Interdisciplinary Studies of the Galapagos Earth System

加拉帕戈斯地球系统的跨学科研究

• 批准号: 1145271
• 负责人: Eric Mittelstaedt
• 金额: $ 25.29万
• 依托单位: Regents of the University of Idaho
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1145271&HistoricalAwards=false
• 关键词: Interdisciplinary; Studies; Galapagos; Earth; System

Interdisciplinary Studies of the Galapagos Earth SystemIntellectual Merit. This proposal is an accomplishment-based renewal of a grant that funded field-based research in volcanology, petrology, and geobiology in the Galápagos Archipelago. The new proposal is to continue these studies, but each component has newly designed hypotheses and field and laboratory studies to address those hypotheses. The volcanologic study is to fund 4 years of data acquisition of the 10-station continuous GPS network on Sierra Negra volcano. Sierra Negra has displayed remarkable extents (meter-scle) and geometries of surface deformation over the past 11 years. We hypothesize that the deformation is due to the filling and pressurization of a 1.9 km-deep subcaldera sill. The magma is accommodated by elastic domical uplift of the chamber?s roof, punctuated by trapdoor faulting. Because nearly the entire amount of deflation that accompanied the 2005 eruption has now been recovered, there is good reason to believe that an entire inter-eruptive cycle might be captured within the next few years, making the proposed measurements both timely and opportunistic. The Galápagos continues to be a natural laboratory for evolutionary studies and is a premier locality for understanding the relationship between the geologic template and biological evolution. This proposal will help fund two such studies. The first is to establish a paleogeographic history of the islands, which is crucial for understanding the phylogeographic pathways that relate diversified organisms. The paleogeographic models require an estimate of the age of emergence of the islands and their subsidence history. The second study will attempt to relate the geologic history of an island to the islands? biodiversity, which is measured by the species richness of taxonomic groups. These studies are in collaboration with biologists and have already yielded important results. The third component of the proposal is a petrologic study of Rabida volcano. Rabida has erupted a diverse sequence of lavas, ranging from basalt to trachyte, and the volcanic deposits contain xenoliths of intrusive rocks. It is hypothesized that the xenoliths are from the mature and dying phases of the volcano?s history, thus their geochronology would establish the duration of volcanism at a Galápagos volcano, a crucial parameter for understanding the geologic history of the archipelago and one that is currently poorly constrained. The crystallization ages of the xenoliths will be measured by the U/Pb method, utilizing the ion microprobe at UCLA (other studies have shown that this is a robust method for oceanic xenoliths). The cumulate complement to the eruptive rocks will also test various hypotheses that have been put forth for the lithospheric evolution of Galápagos magmas. First, an evolutionary model has been proposed, and the compositions of the intrusive rocks should progress from primitive olivine gabbros to intermediate and evolved oxide-rich rocks. Second, the major petrogenetic processes have been proposed to be fractional crystallization and melt-crystal reaction in a thermally buffered mush column. The compositions of the xenoliths and their constituent minerals, determined by electron microprobe and LA ICPMS, will help evaluate these hypotheses. Having the intrusive complement to the erupted liquids in such a diverse suite is a rare opportunity. Broader Impacts. The recently expired grant funded the thesis work of 2 undergraduate and 6 graduate students, each of whom has gone on to further graduate education or a career in science. Most of the students have been coauthors on papers, and all have presented their Galápagos work at international conferences. This renewal will enable a new set of students to pursue similar research. The grant will also help the PI to continue to assist several agencies of the Ecuadorian government in hazards assessment and volcano monitoring, and continue outreach efforts to the local population and U.S. schools.Panel Summary The panel concurred with mail reviewers positive assessment of the accomplishments made by the PI based on previous NSF funding for studies in the Galapagos. A major strength of the PI's work in the Galapagos islands has been its interdisciplinary nature, involving collaborators from geophysics to biology that complement his own strengths in petrology and geochemistry.

加拉帕戈斯地球系统的跨学科研究。该提案是对一项资助加拉帕戈斯群岛火山学、岩石学和地球生物学实地研究的赠款的一项基于合同的更新。新的建议是继续这些研究，但每个组成部分都有新设计的假设和实地和实验室研究，以解决这些假设。火山学研究是为了资助Sierra Negra火山10站连续GPS网络4年的数据采集。Sierra Negra在过去11年中显示出显著的地表变形程度（米级）和几何形状。我们假设，变形是由于1.9公里深的subcaldera窗台填充和加压。岩浆是通过岩浆房的弹性隆起来容纳的。的屋顶，由活板门断层打断。由于伴随2005年火山爆发的几乎全部通缩量现在已经恢复，因此有充分的理由相信，在未来几年内可能会捕获整个喷发周期，从而使拟议的测量既及时又有机会。加拉帕戈斯群岛仍然是进化研究的天然实验室，也是了解地质模板与生物进化之间关系的首选地点。这项建议将有助于资助两项此类研究。首先是建立一个岛屿的古地理历史，这是至关重要的了解与多样化的生物的地理路径。古地理模型需要估计岛屿出现的年龄及其沉降历史。第二项研究将试图将一个岛屿的地质历史与这些岛屿联系起来。生物多样性，这是衡量的物种丰富的分类群体。这些研究是与生物学家合作进行的，已经取得了重要成果。 建议的第三个组成部分是拉比达火山的岩石学研究。拉比达火山喷发了从玄武岩到粗面岩的各种熔岩序列，火山沉积物中含有侵入岩捕虏体。据推测，捕虏体是从成熟和垂死阶段的火山？因此，他们的地质年代学将确定加拉帕戈斯火山的火山活动持续时间，这是了解群岛地质历史的一个关键参数，目前还没有得到很好的限制。捕虏体的结晶年龄将采用U/Pb法，利用加州大学洛杉矶分校的离子微探针进行测量（其他研究表明，这是一种适用于大洋捕虏体的可靠方法）。喷发岩石的堆积补充物也将检验加拉帕戈斯岩浆岩石圈演化的各种假设。首先，提出了侵入岩的成分演化模式，认为侵入岩的成分应是从原始橄榄辉长岩向中间富氧化物岩演化。第二，主要的成岩作用被认为是在热缓冲糊状柱中的分离结晶和熔融-结晶反应。通过电子探针和LA ICPMS确定的捕虏体及其组成矿物的成分将有助于评估这些假设。在这样一个多样化的套房中，对喷发的液体进行侵入性补充是一个难得的机会。更广泛的影响。最近到期的赠款资助了2名本科生和6名研究生的论文工作，他们每个人都继续深造或从事科学工作。大多数学生都是论文的合著者，并且都在国际会议上介绍了他们在加拉帕戈斯的工作。这一更新将使一批新的学生能够从事类似的研究。这笔赠款还将帮助PI继续协助厄瓜多尔政府的几个机构进行灾害评估和火山监测，并继续向当地居民和美国学校开展宣传工作。小组总结小组同意邮件评审员对PI根据以前的NSF资助在加拉帕戈斯进行研究所取得的成就的积极评价。PI在加拉帕戈斯群岛工作的一个主要优势是其跨学科性质，涉及从岩石物理学到生物学的合作者，补充了他在岩石学和地球化学方面的优势。