文章基本信息

标题：Biostratigraphy and Inoceramus survival across the Cenomanian–Turonian (Cretaceous) boundary in the Ram River section, Alberta, Canada
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作者：Ireneusz Walaszczyk ; A. Guy Plint ; William J. Kennedy 等
期刊名称：Acta geologica Polonica
印刷版ISSN：0001-5709
出版年度：2016
卷号：66
期号：4
页码：715-728
语种：English
出版社：Institute of Geology, University of Warsaw
摘要：The biostratigraphy of the uppermost Cenomanian – Lower Turonian succession in the lower part of the Blackstone Formation exposed in the Ram River (Alberta, Canada), is interpreted in terms of the standard inoceramid/ ammonite zonation of the interval. Four successive inoceramid zones are recognized, those of Inoceramus pictus, Mytiloides puebloensis, M. kossmati, and M. mytiloides, as established in the stratotype section at Pueblo, Colorado. Their correlation to Pueblo is confirmed by ammonite data.The mid-Early Turonian zone of M. kossmati yielded an assemblage of Inoceramus, with species showing close affinity to the latest Cenomanian lineages. This multi-species sample proves the survival of Inoceramus lineages into the otherwise Mytiloides-dominated Early Turonian, and indicates that their disappearance from the record of the North American Western Interior was not because of their extinction. It is suggested that the apparent lack of Inoceramus in Lower Turonian strata is due to an extremely low population abundance in the Early Turonian sea.
关键词：Cenomanian–Turonian boundary;Mytiloides;Ammonites;Inoceramus survival;Biostratigraphy;Western Interior Basin;Canada.