StratigrapheR: Concepts for Litholog Generation in R

The StratigrapheR package proposes new concepts for the generation of lithological logs, or lithologs, in R. The generation of lithologs in a scripting environment opens new opportunities for the processing and analysis of stratified geological data. Among the new concepts presented: new plotting and data processing methodologies, new general R functions, and computer-oriented data conventions are provided. The package structure allows for these new concepts to be further improved, which can be done independently by any R user. The current limitations of the package are highlighted, along with the limitations in R for geological data processing, to help identify the best paths for improvements. Introduction StratigrapheR is a package implemented in the open-source programming environment R. StratigrapheR endeavors to explore new concepts to process stratified geological data. These concepts are provided to answer a major difficulty posed by such data; namely a large amount of field observations of varied nature, sometimes localized and small-scale, can carry information on large-scale processes. Visualizing the relevant observations all at once is therefore difficult. The usual answer to this problem in successions of stratified rocks is to report observations in a schematic form: the lithological log, or litholog (e.g., Fig. 1). The litholog is an essential tool in sedimentology and stratigraphy and proves to be equally invaluable in other fields such as volcanology, igneous petrology, or paleontology. Ideally, any data contained in a litholog should be available in a reproducible form. Therefore, the challenge at hand is what we would call "from art to useful data"; how can we best extract and/or process the information contained in a litholog, designed to be as visually informative as possible (see again Fig. 1). 28 29 30 31 32 33 34 44 45a 45b 45c 46 47 48 49 51 35 52a 52b 60a 60b 60c 61 HIATUS lamellar stromatoporoids branching stromatoporoids lamellar tabulate corals branching tabulate corals brachiopods crinoids receptaculitids small fenestrae large fenestrae