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.

埃尔金斯-坦顿大陆溢流玄武岩区是神秘的，因为它们在地质记录中的频率很低，它们的显着大小（至少105立方公里的熔岩），它们的形成速度（西伯利亚和其他几个在大约一百万年内完成）以及它们与其他陆地灾难的明显或可能的年龄一致，包括火山喷发，陨石撞击和海平面变化。 西伯利亚的泛滥玄武岩区是最大的玄武岩区之一，也与地球历史上最大的二叠纪灭绝事件在时间上密切吻合。因此，了解触发和创造大陆溢流玄武岩的过程不仅与地质学和地球物理学有关，而且可能与地球上的生命周期有关，当然也与全球化学系统的相互作用有关。 洪水玄武岩是地球演化和地球生命演化之间的联系。这项工作旨在帮助区分洪水玄武岩形成的竞争理论，更具体地说，是为了更好地理解岩石圈在触发和喷发中的作用。 该项目连接了实验岩石学和数值模拟领域。 这项工作将由PI进行。并且将构成至少一个布朗大学本科生的本科论文。 这项工作将包括两个部分：1。对西伯利亚高MgO岩浆进行了高温高压实验，以评估其形成的压力和温度; 2。数值模拟研究岩石圈下沉作为岩浆焦点和触发器的作用，研究岩石圈边缘地形及其如何影响地幔柱上升，该项目将是对原始溢流玄武岩成分的首批实验研究之一。 实验研究的结果有可能区分模型的熔岩需要非常深，热熔融，并建议替代地幔岩性在较低温度下熔化的模型。 这些结果可能会显着改变洪水玄武岩形成的模型。