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首页> 外文学位 >Systematics and paleoecology of Devonian stromatoporoids from the Cou Falls, Iowa City, and Osage Springs Members, east-central Iowa.
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Systematics and paleoecology of Devonian stromatoporoids from the Cou Falls, Iowa City, and Osage Springs Members, east-central Iowa.

机译：来自爱荷华州的古瀑布和爱荷华州中东部的欧塞奇斯普林斯的泥盆纪叠层孔隙的系统学和古生态学。

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摘要

The ultimate goal of this research is to study the systematics and biodiversity of stromatoporoid species exquisitely preserved in Givetian exposures throughout east-central Iowa. The goal of this study is not only to identify these stromatoporoids using qualitative descriptions, but also to utilize a set of simple quantitative morphometric methods to delineate morphological differences among these stromatoporoid species. In this present study, over 100 specimens of stromatoporoids were collected from exposures of the Cou Falls and Iowa City Members of the Coralville Formation and the Osage Springs Member of the Lithograph City Formation. All specimens were thin sectioned and ten species were identified using both qualitative characteristics and a new set of morphometric methods. A discriminant analysis was performed to differentiate among taxa using the 72 best preserved specimens. Statistically significant differences in several micromorphological characters measured on the longitudinal thin sections clearly separate these species. Formal systematic descriptions were prepared based on the results. Chi-square analyses were used to determine a relationship between stromatoporoid growth form and lithology, providing clues to the depositional environments of sampled horizons of these Members. The species composition of this sample set was also examined in conjunction with other samples sets to determine faunal changes before, during, and after the Taghanic Onlap. R and Q mode hierarchical cluster analyses clearly show that distinctly different faunas thrived on either side of the Transcontinental Arch (TCA), in both the Eastern American and Old World Realm. This provincialism abruptly ended during the Taghanic Onlap when the Transcontinental Arch was breached by a shallow sea. New stromatoporoid faunas, possibly more tolerant of these environmental variations thrived during this period. Although distinctly different stromatoporoid faunas were present on either side of the TCA before the Onlap, cosmopolitan faunas which became established in the early Frasnian thrived throughout the set of transgressive-regressive pulses of the Onlap. The results of these analyses are vital to future understanding of the faunal changes that occurred directly before the Frasnian-Fammenian extinction event.
机译：这项研究的最终目标是研究在爱荷华州中东部地区吉维田暴晒中保存完好的层间孢子物种的系统和生物多样性。这项研究的目的不仅是使用定性描述来鉴定这些基质孔，而且要利用一套简单的定量形态学方法来描述这些基质孔之间的形态差异。在本研究中，从Coral Falls和爱荷华州Coralville组成员以及石印版城市组的Osage Springs成员的暴露中收集了100多个基质多孔样品。所有标本均被切成薄片，并使用定性特征和一套新的形态计量学方法鉴定出十种。使用72个保存最完好的标本进行判别分析以区分类别。在纵向薄片上测得的几个微观形态特征的统计学显着差异清楚地将这些物种分开。根据结果​​准备了正式的系统描述。卡方分析用于确定基质多孔生长形式和岩性之间的关系，为这些成员的采样层的沉积环境提供线索。还与其他样品组一起检查了该样品组的物种组成，以确定在塔汉尼克重叠之前，之中和之后的动物区系变化。 R和Q模式的层次聚类分析清楚地表明，在美洲大陆和旧大陆领域，横贯大陆弓（TCA）两侧都生长着截然不同的动物。当横贯大陆的拱门被浅海破坏时，这种自治主义在塔加尼式的上翻过程中突然结束。在此期间，新的层间孔动物群可能对这些环境变化更加宽容。尽管在Onlap之前，TCA的两侧都存在明显不同的层间孔动物群，但在Frasnian早期建立的世界性动物群却在整个Onlap的海侵-回归脉动中蓬勃发展。这些分析的结果对于将来了解弗拉斯尼亚-法门尼灭绝事件之前发生的动物群变化至关重要。

著录项

  • 作者

    Jannusch, Danielle Elizabeth.;

  • 作者单位

    The University of Iowa.;

  • 授予单位 The University of Iowa.;
  • 学科 Paleontology.
  • 学位 Ph.D.
  • 年度 2008
  • 页码 265 p.
  • 总页数 265
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 古生物学;
  • 关键词

  • 入库时间 2022-08-17 11:39:11

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