Interdisciplinary Studies of the Galapagos Earth System

加拉帕戈斯地球系统的跨学科研究--智力价值。这项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延续。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以及现场和实验室研究来解决这些假设。这项火山学研究将资助塞拉利昂内格拉火山10个站的连续GPS网络为期4年的数据采集。在过去的11年里，内格拉山脉显示了惊人的地表变形范围(米级)和几何形状。我们假设变形是由于1.9公里深的地下火山岩床的充填和加压造成的。岩浆由S顶板的弹性隆起所容纳，其间夹杂着陷门断裂。由于2005年火山喷发带来的通货紧缩现在几乎已经全部恢复，我们有充分的理由相信，整个火山喷发之间的周期可能会在未来几年内被捕捉到，这使得拟议的措施既及时又机会主义。加拉帕戈斯仍然是进化研究的天然实验室，也是了解地质模板和生物进化之间关系的主要场所。这项提议将帮助资助两项这样的研究。首先是建立这些岛屿的古地理历史，这对于理解与各种生物相关的系统地理路径至关重要。古地理模型需要估计岛屿出现的年龄和它们的沉降史。第二项研究将试图将一个岛屿的地质史与这些岛屿联系起来？生物多样性，这是通过分类群的物种丰富度来衡量的。这些研究是与生物学家合作进行的，已经取得了重要成果。提案的第三部分是拉比达火山的岩石学研究。拉比达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的包体。据推测，捕虏体来自火山的成熟期和衰退期--S历史，因此，它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，这是理解该群岛地质历史的关键参数，也是目前约束较差的参数。利用加州大学洛杉矶分校的离子微探针，U/Pb法将测量捕虏体的结晶年龄(其他研究表明，这是一种可靠的海洋捕捉体方法)。对喷发岩石的累积补充也将检验已提出的加拉帕戈斯岩浆岩石圈演化的各种假说。首先，提出了侵入岩的演化模式，认为侵入岩的成分应由原始的橄榄辉长岩向中间演化的富氧化物岩石演化。其次，在热缓冲碎屑柱中，主要的成岩过程是分离结晶和熔融结晶反应。由电子探针和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说。在如此多样化的套房中拥有对喷发的液体的侵入性补充是一个难得的机会。更广泛的影响。最近到期的拨款资助了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事业。大多数学生都是论文的合著者，所有人都在国际会议上展示了他们的加拉帕戈斯作品。这一更新将使一批新的学生能够进行类似的研究。这笔赠款还将帮助国际和平协会继续协助厄瓜多尔政府的几个机构进行危险评估和火山监测，并继续向当地民众和美国学校进行外联工作。专家小组总结专家小组同意邮件审查员的积极评价，即国际和平协会根据以前国家科学基金会对加拉帕戈斯研究的资助所取得的成就。少年派在加拉帕戈斯群岛的工作的一个主要优势是其跨学科性质，涉及从地球物理到生物学的合作者，这些合作者补充了他在岩石学和地球化学方面的优势。

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.