The Life History of an Arc Volcano: Insights from a Collaborative, Petrologic, Paleomagnetic and Geochronologic Study

弧火山的生命史：来自协作、岩石学、古地磁和地质年代学研究的见解

• 批准号: 9017690
• 负责人: Laurie Brown
• 金额: $ 21.83万
• 依托单位: University of Massachusetts Amherst
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-11-01 至 1995-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9017690&HistoricalAwards=false
• 关键词: Life; History; Arc; Volcano; Insights

The Quaternary Southern Volcanic Zone (SVZ) of the Chilean Andes has been investigated by teams of US scientists concerned with quantifying the mantle source components in arc parent magmas, and the degree to which these magmas have interacted with arc crust. Longitudinal variations in crustal age, thickness, and the age of the subducted plate make this an ideal target for regional studies. The primary focus of this project is an exceptionally detailed and comprehensive investigation of Tatara-San Pedro (TSP) (36o S), the youngest edifice (ca. 150ka to Holocene) of the San Pedro-Pellado volcanic complex. This study will be grounded on a wealth of regional information concerning along-strike and across strike variations in Quaternary activity. In addition to its compositional variability, TSP is exceptionally well exposed from its base: 1 km vertical (or composite) sections (up to 150 flows) are exposed in deep glacial canyons from all quadrants of the cone. These sections will be sampled on a 100% flow-by-flow basis (chemistry and paleomagnetism) in conjunction with sampling of abundant crustal xenoliths, lateral sampling of select Pleistocene lavas, and detailed surface sampling of two spectacularly heterogeneous Holocene flows. A detailed reconstruction of the eruptive history of TSP will be made by correlating among these sections through integration of paleosecular magnetic variation data, physical stratigraphy, geochemistry and petrography, and high-resolution geochronology.

一组美国科学家对智利安第斯山脉第四纪南部火山带(SVZ)进行了调查，这些科学家致力于量化弧母岩浆中的地幔来源成分，以及这些岩浆与弧壳相互作用的程度。地壳年龄、厚度和俯冲板块年龄的纵向变化使其成为区域研究的理想目标。该项目的主要焦点是对塔塔拉-圣佩德罗(TSP)(36o S)进行异常详细和全面的调查，这是圣佩德罗-佩拉多火山杂岩中最年轻的建筑物(约150ka至全新世)。这项研究将以关于第四纪活动中沿走向和跨走向变化的大量区域信息为基础。除了成分的多变性，TSP从底部暴露得特别好：1公里的垂直(或复合)部分(最多150股水流)暴露在冰川峡谷深处，从圆锥体的所有象限。这些剖面将在100%逐流(化学和古地磁)的基础上进行采样，同时对丰富的地壳包体进行采样，对选定的更新世熔岩进行横向采样，并对两个壮观的非均质全新世流体进行详细的地表采样。结合古分子磁变化资料、物理地层学、地球化学和岩石学以及高分辨率地质年代学，对TSP的喷发历史进行了详细的对比。