Magmatic Volatiles, Unraveling the Reservoirs and Processes of the Volcanism in the Antarctic Peninsula

岩浆挥发物，揭示南极半岛火山活动的储层和过程

• 批准号: 1643494
• 负责人: Alberto Saal
• 金额: $ 27.01万
• 依托单位: Brown University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-03-01 至 2022-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1643494&HistoricalAwards=false
• 关键词: Magmatic; Volatiles; Unraveling; Reservoirs; Processes

The Earth's mantle influences the movement of tectonic plates and volcanism on the surface. One way to understand the composition and nature of the Earth's mantle is by studying the chemistry of basalts, which originate by volcanic eruptions of partially melting mantle rocks. This study will establish the budget and distribution of volatile elements (hydrogen, carbon, fluorine, chlorine, sulfur) in volcanic basalts to better understand the composition of the Earth's interior. Volatiles influence mantle melting, magma crystallization, magma migration and volcanic eruptions. Their abundances and spatial distribution provide important constraints on models of mantle flow and temperature. Moreover, volatiles are key constituents of the Earth's atmosphere and oceans. Establishing the cycles of volatiles between the Earth's interior and surface is of fundamental importance to understand the long-term evolution of our planet. This project supports a graduate student and research scientist at Brown University. It promotes the collaboration with geochemists from eleven institutions representing six different countries: USA, Germany, United Kingdom, Argentina, South Korea and Japan, and utilizes several NSF-funded USA analytical facilities. Communication of results will occur through: 1) peer-reviewed journals, presentations at conferences and invited university lectures, 2) hands-on science learning activities for local elementary and high school classes, and 3) outreach to the general audience through public lectures.Over the last 60 years of funded research, the Antarctic Peninsula and nearby ocean ridges have been extensively investigated providing information on the origin of the magmatism, and the composition, structure, temperature and evolution of the lithospheric and asthenospheric mantle. Diverse hypotheses have been proposed for the origin of the magmatism in the Antarctic Peninsula, from flux melting of the mantle wedge during devolatilization of the subducted Phoenix plate, to adiabatic decompression melting of a carbonated and hydrous asthenosphere, to melting of a volatile-rich metasomatized subcontinental lithospheric mantle. All proposed hypotheses invoke the role of volatiles. Surprisingly, data on the volatile contents of basalts and mantle from this region are non-existent. This is a significant omission from the geochemical data set, given the important role volatile elements play in the generation and composition of magmas and their sources. The focus of our research is to examine the regional variations in volatile contents (C, H, F, S, Cl) in geochemically well-characterized Pliocene-recent basalts from the Antarctic Peninsula and Phoenix ridge. Our goal is to establish the budget and distribution of volatiles in the mantle to understand 1) the processes responsible for the generation of chemically diverse basalts in close spatial and temporal proximity and 2) the nature (lithology, composition and temperature) of the heterogeneous mantle source beneath the Antarctic Peninsula and Phoenix ridge.

地幔影响地壳板块的运动和地表火山活动。 了解地幔的成分和性质的一种方法是研究玄武岩的化学成分，玄武岩源自部分熔化的地幔岩石的火山喷发。 这项研究将确定火山玄武岩中挥发性元素（氢、碳、氟、氯、硫）的预算和分布，以更好地了解地球内部的组成。 挥发物影响地幔熔化、岩浆结晶、岩浆迁移和火山喷发。 它们的丰度和空间分布为地幔流和温度模型提供了重要的约束。此外，挥发物是地球大气和海洋的主要成分。 建立地球内部和表面之间的挥发物循环对于了解地球的长期演化至关重要。 该项目为布朗大学的一名研究生和研究科学家提供支持。它促进与来自六个不同国家（美国、德国、英国、阿根廷、韩国和日本）的 11 个机构的地球化学家的合作，并利用多个 NSF 资助的美国分析设施。 结果的交流将通过以下方式进行：1) 同行评审期刊、会议演讲和受邀大学讲座，2) 当地小学和高中课堂的实践科学学习活动，以及 3) 通过公开讲座向广大观众进行宣传。在过去 60 年的资助研究中，对南极半岛和附近的海脊进行了广泛的调查，提供了有关岩浆起源及其成分、结构、温度的信息 以及岩石圈和软流圈地幔的演化。关于南极半岛岩浆作用的起源，人们提出了多种假说，从俯冲菲尼克斯板块脱挥发分过程中地幔楔的通量熔化，到碳酸化和含水软流圈的绝热减压熔化，再到富含挥发分的交代化的次大陆岩石圈地幔的熔化。所有提出的假设都涉及挥发物的作用。令人惊讶的是，关于该地区玄武岩和地幔挥发物含量的数据并不存在。鉴于挥发性元素在岩浆及其来源的生成和成分中发挥的重要作用，这是地球化学数据集中的重大遗漏。我们研究的重点是研究来自南极半岛和凤凰山脊的地球化学特征良好的上新世近代玄武岩中挥发物含量（C、H、F、S、Cl）的区域变化。我们的目标是确定地幔中挥发物的预算和分布，以了解 1) 在空间和时间上接近的化学多样性玄武岩的生成过程，以及 2) 南极半岛和凤凰山脊下方的异质地幔源的性质（岩性、成分和温度）。

项目成果

Source variations in volatile contents between Bransfield Strait and Phoenix Ridge, Antarctica

布兰斯菲尔德海峡和南极洲凤凰岭之间挥发物含量的来源变化

• DOI: 10.7185/gold2021.8087
• 发表时间: 2021
• 期刊: Goldschmidt Conference
• 作者: Anderson, Danny;Saal, Alberto;Riley, Teal;Keller, Randall;Haase, Karsten;Mallick, Soumen;Wang, Jianhua
• 通讯作者: Wang, Jianhua

Source Variations in Bransfield Strait and Relation to Nearby Phoenix Ridge

布兰斯菲尔德海峡的源头变化及其与附近凤凰岭的关系

• DOI: 10.46427/gold2020.61
• 发表时间: 2020
• 期刊: Goldschmidt Conference
• 作者: Anderson, Danny W.;Saal, Alberto E.;Riley, Teal R.;Keller, Randall A.;Haase, Karsten M.;Mallick, Soumen;Wang, Jianhua;Boesenberg, Joseph S.
• 通讯作者: Boesenberg, Joseph S.