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

Hart 0106144本项目是一项综合性野外、地质年代学、地球化学和岩石学研究，对约17 - 13 Ma的火山活动进行研究，这些火山活动与黄石-纽伯里热点系统的晚新生代初期表现以及内华达州-俄勒冈州边界地区的岩石圈伸展有关。被调查的地区，圣罗莎-卡利科火山场，位于一个主要的晚中新世大陆裂谷制度的西北投影，并位于其他两个俄勒冈州高原火山场，通常被确定与黄石-纽贝里热点系统的出现。现场和分析战略旨在提供Santa Rosa-Calico火山区的全面视图。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释;喷发产物和成岩过程的岩相学、化学和同位素特征;以及通过Ar-Ar年龄测定进行的绝对喷发历史评估。本研究以圣罗莎-卡利科火山区为例，对以下假说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]地壳熔融和开放系统分异过程在成分多样的岩浆岩套演化中的作用，[4]岩浆期前和同期伸展作用对多喷口火山岩场的位置、喷发样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.