Biostratigraphy, Taxonomy, and Paleogeography of Conodont Sequences in the Middle and Late Devonian (Frasnian) Tropics

黑山的弗拉斯期牙形刺序列 阿尔伯塔的生物地层学非常发达 动物群代表的连续性和良好保存 Palmatolepis生物相。 通过图形对比， 由这两个地区合成的层序将成为 该生物相的参照标准， 整个推断的外陆架到盆地层序 泥盆纪热带。 有很大的矛盾， 已发表的Palmatolepis物种鉴定， Ancyrognathus导致错误理解的范围 这两个主要群体， zonation是基础。 此外，很少有人研究 内陆棚Polygnathus生物相特征 Frasnian序列 我的研究基于多元分类学 平台元素的形状分析已经大幅修改 掌鳞鱼属和钩颌鱼属的种类鉴别， 因此它们的地层范围。 结果是一个接近 Palmatolepis生物相内的区域数量增加了一倍， 但它们的分辨率远远超过了 图形相关 Palmatolepis与 Polygnathus生物相仍然很困难，但可能是 可以通过图形方法来解决。 拟议的研究将 严格检验这些新的生物地层学和分类学成果 分布在泥盆纪热带地区 与发展一个额外的长期目的 弗拉斯期牙形石古地理的综合分析

Frasnian conodont sequences in the Montagne Noire and Alberta are superbly developed in their biostratigraphic continuity and excellent preservation of faunas representative of the Palmatolepis biofacies. Through graphic correlation, the sequence composited from these two areas will become a standard of reference for this biofacies, characteristic of outer shelf to basinal sequences throughout the inferred Devonian tropics. There has been great inconsistency in published identifications of species of Palmatolepis and Ancyrognathus resulting in erroneous understanding of ranges of the two principal groups on which the Frasnian "standard" zonation is based. Furthermore, there has been little study of the Polygnathus biofacies, characteristic of inner shelf Frasnian sequences. My research based on multielement taxonomy and shape analysis of platform elements has drastically revised discrimination of species of Palmatolepis and Ancyrognathus and consequently their stratigraphic ranges. The result is a near doubling in number of zones within the Palmatolepis biofacies, but their resolution is far exceeded by that obtainable through graphic correlation. Correlation between the Palmatolepis and Polygnathus biofacies remains difficult, but is probably resolvable through graphic methods. Proposed research will rigorously test these new biostratigraphic and taxonomic results in widely scattered localities throughout the Devonian tropics, with the additional long-range purpose of developing a comprehensive analysis of Frasnian conodont paleogeography.