝被解释为主要的供给系统，而缺乏优先方向被视为强有力的证据，表明喷发活动高峰并未伴随着显着的延伸；反过来，这也被认为为羽头模型提供了世界范围内可用的一些最佳证据。 然而，该群是一个供给系统的关键结论仅基于对少数堤坝的初步、未发表的研究。 此外，还有另外两个主要的堤防系统：两者的岩脉都有很强的择优方向，并且都处于持续的岩石圈伸展作用下。 尚未对这三个群中的任何一个进行系统的地球化学研究。 幸运的是，最近对这三个国家的许多位置良好的样品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群的堤坝进行详细的微量元素（约 100 个样品）和 Nd-Pb-Sr 同位素（约 65 个样品）分析。 结合的 Nd-Pb-Sr 同位素、微量元素和主要元素数据将用于评估岩脉与熔岩地层的亲和力，并确定主要德干供给系统的位置。 更广泛的影响：培训博士生是该项目的重要组成部分，该项目还需要美国、印度和意大利科学家的合作。