已收录 272993 条政策
 政策提纲
  • 暂无提纲
The volcanic geology of the Pahranagat Range and certain adjacent areas, Lincoln County, southeastern Nevada
[摘要] Extended reconnaissance over 700 square miles of the Pahranagat, Alamo and Hiko Ranges has revealed that more or less continuous emission of fissure type nuees ardentes has been punctuated by periods of fluvio-lacustrine deposition of reworked volcanic ejecta. Use of the exceptional value of ignimbrites as stratigraphic-structural datum planes, and the presence of fresh water limestones and water-laid tuffs, demonstrate that the nuees were extruded over deformed Paleozoic rocks during Oligocene-Miocene time under conditions of gentle topography and at least greater humidity than exists today. Furthermore, the volcanic rocks themselves were extensively faulted as part of the formation of the Basin and Range structures.
[发布日期]  [发布机构] Rice University
[效力级别]  [学科分类] 
[关键词]  [时效性] 
   浏览次数:2      统一登录查看全文      激活码登录查看全文