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

9910456全球范围内的中石炭世生物地层学研究依赖于来自北美大陆中部、西欧、俄罗斯乌拉尔山脉南部和乌克兰顿涅茨克盆地的菊石和牙形石的有据可查的层序。 根据英国在本世纪早期建立的菊石正年代学，北美大陆中部必须被视为在密西西比-宾夕法尼亚边界处拥有一个重要的断裂，代表了近世纪以来一直被解释的缺失的同角石间隔。 在随后的北美Morrowan间隔的重大中断也是由于缺失菊石属网织红虫的指标种的代表性所必需的。如果英国和北美大陆中部之间的相关性是基于一个标准，利用索引牙形石类群的第一次出现，那么一个历时的问题，但同轴的，演替是转移到菊石的出现。接受等尖灭牙形石生物地层学还需要存在一个重要的，但未被认识到，在英国奔宁节的差距。 根据牙形石的相关性，这一空白将由北美大陆中部的下莫罗万继承填补。 对菊石和牙形石序列的明显穿时性的解析对于SCCS和IUGS在建立石炭纪精确年代地层学方面的既定目标至关重要。因此，这个问题的评价与菊石/牙形石穿时性在于整个石炭纪（密西西比/宾夕法尼亚）系统的年代地层框架的基础。 本SGER将尝试评估和解决这些关键相关性。

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.