Conodont chronostratigraphical resolution and Declinognathodus evolution close to the Mid‐Carboniferous Boundary in the Barcaliente Formation type section, NW Spain
Conodont chronostratigraphical resolution and Declinognathodus evolution close to the Mid‐Carboniferous Boundary in the Barcaliente Formation type section, NW Spain
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DOI：
10.1111/let.12021
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发表时间：
2013-10
期刊：
影响因子：
1.5
通讯作者：
J. Sanz-López;S. Blanco-Ferrera;L. S. D. Posada
中科院分区：
文献类型：
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作者：
J. Sanz-López;S. Blanco-Ferrera;L. S. D. Posada
巴卡连特组在其类型剖面中，在中-石炭世界区间(密西西比和宾夕法尼亚亚期之间)提供了重要的牙形刺产状。从最上层的瑟普霍夫到下层的巴什基里期，识别出一系列Declinognathodus的形态类型(这里被认为是种)。这些地貌类型属于Declinognathodus node uliferus(Ellison&Graves)Sensu Lato，这是中石炭世界线全球对比的主要标志。其中，Inaequalis(Higgins)似乎是第一个出现在箭谷GSSP中-石炭统界线层的物种。贝尼斯氏菌之间的一个形态跃层(Sanz-Lopez等人)和Inaequalis在此进行了研究，以确定与GSSP相关的床层。其他诊断首次出现的牙形刺(Rchistogna tus minutus(Higgins&Boukert)，D.nuuliferus，D.lateris(Higgins&Boukert)，Idiognathoides asiaticus Nigmadganov&Nhemrovskaya和I.corrugatus(Harris&Hollingsworth))在它们的全球分布中被评估为时间标记，特别是欧亚动物群。可用的二级标记提供了更好的分辨率，并支持在GSSP以外的区段中进行时间相关。所研究的类群在世界范围内的首次和较晚出现被认为是在中石炭世灭绝事件和牙形刺倾覆的背景下，危机的祖先Declinognathodus产生了Idiognathodontidae家族的成员。首先，祖先分类群是很好的生物地层学工具，而在年龄上被认为是密西西比的属的局部灭绝和危机后后期出现的新分类群表明，早期的巴什基尔古地理和气候条件暂时限制了牙形刺的生物地理分布。
The Barcaliente Formation in its type section provides significant conodont occurrences in the Mid-Carboniferous Boundary interval (between the Mississippian and Pennsylvanian sub-periods). A sequence of Declinognathodus morphotype appearances (considered here as species) is recognized from the uppermost Serpukhovian to the lower Bashkirian. These morphotypes belong to Declinognathodus noduliferus (Ellison & Graves) sensu lato, the primary marker for the worldwide correlation of the Mid-Carboniferous Boundary. Among them, D. inaequalis (Higgins) appears to have been the first species to occur at the Mid-Carboniferous Boundary bed in the Arrow Canyon GSSP. A morphocline between D. bernesgae (Sanz-Lopez et al.) and D. inaequalis is studied here to identify the bed correlated with the GSSP. Other diagnostic first occurrences of conodonts (Rachistognathus minutus (Higgins & Bouckaert), D. noduliferus, D. lateralis (Higgins & Bouckaert), Idiognathoides asiaticus Nigmadganov & Nemirovskaya and I. corrugatus (Harris & Hollingsworth)) are evaluated as chrono-markers throughout their worldwide distribution, particularly for the Eurasian faunas. The available secondary markers provide a better resolution and support chrono-correlation in sections other than that at the GSSP. The worldwide first and late occurrences of studied taxa are considered within the background of the Mid-Carboniferous Extinction Event and the conodont overturn, where crises progenitor Declinognathodus gave rise to members of the Family Idiognathodontidae. Firstly, progenitor taxa are good biostratigraphic tools, whereas local extinction of genera considered Mississippian in age and new taxa arising later in the post-crises radiation suggest an early Bashkirian palaeogeography and climatic conditions confining temporarily the biogeographic distribution of conodonts.