Towards Mass Balancing Arc Magmatic fluxes - Insights from the Central Mexican Volcanic Belt

走向质量平衡弧岩浆通量 - 来自墨西哥中部火山带的见解

• 批准号: 1220481
• 负责人: Susanne Straub
• 金额: $ 9.98万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-15 至 2015-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1220481&HistoricalAwards=false
• 关键词: Towards; Mass; Balancing; Arc; Magmatic; Towards; Mass; Balancing; Arc; Magmatic

Towards mass balancing arc magmatic fluxes - insights from the central Mexican Volcanic Belt Intellectual Merit: A fundamental breakthrough in understanding the solid Earth geochemical cycle was the recognition of slab recycling in arcs. Quantifying the magnitude of the slab flux, however, is a complex task that requires understanding the petrogenesis of arc magmas, and in particular the causes of their high average SiO2 (50-65 wt%) by which they differ globally from magmas produced at mid-ocean ridges and intraplate settings. The purpose of this project is to investigate the provenance of high-Si andesites and dacites (=?silicic magmas?) in the central Mexican Volcanic Belt (MVB) from mantle vs. crustal sources. The presence of equilibrium olivines with high, mantle-type 3He/4He (=7-8 Ra) in coeval basaltic and andesitic MVB magmas suggests the possibility that the high-SiO2 melts may have a mantle origin. Studies of silicic volcanic rocks from Quaternary composite volcanoes Malinche,Popocateptl and Nevada de Toluca and from coeval silicic monogenetic volcanoes of The interjacent Sierra Chichinautzin Volcanic Field are proposed to test this idea. Comprehensive major and trace element and isotopic data (incl. Sr-Nd-Pb-Hf isotopes) will be measured in bulk rocks and phenocrysts to evaluate crust vs. mantle contributions to formation of these rocks, and specifically whether or not the silicic magmas are principally(i) crustal partial melts, vs. (ii) melts generated in a subarc mantle infiltrated by reactive silicic fluids and partial melts from the subducting slab. A crustal origin of the silicic magmas would emphasize the importance of intracrustal processing and recycling at the expense of the recycled crustal flux from slab. Confirming the existence of broader spectrum of basaltic to dacitic initial mantle melts in the central MVB, however, has transformative potential as to models of arc magma genesis, arc and continental crustal growth, arc-trench connectivity and hence the overall impact of arc fluxes on the broader geochemical cycles. Broader Impacts: The project furthers the careers of two female scientists (Straub, with a disability, and Bolge). Participation of undergraduate and graduate students will contribute to the training of the next generation. Scientific interaction between US scientists at Lamont and the Oregon State University and international colleagues in Mexico, Taiwan and Scotland will be furthered. The project proposed is of interest to the broader science community, as it addresses questions on the forefront of the GeoPRISMS Initiative and of the New Science Plan of the post-2013 International Ocean Discovery Program (IODP).

朝向大规模平衡弧形岩浆磁通量 - 墨西哥中部火山带知识分子的见解：理解固体地球地球化学循环的基本突破是对弧的平板回收的认识。然而，量化板通量的大小是一项复杂的任务，需要了解弧岩浆的石化，尤其是其高平均SIO2（50-65 wt％）的原因，它们与全球山脊和次生山脊和静脉内设置的岩浆差异。该项目的目的是调查墨西哥中部火山带（MVB）中高矿床和dacites（=？硅质岩浆？）的出处。在同时基底和安第斯山脉的MVB MAGMAS中，具有高，地幔型3HE/4HE（= 7-8 Ra）的平衡橄榄石的存在表明高sio2熔体可能具有地幔起源。提议研究季节间间塞拉氏菌素火山田的硅质火山岩石岩石，波波特普特尔和内华达州de toluca的硅岩石以及内华达州de Toluca的研究。 Comprehensive major and trace element and isotopic data (incl. Sr-Nd-Pb-Hf isotopes) will be measured in bulk rocks and phenocrysts to evaluate crust vs. mantle contributions to formation of these rocks, and specifically whether or not the silicic magmas are principally(i) crustal partial melts, vs. (ii) melts generated in a subarc mantle infiltrated by reactive silicic俯冲板上的液体和部分融化。 硅质岩浆的地壳起源将强调围内加工和回收的重要性，而牺牲了板的再生地壳通量。然而，确认中央MVB中较广泛的玄武岩到达克特初始地幔的存在，但是对于Arc Magma Genesis，ARC和大陆地壳生长的模型，ARC-TRENCH的连接性，弧形 - 弧形量的整体影响对较大的地球化学循环具有变化潜力。 更广泛的影响：该项目推动了两位女科学家的职业（Straub，有残疾和Bolge）。本科生和研究生的参与将为下一代培训做出贡献。美国科学家在拉蒙特，俄勒冈州立大学与墨西哥，台湾和苏格兰国际同事之间的科学互动将得到进一步。该项目提出的是更广泛的科学界感兴趣的，因为它解决了地理位主义计划的最前沿以及2013年后国际海洋发现计划（IODP）的新科学计划的问题。