RUI: Volcanic, Petrologic, and Geochemical Evolution of Darwin Volcano, Galapagos

RUI：加拉帕戈斯达尔文火山的火山、岩石学和地球化学演化

• 批准号: 0207962
• 负责人: Terry Naumann
• 金额: $ 11.5万
• 依托单位: University of Alaska Anchorage Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-12-01 至 2006-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0207962&HistoricalAwards=false
• 关键词: RUI; Volcanic; Petrologic; Geochemical; Evolution

NaumannEAR-0207962The western Galapagos archipelago is one of the most active volcanic areas on Earth. This volcanologic, petrologic, and geochemical study of Darwin volcano is designed to test competing hypotheses for the growth of Galapagos-type shield volcanoes and their geochemical variations. The origin of their distinct "overturned soup plate" morphology is not merely a provincial issue: Galapagos-type shields may be characteristic of many seamounts and extraterrestrial volcanoes. Little is known of Darwin volcano, but several reconnaissance specimens from the lowermost flanks indicate that it is mostly made up of basalts with isotopic compositions are between those of lavas erupted from mid-oceanic ridges and those erupted from hotspots. Despite their isotopic character, the same lavas are rich in incompatible elements, more typical of ocean-island basalts. Darwin volcano was chosen for this study because although it remains virtually unstudied, it is situated between the two well-studied volcanoes of Alcedo and Wolf on Isabela Island. Alcedo and Wolf volcanoes represent two end members in the western Galapagos with respect to geochemical variation, elevation, shape, and caldera depth, and the study of Darwin volcano will allow for testing and refinement of models that predict the origin of these diverse geochemical systems and volcano morphologies.The goals of this project seek insights into the fundamental processes of ocean-island magmatism. These include: 1) documentation of the eruptive processes and the chronology, distribution and volume of eruptions that have constructed Darwin volcano; 2) determination of the petrologic and geochemical variation of Darwin's lavas in order to document the processes involved with the generation, storage, and eruption of magmas; and 3) a comparison of Darwin volcano with other well-studied western Galapagos volcanoes in order test the hypothesis that the magma supply rate to each volcano is the dominant control not only of the geochemical variation of lavas but also each volcanoes unique size, shape and caldera morphology.

加拉帕戈斯群岛西部是地球上最活跃的火山区之一。这项对达尔文火山的火山学、岩石学和地球化学研究旨在检验加拉帕戈斯型盾状火山生长及其地球化学变化的相互竞争的假设。它们独特的“翻转汤盘”形态的起源不仅仅是一个局部问题：加拉帕戈斯型地盾可能是许多海山和地外火山的特征。人们对达尔文火山知之甚少，但从火山最低侧翼采集的几个勘测标本表明，它主要由玄武岩组成，其同位素组成介于大洋中脊喷发的熔岩和热点喷发的熔岩之间。尽管它们的同位素特征，相同的熔岩富含不相容元素，更典型的洋岛玄武岩。选择达尔文火山进行这项研究是因为尽管它实际上还没有被研究过，但它位于伊萨贝拉岛上两座研究得很好的火山阿尔塞多和沃尔夫之间。阿尔塞多火山和沃尔夫火山代表了加拉帕戈斯群岛西部的两个终端成员，在地球化学变化，海拔，形状和火山口深度方面，达尔文火山的研究将允许测试和改进模型，预测这些不同的地球化学系统和火山形态的起源。其中包括：（1）记录构造达尔文火山的喷发过程和喷发的年代、分布和体积;（2）确定达尔文火山熔岩的岩石学和地球化学变化，以记录岩浆的生成、储存和喷发过程; 3）达尔文火山与其它火山井的对比我研究了西部的加拉帕戈斯火山，以检验这样一个假设，即岩浆对每座火山的供应速率不仅是熔岩地球化学变化的主要控制因素，而且每座火山都有独特的大小、形状和破火山口形态。