Collaborative Research: Deep structure controls on magmatic output of Klyuchevskoy volcanic group, Kamchatka

合作研究：堪察加半岛Klyuchevskoy火山群岩浆产出的深层结构控制

• 批准号: 1015315
• 负责人: Paul Wiita
• 金额: $ 2.11万
• 依托单位: The College of New Jersey
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1015315&HistoricalAwards=false
• 关键词: Collaborative; Research; Deep; structure; controls

Located at the junction of Kamchatka and the Aleutian Arc, the Klyuchevskoy Volcanic Group is arguably the most active island arc volcanic center in the world. Frequent and violent eruptions of its member volcanoes present both an immediate hazard to trans-Pacific air traffic and may have long-term climate implications. Ash from erupting Klyuchevskoy Group volcanoes has been tracked for thousands of miles away from Kamchatka and presents a serious threat to jet engines at high altitudes. Input of large volumes of volcanic ash into the atmosphere has been shown to impact global climate, causing multiple years of depressed temperatures following large eruptions. Yet, despite representing one of the largest volcanic features on the planet, the geodynamic mechanism to drive activity of the Klyuchevskoy Group is poorly understood. When the activity, size and position of the Klyuchevskoy Group is considered in the framework of regional tectonics it becomes apparent that this volcanic cluster simply can not exist in its present form. The position of the Klyuchevskoy relative to the subducting Pacific greatly exceeds typical depths of melt generation for arc volcanoes, and it is not clear where the lavas erupting at the Klyuchevskoy Groups are generated. This projects aims to put new seismological and geochemical constraints on the upper mantle structure beneath the Klyuchevskoy Group and shed light on the mechanism driving volcanic activity at this volcanic center. It is motivated by our previous research effort which identified anomalous feature in the upper mantle beneath the Klyuchevskoy Group which we believe holds the key to understanding the mechanism driving activity of this volcanic center.We propose a detailed investigation of the anomaly we have identified within the mantle wedge beneath the Klyuchevskoy Group, coupled with an effort to relate geochemical tracers present in Klyuchevskoy Group lavas to the proposed seismic feature. The seismic study will utilize new data acquired in the framework of the ongoing NSF Partnership in Researh and Education (PIRE) effort in Kamchatka. We will use different types of teleseismic receiver function analysis to investigate the mantle wedge beneath the Klyuchevskoy Group. In parallel we will assemble a comprehensive database of geochemical information on KG lavas, using databases, published literature and emerging results from ongoing work. The ultimate goal of the project is to develop a geodynamic scenario for the Klyuchevskoy Group, informed by the seismic structure of the mantle wedge beneath it, and the geochemistry of lavas it produces.This project is supported by the Geophysics and Petrology & Geochemistry Programs.

克柳切夫火山群位于堪察加半岛和阿留申群岛弧的交界处，可以说是世界上最活跃的岛弧火山中心。其成员火山频繁而猛烈的喷发不仅对跨太平洋空中交通构成直接危害，还可能对气候产生长期影响。克柳切夫斯科伊群火山喷发产生的火山灰已被追踪到距堪察加半岛数千英里之外，对高海拔地区的喷气发动机构成了严重威胁。大量火山灰进入大气已被证明会影响全球气候，导致大规模喷发后多年的气温下降。然而，尽管代表了地球上最大的火山特征之一，但驱动克柳切夫斯科伊群火山活动的地球动力学机制却知之甚少。当在区域构造框架中考虑克柳切夫斯科伊群的活动、规模和位置时，很明显，这个火山群根本不可能以目前的形式存在。克柳切夫斯科伊火山群相对于俯冲太平洋的位置大大超过了弧火山熔体产生的典型深度，目前尚不清楚克柳切夫斯科伊火山群喷发的熔岩是在哪里产生的。该项目旨在对克柳切夫斯科伊群下方的上地幔结构施加新的地震学和地球化学约束，并揭示驱动该火山中心火山活动的机制。这是受到我们之前的研究工作的推动，该研究工作确定了克柳切夫斯科伊群下方上地幔的异常特征，我们相信这是理解该火山中心驱动活动机制的关键。我们建议对我们在克柳切夫斯科伊群中发现的异常进行详细调查。克柳切夫斯科伊群下方的地幔楔，同时努力将克柳切夫斯科伊群熔岩中存在的地球化学示踪剂与拟议的地震特征联系起来。地震研究将利用在堪察加半岛正在进行的 NSF 研究和教育合作伙伴关系 (PIRE) 工作框架内获得的新数据。我们将使用不同类型的远震接收函数分析来研究克柳切夫斯科伊群下方的地幔楔。与此同时，我们将利用数据库、已发表的文献和正在进行的工作的新结果，建立一个关于 KG 熔岩地球化学信息的综合数据库。该项目的最终目标是根据其下方地幔楔的地震结构及其产生的熔岩的地球化学来开发克柳切夫斯科伊群的地球动力学情景。该项目得到了地球物理学和岩石学与地球化学计划的支持。