Evaluation of Possible Diachroneity in Homotaxial Mid-Carboniferous Ammoid and Conodont Successions, North American midcontinent, Western Europe, Russia

9910456 manger中石炭世的生物地层学在世界范围内的基础上依赖于来自北美中大陆、西欧、俄罗斯乌拉尔南部和乌克兰顿涅茨盆地的菊石和牙形刺的充分记录的演替。根据本世纪初建立的英国氨类正年代学，北美中大陆必须被认为在密西西比-宾夕法尼亚边界处有一个重要的断裂，代表了近一个世纪以来一直被解释的缺失的同古纪间隔。北美洲Morrowan间隔的重大断裂，也因菊属Reticuloceras的指标种的缺失而成为必然。如果英国和北美中部大陆之间的相关性是基于利用指数形牙形石分类群首次出现的标准，那么历时性但同质性的演替问题就转移到了类氨物种的出现上。接受等时牙形石生物地层学也需要在英国的奔宁地区存在一个重要的，但尚未被认识到的缺口。根据牙形石的对比，这一空缺将由来自北美中大陆的下Morrowan演替填补。对于SCCS和IUGS建立石炭纪精确年代地层的既定目标来说，确定氨类和牙形石序列的表观历时性至关重要。因此，用氨样/牙形石历时性评价这一问题是石炭系（密西西比系/宾夕法尼亚系）整个年代地层格架的基础。这次SGER将尝试评估和解决这些关键的相关性。

9910456MangerBiostratigraphy of the Middle Carboniferous on a worldwide basis has relied on the well-documented successions of ammonoids and conodonts from the North American mid-continent, Western Europe, the southern Urals, Russia and the Donets Basin, Ukrainia. Based on the British ammonoid orthochronology established in the early part of this century, the North American midcontinent must be regarded as possessing a significant break at the Mississippian-Pennsylvanian boundary representing the missing Homoceras interval as it has been interpreted for nearly a century. Significant breaks in the succeeding Morrowan interval of North America are also necessitated by the missing representation of index species of the ammonoid genus Reticuloceras. If correlations between Great Britain and the North American midcontinent are based on a standard utilizing the first appearances of index conodont taxa, then the problem of a diachronous, yet homotaxial, succession is transferred to ammonoid occurrences. Acceptance of an isochronous conodont biostratigraphy also necessitates the presence of a significant, yet unrecognized, gap in the Pennine section of Great Britain. This gap would be filled by the lower Morrowan succession from the North American midcontinent based on conodont correlations. Resolution of the apparent diachroneity of the ammonoid and conodont successions is critical to the stated goals of the SCCS and IUGS in establishing a precise chronostratigraphy for the Carboniferous. Thus, evaluation of this problem with ammonoid/conodont diachroneity lies at the foundation of the entire chronostratigraphic framework for the Carboniferous (Mississippian/Pennsylvanian) System. This SGER will attempt to evaluate and resolve these critical correlations.