Lithospheric Controls on Flood Basalt Volcanism

岩石圈对溢流玄武岩火山活动的控制

• 批准号: 0309057
• 负责人: Linda Elkins-Tanton
• 金额: $ 11.39万
• 依托单位: Brown University
• 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 2006-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0309057&HistoricalAwards=false
• 关键词: Lithospheric; Controls; Flood; Basalt; Volcanism

EAR-0309057Elkins-TantonContinental flood basalt provinces are enigmatic due to their infrequency in the geologic record, their remarkable size (at least 105 km3 of lava), their speed of formation (the Siberian and several others were complete in about a million years) and their apparent or possible age coincidences with other terrestrial catastrophes, including extinctions, meteorite impacts, and sea level changes. The Siberian flood basalt province, one of the largest, is also closely coincident in time with the Permian extinction, the largest in Earth history. Understanding the processes that trigger and create continental flood basalts therefore has relevance not only to geology and geophysics, but possibly to cycles of life on earth and certainly to interactions of global chemical systems. Flood basalts are a link between the evolution of the Earth and evolution of life on Earth.The work is designed to help differentiate among competing theories for the formation of flood basalts, and, more specifically, to create better understanding of the role of lithosphere in triggering and eruption. The project bridges the fields of experimental petrology and numerical modeling. The work will be carried out by the P.I. and will also constitute the undergraduate thesis of at least one Brown University undergraduate. The work will consist of two parts: 1. High-pressure and temperature experiments on high-MgO magmas from Siberia to assess their pressure and temperature of formation; and 2. Numerical modeling to study the role of lithospheric foundering as a magmatic focus and trigger, and to study lithospheric topography at the edge of cratons and how it affects plume ascent.This project will be one of the first experimental studies on primitive flood basalt compositions. The results of the experimental study have the potential to differentiate between models for lavas requiring very deep, hot melting, and models suggesting alternative mantle lithologies melting at lower temperatures. These results may significantly alter models for flood basalt formation.

EAR-0309057ELKINS-TANTONCONTINANTALTH洪水盆地省由于其在地质记录中的不足而变得神秘，它们的尺寸显着（至少105 km3的熔岩），它们的地层速度（西伯利亚人和其他几个在一百万年内都完整了）和它们与其他陆地灾难（包括灭绝，陨石撞击和海平面变化）的明显或可能的年龄相吻合。 西伯利亚洪水玄武岩省是最大的省之一，与二叠纪灭绝时期也紧密相吻合，二叠纪灭绝是地球历史上最大的。因此，了解触发和创造大陆洪水盆地的过程不仅与地质和地球物理学有关，而且可能与地球上的生命周期以及全球化学系统的相互作用相关。 洪水底层是地球演变与生命在地球上的发展之间的联系。该工作旨在帮助区分竞争理论以形成洪水盆地，更具体地说，是为了更好地理解岩石圈在岩石圈中的作用触发和喷发。 该项目桥接了实验性岩石学和数值建模领域。 这项工作将由P.I.进行并将构成至少一所布朗大学本科生的本科论文。 这项工作将由两个部分组成：1。在西伯利亚的高压岩浆上进行高压和温度实验，以评估其形成的压力和温度；和2。数值建模，以研究岩石圈基础作为岩浆焦点和触发的作用，并研究克拉通边缘的岩石圈地形以及它如何影响羽流的上升。该项目将是关于原始洪水基础的最早的实验研究之一组成。 实验研究的结果有可能区分需要非常深，热熔化的熔岩模型，并提示在较低温度下融化的替代地幔岩石学模型。 这些结果可能会显着改变洪水盆地形成的模型。