Mass and Heat Flux From Miocene to Present at Aucanqvilcha Volcano, Andes of Northern Chile

智利北部安第斯山脉 Aucanqvilcha 火山中新世至今的质量和热通量

• 批准号: 9814941
• 负责人: Anita Grunder
• 金额: $ 20万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-04-01 至 2004-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9814941&HistoricalAwards=false
• 关键词: Mass; Heat; Flux; Miocene; Present

9814941GrunderThe links between subduction-zone tectonic activity and volcanism remain fundamental problems in geology. The object of this study is a volume and time-constrained analysis of a large and long-lived volcano in the Central Andes with a view toward evaluating the mass and heat flux in this classic continental subduction zone setting.Aucanquilcha volcano and the surrounding cluster of volcanoes span at least 9.4 million years of volcanic history and constitute an erupted volume of about 170 km3. The preserved record of volcanic edifices from Miocene to present is unparalleled due to a prolonged arid climate. Compositionally and isotopically the Aucanquilcha cluster conforms with regional trends and so is typical of this remarkable continental arc. The approach to this study is: (1) to document changes in volume and composition in time through extensive mapping and radiometric dating; (2) to identify the petrologic processes and crustal reservoirs at each stage and to obtain a mass balance through time; and (3) to calculate the heat budget dictated by the mass flux and evaluate temporal variations in crustal thickening and mafic magma input into the crust. The emphasis is to place all processes in a temporal context through geologic and geochronologic data. It is precisely because volcanism provides sequential sampling of magmatic processes that the planned approach yields significant promise of addressing fundamental unresolved issues pertaining to magmatism in continental arc settings.

俯冲带构造活动和火山活动之间的联系仍然是地质学中的基本问题。本研究的目的是对安第斯山脉中部的一座大型长寿火山进行体积和时间限制分析，以期评估这一典型大陆俯冲带背景下的质量和热通量，Aucanquilcha火山和周围的火山群至少有940万年的火山历史，喷发体积约为170立方公里。由于长期干旱气候，从中新世至今保存的火山建筑记录是无与伦比的。Aucanquilcha星团的成分和同位素符合区域趋势，因此是这一引人注目的大陆弧的典型代表。这项研究的方法是：（1）通过广泛的绘图和放射性测年，记录体积和成分随时间的变化;（2）确定每个阶段的岩石学过程和地壳储集层，并获得随时间的质量平衡;（3）计算由质量通量决定的热量收支，并评估地壳增厚和镁铁质岩浆输入地壳的时间变化。重点是通过地质和地质年代学数据将所有过程置于时间背景中。正是因为火山活动提供了岩浆过程的连续采样，计划中的方法产生了解决有关大陆弧环境中岩浆活动的根本未决问题的重大希望。