Evaluating The Effects Of The Alamo Impact Event On Carbonate Platform Recovery And Regional Tectonics: A Research Focus For Educators In The Great Basin

评估阿拉莫撞击事件对碳酸盐台地恢复和区域构造的影响：大盆地教育工作者的研究重点

• 批准号: 1024843
• 负责人: Leif Tapanila
• 金额: $ 22万
• 依托单位: Idaho State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-10-01 至 2014-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1024843&HistoricalAwards=false
• 关键词: Evaluating; Effects; Alamo; Impact; Event

Evaluating The Effects Of The Alamo Impact Event On Carbonate Platform Recovery And Regional Tectonics: A Research Focus For Educators In The Great BasinLeif Tapanila, Idaho State University The Late Devonian (382 Ma) Alamo Impact Event was caused by a km-scale bolide impact that devastated a 200 km portion of the expansive carbonate platform in the Great Basin. Shortly following the event, faunas recolonized the surface of the Alamo impact breccia without any evidence for biotic extinctions or any long-lived geochemical change to the environment. As such, the Alamo Impact Event is comparable to moderately frequent (103-106 yr) catastrophic physical events, such as large storms, tsunamis, and other modest bolide impacts, that shape carbonate platform evolution. This project will conduct detailed field mapping of the Guilmette Formation in southern Nevada to provide the first high resolution 3D model of platform strata before, during and after the Alamo Event and allow site-specific correlation of impact features with overlying elements of recovery. Objectives of the project include (1) testing and refining the current model for marine-target impacts; (2) assessing the hypothesized Devonian activity of a major E-W structural lineament in the Great Basin; and (3) evaluating faunal recolonization and facies evolution as a function of the physical attributes of the seafloor left by the Alamo impact event. These objectives will be accomplished in a novel way by using Vulcan GIS software, originally designed for the mining industry, to compile stratigraphic thickness, paleocurrent, sedimentary and paleontological attributes from more than 100 stratigraphic sections of the Guilmette Formation exposed in outcrops of southeast Nevada. Maps produced from these data will be used to identify depositional pathways and depocenters of Alamo Breccia subunits; to calculate net rock volume displacement from impact excavation and subsequent debris-flow and tsunami deposition; and to recreate the post-impact seafloor topography and relative bathymetry in the study area. Sedimentary, faunal and ichnological data collected above the impact deposits will be compared to underlying physical parameters of the post-impact seafloor, e.g., topography, relative bathymetry, substrate type, and geographic position, to identify variations in short-term (100 yrs) and long-term (~500 kyrs) recovery of the carbonate platform ecosystem. The Alamo research will involve the training of two graduate students in field geology and GIS applications. More significantly, research activities will merge with a comprehensive educational outreach effort through the Impact Initiative on Great Basin Field Geology. Partnering with the U.S. Department of Education's GEAR UP programs in Nevada and Idaho, our Impact Initiative includes a four-pronged approach to provide STEM education and training opportunities to K-12 teachers and students, with an emphasis on involving female high school students in research.

阿拉莫撞击事件对碳酸盐岩台地恢复和区域构造影响的评估：大盆地教育工作者的研究重点--爱达荷州州立大学Leif Tapanila 晚泥盆世（382 Ma）阿拉莫撞击事件是由一个公里级的火流星撞击造成的，它摧毁了大盆地中200公里长的广阔碳酸盐台地。事件发生后不久，动物群使阿拉莫撞击角砾岩的表面离子化，没有任何证据表明生物灭绝或任何长期存在的环境地球化学变化。因此，阿拉莫撞击事件与中等频率（103-106年）的灾难性物理事件（如大风暴，海啸和其他适度的火流星撞击）相当，这些事件塑造了碳酸盐岩平台的演变。该项目将对内华达州南部的Guilmette地层进行详细的实地测绘，以提供阿拉莫事件之前、期间和之后的第一个高分辨率3D平台地层模型，并允许将撞击特征与恢复的上覆要素进行现场相关。该项目的目标包括：（1）测试和改进海洋目标撞击的现有模型;（2）评估大盆地一个主要东西向构造线的假设泥盆纪活动;（3）评价阿拉莫撞击事件所留下的海底物理属性对动物群落的影响和相的演变。这些目标将通过使用Vulcan GIS软件以一种新颖的方式实现，该软件最初是为采矿业设计的，用于从内华达州东南部露头中暴露的Guilmette组的100多个地层剖面中汇编地层厚度、古水流、沉积和古生物学属性。根据这些数据制作的地图将用于确定阿拉莫角砾岩亚单元的沉积路径和沉积中心;计算撞击挖掘和随后的碎屑流和海啸沉积产生的净岩石体积位移;并重建研究区撞击后的海底地形和相对水深。在撞击沉积物上方收集的沉积、动物和遗迹数据将与撞击后海底的基本物理参数进行比较，地形、相对水深、底质类型和地理位置，以确定碳酸盐台地生态系统短期（100年）和长期（~500 kyrs）恢复的变化。 阿拉莫研究将涉及对两名研究生进行野外地质学和地理信息系统应用方面的培训。更重要的是，研究活动将通过大盆地野外地质影响倡议与全面的教育外展工作相结合。与美国教育部在内华达州和爱达荷州的GEAR UP计划合作，我们的影响倡议包括四管齐下的方法，为K-12教师和学生提供STEM教育和培训机会，重点是让女高中生参与研究。