Ichnology of Late Cretaceous Turbidites from the Rosario Formation, Baja California, Mexico
Ichnology of Late Cretaceous Turbidites from the Rosario Formation, Baja California, Mexico
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DOI：
10.1080/10420940.2012.734763
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发表时间：
2013-02
期刊：
影响因子：
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通讯作者：
R. Callow;D. McIlroy;B. Kneller;M. Dykstra
中科院分区：
文献类型：
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作者：
R. Callow;D. McIlroy;B. Kneller;M. Dykstra
晚白垩世墨西哥罗萨里奥组中的峡谷圣费尔南多水道-堤坝系统包含了第一次完整记录的多种遗迹化石组合。本研究的目的是描述的痕迹化石，并记录其古环境范围横跨浊积岩通道堤坝系统，从粗粒通道轴内的通道带的最远部分的外部堤坝。遗迹化石的分布受浊积岩体系内的古环境和物理化学条件的强烈控制。大型深层沉积物摄食大型底栖动物在水道轴线及其附近最为丰富（即，在更远的阶地和外部堤坝环境中，形成Ophiomorpha rudis和Scolicia的生物以及较小的沉积物喂养和园艺生物更为丰富。浅层遗迹分类群的分布（例如，graphoglyptids）仅限于堤坝和阶地/漫滩设置。目前还不清楚这是否代表了痕迹生物的真实生态范围，或者是它们保存所需的适当埋藏条件的限制。这种类型的进一步研究将有助于进一步阐明生物，物理和化学控制的痕迹化石组合在整个中生代的各种浊积岩沉积体系。深海碎屑沉积物的遗迹学和古环境综合分析在地下油气藏的分析和表征中具有重要的潜在作用。
The Late Cretaceous Canyon San Fernando channel-levee system in the Rosario Formation of Mexico contains a diverse assemblage of trace fossils that is fully documented for the first time. The aim of this study is to describe the trace fossils present and document their palaeoenvironmental range across a turbidite-channel-levee system, from the coarse-grained channel axes within the channel belt to the most distal parts of the external levee. Trace fossil distributions are strongly controlled by palaeoenvironments and physical and chemical conditions within the turbidite system. Large, deep-tier deposit-feeding macrofauna are most abundant in and close to the channel axes (i.e., organisms forming Ophiomorpha rudis and Scolicia), and smaller, deposit-feeding and gardening organisms are more abundant in more distal terrace and external levee environments. The distribution of shallow-tier ichnotaxa (e.g., graphoglyptids) is restricted to levee and terrace/overbank settings. It is not known whether this represents the true ecological range of the trace-making organisms, or the limit of the suitable taphonomic conditions required for their preservation. Further studies of this kind will help shed further light on the biological, physical, and chemical controls on trace fossil assemblages across a variety of turbidite depositional systems throughout the Phanerozoic. Integrated ichnological and palaeoenvironmental analysis of deep marine clastic sediments has an important potential role to play in the analysis and characterization of hydrocarbon reservoirs in the subsurface.