The Santa Rosa - Calico Volcanic Field: A Case Study of Magmatic Processes Associated with the Yellowstone Hotspot and Lithospheric Extension

本项目是内华达-俄勒冈交界地区与黄石-纽伯里热点系统晚新生代初期表现和岩石圈延伸有关的约17 ~ 13 Ma火山活动的综合野外、地质年代学、地球化学和岩石学调查。被调查的地区是圣罗莎-卡里科火山场，它位于一个主要的晚中新世大陆裂谷区的西北部，位于另外两个俄勒冈高原火山场之间，这两个火山场通常与黄石-纽伯里热点系统的出现有关。该领域和分析策略旨在提供圣罗莎-卡利科火山领域的全面视图。将采用的技术包括全球定位系统/地理信息系统辅助的实地测绘；航空照片和卫星遥感解译；喷发产物和成岩过程的岩石学、化学和同位素特征；以及通过测定Ar-Ar年龄来评估绝对爆发历史。本研究将以Santa Rosa-Calico火山场为例，对以下假设进行检验并提供新的约束：[1]伸展环境中中间岩浆的起源，[2]玄武岩岩浆作用在演化岩浆的形成和演化中的作用，[3]地壳熔融和开放体系分异过程在组成多样的岩浆套演化中的作用。岩浆前伸展和岩浆同期伸展对多喷口火山场的位置、喷发方式和成分多样性的控制作用。

Hart0106144This project is an integrated field, geochronologic, geochemical, and petrologic investigation of circa 17 to13 Ma volcanism associated with the initial late Cenozoic manifestations of the Yellowstone-Newberry hotspot system and with lithospheric extension in the Nevada - Oregon border region. The area under investigation, the Santa Rosa-Calico volcanic field, lies within the northwestern projection of a major late Miocene continental rift regime and is located between two other Oregon Plateau volcanic fields that typically are identified with the emergence of the Yellowstone-Newberry hotspot system. The field and analytical strategy is designed to provide a comprehensive view of the Santa Rosa-Calico volcanic field. Techniques to be employed include GPS/GIS assisted field mapping; air photo and satellite remote sensing interpretations; petrographic, chemical and isotopic characterization of eruptive products and petrogenetic processes; and absolute eruptive history assessment via Ar-Ar age determinations. Using the Santa Rosa-Calico volcanic field as a case study this research will test and provide new constraints on hypotheses for [1] the origin of intermediate magmas in extensional settings, [2] the role of basaltic magmatism in the formation and evolution of evolved magmas, [3] the role of crustal melting and open system differentiation processes in the evolution of compositionally diverse magmatic suites, and [4] the role that pre- and syn-magmatic extension plays in controlling the location, eruptive style(s), and compositional diversity of multi-vent volcanic fields.