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首页> 外文学位 >Revision of the Upper Devonian in the central-southern Appalachian basin: Biostratigraphy and lithostratigraphy.
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Revision of the Upper Devonian in the central-southern Appalachian basin: Biostratigraphy and lithostratigraphy.

机译：阿巴拉契亚中南部盆地上泥盆统的修订：生物地层学和岩石地层学。

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摘要

The Upper Devonian of the central-southern Appalachians Valley and Ridge province of Virginia lacks stratigraphic resolution, revised formal nomenclature, and detailed biostratigraphic data. Eight of the most complete sections available in a three thousand square mile area were used to build a framework for revising the stratigraphy of the Upper Devonian strata in southwestern Virginia. Detailed lithologic descriptions of about four thousand feet (1.3 km) of rock were made at each outcrop. John Dennison's (1970 and 1976) nomenclature for the Upper Devonian along the Alleghany Front was successfully tested for it usefulness in Southwestern Virginia and are hereby applied to these rocks. The stratigraphic interval ranges in age from the Middle Devonian to the Lower Carboniferous. The stratigraphic units include the Middle Devonian Millboro Shale, the Upper Devonian Brallier, Scherr, Foreknobs (formally the “Chemung”), Hampshire, and the Lower Carboniferous Price Formation. The Brallier contains two members (Back Creek Siltstone and Minnehaha Springs), the Foreknobs is divided into five members (Mallow, Briery Gap, Blizzard, Pound, and Red Lick), and the lower Price is divided into three members (the Cloyd Conglomerate, Sunbury Shale, and the Ceres). 23046 fossils were collected and 160 taxa were identified. The biostratigraphic range of each taxon was compiled, analyzed, and then divided into biostratigraphic zones. 19 local biozones are described. The Frasnian/Famennian boundary is accurately placed based on occurrences of internationally known index fossils. The Frasnian/Famennian extinction event is recognized and is determined to have two pulses. The local biostratigraphic zonations doubled the resolution of previous studies. Lithostratigraphic and biostratigraphic data were combined to look at the timing and rates of events. The lithostratigrapic divisions were tested to see if their boundaries are or are not time transgressive. The Brallier/Foreknobs, Blizzard/Pound, and Pound/Redlick boundaries are crossed by biozones. Conversely the Frasnian/Famennian boundary crosses the lithologic boundary between the Pound and Red Lick Members. This documents the prograding nature of the clastic wedge. Composite biostratigraphic ranges correlate with ranges in New York and western Maryland. This detailed lithostraigraphic and biostratigraphic study documents a comprehensive and higher resolution understanding of the Upper Devonian in the Central-Southern Appalachian Basin.
机译：中南部的阿巴拉契亚河谷和弗吉尼亚的里奇省的上泥盆统缺乏地层解析度，经过修订的正式术语和详细的生物地层数据。在三千平方英里的区域中，有八个最完整的断面被用来建立一个框架，以修正弗吉尼亚西南部上泥盆统地层的地层学。每个露头都对约四千英尺（1.3公里）的岩石进行了详细的岩性描述。约翰·丹尼森（John Dennison）（1970和1976）沿Alleghany Front上泥盆纪的命名法已在弗吉尼亚州西南部成功进行了测试，并据此应用于这些岩石。地层间隔的年龄范围从中泥盆纪到下石炭统。地层单元包括泥盆纪中部Millboro页岩，泥盆纪上层Brallier，Scherr，前肢（前身为“ Chemung”），汉普郡和石炭纪下层价格。 Brallier包含两个成员（Back Creek Siltstone和Minnehaha Springs），Foreknobs分为五个成员（Mallow，Briery Gap，Blizzard，Pound和Red Lick），较低的Price分为三个成员（Cloyd Conglomerate， Sunbury页岩和谷神星）。收集了23046个化石，并鉴定了160个分类单元。汇编，分析每个分类单元的生物地层范围，然后划分为生物地层区带。描述了19个本地生物区。根据国际上已知的索引化石的出现，准确地确定弗拉斯尼亚/法门边界。识别了弗拉斯尼亚/法门尼灭绝事件，并确定它具有两个脉冲。当地的生物地层带使先前研究的分辨率翻了一番。结合岩性地层学和生物地层学数据来研究事件发生的时间和发生率。测试了lithostratigrapic部门，以了解其界限是否违反时间。 Brallier / Foreknobs，Blizzard / Pound和Pound / Redlick边界被生物区划过。相反，弗拉斯尼亚/法门尼边界越过磅和红利克成员之间的岩性边界。这证明了碎屑楔的渐进性。复合生物地层范围与纽约和马里兰州西部的范围相关。这项详细的岩相地层学和生物地层学研究记录了对中南部阿巴拉契亚盆地上泥盆统的全面和高分辨率的了解。

著录项

  • 作者

    Brame, Roderic Ian.;

  • 作者单位

    Virginia Polytechnic Institute and State University.;

  • 授予单位 Virginia Polytechnic Institute and State University.;
  • 学科 Paleontology.; Geology.
  • 学位 Ph.D.
  • 年度 2002
  • 页码 320 p.
  • 总页数 320
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 古生物学;地质学;
  • 关键词

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