Correlation, Dating, and Geologic Significance of Late Teriary Tephra-Rich Strata in the Basin and Range Province

盆岭省晚第三纪富含火山灰地层的对比、测年及地质意义

• 批准号: 9204700
• 负责人: Francis Brown
• 金额: $ 11万
• 依托单位: University of Utah
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-01-15 至 1995-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9204700&HistoricalAwards=false
• 关键词: Correlation; Dating; Geologic; Significance; Late

Late Tertiary, tephra-rich sedimentary strata widespread in the Basin and Range Province of the Western United States are markedly more abundant than older. Tertiary sedimentary strata, and have accumulated in fault- bounded extensional basins formed province-wide. As a step towards better understanding the nature and regional significance of these tephra-rich strata and their associated basin, better control is needed on their age and geographical distribution. Towards this end PIs will establish the sequence of silicic tephra layers in these sparsely fossiliferous Late Tertiary strata in the northern Basin and Range, and will date selected samples. The tephra will be characterized using trace/minor element chemistry of the glass phase, and size, and shape analysis of the glass particles. For dating the layers PIs will use the 40Ar/39Ar laser fusion technique on sanidine and biotite, common phenocrysts in the tephra. The results will also add to the understanding of time, frequency, and magnitude of silicic volcanism in the Late Tertiary of the region, and the tephrochronology will provide a fundamental reference framework for future structural, stratigraphic, and paleontologic studies of these strata.

晚第三纪，富含火山灰的沉积地层 在西部的盆地和山脉省广泛分布 美国人明显比老年人更丰富。 第三纪沉积地层，并在断层中堆积- 有界伸展盆地形成全省范围。 的方向迈出了一步 为了更好地了解自然和区域 这些富火山灰层及其 相关盆地，需要更好地控制其年龄， 地理分布。 为此，PI将 建立其中的硅质火山灰层序列 北方稀疏的晚第三纪地层 盆地和山脉，并将日期选定的样品。 火山灰 将使用痕量/微量元素化学进行表征， 玻璃的相态、尺寸和形状分析 粒子 为了测定地层的年代，PI将使用40Ar/39Ar 透长石和黑云母的激光熔融技术 火山灰中的斑晶 结果也将增加 了解地震的时间、频率和震级 该地区晚第三纪的火山活动， 火山灰年代学将提供一个基本的参考 未来构造、地层和 对这些地层的古生物学研究。