ROCKR! A PETROGRAPHIC PLOTTING TOOL

RockR!, a browser application created with the programming language R, is designed to take data inputs and create publication-quality geoscience discrimination and classification plots, making it a valuable tool for both classroom and professional settings. The app is separated into four sections: general information, ternary plots, general bivariate plots, and metamorphic pressure-temperature bivariate plots. The general information tab describes the application’s purpose and details how to input data and download the created plots. The three plotting sections have plot-specific background information and instructions, a place to load in Excel data files, and the plot output. RockR! allows for customization of axes and both coloration and styling of points based on a user-determined grouping variable, providing the user substantial aesthetic control. The completed plots can be downloaded as .png or .pdf files, and individual plot elements of the .pdf files can be further adjusted in editing software. This is especially useful for adjusting text placement or font type.

One of the more unique capabilities of RockR! is the ability to select pre-created discrimination and classification diagrams for the ternary and bivariate plots. The ternary plot section includes quartz-feldspar-lithic fragments (QFL) provenance, QFL lithology, intrusive quartz-alkali feldspar-plagioclase (QAP), extrusive QAP, normative quartz-rich intrusive igneous rocks, modal quartz-rich intrusive igneous rocks, normative quartz-rich extrusive igneous rocks, Shepard’s soil classification, USDA soil classification, and feldspar classification. Intrusive and extrusive total alkali-silica plots are included in the bivariate section. The metamorphic pressure-temperature bivariate plot also has a collection of petrologically important curves, like mineral boundaries and geothermal gradients, which can be toggled on or off by the user. Models for intrusion and extrusion highlight progradation and retrogradation over time to serve as classroom resources.