Paleosol Development and Trace Fossils in the Upper Triassic Cooper Canyon Formation of the Dockum Group in Andrews County, Texas

摘要

It is unknown whether a relationship exists between paleosol development and the number of burrows in a paleosol. It is also unknown whether a relationship exists between the number of burrows in a paleosol and the diameters of those burrows. This paper details the methods, results, and conclusions of an investigation of these relationships. I assess the development of several paleosols in a core sample of the Upper Triassic Cooper Canyon Formation of the Dockum Group from well B-133 in Andrews County, Texas, using development scales based on methods from Bown and Kraus (1993) and Abels et al. (2013). I assess the abundance of burrows by estimating the Droser and Bottjer (1986) ichnofabric index (II) value of the core at generally one-foot intervals. I assess the sizes of the burrows by measuring diameters of representative samples of burrows throughout the core. I analyze the results to determine if a relationship exists between paleosol development and II at a given depth and if a relationship exists between II and burrow diameter at a given depth. The results indicate a slight positive correlation between paleosol development and II. The results show a negative correlation between II and burrow diameter. In order to determine whether a relationship exists between paleosol development and the number of burrows in a paleosol, I suggest future studies that assess a larger number of paleosols which vary more from each other in development stages than those I examined. I also suggest future studies that estimate abundances of burrows separately from abundances of other bioturbation. These studies will enable more trustworthy answers to both questions posed in this investigation. This study may contribute to future studies of soil and paleosol development by illuminating the possibility that some well-developed soils have not undergone much bioturbation.