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

HART0106144这个项目是一项综合的野外、地质年代学、地球化学和岩石学研究，大约在17-13 Ma，与黄石-纽伯里热点系统的晚新生代初始表现和内华达-俄勒冈边界地区的岩石圈伸展有关。所研究的地区是圣罗莎-卡利科火山田，位于晚中新世大陆裂谷体制的西北投影内，位于另外两个通常被认为是黄石-纽伯里热点系统出现的俄勒冈高原火山田之间。实地和分析战略旨在提供对圣罗萨-卡利科火山田的全面看法。将采用的技术包括全球定位系统/地理信息系统协助的实地测绘；航空照片和卫星遥感解译；喷发产物和岩石形成过程的岩石学、化学和同位素特征；以及通过Ar-Ar年龄测定进行绝对喷发历史评估。以圣罗莎-加里科火山岩为例，这项研究将检验并对下列假设提出新的约束：[1]伸展环境中的中间岩浆起源，[2]玄武岩岩浆作用在演化岩浆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化的岩浆岩套演化中的作用，以及[4]前和同岩浆伸展作用在控制多喷口火山岩田的位置、喷发方式(S)和成分多样性方面所起的作用。

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.