Anatomy and Evolution of the Intracontinental Reno-MarysvaleMagmatic Zone in the Great Basin of Nevada and Utah

内华达州和犹他州大盆地里诺-马里斯维尔陆内岩浆带的解剖和演化

• 批准号: 8904245
• 负责人: Myron Best
• 金额: $ 7.36万
• 依托单位: Brigham Young University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-09-01 至 1993-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8904245&HistoricalAwards=false
• 关键词: Anatomy; Evolution; Intracontinental; Reno; MarysvaleMagmatic

This is the continuation of a two -year, NSF-funded project begun August, 1986 to obtain integrated space-time-composition-volume data on the Reno-Marysvale magmatic zone, a region that spans across the Great Basin of Nevada and Utah consisting of voluminous, Oligocene through early Miocene ash-flow tuffs and minor andesite to rhyolite lavas. The research involves: (a) Field study and sampling of volcanic sequences and petrographic, whole-rock XRF, and microprobe analyses of phenocrysts and glass by PI's at BYU. (b) Determination of high-precision, single- crystal 40Ar/39Ar ages and natural remanent magnetization directions of regionally-extensive ash-flow sheets by A.L. Deino at the Berkeley Geochronology Center and C.S. Gromme at the USGS, Menlo Park, CA, respectively. (c) Correlation of regional ash- flow tuff sheets and compilation of space-time-volume-composition data on tuffs and lavas by PI's at BYU. (d) Determination of Sr, Nd, and Pb isotopic data by J. Ruiz and J.L. Wooden at the Univ. of Arizona and USGS, Menlo Park, CA respectively. These data will provide a detailed picture of the evolution in time and space of a major intracontinental volcanic province and will allow conception of interpretive models dealing with: (1) Time- and space-dependent changes i composition of extruded magma and in type of eruption--pyroclastic versus lava. (2) Relative contributions of mantle-derived versus crustal components to the mass and thermal energy budget of the magma systems. (3) Contributing roles played by subducting oceanic lithosphere and changing thermal, mechanical, and density state of the crust.***//

这是一个由美国国家科学基金会资助的为期两年的项目的继续，该项目始于1986年8月，目的是获得雷诺-马里斯维尔岩浆带的综合时空成分-体积数据，该地区横跨内华达州和犹他州的大盆地，由大量的渐新世至早中新世的火山灰流凝灰岩和小安山岩到流纹岩熔岩组成。研究内容包括：(A)杨百翰岩石学、岩相学、全岩X射线荧光、斑晶和玻璃的野外研究和取样。(B)伯克利地质年代学中心的A.L.Deino和加利福尼亚州门洛帕克USGS的C.S.Gromme分别测定了区域广泛的火山灰流片的高精度单晶40Ar/39Ar年龄和自然剩余磁化方向。(C)扬子江大学区域火山灰流凝灰岩岩层对比和凝灰岩和熔岩的空间-时间-体积-成分数据汇编。(D)J·鲁伊斯和J·L·伍德在大学对锶、钕和铅同位素数据的测定。分别来自亚利桑那州和加利福尼亚州门洛帕克的USGS。这些数据将提供一个主要的陆内火山省在时间和空间上的演化的详细图景，并将使解释模型的构想能够处理：(1)喷出岩浆的组成和喷发类型--火山碎屑与熔岩--随时间和空间的变化。(2)地幔成分与地壳成分对岩浆系统质量和热能收支的相对贡献。(3)俯冲大洋岩石圈和改变地壳的热、力学和密度状态所起的贡献作用。