Collaborative Research: Record of Mafic Inputs to an Arc Magma System: Analysis of Enclaves and Their Host Lavas Cored During Phase I, Unzen Scientific Drilling Program

合作研究：弧岩浆系统的镁铁质输入记录：云仙科学钻探计划第一阶段期间对飞地及其宿主熔岩进行分析

• 批准号: 0106834
• 负责人: John Eichelberger
• 金额: $ 5.96万
• 依托单位: University of Alaska Fairbanks Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-08-01 至 2003-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0106834&HistoricalAwards=false
• 关键词: Collaborative; Research; Record; Mafic; Inputs

EichelbergerEAR-0106834This proposal seeks support for the PIs to participate in internationally collaborative geochemical investigations of samples now being obtained during the first phase of the Unzen Scientific Drilling Project (USDP), Japan. USDP is a developing project of the International Continental Drilling Program (ICDP), which seeks to use drilling as a tool to advance understanding of fundamental processes of continental crust. The United States is a major partner and funding source for ICDP, through the National Science Foundation. The goal of USDP is to understand the eruptive behavior of Unzen as representative of an important class of andesitic arc volcanoes. This is to be done through a program of drilling, borehole observation, and core analysis in complement with ongoing surface geological and geophysical studies as well as the remarkable suite of geophysical and geochemical observations made during the recent eruption. That devastating episode occurred during 1991 to 1994, claimed 44 lives, and did some $2 billion in damage.In the first phase of the project, for which support is requested through this proposal, flank holes of 750 m and 1500 m are being drilled to the base of the edifice in order to obtain a complete physical and chemical record of the volcano's activity. Simultaneously, and also to be supported under this request, planning will be undertaken for the second phase in which multiple core sections through the conduit will be obtained in order to address problems of magma transport and degassing. These observations will aid in understanding the paradox of effusive eruption of water-rich magma. The overall scientific rationale and plan for this undertaking are presented in the proposals to ICDP and will be repeated in condensed form here to provide context. ICDP itself supports drilling only, not the associated science, hence the need for this request.Recent eruptions of Unzen, Pinatubo, and Soufriere Hills volcanoes have graphically demonstrated the concept that injection of mafic magma into a crustal slush is an important petrologic process and a volcanic trigger. The high visibility of these events has served to strengthen a dialog between workers on volcanic and plutonic rocks, and reinvigorated the investigation of mafic enclaves and disequilibrium phenocryst assemblages. A basic question has become: how do we fit these products of open system behavior of magma systems, produced by mafic recharge or replenishment, into the broader picture of crustal plutonism and volcanism? A subset of that question, which this proposal seeks to answer, is: What are the long term-petrologic consequences of repeated mafic inputs to the crustal magma system? Studies to date have elucidated single events as sampled by eruption products or viewed the end product of many such events in the form of mafic and silicic layered intrusions (MASLI). We wish to look at the time series provided by 500,000 years of Unzen eruptions, to characterize the inputs to the system and understand their influence on its chemical evolution. The work will be coordinated with complementary efforts in Japan on dating the sequence and documenting the geologic and chemical evolution of the volcano.

Eichelbergerear-0106834这项提案寻求对PI的支持，以参与日本未完成的科学钻探项目（USDP）的第一阶段获得的样本的国际合作地球化学研究。 USDP是国际大陆钻探计划（ICDP）的发展项目，该项目试图使用钻探作为一种工具来提高对大陆壳的基本过程的了解。通过国家科学基金会，美国是ICDP的主要合作伙伴和资金来源。 USDP的目的是理解Uneze的爆发行为，代表了一类重要的安第斯山脉弧火山。这是通过钻探，钻孔观察和核心分析的程序进行的，该计划与持续的地面地质和地球物理研究以及最近喷发期间进行的地球物理和地球化学观测值的显着套件相辅相成。那个毁灭性的事件发生在1991年至1994年期间，夺走了44人的生命，造成了约20亿美元的损失。在该项目的第一阶段，通过该提案要求支撑，钻了750 m和1500 m的侧面孔向建筑物的底部钻取，以便获得火山活动的完整物理和化学记录。同时，还应根据本请求得到支持，将对第二阶段进行计划，在该阶段中，将获得通过导管的多个核心部分，以解决岩浆运输和脱气问题。这些观察结果将有助于理解富含水的岩浆爆发的悖论。这项工作的总体科学原理和计划是在提交给ICDP的提案中，并将在此处以凝结形式重复以提供背景。 ICDP本身仅支持钻探，而不是相关的科学，因此需要该请求。未开除，Pinatubo和Soufriere Hills火山的爆发显示了以下概念：将镁铁质岩浆注入地壳泥浆中是一个重要的质储过程和火山触发器。这些事件的高吸收性已加强了火山和冥王星岩石上的工人之间的对话，并重新启动了对镁铁质飞地和不平衡现象的研究。一个基本的问题已经成为：我们如何拟合由镁铁质补给或补给产生的岩浆系统开放系统行为的这些产品，以更广泛的地壳岩石岩和火山主义的范围？该提案试图回答的一个子集是：重复的镁铁质输入对地壳岩浆系统的长期远程学后果是什么？迄今为止，研究阐明了通过喷发产品取样的单一事件，或以镁铁质和硅质分层侵入（MASLI）的形式查看了许多此类事件的最终产物。我们希望查看500，000年的未开除喷发提供的时间序列，以表征系统的投入，并了解它们对其化学演化的影响。这项工作将与日本的补充努力协调，以与序列约会并记录火山的地质和化学演化。