RUI: Petrologic Evolution and Tectonic Setting in the Sutter Buttes Volcano, California

RUI：加利福尼亚州萨特巴特斯火山的岩石演化和构造环境

• 批准号: 9706682
• 负责人: Brian Hausback
• 金额: $ 9.5万
• 依托单位: University Enterprises, Incorporated
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-05-15 至 2002-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9706682&HistoricalAwards=false
• 关键词: RUI; Petrologic; Evolution; Tectonic; Setting

9706682 Hausback This project aims at studying the poorly known Sutter Buttes, an isolated volcano that contain the only indigenous mag matic rock exposures in the entire Central Valley of California. The volcano is composed of a central core of volcanic domes surrounded by a large fragmental apron that record a lengthy evolution of explosive volcanism in this area. The volcanic rocks of Sutter Buttes represent a diverse sub-alkalic suite ranging from rhyolite to mafic andesite that erupted in early Pleistocene time, during the profound tectonic transition from subduction to transform faulting, of the western North America plate boundary. This unique tectonic setting of the Sutter Buttes provides an unprecedent opportunity to understand magma production during this type of transition. It is proposed to establish a framework of integrated geological mapping, petrographic documentation, microprobe mineral analyses, and 40Ar/39Ar geochronologic studies of the volcanic rocks and their basement. At this stage, it is unclear if the Sutter Buttes are related to any other magmatic feature, such as the Cascades or to the young volcanic activity in the Sonoma and Clear Lakes areas. The results of this work should constrain some of the genetic features of this unique volcano and help put its magmatism into the regional tectonic framework.

9706682 Hausback 该项目旨在研究鲜为人知的萨特巴特斯（Sutter Buttes），这是一座孤立的火山，包含整个加州中央山谷唯一的本土岩浆岩暴露区。这座火山由火山圆顶的中央核心组成，周围环绕着一个巨大的碎片围裙，记录了该地区爆发性火山活动的漫长演变。萨特孤峰的火山岩代表了从流纹岩到基性安山岩的多种次碱性岩系，这些岩系在更新世早期喷发，处于北美西部板块边界从俯冲到转换断层的深刻构造转变期间。萨特孤峰这种独特的构造环境为了解这种转变期间岩浆的产生提供了前所未有的机会。建议建立火山岩及其基底的综合地质测绘、岩相记录、微探针矿物分析和 40Ar/39Ar 年代学研究框架。现阶段，尚不清楚萨特孤峰是否与任何其他岩浆特征有关，例如喀斯喀特或与索诺玛和克利尔湖地区的年轻火山活动有关。 这项工作的结果应该会限制这座独特火山的一些遗传特征，并有助于将其岩浆活动纳入区域构造框架。