RUI: Upper Devonian Black Shales in Eastern North America, Conodont Biostratigraphy, Frasnian-Famennian Mass Extinction Horizon, and Absolute Dates from Associated Ash Layers

RUI：北美东部上泥盆统黑色页岩、牙形刺生物地层学、法拉斯尼阶-法门阶大灭绝地平线以及相关灰层的绝对日期

• 批准号: 9614314
• 负责人: D. Jeffrey Over
• 金额: $ 7.8万
• 依托单位: SUNY College at Geneseo
• 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: 1997-02-15 至 2002-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9614314&HistoricalAwards=false
• 关键词: RUI; Upper; Devonian; Black; Shales

9614314 Over The Upper Devonian black shales in eastern North America are important for hydrocarbon resources, understanding of global climate change, and the occurrence of a global mass extinction event, have never been systematically collected to determine the complete conodont biozoneation. this is simply because workers have had difficulties recovering conodonts from the black shales and have instead focused on green shale and carbonate interbeds. The result is undescribed taxa, incomplete zonations, and tenuous correlations of black shales in the Appalachian, Illinois, and Michigan basins. High resolution biostratigraphy and recognition of global event horizons is possible by careful sampling of black shale horizons. Biozones, cryptic disconformities, the Frasnian-Famennian boundary, and the Devonian-Carboniferous boundary have been recognized in the Woodford Shale of Oklahoma - entirely within black shale. Similar sampling and processing techniques in the northern Appalachian Basin have recovered new taxa, as well as isolated the Frasnian-Famennian boundary in the Hanover Shale of New York and the Upper Olentangy Shale of Ohio. Conodonts have been described from the Middlesex and Pipe Creek shales, two petroliferous black shales that had previously been unzoned. The purpose of this project is to expand upon previous studies and preliminary sample materials that are currently under investigation to systematically collect black shale sequences in the three eastern North American basins, describe conodont faunas, and utilize revised taxonomy and correlation techniques to prepare complete zonal schemes for the Antrim Shale (Michigan Basin), Chattanooga Shale (southern Appalachian Basin), and New Albany Shale (Illinois Basin). This study will differ from previous works by collecting the black shale horizons. This will enable recognition of minor disconformities, ash horizons, and determine the ranges of biozones. Within this biostratigraphic framework small scale depositional cyc les will be correlatable between basins and absolute dates of known ash beds (e.g., Center Hill, Belpre), as well as ash beds found during recent sampling, will be tied together. The result will be a clearer understanding of biozone and depositional cycle intervals, and an indication of depositional rates for the different members of the eastern shale formations on relative and absolute time scales. This will also allow precise correlation of discrete members and beds within the black shale facies. Undergraduate research participation is a primary focus within the project. Students will collect, process, and analyze strata for microfossils and characterize ash horizons utilizing petrographic techniques, the scanning electron microscope, and energy dispersive x-ray analysis for elemental determination.

9614314北美东部上泥盆统黑色页岩对油气资源、对全球气候变化的认识和全球大灭绝事件的发生具有重要意义，但从未被系统地收集以确定完整的牙形石生物分带。这很简单，因为工人们很难从黑色页岩中恢复牙形刺，而是专注于绿色页岩和碳酸盐互层。结果是未描述的类群，不完整的分区，以及在阿巴拉契亚，伊利诺伊和密歇根盆地的黑色页岩的脆弱的相关性。通过对黑色页岩层位的仔细采样，可以实现高分辨率生物地层学和全球事件层位的识别。生物带、隐不整合面、弗拉斯纪-法门纪边界和泥盆纪-石炭纪边界已在俄克拉荷马的伍德福德页岩中被识别出来——完全在黑色页岩中。在阿巴拉契亚盆地北部，类似的采样和处理技术已经恢复了新的分类群，并在纽约的汉诺威页岩和俄亥俄州的上奥尔坦基页岩中分离出了弗拉斯-法门尼纪边界。在Middlesex和Pipe Creek页岩中发现了牙形刺，这两种富含石油的黑色页岩以前未被划分。该项目的目的是在之前的研究和目前正在调查的初步样品材料的基础上，系统地收集北美东部三个盆地的黑色页岩序列，描述牙形石动物群，并利用修订的分类和对比技术，为安特里姆页岩（密歇根盆地）、查塔努加页岩（南阿巴拉契亚盆地）和新奥尔巴尼页岩（伊利诺斯盆地）准备完整的分区方案。这项研究与以往的研究不同，它收集了黑色页岩的层位。这将有助于识别较小的不整合面、灰层和确定生物带的范围。在这个生物地层学框架内，小规模的沉积旋回将在盆地和已知灰层（例如，中央山，贝尔普雷）的绝对日期之间相互关联，以及在最近采样中发现的灰层将被联系在一起。结果将更清楚地了解生物带和沉积旋回间隔，并在相对和绝对时间尺度上指示东部页岩组不同成员的沉积速率。这也将允许在黑色页岩相的离散成员和层之间进行精确的对比。本科生的研究参与是该项目的主要焦点。学生将收集、处理和分析地层的微化石，并利用岩石学技术、扫描电子显微镜和能量色散x射线分析进行元素测定来表征火山灰层。